Colloquia

Colloquia are held at 2:30 pm on Thursdays in the Dennis Sciama Building, normally in room 2.14 unless otherwise announced. They feature talks by external speakers. Talks are preceded by lunch with the speaker, and followed by tea.

Colloquium organisers: Daniel Whalen, Thomas Collett
Hide past events
Events from before 2013 are on our old website here.

• 10th Jan 2013 2:30 pm: Cosmology with low-mass galaxies, Speaker: Ivan Baldry (Liverpool John Moore University)
   
• 24th Jan 2013 2:30 pm: The Nature of Spiral Arms, Speaker: Mark Cropper (MSSL)
   
• 31st Jan 2013 12:00 am: Holography and the very early universe, Speaker: Kostas Skenderis (Southampton)
   
• 14th Feb 2013 2:30 pm: The Case for Testing Modified Gravity in the Solar System, Speaker: Ali Mozaffari
   
• 28th Feb 2013 2:49 pm: Constraining the small scale perturbations in a big universe, Speaker: Chris Byrnes (Sussex)
   
• 7th Mar 2013 2:49 pm: From Supernova to Hypernova: Understanding Supernova Diversity, Speaker: Phillip Podsialovski (Oxford University)
   
• 21st Mar 2013 12:00 am: Measurement of weak lensing shear in CFHTLenS and future surveys, Speaker: Lance Miller (Oxford)
   
• 28th Mar 2013 12:00 am: 3D Weak Lensing with Sizes and Shapes, Speaker: Alan Heavens (Imperial)
   
• 18th Apr 2013 2:30 pm: Primordial non-Gaussianity from Inflation, Speaker: David Wands
   
• 25th Apr 2013 12:00 am: WIMP hunting: the search for dark matter, Speaker: Anne Green (Nottingham)
   
• 2nd May 2013 12:00 am: Galaxies in the first billion years: probing cosmic dawn, Speaker: Pratika Dayal (ROE)
   
• 9th May 2013 2:30 pm: The Clipped Power Spectrum, Speaker: Fergus Simpson (Edinburgh)
   
• 16th May 2013 12:00 am: The evolution of starburst galaxies, Speaker: Vivienne Wild (St. Andrews)
   
• 23rd May 2013 2:30 pm: How cold filamentary gas flows shape galaxies, Speaker: Adrianne Slyz (oxford)
   
• 30th May 2013 2:30 pm: no seminar (UK cosmology meeting), Speaker:
   
• 6th Jun 2013 2:30 pm: Determining the Hubble constant, Dark Energy Equation of State and matter content of the Universe with Giant HII region and HII, Speaker: Roberto Terlevich (Cambridge and Mexico University)
   
• 13th Jun 2013 2:30 pm: Modified Gravity, Pulsars and Black Holes, Speaker: Anne Davis (Cambridge)
   
• 27th Jun 2013 12:00 am: PROBING THE REIONIZATION EPOCH WITH HIGH REDSHIFT GALAXIES, Speaker: Laura Pentericci (Rome, visiting Cambridge)
   
• 11th Jul 2013 2:30 pm: The Gravity of Cosmic Acceleration, Speaker: Wayne Hu (Chicago)
   
• 29th Aug 2013 12:00 am: Acceleration, then and now, Speaker: Cliff Burgess
   
• 3rd Oct 2013 2:30 pm: Uncharted territories of the density and gravitational fields, Speaker: Martin Sahlén (Oxford)
   
• 10th Oct 2013 2:30 pm: Galaxy properties as a fingerprint of cosmology & fundamental physics, Speaker: Martin Stringer (IAP)
   
• 24th Oct 2013 2:30 pm: Massive Stars: Evolution, Fate and Nucleosynthesis, Speaker: Raphael Hirschi (Keele)
   
• 31st Oct 2013 2:30 pm: Probing cosmological parameters with strong lenses, Speaker: Thomas Collett (Cambridge)
   
• 7th Nov 2013 2:30 pm: Improved cosmological constraints from a joint analysis of the SNLS and SDSS supernova surveys., Speaker: Marc Betoule (France)
   
• 14th Nov 2013 2:30 pm: Cosmological challenges: dark energy, non-Gaussianity, and massive neutrinos, Speaker: Graziano Rossi (CEA, Paris)
   
• 21st Nov 2013 1:00 pm: The interaction between distant galaxies and their environments, Speaker: Omar Almaini (Nottingham)  
• 28th Nov 2013 2:30 pm: APOGEE: The Apache Point Observatory Galactic Evolution Experiment, Speaker: Vivienne Wild (St. Andrews)
   
• 12th Dec 2013 1:00 pm: Constraining properties of the dark universe, Speaker: Jonathan Pearson (Durham)
   
• 16th Jan 2014 2:30 pm: Astrophysical probes of dark matter, Justin Read (Surrey University) 
• 21st Jan 2014 10:28 am: Stellar and dark mass assembly of galaxies, Niv Drory, McDonald Observatory & Dept. of Astronomy The University of Texas at Austin, Texas 
• 30th Jan 2014 2:30 pm: Voids, cosmology and the integrated Sachs-Wolfe effect, Shaun Hotchkiss (Sussex) 
• 6th Feb 2014 2:30 pm: Molecular gas as a probe of galaxy evolution, Amelie Saintonge (UCL) 
• 13th Feb 2014 2:30 pm: (cancelled due to illness) Cosmological Magnetic Field – Observation with Gamma-Rays –, Keitaro Takahashi (Kumamoto, Japan) 
• 27th Feb 2014 2:30 pm: Non-Gaussianity in light of Planck, James Fergusson (Cambridge) 
• 6th Mar 2014 2:30 pm: Supermassive Black Holes in Nearby Galaxies,  Ralf Bender (Max-Planck Institute for extra-terrestrial Physics, Munich)  
• 13th Mar 2014 2:30 pm: Understanding Disc Galaxy Evolution, Viktor Debattista (UCLAN) 
• 20th Mar 2014 2:30 pm: IoP Homi Bhabha Lecture “The Cosmological constant: Its problem and a possible solution”, Prof. Thanu Padmanabhan (IUCAA) 
• 27th Mar 2014 2:30 pm: The AGN-Star Formation Connection, Joe Silk (Oxford and Paris)  
• 3rd Apr 2014 2:30 pm: Practical tests of Gravity with Dark Energy Survey (DES), Donnacha Kirk (UCL) 
• 10th Apr 2014 2:30 pm: Errors of errors and systematics of systematics,  Benjamin Joachimi (UCL) 
• 24th Apr 2014 2:30 pm: Planck Confronts the Standard Model(s), Andrew Jaffe (Imperial) 
• 1st May 2014 2:30 pm: The use of voids in cosmology, Seshadri Nadathur (Helsinki, Finland) 
• 8th May 2014 2:30 pm: Probing the free-streaming of dark matter with the Lyman-alpha forest, Martin Haehnelt (Cambridge) 
• 15th May 2014 2:30 pm: Neutrinos: from present discoveries to questions for the future, Silvia Pascoli (Durham) 
• 22nd May 2014 2:30 am: An Analyst’s View of Modern Astrophysics, Fahran Feroz, Cambridge  
• 5th Jun 2014 2:30 pm: Supernovae by Stephen Smartt (University of Belfast), Steven Smartt 
• 12th Jun 2014 2:30 pm: Model-free Tests of Gravity, Tessa Baker (Oxford)  
• 19th Jun 2014 2:30 pm: NAOC-ICG joint workshop,  
• 9th Oct 2014 2:30 pm: From the end of inflation to hot Jupiters, Mustafa Amin (Cambridge) 
• 16th Oct 2014: Re-ionization and the Cosmic Dawn, Leon Koopmans, Kapteyn Astronomical Institute 
• 6th Nov 2014 2:30 pm: Cosmology through the microphones of gravitational wave detectors, Bernard Schutz (MPI and Cardiff) 
• 13th Nov 2014 2:30 pm: Black holes, extra dimensions and the LHC, Elizabeth Winstanley (Sheffield) 
• 20th Nov 2014 2:30 pm: Bubble-induced star formatoin in dwarf irregular galaxies, Daisuke Kawata (MSSL, UCL) 
• 27th Nov 2014 2:30 pm: Magnetic Fields and Massless Particles, Anna Scaife (Southampton) 
• 8th Jan 2015: Timothy Davis (Herts), “New life in dead galaxies: star formation and black holes”, Massive early-type galaxies (ETGs) are often assumed to be ‘red and dead’ systems, which have been passively evolving since z~2. In fact, many such systems host residual star formation and contain large cold gas reservoirs. I will show how observations of the cold and warm ISM, combined with simulations and models, can be used to... 
• 15th Jan 2015: “Galaxy Clusters as Tele-ALP-scopes”, Joseph Conlon, Rudolf Peierls Centre for Theoretical Physics, Oxford, Axion-like particles have good theoretical motivation and are characterised by conversion to photons in astrophysical magnetic fields... 
• 22nd Jan 2015: “Cosmology on the Largest Scales”, Stefano Camera, Manchester, Ultra-large cosmic scales supply a wealth of information most valuable for strengthening our knowledge of the Universe... 
• 29th Jan 2015: Alessia Gualandris, Sussex University,  
• 12th Feb 2015: Sarah Kendrew, Oxford,  
• 19th Feb 2015: “Testing structure formation with the Dark Energy Survey and the CMB”, Tommaso Giannantonio, Kavli Institute for Cosmology, Cambridge, The Planck 2015 results, together with the precise measurement of the expansion history of the Universe from the BOSS baryon acoustic oscillations, confirm the standard LCDM model of cosmology to unprecedented precision. However, it still remains to be tested whether general relativity with a cosmological constant can accurately explain the formation and growth of the large-scale... 
• 26th Feb 2015: Judith Croston, Southampton, “Where and when does galaxy feedback via AGN jets matter?”, At the moment our knowledge of the impact of AGN jets is limited to the nearby Universe: we can only study the most extreme outbursts at high redshifts. Future radio surveys will reveal for the first time the intermediate and low-luminosity radio-loud AGN population out beyond the epochs of group and cluster formation, but several... 
• 5th Mar 2015: Jens Chluba, Cambridge,  
• 12th Mar 2015: Camille Bonvin, CERN, Switzerland,  
• 19th Mar 2015: Steve Eales, Cardiff, “The Herschel View of Galaxy Evolution”, The current paradigm for galaxy evolution is that there are two classes of galaxy: blue star-forming galaxies on the ‘Galaxy Main Sequence’ and a class of red passive galaxies that contain very little gas and in which few stars are currently being formed. It is generally assumed that some catastrophic quenching process converts the star-forming... 
• 26th Mar 2015: Chris Collins,  
• 16th Apr 2015: Franz Elsner, UCL,  
• 23rd Apr 2015: Brad Gibson (UCLan),  
• 30th Apr 2015: Inhomogeneous cosmological models, Friedmann backgrounds, and the influence of structure on the large-scale evolution of the Universe. Tim Clifton, Queen Mary University of London,   The standard model of cosmology is based on a homogeneous and isotropic Friedmann solution, with small perturbations accounting for almost all structure. Such an approach inherently assumes that a universe that has a statistically homogeneous matter content is well modelled by a homogeneous solution of Einstein’s equations, with the energy-momentum tensor being given by... 
• 7th May 2015: Mark Lovell (UVA, The Netherlands), Sterile neutrino dark matter: galaxy formation and other stories The identity of dark matter remains unknown despite considerable efforts to find WIMPS at colliders and direct detection experiments. One alternative candidate particle is the sterile neutrino, which forms part of a theory that, in addition to dark matter, can explain neutrino masses and baryogenesis. It... 
• 14th May 2015: James Allen, University of Sydney,  
• 21st May 2015: Paolo Mazzali, Liverpool John Moores University,  
• 4th Jun 2015: Julien Lesgourgues, TTK, RWTH Aachen University,  
• 11th Jun 2015: Dave Wilman (MPE, Munich), “Resolved Halpha maps and profiles from KMOS3D and HAGGIS at z=0-2.6: Painting a picture of growth and quenching”, Most stars form in rotationally supported disks, at a rate closely correlated with a galaxy’s mass. This is as true in the local Universe as it was at a redshift of 2: However much else has changed. At low redshift pre-existing stars dominate the local potential, molecular gas fractions and star formation rates are low,... 
• 18th Jun 2015: Luca Amendola (Heidelberg): “Two new methods for testing gravity at cosmological scales”, Testing gravity at large scales is one of the most interesting goals of current and planned  surveys. In this talk I will present two new methods that complement and enrich the cosmologist toolbox. The first employs CMB B-mode polarization to test for modification of the gravitational wave propagation at early times. The second one uses... 
• 2nd Jul 2015: Clare Burrage (Nottingham) “Detecting Dark Energy with Atom Interferometry”,   I will discuss the possibility that the nature of the dark energy driving  the observed acceleration of the Universe on giga-parsec scales may be  determined first through metre scale laboratory based atom  interferometry experiments. I will begin by introducing the scalar  fields that could be responsible for dark energy and show that in order... 
• 9th Jul 2015: Elena Sellentin (Heidelberg),  
• 15th Oct 2015: “Chemodynamical evolution of galaxies”, by Chiaki Kobayashi, University of Hertfordshire, Star formation and chemical enrichment histories of galaxies are imprinted in their internal structures of galaxies, i.e., kinematics and elemental abundances of stars within galaxies. We predict the time evolution of internal structures using our cosmological, hydrodynamical simulations with the feedback from active galactic nuclei (AGN). In the simulations, we have applied a new model... 
• 22nd Oct 2015: Cosmology with the Lyman-alpha forest, Anže Slosar ( Brookhaven National Laboratory), Lyman-alpha forest is a unique tracer of structure at high redshift. It probes an important epoch in the evolution of the Universe, just before dark energy kicks in, covers massive amounts of volume and has systematics that are very different to those in galaxy surveys. BOSS has given us unprecedented amount of data, allowing Lyman-alpha... 
• 29th Oct 2015: Chiara Caprini, (Institut de Physique Théorique, Gif-sur-Yvette) “Cosmology with gravitational waves”, Gravitational waves can constitute a unique probe of the universe. In many cases of sources operating in the early universe, the characteristic frequency of the emitted GW is directly related to the energy scale at which the GW source acts. Consequently, different GW detectors can probe different energy scales in the evolution of the universe,... 
• 12th Nov 2015: Laura Salvati (University of Rome “La Sapienza”) “Constraining fundamental physics with cosmology”, In this talk, we show how it is possible to constrain fundamental physics with cosmology, using Cosmic Microwave Background (CMB) temperature and polarization anisotropies in combination with other cosmological datasets and other observations. We start deriving new constraints on the neutron lifetime. Under the assumption of standard Big Bang Nucleo- synthesis, the abundance of light... 
• 19th Nov 2015: Anne-Marie Wejimans (St.Andrews),  
• 26th Nov 2015: Valerio Faraoni (Bishop University, Canada), “Two cosmological applications of the Hawking quasilocal mass”, We present two applications of the (rather formal) Hawking quasilocal mass construct to cosmology. We first apply it to simulations of large scale structures, which are Newtonian even though the size of the box used exceeds the Hubble radius. The Hawking mass splits into a “Newtonian” part due to local perturbations and a “relativistic” part... 
• 3rd Dec 2015: Chris Lintott (Oxford), Tales from the Zooniverse : Galaxy Zoo and beyond, The Zooniverse is the world’s largest and most successful scientific crowdsourcing platform, engaging more than a million volunteers in tasks including classifying galaxies, discovering planets and mapping star formation in the Milky Way. This talk will present highlights from the last seven years, including the latest results from Galaxy Zoo regarding AGN feedback and the... 
• 7th Jan 2016: Martha Haynes (Cornell University), Extragalactic HI Surveys: Results from ALFALFA and Plans for the SKA Pathfinders, Exploiting the huge collecting area of the Arecibo 305 meter antenna, the ALFALFA HI 21 cm line survey has mapped 7000 square degrees of the high Galactic latitude sky out to z~0.06, cataloging ~30,000 HI sources. Virtually all star-forming galaxies contain atomic gas; in this talk, I will review the relationship between the optically- and... 
• 14th Jan 2016: Kristine Spekkens (Royal Military College, Canada), Measuring Disk Galaxy Structure using Large Spectroscopic Surveys, The next few years will be exciting ones for studying disk galaxy structure, with the advent of the first large spectroscopic surveys at optical and radio wavelengths that will resolve the kinematics of thousands of nearby systems. This talk will focus on exploiting those surveys to measure the physical structure of disk galaxies. I will... 
• 21st Jan 2016: Aaron Ludlow (Durham), Non-linear structure in cold and warm dark matter cosmologies, I will discus progress made over the past couple of years in understanding the origin of the universal NFW density profile, and how the scaling relations between its relevant parameters can be inferred for dark matter halos knowing only trivial aspects of their assembly histories. Focusing separately on cold dark matter halos, I will emphasize... 
• 28th Jan 2016: Or Graur (New York University) Revealing the Progenitors of Explosive Transients with Spectroscopic Surveys, We still do not know what types of stellar systems end up exploding as most types of supernovae (SNe). In my talk, I will show how we can use observed correlations between the SN rates and various host-galaxy properties to constrain the progenitor scenarios of different types of SNe. Most of the results I will... 
• 4th Feb 2016: Giulio Fabbian (SISSA) Modeling and measuring CMB lensing in the cross-correlation era., Being less sensitive to systematic effects, the cross-correlations between Cosmic Microwave Background (CMB) data sets and large-scale structures surveys are expected to provide excellent astrophysical and cosmological constraints in the upcoming years. In order to capitalize on the advantages offered by these joint analysis techniques, an accurate physical modeling of both the observables involved is... 
• 25th Feb 2016: Brooke Simmons (San Diego): Disentangling The Pathways to Co-Evolution of Supermassive Black Holes and Galaxies, Supermassive black holes and AGN co-evolve over cosmic time, but despite more than a decade of research the engine(s) for this co-evolution are still not fully understood. The typical co-evolution picture invokes major galaxy mergers to both drive material toward the centre of the gravitational potential and trigger star formation, growing both galaxy and black... 
• 3rd Mar 2016: B. S. Sathyaprakash and F. Pannarale (Cardiff): Observing gravitational waves from binary black hole mergers, On September 14, 2015 the twin LIGO detectors registered triggers that were later confirmed to be the first direct detection of gravitational waves and the first observation of a black hole binary. In this talk we will discuss the nature of gravitational waves, the property of black holes observed and new strong field tests of... 
• 10th Mar 2016: Baerbel Koribalski (CSIRO): WALLABY – the ASKAP HI All Sky Survey, I will provide an update on the Australian SKA Pathfinder (ASKAP), highlight the planned surveys, incl. my ASKAP HI All Sky Survey (known as WALLABY) and outline our plans for Early Science with the first 12 PAF-equipped ASKAP antennas. Our novel Phased-Array Feeds have a field-of-view of 30 square degrees, making ASKAP a fast 21-cm... 
• 17th Mar 2016: Ben Metcalf (Bologna) TBA,  
• 24th Mar 2016: Elisa Chisari (Oxford), Intrinsic alignments of galaxies, The intrinsic correlations of galaxy shapes are a recognised contaminant to weak gravitational lensing measurements. Luminous red galaxies have been observed to point radially towards each other, likely as a consequence of the action of the tidal field of the large-scale structure on their shapes and orientations; blue, disc-like galaxies are thought to be subject... 
• 21st Apr 2016: Sebastien Renaux-Petel (IAP), Geometrical destabilization of heavy scalar fields during inflation, We show the existence of a general mechanism by which heavy scalar fields can be destabilized during inflation. It relies on the fact that the effective mass of fluctuations orthogonal to the inflationary direction contains a contribution proportional to the curvature tensor of the field space metric, and that it can render the entropic fluctuations tachyonic.... 
• 28th Apr 2016: Kate Rowlands (University of St Andrews), Caught in the Act: Charting Galaxy Transformation over Cosmic Time, One of the key problems in astrophysics is understanding how and why galaxies switch off their star formation, building the “red-sequence” that we observe in the local Universe. Post-starburst (“E+A”) galaxies, where a galaxy has recently undergone a massive starburst, are sufficiently common at z~1-2 that they may contribute significantly to the growth of the... 
• 5th May 2016: David Valls-Gabaud (CNRS, Observatoire de Paris), The MESSIER Orbiter: Lifting the Veil on the Ultra-Low Surface Brightness Universe, The S-class MESSIER satellite has been designed to explore the extremely low surface brightness universe at UV and optical wavelengths.  The two driving science cases target the mildly- and highly non-linear regimes of structure formation to test two key predictions of the LCDM scenario: (1) the detection of the putative large number of galaxy satellites, and... 
• 12th May 2016: Erminia Calabrese (Oxford), Cosmology and Astrophysics from the Cosmic Microwave Background, Observations of the early Universe from Cosmic Microwave Background experiments pin down cosmological parameters characterizing the Universe content and evolution to percent precision. In this talk I will give a brief overview of the current status of CMB observations, focussing on the recent data from the Planck satellite and the ground-based ACT and SPT telescopes.... 
• 19th May 2016: Daniel Whalen (Institute for Cosmology and Gravitation, University of Portsmouth) How Supermassive Black Holes Form by z > 7, About 50 supermassive black holes (SMBHs) have now been found at z > 6, including a 12 billion solar mass candidate at z = 6.3 and a 2 billion solar mass object at z = 7.1. The discovery of these high redshift quasars severely challenged current paradigms of early structure formation, but new simulations have now shown that they... 
• 26th May 2016: Violeta Gonzalez-Perez (ICG Dennis Sciama Fellow): Issues with making galaxies in the computer relatively fast, In this talk I will introduce the different methods for modelling the formation and evolution of galaxies, giving a more thorough review on the semi-analytical approach. I will focus then on some of the challenges we encounter when trying to understand the formation and evolution of relatively big and ‘normal’ galaxies. 
• 9th Jun 2016: David L. Witshire (University of Canterbury, new Zealand), Models of inhomogeneity and backreaction in cosmology, On scales < 100/h Mpc the Universe displays a complex cosmic web of inhomogeneity. The possibility of backreaction – that the growth of structures on small scales can change average cosmic expansion relative to a homogeneous isotropic FLRW cosmology – is a subject of much debate. A model-independent test of local expansion in our <... 
• 16th Jun 2016: Lado Samushia (Kansas State University), Optimal measurements of the power spectrum of the Universe, The power spectrum of galaxies provides invaluable information about dark energy, gravity and initial conditions of the Universe. It is therefore extremely important that we measure it in the most optimal way possible, especially given that the total cosmological volume available to galaxy surveys is limited. My talk will be based on a recent work by my group... 
• 20th Jun 2016: Jarrett L. Johnson (Los Alamos National Laboratory), The Brightest Primordial Sources: Population III Galaxies and Accreting Black Holes, While future observatories such as the James Webb Space Telescope are likely to reveal many candidate primordial objects in the high-redshift universe, there has already been detected at least one very bright source at z > 6, in CR7, which may in fact be powered by emission from primordial gas.   This source may be powered by either... 
• 7th Jul 2016: Claes-Erik Rydberg (ITA / University of Heidelberg) Cluster Lenses as Cosmic Telescopes: Finding the First Stars and Galaxies, We are on the cusp of the JWST / ELT era, in which cosmic structure at the earliest epochs will be revealed in unprecedented detail in the coming decade. However, even JWST and the 30 – 40 meter class ground-based telescopes will not be able to directly observe individual primordial stars or most of the earliest galaxies... 
• 22nd Sep 2016: Ken Chen (NAOJ), Lighting up the Universe with the First Stars, Supernovae, and Galaxies, One of the paramount problems in modern cosmology is to elucidate how the first generation of luminous objects, stars, supernovae, accreting black holes, and galaxies, shaped the early universe at the end of the cosmic dark ages. According to the modern theory of cosmological structure formation, the hierarchical assembly of dark matter halos provided the... 
• 13th Oct 2016: Francesca Vidotto (Radboud University), Quantum Gravity Phenomenology with Primordial Black Holes, Quantum gravity may allow black holes to decay into white holes. If so, the lifetime of a black hole would be shorter than the one given by Hawking evaporation, avoiding the information paradox. This could open to a new window for quantum-gravity phenomenology, in connection with the existence of primordial black holes. I discuss the... 
• 20th Oct 2016: Pat Scott (Imperial College London) Ultracompact Minihalos and Small-Scale Cosmology, High-amplitude over-densities in the early Universe are expected to gravitationally collapse shortly after matter-radiation equality, triggering the formation of ultracompact minihalos of dark matter (UCMHs).  Because the mass of a UCMH is directly linked to the scale of the density perturbation from which it formed, UCMHs turn out to be very clean (and sensitive) probes... 
• 27th Oct 2016: Daniel Whalen (ICG) How Supermassive Black Holes Form by z ~ 7, Over 100 quasars have now been discovered at z > 6, less than a Gyr after the Big Bang. The discovery of supermassive black holes (SMBHs) by this epoch posed severe challenges to current theories of structure formation because it is not known how objects so massive appeared by such early times. However, we have... 
• 3rd Nov 2016: Jillian Scudder (University of Sussex), Picking Apart Blended FIR Sources in the COSMOS Field, Bright sub-mm and FIR sources have historically been counted amongst the most star-forming objects in the early universe. However, unambiguously identifying a physical counterpart at other wavelengths (in particular, at the optical, where dust extinction is usually severe) has proven very difficult. In this talk, I will discuss new results from a recent project, wherein... 
• 10th Nov 2016: Cora Uhlemann (Utrecht University), From the Cosmic Microwave Background to the Cosmic Web, How did our Universe evolve from a nearly uniform initial state into today’s cosmos with structures on a wide range of scales? And what does that structure tell us about our Universe and its constituents? Large-scale structure formation investigates the emergence of the Cosmic Web – the skeleton of matter in the present universe – from small density fluctuations observed in the Cosmic Microwave... 
• 24th Nov 2016: Russell Smith (Durham University), Low-Redshift Strong Lenses and the Stellar Initial Mass Function, Does the Chabrier/Kroupa form of the Initial Mass Function (IMF), as established from observations in the Milky Way, hold universally in galaxies of all types, formations epochs and metallicities?  In recent years, several independent indirect probes of the IMF in massive elliptical galaxies (spectral synthesis; stellar dynamics; gravitational lensing) have been interpreted as evidence for... 
• 1st Dec 2016: Tony Padilla (University of Nottingham), We Need to Talk about Lambda, The Universe was never supposed to accelerate; certainly not in the feeble way that it does. Now, nearly twenty years since the supernova observations, it is time for us to come to terms with gravity, quantum field theory and Lambda’s totally in explicable value. Not yet ready to sell out to the landscape, we will... 
• 8th Dec 2016: David Sobral (University of Lancaster), Exploring the early Universe with the largest emission-line surveys, I will present new results regarding the first ~2 Gyrs of cosmic time using very wide-field Lyman-alpha (Lya) narrow-band surveys, including a large, matched Lya-Halpha survey to investigate how Lya and Lyman-continuum (LyC) photons escape from typical star-forming galaxies at high-redshift. We find that large Lya halos are ubiquitous in star-forming galaxies, and that the typical... 
• 12th Jan 2017: Cosimo Inserra (Queen’s University Belfast), The Brightest Supernova Explosion in Cosmology,  
• 19th Jan 2017: Pier-Stefano Corasaniti (Observatoire de Paris) Physical Cosmology and Complexity: the Quest for the Invisible Universe, Abstract: Understanding the nature of the invisible components in the universe is the central challenge of modern physical cosmology. There is a consensus that probing the formation and evolution of cosmic structures may provide key insights on the origin of Dark Energy and Dark Matter (and perhaps the only way to make progress). However, these... 
• 26th Jan 2017: Chris Clarkson (QMUL) Roulettes: A weak lensing formalism for strong lensing, Abstract: I will present a new perspective on gravitational lensing. I will discuss a new extension of the weak lensing formalism capable of describing strongly lensed images. By integrating the non-linear geodesic deviation equation, the amplification matrix of weak lensing is generalised to a sum over independent amplification tensors of increasing rank. An image distorted... 
• 2nd Feb 2017: Daniel B. Thomas (Cyprus) TBA,  
• 9th Feb 2017: Paul Clark (Cardiff University), The Star-Forming ISM: Bottom-up versus Top-down Approaches, Observations of the star formation activity in galaxies has revealed a relationship between the star formation rate and the surface density of the gas, especially when one looks at the cold, H2-dominated phase.  Although the physical process behind this phenomenon is not fully understood, it has been used by the galaxy formation community as a... 
• 16th Feb 2017 2:30 pm: Ian Harrison (Manchester), The Past, Present and Future of Radio Weak Lensing, Wide and deep surveys with the Square Kilometre Array (SKA) radio telescope will see the large number density of resolved galaxies over large areas necessary for cosmology with weak gravitational lensing. These surveys will be competitive with other “Stage IV” dark energy experiments taking place at optical and near-IR wavelengths with Euclid, LSST and WFIRST.... 
• 2nd Mar 2017 2:30 pm: Silvia Zane (UCL), Observational Properties of Neutron Stars, XDINS and Magnetars, and Future Perspectives for X-ray Timing and Polarimetry, Multi-wavelength observations over the last decades proved the existence of observationally very diverse manifestations of isolated NSs (INSs) and led to the separation of INSs into distinct classes. Most of the ~2,300 known INSs are radio pulsars with periods P < 8 s and magnetic field B ~ 10 12 G, but there are objects... 
• 9th Mar 2017 2:30 pm: Marta Volonteri (IAP), Growing black holes in growing galaxies, Massive black holes, weighing millions to billions of solar masses, inhabit the centers of today’s galaxies. Black hole masses typically scale with properties of their hosts, such as bulge mass and velocity dispersion. The progenitors of these black holes powered luminous quasars within the first billion years of the Universe. The first massive black holes... 
• 16th Mar 2017 2:30 pm: Rob Crain (Liverpool John Moores University) Cosmological Hydrodynamical Simulations of the Galaxy Population, I will briefly recap the motivation for, and progress towards, numerical modeling of the formation and evolution of the galaxy population – from cosmological initial conditions at early epochs through to the present day. I will focus in particular on the EAGLE simulations. They represent a significant development in this arena, since they broadly reproduce... 
• 23rd Mar 2017 2:30 pm: Luca Amendola (University of Heidelberg) TBA,  
• 30th Mar 2017 2:30 pm: Daniel Baumann (Cambridge and Amsterdam): Relics from the Early Universe, Modern cosmology has made remarkable progress in describing the history of the Universe from one second after the Big Bang until today.  The events that have taken place during that period are now known with certainty. What is much less certain is what happened before.  In this colloquium, I will explain that future cosmological observations... 
• 6th Apr 2017 2:30 pm: Marius Cautun (ICC Durham), Testing Modified Gravity using Voids and Tunnels, I will discuss a new way to characterize voids and some practical applications of voids as probes of theories of modified gravity. During the first part, I will present the void boundary profile in which voids are described with respect to their boundary and not their ill defined centres. In contrast to haloes, voids are... 
• 27th Apr 2017 2:30 pm: Marzia Rivi (UCL), Bayesian Techniques for Radio Weak Lensing Measurement, The new generation of radio telescopes, such as the Square Kilometre Array, will reach enough sensitivity to provide a density of detected galaxies comparable to that found at optical wavelengths, allowing weak lensing measurements in the radio band. Standard techniques for the measurement of cosmic shear are based on the best fitting of galaxy shapes from... 
• 4th May 2017 2:30 pm: Roberto Maiolino (Cambridge University) The Multiple Routes of Galaxy Transformation, Understanding the mechanisms responsible for transforming star forming galaxies into quiescent system is currently one of the most interesting challenges in astrophysics.  I will discuss various observational results that suggest that different mechanisms are responsible for quenching star formation in different classes of galaxies. I will focus in particular on the observational evidence for “starvation”... 
• 11th May 2017 2:30 pm: Muhammad Latif (Institut Astrophysique de Paris), Songlines of Supermassive Black Holes, Black holes are one of the most enigmatic objects in our cosmos, with masses of up to a few billion times the mass of our Sun. Most of the present day galaxies if not all harbor black holes of a few million to billion solar masses at their centers. These supermassive black holes are not... 
• 18th May 2017 2:30 pm: Thomas de Boer (Cambridge), Reconstructing the Sagittarius Dwarf Galaxy, The Sagittarius (Sgr) dwarf spheroidal galaxy and associated stellar streams provide valuable tools for the study of galaxy formation and evolution in the more massive surviving satellites of the MW as well as giving insights into the (dark) properties and assembly of the Galactic halo.  Using data from the Sloan Digital Sky Survey (SDSS), we... 
• 25th May 2017 2:30 pm: Chris Frohmaier (Southampton), Volumetric Supernova Rates in the Local Universe, Type Ia supernovae (SNe Ia) are bright thermonuclear explosions of carbon-oxygen white dwarfs as they accrete mass and approach the Chandrasekhar limit. Famously, these standardisable candles were used to measure the accelerating expansion of the Universe. SNe Ia are still extensively used as cosmological tools, but the precise nature of the progenitor to these explosions... 
• 1st Jun 2017 2:30 pm: Andrew Lundgren (AEI) – “Coalescing Binaries in aLIGO and Beyond: Optimizing the Detection Rate”, In 2015, we made the first detection of gravitational waves from the merger of two black holes, each around thirty solar masses. I’ll talk about the first few detections, then talk about the future. What can we learn about the mass and spin distributions of compact binaries? Can we infer where, when, and how they... 
• 21st Jun 2017 2:30 pm: Stefano Borgani (Trieste, Italy): Understanding Galaxy Clusters with Simulations, Abstract: I will overview recent advancements in the study of galaxy clusters, both as astrophysical objects and as cosmological tools, using detailed hydrodynamic simulations.  I will discuss how improvements in the numerical description of galaxy formation processes, related to star formation and gas accretion onto super-massive black holes, is leading to the production of realistic... 
• 22nd Jun 2017 2:00 pm: ICG@15 Science talks,  
• 23rd Jun 2017 12:30 pm: ICG@15 Careers event,  
• 29th Jun 2017 2:30 pm: Duncan Forbes (Swinburne University, Melbourne), Prof. Duncan Forbes‘s interests span most of extragalactic astronomy and cosmology, however he focusus on observational aspects of galaxy formation and evolution. He has a leading role in the international SAGES project (Study the Astrophysics of Globular clusters in Extragalactic Systems) which combines HST and Subaru imaging with Keck spectra to better understand globular cluster... 
• 13th Jul 2017: Germano Nardini (University of Bern) TBA,  
• 5th Oct 2017 11:00 am: Cosmology with Peculiar Velocity Surveys – Cullan Howlett (Perth), Peculiar velocity surveys offer a unique way of understanding our cosmological model and testing the nature of gravity. In this talk I will give an overview of how these can be used, focussing on recent constraints from the 2MASS Tully Fisher Survey and plans for future surveys such as Taipan and LSST. In particular, I’ll... 
• 12th Oct 2017 2:30 pm: Chris Miller (Michigan), Galaxy Clusters: A Standard Cannon for Cosmology, Einstein’s theory of general relativity (GR) entwines the dynamics of matter-energy and the universe’s spacetime expansion. It is often said: matter-energy tells space-time how to curve and space-time tells matter-energy how to move. In the weak-field limits of GR, Newtonian dynamics allows us to relate the escape speed to the local potential via the Poisson equation. Objects moving faster than... 
• 19th Oct 2017 2:30 pm: Christopher Usher (Liverpool), Using Globular Cluster Stellar Populations to Understand Galaxy Formation, Globular clusters are important tools to help us understand how galaxies form and evolve. Globular cluster formation tells us about the conditions of extreme star formation while their survival from high redshift tell us about the processes of galaxy assembly. Being much brighter than red giant stars, globular clusters allow the stellar populations of galaxies... 
• 26th Oct 2017 2:30 pm: Syksy Rasanen (Helsinki) Breaking the symmetry: accelerated expansion without dark energy, Accelerated expansion of the universe is one of the greatest discoveries in modern cosmology. Its cause remains a mystery, and is usually attributed to a hypothetical substance called dark energy. I will discuss the backreaction conjecture, according to which cosmological structure formation alone could explain the accelerated expansion without any new fundamental physics. 
• 2nd Nov 2017 2:30 pm: Stefano Liberati (SISSA, Italy) From Analogue to Emergent gravity: lessons and pitfalls, The analogue gravity framework uses condensed matter systems to simulate phenomena characteristics of quantum field theory in curved spacetimes (e.g. cosmological particle production or black hole evaporation).  In this seminar I will review the state of this field and explore its extension towards the simulation of the emergent gravity paradigm. In doing so I will discuss lessons and pitfalls as well as the... 
• 9th Nov 2017 2:30 pm: Carsten van de Bruck (Sheffield) Interactions in the dark sector: the cosmology of conformally and disformally coupled dark matter, A fifth force between the standard model particles is highly constrained. On the other hand, dark matter particles could interact for example via a force mediated by dark energy scalar field. Such interactions are currently constrained only by cosmological observations. In this talk I will discuss scalar-tensor theories of interacting dark matter-dark energy, allowing for... 
• 16th Nov 2017 2:30 pm: Carlos Sopuerta (Barcelona) LISA and the gravitational-wave low-frequency band, LIGO and Virgo have inaugurated the era of Gravitational Wave Astronomy by observing several binary black hole mergers and the merger of a neutron star binary.  They have also made possible multimessenger astronomy with gravitational waves producing key discoveries.  At the same time there are efforts to detect gravitational waves beyond the high-frequency band of... 
• 23rd Nov 2017 2:30 pm: Silke Weinfurtner (Nottingham) Rotational superradiant scattering in a vortex flow, When an incident wave scatters off of an obstacle, it is partially reflected and partially transmitted. In theory, if the obstacle is rotating, waves can be amplified in the process, extracting energy from the scatterer. Here we describe in detail the first laboratory detection of this phenomenon, known as superradiance. We observed that waves propagating... 
• 30th Nov 2017 2:30 pm: Andrina Nicola (ETH Zurich), Integrated Approach to Cosmology, Recent progress in observational cosmology and the establishment of ΛCDM have relied on the combination of different cosmological probes. These probes are not independent, since they all measure the same physical fields. The resulting cross-correlations allow for a robust test of the cosmological model through the consistency of different physical tracers and for the identification... 
• 4th Dec 2017 10:00 am: Storing light in atoms for quantum computing – Josh Nunn (University of Bath), Photonics has the potential to serve as a uniquely powerful platform for quantum information processing, operating at room temperature, at high clock speeds and providing a natural networking capability. However the difficulty in implementing deterministic entangling operations has so far prevented photonic architectures from achieving this potential. One way to solve this problem is by... 
• 14th Dec 2017 2:30 pm: Tilman Hartwig (University of Tokyo), Observing the First Stars with Gravitational Waves, High-Redshift Supernovae, and Galactic Archaeology, I will present different methods and theoretical models on the detection of the first stars, which play a crucial role in galaxy formation, but which have not yet been observed. The first stars, which are believed to be more massive than present-day stars, might be indirectly observable by the gravitational wave emission of the merger... 
• 11th Jan 2018 2:30 pm: Peter Nugent (Berkeley), Precision Cosmology from Gravitationally Lensed Supernovae, In 1929 Edwin Hubble rocked the physics community with his announcement that the universe was expanding – characterized shortly thereafter by his eponymous constant. Nearly 80 years later the field of cosmology has advanced tremendously with the discoveries of the accelerated expansion of the universe and precision measurements of both the universe’s mass and energy... 
• 18th Jan 2018 2:30 pm: Nina Hatch (Nottingham), The formation of galaxy clusters, Distant galaxy clusters are powerful laboratories for observing the hierarchical growth of large-scale structure, constraining cosmological parameters, and for studying the formation of galaxies. However, distant (z>1.5) clusters are extremely rare and faint, so locating and studying them poses a significant observational challenge. In this seminar, I will review the theory of cluster formation and... 
• 25th Jan 2018 2:30 pm: Helvi Witek (King’s College London) Testing Gravity with Black Holes and Gravitational Waves, The breakthrough discovery of gravitational waves has given us a new sense to probe and test gravity in its most extreme, strong-field regime. Although General Relativity (GR), our standard model of gravity, seems to have passed this new stress-test, many questions concerning, e.g., a unifying theory of quantum gravity or the constituents of dark matter... 
• 8th Feb 2018 2:30 pm: Diederik Roest (Groningen), Inflation and Geometry, Recent measurements of the CMB confirm predictions of a period of inflation in the primordial Universe. We will give a pedagogical outline of the observational evidence and theoretical motivations for this phenomenon. Moreover, we will argue for a class of inflationary models that can be characterized in terms of geometry rather than potential energy, and... 
• 15th Feb 2018 2:30 pm: Kelley Hess (ASTRON), Hot and cold gas in galaxy groups, Galaxy groups are believed to be important sites of gas pre-processing in galaxies, which in turn impacts their stellar and morphological evolution.  As groups accrete more galaxies, the groups themselves become increasingly poor in neutral atomic hydrogen (HI), and more cluster-like.  Studies of compact groups suggest that gas processing through tidal interactions simultaneously depletes the... 
• 22nd Feb 2018 2:30 pm: Johan Comparat (MPE), A holistic approach for cosmology with extragalactic surveys, Physical cosmology studies our Universe, its origin, evolution and the laws governing it. In the last decades a concordance cosmological model and the concept of precision cosmology emerged. The concordance model successfully explains the most accurate cosmological measurements available to date.. Precision cosmology now seeks after shrinking all possible measurement error. The forward model approach... 
• 26th Feb 2018 1:00 pm: From the Detected to the Detectors: Using Gravitational Waves to Enable Insights from the Stellar Graveyard & the Next Generation of Citizen Science – Michael Zevin (Northwestern Uni), The recent observations of gravitational waves (GWs) have enticed further exploration as to how this new cosmic messenger can yield information about the lives and deaths of progenitor systems to binary compact objects. In the first part of this talk, I will highlight efforts to use GW observations to constrain uncertain aspects of progenitor systems... 
• 8th Mar 2018 2:30 pm: Elena Rossi (Leiden), Mapping the Milky Way from the Centre to the Dark Matter Halo with Gaia and LISA, I will present my work on two novel ways to map the Galaxy. The first one exploits a particular class of dark matter tracers — hypervelocity stars. These are stars observed in the halo with trajectories consistent with coming from the Galactic. My group has undertaken a comprehensive program to find them in the Gaia... 
• 15th Mar 2018 2:30 pm: Vincenzo Tamma (Portsmouth), Linear Optics Quantum Information Processing: Toward Scalable “Real World” Quantum Sensing and Computing Technologies, Multiphoton quantum interference underpins fundamental tests of quantum mechanics and quantum technologies, including applications in quantum computing, quantum sensing and quantum communication. Standard quantum information processing schemes rely on the challenging need of generating a large number of identical photons. In this talk, we show how the difference in the photonic spectral properties, instead of... 
• 29th Mar 2018 2:30 pm: Aurélie Pénin (University of the Western Cape), Neutral Hydrogen as a Cosmological Probe, The distribution of neutral hydrogen (HI) will be mapped over unprecedented volumes of the Universe thanks to the intensity mapping technique with several forthcoming experiments such as the Square Kilometre Array and its South African pathfinder, MeerKAT. Unveiling cosmological information over a wide scale range requires the understanding of the spatial distribution of HI, a... 
• 12th Apr 2018 2:30 pm: Martin Haehnelt (Cambridge), Probing Reionization with Lyman-alpha and 21cm Emission / Absorption, I will give an overview of recent constraints on reionization from Lyman-alpha and 21cm emission/absorption with special emphasis on the implications of the rather large scales (>=50cMpc) of observed large Lyman-alpha opacity fluctuations at z>~5.5 for the nature of ionizing sources. 
• 16th Apr 2018 2:00 pm: Forward Modelling the Universe – Adam Amara, Title: Forward Modelling the Universe Abstract: ​ Observational cosmology is going through a golden age. In particular, we are in the midst of an influx of data from on-going experiments, such as the Dark Energy Survey (DES). In the coming five years, the volume and quality of data will rapidly increase as Stage IV surveys,... 
• 16th Apr 2018 2:45 pm: TBA – Peter Melchoir, TBA 
• 16th Apr 2018 3:30 pm: Cosmology with weak lensing surveys: past, present, and future – Hendrik Hildbrandt, Title: Cosmology with weak lensing surveys: past, present, and future. Abstract: Gravitational lensing represents a unique tool to study the dark Universe. In the weak lensing regime, small distortions in the images of galaxies caused by the large-scale structure can be detected over the whole sky. Measuring these coherent distortions yields cosmological insights complementary to other probes... 
• 17th Apr 2018 10:30 am: Into the golden era of large-scale structure cosmology – Benjamin Joachimi, Title: Into the golden era of large-scale structure cosmology. Abstract: Large galaxy surveys probe the cosmic large-scale structure via the clustering of galaxies and the weak gravitational lensing effect, which are the most promising cosmological probes to reveal the nature of dark matter and dark energy, and to discover new physics beyond the concordance model... 
• 19th Apr 2018: BritGrav at ICG, no Thursday colloquium this week 
• 3rd May 2018 2:30 pm: Alvio Renzini (Padova), Bulge Formation, in the Milky Way and in High Redshift Galaxies,  
• 4th May 2018 9:30 am: Google Cloud Workshop, Lunch will be provided by the Google guys (I’ve heard it’s pizza!), so please can you re.confirm your attendance. 
• 10th May 2018 2:30 pm: Rita Tojeiro (St Andrews), The impact of structure formation on galaxy formation and evolution,  
• 17th May 2018 2:30 pm: John Regan (Dublin City University), Can Supermassive Stars form in the early Universe?, The existence of quasars in the early Universe and their associated supermassive black holes with masses of around 1 billion solar masses has been used to argue that supermassive stars are required to seed these black holes. While the existence of a first generation of stars (which must be metalfree) is not disputed – their... 
• 31st May 2018 2:30 pm: Mark Swinbank (Durham), The evolution of dynamics, chemistry and star formation in galaxies from z~0 to z~3, The redshift range z=1-2 corresponds to the era when the star formation density of the Universe peaked, and the time when most of the stars in today’s massive galaxies were formed.  Galaxies at these early times were drastically different from those locally, with massive, gas-rich galaxies undergoing rapid star formation in globally unstable disks, and... 
• 7th Jun 2018 2:30 pm: Annual Research and Innovation Conference (no ICG colloquium this day),  
• 12th Jul 2018 2:30 pm: Richard Ellis (UCL), Early Galaxies and Cosmic Reionisation: Progress and Challenges, The birth of galaxies represents the last unexplored frontier of cosmic history and it is commonly believed such early systems led to the transformation of neutral gas in the intergalactic medium into its present fully ionised state. Some progress has been made in charting the demographics of early galaxies into the era when reionisation is thought... 
• 11th Oct 2018 2:30 pm: Tyrone Woods (Birmingham), Titans of the Early Universe: The Origin of the Most Massive High-z Quasars, The discovery of billion solar mass quasars at redshifts of 6-7 challenges our understanding of the early Universe; how did such massive objects form in the first billion years? Observational constraints and numerical simulations increasingly favour the “direct collapse” scenario. In this case, an atomically-cooled halo of primordial composition accretes rapidly onto a single protostellar... 
• 25th Oct 2018 2:30 pm: Chris Conselice (University of Nottingham), TBA,  
• 1st Nov 2018 2:30 pm: Anastasia Fialkov (Kavli, IoA, Cambridge), Evaluating Cosmic Dawn, Cosmic dawn is one of the least-explored epochs in the history of the Universe illuminated by the very first stars and black holes. 21-cm radio signal produced by the intergalactic neutral hydrogen is tied to the intensity of radiation generated by the first sources of light. The signal can be used to constrain process of primordial star and... 
• 8th Nov 2018 3:30 pm: Nikku Madhusudhan (Cambridge), Chemical Characterization of Extrasolar Planets, Exoplanetary discoveries in the past two decades have unveiled an astonishing diversity in the physical characteristics of exoplanetary systems, including their orbital properties, masses, radii, equilibrium temperatures, and stellar hosts. Exoplanets known today range from gas-giants to nearly Earth-size planets, and some even in the habitable zones of their host stars. Recent advances in exoplanet... 
• 15th Nov 2018 2:30 pm: Pratika Dayal (Groningen), Early Galaxy Formation and its Large-scale Effects, Galaxy formation in the first billion years mark a time of great upheaval in the history of the Universe: as the first sources of light, these galaxies ended the ‘cosmic dark ages’ and produced the first photons that could break apart the hydrogen atoms suffusing all of space starting the process of cosmic reionization. As... 
• 22nd Nov 2018 2:30 pm: Katy Clough (Oxford), Collisions of Axion Stars with Black Holes and Neutron Stars, Axions are a potential dark matter candidate, which may condense and form self gravitating compact objects, called axion stars. In recent work, we studied head-on collisions of relativistic axion stars with black holes and neutron stars. In the black hole case we find that relatively large scalar clouds are produced by mergers of low compactness... 
• 29th Nov 2018 2:30 pm: Shinji Tsujikawa (Tokyo University of Science), Dark Energy in Generalized Proca Theories, The gravitational-wave event GW170817 together with the electromagnetic counterpart showed that the speed of tensor perturbations cT on the cosmological background is very close to that of light c for the redshift z < 0.009. In generalized Proca theories, the Lagrangians compatible with the condition cT = c are constrained to be derivative interactions up to cubic order besides... 
• 6th Dec 2018 2:30 pm: David Keitel (ICG), The Newly Released LIGO-Virgo Gravitational-Wave Transient Catalog (GWTC-1), This weekend, the LIGO and Virgo collaborations have released their catalog of compact binary coalescence observations from the first two observing runs, including four more previously unpublished binary black hole mergers. This talk will summarize the astrophysical results from matched-filter and burst searches, estimates of the source properties of binary coalescences found with Bayesian inference... 
• 13th Dec 2018 2:30 pm: Andreas Koch (Heidelberg), Halo vs. Bulge: a Mixed Bag of Chemical Enrichments, The bulge is one of the oldest, yet very metal rich Galactic components suggesting that it experienced early, rapid chemical enrichment.  Large spectroscopic surveys are beginning to unearth progressively more metal-poor stars ([Fe/H] < -2 dex) that are predicted to exist in models of galactic evolution, according to which the first stars did form in... 
• 10th Jan 2019 3:30 pm: Seshadri Nadathur (ICG), Beyond BAO: a 1% cosmological distance measure from the void-galaxy cross-correlation in BOSS, A key observational tool in cosmology is the measurement of the expansion history of the Universe that is possible with spectroscopic galaxy redshift surveys. Until now, the best constraints on this have come from a combination of BAO and redshift-space distortions (RSD), which allow measurements of the angular diameter distance D_A, the Hubble rate H,... 
• 16th Jan 2019 1:30 pm: South Coast Cosmology, The latest iteration of the regular South Coast Cosmology meeting. 
• 17th Jan 2019 2:30 pm: Eugene Lim (King’s College London), Can Inflation Really Inflate?, Inflation is the paradigmatic theory of the early universe, conjectured to explain why our Universe today is homogenous and isotropic across the largest scales. In this talk, I will describe how inflation asserts to solve these problems. I will then show that inflation itself may require homogenous initial conditions to begin with, and hence challenges... 
• 24th Jan 2019 2:30 pm: Bodo Ziegler (University of Vienna), Studying Galaxy Evolution in Clusters, We investigate the impact of environment on galaxy evolution exploiting diverse scaling relations for different samples at important cosmological epochs. At the peak of cluster mass assembly around z=0.5 the mass-size relation reveals differences to the field population are driven by transition objects between spheroids and disks. The mass-metallicity relation in phase space displays a higher metallicity enrichment for accreted galaxies... 
• 31st Jan 2019 2:30 pm: Eiichiro Komatsu (MPA), Non-Gaussian Gravitational Waves from Inflation, It has been widely assumed that detection of primordial gravitational waves from inflation in, for example, B-mode polarisation of the cosmic microwave background, immediately implies discovery of the quantum nature of spacetime. While this statement is true for the vacuum solution, it does not apply if the gravitational waves originate from the matter fields. How... 
• 7th Feb 2019 2:30 pm: Alex Barreira (MPA), Responses in and on Large-Scale Structure, The large-scale distribution of matter in the Universe encodes a wealth of information about the most fundamental ingredients of our Universe. The most popular way to describe this information is via the power spectrum (the 2-point correlation function), but there is additional important information contained in higher-order correlation functions. In this talk, I will describe a formalism that allows... 
• 14th Feb 2019 2:30 pm: Jonathan Tan (Chalmers / UVA), Formation of Supermassive Black Holes from Population III.1 Seeds, The origin of supermassive black holes (SMBHs) is one of the major unsolved problems of astrophysics. I review different formation theories and then discuss a scenario of formation from supermassive (~10^5 Msun) Population III.1 stars. These are primordial composition first collapse objects unaffected by any external influence from other astrophysical sources, i.e., their formation is... 
• 21st Feb 2019 2:30 pm: Sadegh Khochfar (Edinburgh), The Cosmic Nursery: Baby Galaxies and Seed Black Holes at Play, In my talk I will present results from high-resolution cosmological simulations focusing on the formation of galaxies and black holes during the first few billion years of the Universe. I will discuss how proto-galaxies impact their environments promoting the formation of seed black holes and how in turn these seed black holes affect the growth... 
• 28th Feb 2019 2:30 pm: Avery Meiksin (University of Edinburgh), The Intergalactic Medium, Galaxies and QSOs, The Intergalactic Medium (IGM) is the principal reservoir of baryons produced in the Big Bang. Its structure and evolution have been elucidated within the context of a LCDM cosmology in great detail, with a precision second only to predictions for the Cosmic Microwave Background (CMB), but on much smaller scales. A review will be presented of the achievements in modelling... 
• 14th Mar 2019 2:30 pm: Harry Desmond (Oxford), Fifth Force Searches in Galaxies, Extra (“fifth”) forces generically follow from new dynamical fields, and hence are ubiquitous in extensions to the standard models of particle physics and cosmology. Universally-coupled fifth forces are sufficiently strongly constrained by lab and Solar System tests so as to be virtually irrelevant for cosmology. However, broad classes of Lagrangian exhibit “screening mechanisms” which hide... 
• 21st Mar 2019 2:30 pm: Andreu Font Ribera (UCL) Studying the Expansion of the Universe with Quasar Spectra, From 2009 to 2014, the Baryon Oscillation Spectroscopic Survey (BOSS) used the SDSS telescope to obtain spectra of 1.5 million galaxies to get very accurate measurements of the Baryon Acoustic Oscillations (BAO) scale at redshift z ~0.5. At the same time, BOSS observed over 184 000 high redshift quasars (z>2.15) with the goal of detecting... 
• 28th Mar 2019 2:30 pm: Alessandra Papa (MPI, Hanover) Searching for Continuous Gravitational Waves, There has been much excitement about the first gravitational wave detection and the first multi-messenger signal. LIGO/Virgo have issued the first gravitational wave catalogue that comprises 11 signals, all from the merger of compact objects. We expect however to see a broader variety of signal morphologies than the ones observed so far, reflecting a broader... 
• 4th Apr 2019 2:30 pm: Clare Saunders (LPNHE, Paris), Improving Type Ia Supernovae as Cosmological Indicators, Type Ia Supernovae have provided a powerful tool for measuring the accelerating expansion of the Universe, and current and planned surveys will eliminate any significant source of statistical uncertainty at medium-range redshifts. However, the persistent presence of intrinsic dispersion in supernova magnitudes indicates latent unmodeled processes, which can lead to systematic bias in the standardized... 
• 9th May 2019 2:30 pm: Carlo Contaldi (Imperial College, London), Mapping the Stochastic Gravitational Wave Background, I will explain how to use gravitational wave data from detectors such as LIGO to map gravitational wave power on the sky. This technique provides constraints on the background density $\Omega_{\rm GW}$ and its anisotropies. I will present the results from the latest application of our method to LIGO data runs O1 and O2. 
• 23rd May 2019 2:30 pm: Yashar Akrami (École Normale Supérieure, Paris), Dark Energy Observations and Fundamental Physics: the Landscape, the Swampland, and All That, While theoretical efforts continue to explore possible explanations for the late-time cosmic acceleration, as well as the problem of the cosmological constant, we expect future cosmological surveys to test and constrain many of the proposed theories. In this talk, I will first review the status of models of dark energy provided by fundamental physics (supergravity... 
• 24th May 2019 1:30 pm: Research with PRACE – Kristina Kapanova (Trinity College, Dublin), We will have Kristina Kapanova (Trinity College, Dublin) visiting us in Portsmouth for the DISCnet HPC summer school and she will give us an overview of what PRACE, a European scientific association in the field of high performance computing, has to offer and how to get access to/apply for such resources for our computation-heavy scientific... 
• 30th May 2019 2:30 pm: Sugata Kaviraj (University of Hertfordshire), The low-surface-brightness Universe: a New Frontier in the Study of Galaxy Evolution, Low-surface-brightness (LSB) galaxies, a heterogeneous population ranging from dwarfs to large, diffuse spirals, are faint systems that are largely invisible in past surveys (e.g. the SDSS). However, LSB galaxies dominate the local number density and understanding their formation is central to a complete understanding of galaxy evolution. Using a cosmological hydro-dynamical simulation, we explore how... 
• 6th Jun 2019 2:30 pm: Ruth Gregory (Durham University), Primordial Black Holes and the Decay of the Universe, Phase transitions are part of everyday life, yet are also believed to be part of the history of our universe, where the nature of particle interactions change as the universe settles into its vacuum state. The recent discovery of the Higgs and its mass suggests that our vacuum may not be entirely stable, and that... 
• 13th Jun 2019 2:30 pm: Diego Blas (King’s College London), Constraints on Ultra-Light Dark Matter from Galactic Rotation Curves, Bosonic ultra-light dark matter (ULDM) in the mass range m ~ 10^{-22} – 10^{-21}  eV has been invoked as a motivated candidate with new input for the small-scale `puzzles’ of cold dark matter. Numerical simulations show that these models form cored density distributions at the center of galaxies (‘solitons’). These works also found an empirical... 
• 20th Jun 2019 2:30 pm: Giovanna Tinetti (UCL), TBA,  
• 18th Sep 2019 12:00 pm: || Sam Passaglia, KICP || (special time, 12pm!), || Title: Does inflation produce enough primordial black holes to explain the dark matter? || Abstract: I will discuss the inflationary side of the primordial black hole dark matter story. I will show why in single-field inflation, slow-roll conditions must be violated for PBH production to occur. I will discuss the leading single-field model which... 
• 10th Oct 2019 2:30 pm: Chiaki Hikage (IPMU, University of Tokyo), Cosmology from cosmic shear power spectra with Subaru Hyper Suprime-Cam data, We measure cosmic weak lensing shear power spectra with the Subaru Hyper Suprime-Cam (HSC) survey first-year shear catalog covering 137 sq. deg. of the sky. Thanks to the depth and the excellent-image quality of HSC, we obtain a high significance measurement of the cosmic shear power spectra in 4 tomographic redshift bins in the redshift... 
• 11th Oct 2019 11:00 am: Science chat: nobel prizes 2019, We’ll discuss the 2019 nobel prizes: J. Peebles for his long career in cosmology and M. Mayor & D. Queloz for the discovery of the exoplanet 51 Pegasi b. 
• 15th Oct 2019 4:00 pm: Impact Tea (+ CAKE), In the last few years ICG science has been used to look at Smart Meter and Cardiology Data; current projects are looking at changes in moles to predict skin cancer and the effect of blood donation on running performance. On Tuesday there will be an opportunity to look at how ICG science could be used... 
• 17th Oct 2019 2:30 pm: Stephen Wilkins (Sussex), Exploring the First Light And Reionisation Epoch, The First Light And Reionisation Epoch (FLARE), roughly the first billion years, is a critical period in the Universe’s history. The FLARE encompasses: the formation of the formation of the first stars; the transition from metal-free (population III) to metal enriched (Population II) star formation; early enrichment of the ISM including the first production of... 
• 18th Oct 2019 11:00 am: Science Chat: LIGO-Virgo O3a run results, The LIGO-Virgo Observing run O3 started in April 2019 and is currently on hold for a commissioning break during October, due to resume from Nov1 and then continue to April 2020. We will discuss the current status of the ~30 event candidates from this first half of the run and near-future prospects (e.g. the Japanese... 
• 24th Oct 2019 2:30 pm: Jess McIver (UBC), Cosmic Collisions Observed by LIGO and Virgo, The LIGO-Virgo collaboration has thus far issued 33 un-retracted public candidate event alerts during our third observing run, potentially adding dozens more known compact binary object mergers to the eleven confident detections from the first two Advanced-era observing runs. I’ll give an overview of the process of detecting, characterizing, and assessing the significance of gravitational... 
• 25th Oct 2019 11:00 am: Science Chat: H0 tension, eROSITA and quantum supremacy, We’ll discuss some recent research highlights: the controversial Google “quantum supremacy” announcement, the eROSITA first light observations, and/or some recent arXiv papers on the chronic Hubble tension, new measurements and possible recalibrations. 
• 1st Nov 2019 11:00 am: science chat: recent AI advances, We’ll discuss some recent highlights in AI research: DeepMind plays Starcraft and “Newton vs the machine” 
• 7th Nov 2019 2:30 pm: Mar Mezcua (ICE, Barcelona), Feeding and Feedback from Little Monsters: Black Holes in Dwarf Galaxies, Supermassive black holes of 10^10 solar masses already existed when the Universe was ~0.8 Gyr old. To reach this mass they should have started as seed intermediate-mass black holes (IMBHs) of 100-10^6 solar masses. Detecting such IMBHs in the early Universe is extremely challenging; however, those that did not grow into supermassive black holes should be found... 
• 8th Nov 2019 11:00 am: science chat: recent cosmology papers, We’ll discuss recent arXiv papers on H0 measurements and the claimed “curvature tension”. 
• 14th Nov 2019 2:30 pm: Otto Hannuksela (Nikhef), Gravitational Wave Lensing in LIGO/Virgo, LIGO/Virgo is currently running its third observation run and is recording gravitational waves almost weekly. Future observations with additional detector upgrades will observe even more. Gravitational waves, like light, could be gravitationally lensed. Recent studies suggest that we might see gravitational wave lensing already within the next few years. I will discuss some of the... 
• 15th Nov 2019 11:00 am: science chat: recent arXiv papers, We’ll discuss two recent arXiv papers: “Quantifying tensions in cosmological parameters: Interpreting the DES evidence ratio” and “Neutron Star as Mirror for Gravitational Waves”. 
• 21st Nov 2019 2:30 pm: Jennifer Schober (EPFL), Origin and Evolution of Cosmic Magnetic Fields, Magnetic fields are observed on all astrophysical scales of the modern Universe, from planets and stars to galaxies and galaxy clusters. There are also hints of Mpc-scale magnetic fields in the intergalactic medium. Such large-scale fields, if confirmed, have most likely been generated shortly after the Big Bang and might hold a key for solving... 
• 22nd Nov 2019 11:00 am: science chat: recent lensing and cosmology papers, We’ll discuss the recent papers “Over-constrained Gravitational Lens Models and the Hubble Constant” and “Evidence for anisotropy of cosmic acceleration”. 
• 28th Nov 2019 2:30 pm: Britton Smith (University of Edinburgh), The Origin of Normal Stars, It is well known that stars observed in the local Universe form with something very close to a universal initial mass function (IMF) where the vast majority are of low mass. However, theory and simulations of the formation of the first stars in the Universe predict a top-heavy IMF with significant dependence on environment. How... 
• 29th Nov 2019 11:00 am: science chat: recent papers and scientific topics, We’ll discuss topics of current interest, including the claimed fifth force / new particle detection in Beryllium decay. 
• 5th Dec 2019 2:30 pm: Shahab Joudaki (Oxford), The Current Status of Weak Lensing Cosmology, I will present the latest tomographic cosmic shear measurements from the Kilo Degree Survey (KiDS), and the resulting cosmological parameter constraints. I will explore the sensitivity of the parameter constraints to the systematic uncertainties and improvements that come from incorporating overlapping near-infrared data from VIKING. I will discuss the combined analysis of weak lensing tomography... 
• 13th Dec 2019 11:00 am: science chat: common misconceptions about MCMC, We’ll discuss common misconceptions about how MCMC works. 
• 10th Jan 2020 11:00 am: Science Chat: supernovae cosmology, We will discuss the possibility that the luminosity evolution of supernovae could mimic the effects of dark energy. 
• 17th Jan 2020 11:00 am: Science chat: cloud computing, Cloud computing is a new way of accessing computer resources on-demand over the internet. This will be a basic tutorial on Amazon Web Services (AWS), one provider of cloud computing. The tutorial will show how to use the Elastic Compute Cloud (EC2) to set up a virtual computer with the necessary hardware and software: CPUs,... 
• 23rd Jan 2020 2:30 pm: Amol Upadhye (UNSW, Australia), TBA,  
• 10th Feb 2020 10:00 am: Astrophysics and cosmology research seminars: Yashar Akrami, Tom Collett, Subodh Patil, Monday 10th February 3.23 Park building 10am Yashar Akrami 10.50am Tom Collett 11.40am Subodh Patil 
• 12th Feb 2020 10:00 am: Astrophysics and cosmology research seminars (Rebecca Canning, Giulia Rodighiero, Johannes Noller), 3.17 St Michael’s building 10am Rebecca Canning 10.50am Giulia Rodighiero 11.40am Johannes Noller 
• 3rd Mar 2020 3:30 pm: Impact Tea – Science in Parliament, Andew Williamson will speak about the recent “Science in Parliament Conference” at the IOP. There were two speakers, both with STEM PhDs, who work in different roles that allow them to apply their analytical expertise and scientific training to promote informed policy/decision making within Parliament. Both of them emphasised  how much they enjoyed the wide variety... 
• 6th Mar 2020 11:00 am: Science chat: ZEUS code, Minas Karamanis will tell us about a code he has developed named ZEUS to run MCMC and what are the advantages of his implementation. The code is publicly available at https://zeus-mcmc.readthedocs.io/en/latest/index.html 
• 12th Mar 2020 2:30 pm: Thomas Sotiriou (Nottingham), Probing Gravity in the Strong Field Regime, Gravitational waves astronomy promises to reveal to us the nature and structure of black holes and compact stars. This information comes encoded in the waveforms current and future detectors will pick up.  Extracting it is well known to be a significant data analysis challenge. Interpreting it, and using it to probe gravity itself and fundamental... 
• 19th Mar 2020 2:30 pm: Ruth Durrer (Geneva), TBA,  
• 20th Mar 2020 11:00 am: Science chat: working from home, In a time in which we are all re-thinking how to carry on with our science and projects, let’s have a discussion on what things work for each of us to work at home: tricks, ideas, recommendations 
• 31st Mar 2020 3:30 pm: Impact Tea, Systems of Innovation – Sercan Ozcan (Faculty of Business and Law) 
• 3rd Apr 2020 11:00 am: Science chat: the impact of Covid-19 on astronomy experiments,  
• 23rd Apr 2020 2:30 pm: Colloquium (virtual) – Anowar Shajib, Virtual seminar 
• 24th Apr 2020 11:00 am: Science chat: matter-antimatter symmetry violation,  
• 30th Apr 2020 2:30 pm: Colloquium (virtual) – Katelin Schutz, Virtual seminar 
• 7th May 2020 2:30 pm: Bernard Carr (Queen Mary University, London), TBA,  
• 7th May 2020 2:30 pm: Colloquium (virtual): Michelle Lochner, Virtual seminar 
• 14th May 2020 2:30 pm: Colloquium (virtual): Michelle Lochner, Virtual seminar 
• 21st May 2020 2:30 pm: Colloquium (virtual): Michelle Lochner, Virtual seminar 
• 28th May 2020 2:30 pm: Colloquium (virtual) – Erin Kara, Virtual seminar 
• 29th May 2020 11:00 am: Science chat: misinformation and conspiracy theories,  
• 4th Jun 2020 2:30 pm: Colloquium (virtual): Michelle Lochner, Virtual seminar 
• 5th Jun 2020 11:00 am: Science chat: how can we support black astronomers?, We can’t be inactive or neutral in the work of anti-racism. Let’s discuss what we can do in our institute 
• 9th Jun 2020: Impact Tea, Jascha will talk about the recent AI v Covid hack. 
• 11th Jun 2020 2:30 pm: Serena Viti (UCL), TBA,  
• 11th Jun 2020 2:30 pm: Colloquium (virtual): Michelle Lochner, Virtual seminar 
• 12th Jun 2020 11:00 am: Science chat: Taking action on inclusivity and diversity,  
• 18th Jun 2020 2:30 pm: Michele Cappellari (Oxford), TBA,  
• 18th Jun 2020 2:30 pm: Colloquium (virtual): Michelle Lochner, Virtual seminar 
• 19th Jun 2020 1:30 pm: UK HPC and Data facilities – David Henty (ARCHER, Edinburgh), Agenda: David is going to provide an overview over the available public upper Tier HPC infrastructure in the UK (Archer, Dirac, etc.) and how to get access to it for your research. Location: https://meet.google.com/zfs-cqgj-afm 
• 19th Jun 2020 3:30 pm: Amazon Web Services – Phil Edwards, Lucy Antysz (AWS), Agenda: * AWS Introduction – Phil Edwards * AWS in Education and Research – Phil Edwards * Demonstration of Setting up a HPC Cluster on AWS – Phil Edwards * Educational Programs – Lucy Antysz Location: AWS Chime (https://chime.aws/philipedwards) 
• 25th Jun 2020 2:30 pm: Colloquium, Julie Wardlow, Title: Unveiling extreme dusty star-formation in the distant Universe Abstract: In recent years the high-redshift Universe has been increasingly opened to scrutiny at far-infrared wavelengths, where cool dust emission from star-formation dominates. The dusty star-forming galaxies (DSFGs), selected at these wavelengths likely represent an important, but short-lived phase in the growth of massive galaxies. These DSFGs often have... 
• 26th Jun 2020 11:00 am: Science chat,  
• 3rd Jul 2020 11:00 am: Science Chat,  
• 10th Jul 2020 11:00 am: Science chat,  
• 21st Jul 2020 3:30 pm: Impact Tea -POSTPONED, Jascha will talk about the  AI v Covid19 hack held earluier this year Title: DataBiology #CORONAHACK virtual hackathon – COVID Spread & Mobility Studies (Team PandEnemies) Abstract: In this talk, I discuss the week-long #CORONAHACK virtual hackathon, I attended during the week after Easter and the project of COVID-19 modelling I was part of. As part... 
• 24th Jul 2020 11:00 am: Science Chat: book club, Book Club led by Natalie and Laura: Why I’m no longer talking about race by by Reni Eddo-Lodge. The discussion session will be open to everyone, everyone is encouraged to attend even if you have not read the book. 
• 4th Sep 2020 11:00 am: Science chat,  
• 25th Sep 2020 11:00 am: Science chat: book club, Equality and Diversity Book Club. Black and British: a forgotten history, by David Olusoga 
• 2nd Oct 2020 11:00 am: Science chat, Current covid situation and plans 
• 7th Oct 2020 11:00 am: Gravity Meeting, Meet the members of the gravity/ theory group!   We use Benty-fields to volunteer and vote for papers to discuss http://www.benty-fields.com/manage_jc   Google Meet link: https://meet.google.com/zen-ddfa-jvw?authuser=0&hl=en_GB   See you there!     
• 9th Oct 2020 11:00 am: Science chat: International Law as a Colonial Enterprise, Its Critique and the Critique of the Critique by Leïla Choukroune, Leïla will first introduce the Democratic Citizenship theme and relate to the need for democracy, equality and justice in science. She will then present on the topic of international law as a colonial enterprise, addressing concepts such as positivism and reason and intellectual property. Leïla Choukroune is a professor of international law and director of... 
• 15th Oct 2020 2:30 pm: Umberto Maio (INAF, Rome), Exploring the Primordial Universe, Understanding the formation of stars, galaxies and black holes in primordial cosmological epochs is one of the most striking challenges of modern astrophysics. In order to do that, theoretical models are embedded in large numerical simulations that follow the behavior of cosmic gas in different environments, its cooling capabilities, star formation processes and feedback effects.... 
• 16th Oct 2020 11:00 am: Science Chat,  
• 22nd Oct 2020 2:30 pm: Helen Fraser (The Open University), Ice mapping in the JWST ERA: Shining (Star) Light on Cold-Dark Mysteries of Star-Formation, In star-forming regions chemical processes progress on timescales similar to those of other physical processes governing star (and planet) formation. However the ingredients of stellar systems are set long before these processes begin, in the dense dark regions of interstellar clouds. Seemingly ubiquitous across our own galaxy (and as resolution improves  – in interstellar regions... 
• 23rd Oct 2020 11:00 am: Science Chat,  
• 29th Oct 2020 2:30 pm: Tomasz Kacprzak (ETH Zürich), Cosmology with Artificial Intelligence, In recent years artificial intelligence methods have found multiple applications in cosmology. These methods are particularly well suited for the analysis of large scale structure, as they are capable of creating rich and complex models of non-linear data. In this talk I will present the first cosmology constraints derived using deep convolutional neural networks, using... 
• 30th Oct 2020 11:00 am: Science Chat,  
• 5th Nov 2020 2:30 pm: Matteo Viel (SISSA), Hydrogen as a Cosmological Probe, I will review the use of neutral hydrogen (HI) in the post reionization era as a tracer of the structure formation process. I will focus on atomic hydrogen both in absorption (IGM) and in emission (21cm intensity mapping). IGM is a probe of HI in volume, while intensity mapping is sensitive to the HI mass... 
• 6th Nov 2020 11:00 am: Science Chat,  
• 12th Nov 2020 2:30 pm: Alessandra Silvestri (Leiden), Probing Gravity and Dark Energy in the Era of Multi-Messenger Cosmology, It is now an exceptional time for modern cosmology, when we can observe the universe with high precision and connect cosmological measurements with theory. The excitement about the advances of observational cosmology is accompanied by the awareness that we face some major challenges: we still lack compelling theoretical models for dark matter, (that accounts for... 
• 13th Nov 2020 11:00 am: Science Chat,  
• 19th Nov 2020 2:30 pm: Jaiyul Yoo (University of Zurich), Are We Ready for Precision Cosmology? General Relativistic Effects and Gauge-Invariant Formalism, The current and upcoming surveys in cosmology will soon deliver an unprecedented amount of precision measurements, truly opening an era of precision cosmology.  However, this rapid development in experiments and observations demands substantial advances in theoretical modeling to avoid any systematic errors in our interpretation.  The standard theoretical descriptions of galaxy clustering, weak gravitational lensing,... 
• 20th Nov 2020 11:00 am: Science Chat,  
• 26th Nov 2020 2:30 pm: Paolo Pani (Rome), Testing the Nature of Dark Compact Objects with Gravitational Waves, Gravitational wave astronomy allows us for unprecedented tests of the nature of dark compact objects to search for new exotic species of compact objects. I will give an overview, focusing on some recent results, including ringdown tests, gravitational-wave echoes, inspiral tests of the multipolar structure of supermassive objects, tests of the Kerr bound on the... 
• 27th Nov 2020 11:00 am: Science Chat,  
• 3rd Dec 2020 2:30 pm: Graham Smith (Birmingham), Galaxy Cluster Density Profiles — from Gravitationally Lensed Gravitational Waves to the Splash Back Radius, Gravitational waves can be gravitationally lensed, i.e. magnified and multiply-imaged, by foreground massive galaxies or galaxy clusters in much the same way as the more familiar galaxies and quasars can be lensed.  The first detection of a gravitationally lensed gravitational wave is expected in the 2020s and will be a major milestone because it will... 
• 4th Dec 2020 11:00 am: Science Chat,  
• 10th Dec 2020 2:30 pm: Blake Sherwin (Cambridge), CMB Lensing and New Constraints on the Early Universe, Measurements of gravitational lensing in the cosmic microwave background (CMB) allow the dark matter distribution to be mapped out to uniquely high redshifts. After giving an overview of current and upcoming CMB lensing measurements with the Atacama Cosmology Telescope and beyond, I will focus on two new ways of using CMB lensing, in combination with... 
• 11th Dec 2020 11:00 am: Science Chat,  
• 14th Jan 2021 2:30 pm: Daniel Whalen (ICG), The First Quasars in the Universe, Although most massive galaxies harbor supermassive black holes (SMBHs) today, over 300 quasars have now been found at z > 6, less than a Gyr after the Big Bang (with seven at z > 7).  How such massive BHs formed by such early epochs poses significant challenges to current paradigms of early structure formation.  I... 
• 21st Jan 2021 2:30 pm: Kate Maguire (TCD), Exploding Stars and Catastrophic Collisions, I will present an overview of the dramatic and highly energetic explosions of stars at the end of their lives. They are essential as cosmological distance indicators, in heavy element production, and driving galaxy dynamics. New state-of-the-art sky surveys have uncovered an incredible diversity in the properties of supernovae and stellar collisions, which is testing... 
• 28th Jan 2021 2:30 pm: Bertram Bitsch (MPIA), Formation of Super-Earths and Mini-Neptunes, When a star is born, a protoplanetary discs, consisting of dust grains and gas, forms around it. Inside this disc, the dust grains can start to grow and form larger and larger objects until finally planetesimals – objects of about 100km in size – are formed. These planetesimals can then grow by further accreting other... 
• 4th Feb 2021 2:30 pm: Paola Caselli (MPE Garching), Our Astrochemical Origins, Our Solar System was born from a dark and cold cloud made out of molecular gas and small dust particles. Thanks to powerful telescopes, we can now study in detail these clouds, their chemical ingredients and their evolution. We can then reconstruct our origins. Interstellar molecules are unique tracers of the dynamical and chemical evolution... 
• 11th Feb 2021 2:30 pm: Brad Gibson (Hull), Simulated vs Real Galaxies: The Good, The Bad, and The Ugly, Using computers to mimic the beautiful Grand Design spirals seen through telescopes has been a century-long challenge.  While the physics which makes galaxies is fairly simple and covered at A-level, implementing that physics inside supercomputers has been frustratingly difficult.  In the past 10 years, we have finally started to generate galaxies which actually look “real”. ... 
• 18th Feb 2021 2:30 pm: Hong Qi (Cardiff), Fast and Accurate Gravitational Wave Inference with PyROQ, Gravitational wave inference with very long and complex waveforms can take months. Inference of large synthetic gravitational wave populations as required in scenario studies can also be months even years. The expensive runtime has been challenging for the measurements of astrophysical quantities such as Hubble constant and neutron star Equation of State, as well as studies of systematic effects on parameter... 
• 25th Feb 2021 2:30 pm: Johannes Noller (ICG), Testing Gravity on all Scales, Recent years have seen great progress in probing gravitational physics on a vast range of scales, from the very largest cosmological scales to the microscopic ones associated with high energy particle physics. In this talk I will give a whistle stop tour of some of the different physical systems we can use to learn more about gravity in... 
• 4th Mar 2021 2:30 pm: TBA,  
• 22nd Apr 2021 2:30 pm: Laura Wolz (Manchester), Cold Gas Constraints via HI Intensity Mapping, Intensity mapping surveys of neutral hydrogen (HI) are a new way to measure the large-scale matter distribution of our Universe over a wide range of redshifts, and thus constrain cosmological parameters describing the Universal expansion. The next generation of radio telescopes and interferometers are being designed and built to optimise the detection of the HI... 
• 29th Apr 2021 2:00 pm: Diego Blas (King’s College London), New Ideas on Quenching and Detecting BH Rotational Superradiances, In this talk I’ll discuss two recent results on BH superradiance: first, I will describe how BH photon superradiance is typically quenched by interactions of the photon cloud with the ambient electrons. Second, I will explain how an axionic cloud may impact the CMB if it decays into low energy photons which quickly heat and... 
• 6th May 2021 2:30 pm: Andrew Pontzen (UCL), Dwarf Galaxies in Cosmology, Understanding dwarf galaxies is crucial for verifying and improving our broader picture of galaxy formation in the universe. They contain so few stars that their gravitational effects are almost entirely dominated by dark matter. They are also exquisitely sensitive to stellar processes that can heat and eject gas, which in turn prevent further stars from forming. The... 
• 13th May 2021 2:30 pm: Ewen Campbell (Edinburgh), Cosmic Chemistry in the Laboratory, Recent advances in laboratory methods have enabled gas phase measurement of the electronic spectra of large molecular ions of astrochemical interest at temperatures below 10 K. By exploiting the unique capabilities of ion traps, the first identification of a molecular carrier responsible for some of the enigmatic diffuse interstellar bands (DIBs) could be made. The... 
• 20th May 2021 2:30 pm: Tessa Baker (QMUL), Testing Gravity with Gravitational Waves, The past five years of discoveries in gravitational wave astronomy have had a profound impact on cosmology. In particular, they have triggered a host of new ideas on how to probe the fundamental nature of gravity on large scales. This work is rapidly becoming a crucial pillar in the long-standing challenge to understand dark energy. ... 
• 27th May 2021 2:30 pm: Luca Matra (NUI Galway), Exocometary Science, Over the past decade, rapidly increasing evidence for exocomets, icy bodies in extrasolar planetary systems, has given rise to the budding field of Exocometary Science.  Exocomets are detected through the gas and dust they release as they collide and grind down within their natal belts, or – like Solar System comets – as they sublimate... 
• 17th Jun 2021 2:30 pm: Manuela Zoccali (Universidad Catolica), The Stellar Population of the Galactic Bulge, The Milky Way galaxy includes three main stellar components, in order of decreasing mass: the disk, the bulge and the halo. Bulge and halo are the oldest ones, according to our understanding, with the halo being likely older than the bulge, but about 30 times less massive. Therefore, being the first massive component to be... 
• 7th Oct 2021 2:30 pm: Colloquium: Aurel Schneider,  
• 14th Oct 2021 2:30 pm: Colloquium: Beatriz Sanchez-Cano,  
• 21st Oct 2021 3:30 pm: Colloquium: Peter Taylor (JPL), Title: Separation of Scales in Projection Abstract: I show how simple modifications of existing two-point statistics can reap large rewards. In the first half of the talk I discuss an optimal strategy for extracting information from the redshift-space distortion (RSD) signal using projected angular statistics. This is a first step towards performing an optimal joint... 
• 28th Oct 2021 2:30 pm: Colloquium: Michele Levi (NBI Copenhagen),  
• 4th Nov 2021 2:30 pm: Colloquium: Adam Riess (JHU),  
• 11th Nov 2021 2:30 pm: Colloquium: Rowan Smith (Manchester),  
• 18th Nov 2021 2:30 pm: Colloquium: Clare Burrage (Nottingham),  
• 25th Nov 2021 2:30 pm: Colloquium: Harry Desmond (Oxford),  
• 2nd Dec 2021 3:30 pm: Colloquium: Katerina Chatziioannou (Caltech),  
• 9th Dec 2021 2:30 pm: Colloquium: Boris Gaensicke (Warwick),  
• 20th Jan 2022 2:30 pm: Colloquium: Sarah Gossan (Toronto), Exploring the multi-messenger Milky Way   The era of multi-messenger astronomy is well and truly upon us, with 90 compact binaries observed since the Advanced LIGO detectors saw first light in 2015. Despite our very own cosmic backyard, the Milky Way, being ripe with prospective sources for ground-based gravitational wave detectors, the closest source detected thus far... 
• 27th Jan 2022 2:30 pm: Colloquium: Colin Hill (Columbia), Title: Searching for New Physics in the Universe’s Oldest Light with the Atacama Cosmology Telescope Abstract: I will discuss recent and ongoing work focused on attempts to restore concordance amongst cosmological data sets, motivated by discrepancies amongst some measurements of the cosmic expansion rate (H_0) and the matter clustering amplitude (S_8).  Particular attention will be... 
• 10th Feb 2022 2:30 pm: Colloquium: Karl Gebhardt (Austin), “Black Holes in the Extremes, from the smallest to the largest to the naked”: Our understanding of black holes have gone from being considered interesting oddities of nature to essential components of both formation and evolution of stellar systems. While there has been significant progress in defining the relationships between the black hole masses and... 
• 17th Feb 2022 2:30 pm: Colloquium: Diederik Roest (Groningen), “Binary black holes with scalar hair and Kepler orbits”: The spectacular discovery of gravitational waves provides a strong impetus to understand black hole binary systems. Being intrinsically relativistic, these systems destroy the simplicity of the starting point in classical mechanics, the Kepler problem. Our aim will be to investigate relativistic corrections in a more general... 
• 24th Feb 2022 3:30 pm: Colloquium: Raffaella Margutti (Northwestern), The Renaissance of Astrophysics: a landscape of opportunities in the era of Time Domain Multi-Messenger investigations Astronomical transients are signposts of catastrophic events in space, including the most extreme stellar deaths, stellar tidal disruptions by supermassive black holes, and mergers of compact objects. Thanks to new and improved observational facilities we can now sample the... 
• 3rd Mar 2022 2:30 pm: Colloquium: Isobel Hook (Lancaster), Cosmology with supernovae: past, present and future In this talk I will give an overview of the use of Type Ia supernovae in cosmology. I will briefly describe the work that led to the 1998 discovery of the accelerating expansion of the universe, and some of the major supernova surveys that have been carried out... 
• 24th Mar 2022 2:30 pm: Colloquium: Raphaëlle Haywood (Exeter), There’s no place like home: Placing Earth in its astronomical and geological contexts Recent revolutionary discoveries in astronomy are showing that Earth is one of billions of planets, and that terrestrial, temperate planets are commonplace in our galaxy. Geological records indicate that Earth has been many different worlds over time, and life has shown extraordinary... 
• 31st Mar 2022 2:30 pm: Colloquium: Sam Robson (Portsmouth), “Sequencing and Tracking of Phylogeny in COVID-19 (STOP-COVID19): The University of Portsmouth’s genomic epidemiological response to the COVID-19 pandemic” The novel coronavirus SARS-CoV-2 has led to severe disruption across the globe. Case numbers rose significantly in the UK over the winter period of 2020 due to the emergence of a novel variant, the Alpha variant... 
• 29th Sep 2022 2:30 pm: Colloquium: Adam Coogan (Montreal), Measuring dark matter’s properties in strong gravitational lenses using machine learning Dark matter’s microphysical properties are imprinted on the structure of the universe at subgalactic scales. Images of strong lenses, where the light from a distant galaxy is dramatically distorted into a ring by the mass of an intervening galaxy, provide an avenue for probing... 
• 6th Oct 2022 2:30 pm: Colloquium: Christine Davies (Glasgow), Tightening the screws on the Standard Model: theory predictions for the anomalous magnetic moment of the muon The muon, a heavier cousin of the electron, has electric charge and spin and therefore a magnetic moment. The muon’s magnetic moment is related to its spin via a factor g which would take the value 2 from... 
• 13th Oct 2022 2:30 pm: Colloquium: Raphael Hirschi (Keele),  
• 20th Oct 2022 2:30 pm: Colloquium: Pedro Carrilho (Edinburgh),  
• 27th Oct 2022 2:30 pm: Colloquium: Tim Davis (Cardiff), Tracing out the darkness with cold gas: dynamically probing galaxy evolution In this talk I will describe how mapping the dynamics of gas clouds in the centre of galaxies can help us to constrain a wide range of astrophysical problems. From the enigmatic relation between galaxies and their supermassive black holes, to the suppression of...