This week, the ICG welcomes a new member of staff Andy Lundgren. As a new Reader in Gravitational Waves, Andy kick-starts our new initiative in gravitational wave science; helping to bolster the G in ICG!
Andy joins us from the Albert Einstein Institute (AEI), Max-Planck-Institut für Gravitationsphysik Hannover and leads the detection characterisation of LIGO. Here is a video of Andy explaining the first detection of LIGO back in 2015.
Today, the ICG came together to enjoy the announcement of the LIGO+VIRGO detection of colliding neutron stars in the galaxy NGC4993, only 130 million light years away. As shown in the photo below, the whole ICG watched the official NSF press conference to celebrate this great discovery
ICG researchers listen to the announcement of LIGO+VIRGO NS-NS merger event
What makes this event even more incredible is the almost simultaneous detection of electromagnetic radiation from this merger using telescopes from gamma rays to radio waves. Hundreds of observatories around the world, and in space, have now seen light from this event heralding the arrival of “multi-messenger astronomy” i.e., seeing the universe with light, gravity waves and particles.
ICG researchers have been involved in this discovery in various ways. First, our new Reader in Gravitational Wave Science Andy Lundgren is part of the LIGO team and responsible for much of the instrument characterisation work needed to believe such events – today was his first official work day at the ICG! Secondly, Bob Nichol and colleagues have been long-time members of the Dark Energy Survey collaboration which was part of the global follow-up of NGC4993. Below is a DES image showing the new “kilonova” event that is the optical counterpart to the gravitational wave neutron star merger.
Finally, Chris Frohmaier (Fellow in Data Intensive Science at ICG) was most involved at the ICG in studying this kilonova, specifically in the characterisation of the event and most crucially, in estimating the rate of such events in the nearby Universe. As outlined in the University of Portsmouth story, Chris’s work has been important for estimates of the amount of heavy elements produced by such explosions and he and his colleagues found, in their recent Science paper, that approximately half the abundance of such matter could be produced in neutron star mergers.
This has profound implications for science but also has an incredible consequence for all of us as it implies that half the gold on our planet was forged in such explosive events. Not a bad days work when you consider it.
Astronomy on Tap – Portsmouth, UK returns with a fun filled evening on The History of The Universe! Come and join us from 7.15pm on 22nd November at the Kings Pub, Albert Road, Southsea. We have talks by two ICG scientists who are experts in their field:
Dr Violeta Gonzalez-Perez: From the Greeks to First Light
and
Mr Robert Hardwick: From First Light to the Beginning of Everything.
Doors are open from 7.15pm with the first talk starting at 7.30pm. There will be a quiz with space-themed prizes to be won, and many astronomers to meet and to answer to all your burning astronomy and cosmology questions!
This event is for ages 16+ (alcohol only served to 18+) and entry is free. For more information please see our website, event or Facebook event. You can get into contact with us at astronomyontapportsmouth@gmail.com.
This event is brought to you by Astronomy on Tap and The Institute of Cosmology and Gravitation, a department of University of Portsmouth.
For the summer of 2017 ICG hosted five different summer undergraduate placements, three focused on scientific research, and two on public engagement with research.
Summer 2017 placement students and supervisors on the balcony of the Dennis Sciama Building. From left to right: Virginia d’Emilio, Jen Gupta, Santiago Avila, Sesh Nadathur (rear), Wiktoria Kedziora (front), Coleman Krawczyk, Lewis Watt, Andy Cook and Thomas Divers.
The projects for 2017 were:
SEPnet placements:
Ogden Trust Placement
Public Engagement Placements:
As usual it was a pleasure to host such enthusiastic young people in the department for these 6-8 week placements, and we look forward to hearing more about the outcomes of the work, and the future careers of our placement alumni in the future.
Scientists from University of Portsmouth have helped to create the most accurate map of the structure of dark matter in the Universe, supporting the theory that dark energy and dark matter make up most of the Universe.
For the first time, scientists from the international Dark Energy Survey (DES) collaboration, including Dr David Bacon from the University’s Institute of Cosmology and Gravitation (ICG), can see the structure of the current Universe with the same clarity that they can see the Universe at its very beginning – and therefore can answer many questions about how it evolved.
The results from this survey could help to provide answers to one of the most pressing questions of the Universe – why the Universe is expanding at an ever-increasing rate. Crucially, these findings support the theory that about 4 per cent of the present composition of the Universe is ordinary matter, 26 per cent comes in the form of mysterious cold dark matter, and 70 per cent is in the form of an elusive dark energy, possibly causing the accelerating expansion of the Universe.
Dr Bacon, a Reader in Cosmology, said: “Dark matter is invisible to us, but we can see its effects – its gravity is bending the light from distant galaxies, so they look distorted to us. We can work back from measuring the distortions to mapping the cause. It’s so exciting to see this truly vast map of the dark Universe at last.”
Dr Bacon co-led the team which created dark matter maps using data from the 570-megapixel Dark Energy Camera on the Blanco telescope in Chile, one of the most powerful cameras in existence, able to capture digital images of light from galaxies eight billion light years from Earth.
Dark Energy Survey scientists created maps of galaxy positions as tracers, and second, they precisely measured the shapes of 26 million galaxies to directly map the patterns of dark matter over billions of light years, using a technique called gravitational lensing.
Professor Bob Nichol, Director of the ICG and long-time DES collaborator, added: “These results come after a decade of dedicated effort from scientists around the world including here at the ICG. Even though these DES measurements clearly show we live in a Universe dominated by lots of dark stuff; its origin remains a huge mystery to science.”
Surprisingly, it is easier to measure the large-scale distribution of matter in the Universe in the distant past than it is to measure it today.
In the first 400,000 years following the Big Bang, the Universe was filled with a glowing gas, the light from which survives to this day. The European Space Agency’s orbiting Planck observatory created a map of this cosmic microwave background radiation, giving us a snapshot of the Universe at that very early time.
Figure 1: Map of dark matter made from gravitational lensing measurements of 26 million galaxies in the Dark Energy Survey. The map covers over 1300 square degrees of the entire sky and spans several billion light years in extent. Red regions have more dark matter than average, blue regions less dark matter. Image credit: Chihway Chang of the Kavli Institute for Cosmological Physics at the University of Chicago, and the DES collaboration. (Image credit: Chihway Chang of the Kavli Institute for Cosmological Physics at the University of Chicago, and the DES collaboration)
Since then, the gravity of dark matter has pulled mass together over time, while dark energy has been pushing matter apart. Using the Planck map as a start, cosmologists can calculate precisely how this dynamic plays out as the Universe evolves over 14 billion years.
Figure 2: The 4-meter Blanco telescope in Chile, where the DES observations have been taken. (Image credit: the DES collaboration)
Dr Bacon added: “These new DES measurements are very intriguing, as they support the simplest version of our dark universe theory.”
The new results released today draw only from data collected during the survey’s first year, which covers one thirtieth of the sky. Scientists on DES will map an eighth of the sky in unprecedented detail over five years. The fifth year of observation will begin in August.
These results and others from the first year of the Dark Energy Survey will be released today online at
https://www.darkenergysurvey.org/des-year-1-cosmology-results-papers
Astronomers have constructed the first map of the Universe based on the positions of supermassive black holes, which reveals the large-scale structure of the Universe.
The map precisely measures the expansion history of the Universe back to when the Universe was less than three billion years old. It will help improve our understanding of ‘Dark Energy’, the unknown process that is causing the Universe’s expansion to speed up.
An artist impression of a quasar. [credit: Hubble telescope].
The map was created by scientists from the Sloan Digital Sky Survey (SDSS), an international collaboration including astronomers from the University of Portsmouth.
As part of the SDSS Extended Baryon Oscillation Spectroscopic Survey (eBOSS), scientists measured the positions of quasars – extremely bright discs of matter swirling around supermassive black holes at the centres of distant galaxies. The light reaching us from these objects left at a time when the Universe was between three and seven billion years old, long before the Earth even existed.
The map findings confirm the standard model of cosmology that researchers have built over the last 20 years. In this model, the Universe follows the predictions of Einstein’s General Theory of Relativity but includes components that, while we can measure their effects, we do not understand what is causing them.
Along with the ordinary matter that makes up stars and galaxies, Dark Energy is the dominant component at the present time, and it has special properties that mean that it causes the expansion of the Universe to speed up.
Will Percival, Professor of Cosmology at the University of Portsmouth, who is the eBOSS survey scientist said: “Even though we understand how gravity works, we still do not understand everything – there is still the question of what exactly Dark Energy is. We would like to understand Dark Energy further. Not with alternative facts, but with the scientific truth, and surveys such as eBOSS are helping us to build up our understanding of the Universe.”
To make the map, scientists used the Sloan telescope to observe more than 147,000 quasars. These observations gave the team the quasars’ distances, which they used to create a three-dimensional map of where the quasars are.
But to use the map to understand the expansion history of the Universe, astronomers had to go a step further and measure the imprint of sound waves, known as baryon acoustic oscillations (BAOs), travelling in the early Universe. These sound waves travelled when the Universe was much hotter and denser than the Universe we see today. When the Universe was 380,000 years old, conditions changed suddenly and the sound waves became ‘frozen’ in place. These frozen waves are left imprinted in the three-dimensional structure of the Universe we see today.
A slice through largest-ever three-dimensional map of the Universe. Earth is at the left, and distances to galaxies and quasars are labelled by the lookback time to the objects (lookback time means how long the light from an object has been travelling to reach us here on Earth). The locations of quasars (galaxies with supermassive black holes) are shown by the red dots, and nearer galaxies mapped by SDSS are also shown (yellow). The right hand edge of the map is the limit of the observable Universe, from which we see the Cosmic Microwave Background (CMB) – the light “left over” from the Big Bang. Fluctuations in the CMB as observed by the recent ESA Planck satellite mission are shown. The bulk of the empty space in between the quasars and the edge of the observable universe are from the “dark ages”, prior to the formation of most stars, galaxies, or quasars.
A slice through largest-ever three-dimensional map of the Universe made from the locations of quasars. Earth is at the left, and distances to galaxies and quasars are labelled by the lookback time to the objects (lookback time means how long the light from an object has been travelling to reach us here on Earth). The locations of quasars (galaxies with supermassive black holes) are shown by the red dots, and nearer galaxies mapped by SDSS are also shown (yellow). The right hand edge of the map is the limit of the observable Universe, from which we see the Cosmic Microwave Background (CMB) – the light “left over” from the Big Bang. Fluctuations in the CMB as observed by the recent ESA Planck satellite mission are shown. The bulk of the empty space in between the quasars and the edge of the observable universe are from the “dark ages”, prior to the formation of most stars, galaxies, or quasars. Credit Anand Raichoor and the SDSS Collaboration. Credit Anand Raichoor and the SDSS Collaboration.
Using the new map, the observed size of the BAO can be used as a ‘standard ruler’ to measure distances in our universe. “You have metres for small units of length, kilometres or miles for distances between cities, and we have the BAO for distances between galaxies and quasars in cosmology,” explained Pauline Zarrouk, a PhD student at the Irfu/CEA, University Paris-Saclay, who measured the distribution of the observed size of the BAO.
The current results cover a range of times where they have never been observed before, measuring the conditions when the Universe was only three to seven billion years old, more than two billion years before the Earth formed.
The eBOSS experiment continues using the Sloan Telescope, at Apache Point Observatory in New Mexico, USA, observing more quasars and nearer galaxies, increasing the size of the map produced. After it is complete, a new generation of sky surveys will begin, including the Dark Energy Spectroscopic Instrument (DESI) and the European Space Agency Euclid satellite mission. These will increase the fidelity of the maps by a factor of ten compared with eBOSS, revealing the Universe and Dark Energy in unprecedented detail.
The Institute of Cosmology and Gravitation is 15 years old this year and we plan to celebrate with an event to bring together past and present students, staff and visitors. We will hold a series of talks, seminars and a family barbecue this June.
Registration is now open for UK Cosmology meeting at Portsmouth on Wednesday 5th April 2017.
https://www.icg.port.ac.uk/uk-cosmo-at-portsmouth-2017/
You can submit a title and abstract if you would like to contribute a talk. In case we cannot accommodate all contributors, priority will be given to people who did not talk in the last UK Cosmo meetings. Submissions of contributions for talks are welcomed until the 19th of March, and a program will be made available on the web page soon after.
Invited speakers are Prof. Kathy Romer from Sussex and Dr. Claudia de Rham from Imperial.
Edited from a story on the University of Portsmouth website:
Astronomers of all ages explored the wonders of the Universe thanks to a Stargazing event in Portsmouth last week.
University of Portsmouth astronomers hosted the event at Portsmouth Historic Dockyard on Tuesday 31st January 2017 and over 600 people visited despite the misty skies and rain. The event was organised by the University’s Institute of Cosmology and Gravitation in collaboration with Action Stations and HMS Warrior 1860.
Stargazing guests explore Action Stations
Budding astronomers and amateur stargazers were given the opportunity to explore the Universe, learn how sailors navigate by the stars, build rockets, learn about gravity, listen to talks on cosmology and identify galaxies.
Dr Jen Gupta, astrophysicist and outreach officer, said: “The weather may not have been on our side last night, but this certainly didn’t affect our event, which saw hundreds of people engaging with the activities on offer. This is the fifth time we’ve run Stargazing at Portsmouth Historic Dockyard and we’re so pleased with how it went. It’s wonderful to see people of all ages taking part in activities that enthuse them about the Universe.”
Isaac Wagstaff, aged five, said: “My favourite part was having my face painted with a sparkly red star. I learnt that if a star is red it means it’s a really old star – even older than my daddy!”
Isaac Wagstaff having his face painted
University astrophysicists, cosmologists and physics students were joined by Hampshire Astronomical Group, Airbus Defence & Space, Raspberry Pi Foundation, and the South Downs National Park Authority to talk to attendees, while staff and volunteers from HMS Warrior 1860 and Action Stations were on hand with activities on navigation and rockets.
Astronomical arts and crafts
Director of the Institute of Cosmology and Gravitation, Professor David Wands, said: “Our annual Stargazing event gives me and my academic colleagues the chance to share our excitement about cosmology with the local public, which makes for a fun-filled community occasion.”
HMS Warrior
Photos from the event can been seen on the ICG facebook page. Details of future public events will be posted to our website, and on twitter and facebook.
This news item is slightly edited from a University of Portsmouth press release, which also appears on phys.org.
Cosmologists trying to understand how to unite the two pillars of modern science – quantum physics and gravity – have found a new way to make robust predictions about the effect of quantum fluctuations on primordial density waves, ripples in the fabric of space and time.
Researchers from the University of Portsmouth have revealed quantum imprints left on cosmological structures in the very early Universe and shed light on what we may expect from a full quantum theory of gravity.
Dr Vincent Vennin, from the Institute of Cosmology and Gravitation said: “We haven’t solved quantum gravity but we’ve learnt a little more about how it would work.
“Physicists do not yet know how to combine theories of gravity and the quantum world. Yet both play a crucial role in the very early Universe where the expansion of space is driven by gravity and cosmological structures that arise from quantum fluctuations.
“Quantum fluctuations during inflation are thought to be the origin of all structure in the Universe. Structures we see today such as galaxies, stars, planets and people can be traced back to these primordial fluctuations.”
The paper is co-authored by Professor David Wands and Dr Hooshyar Assadullahi from the ICG and Hassan Firouzjahi and Mahdiyar Noorbala from the Institute for Research in Fundamental Sciences in Tehran. It was published today in the Physical Review Letters.
