HDU4
XTENSION= ‘IMAGE ‘ / Image extension
BITPIX = -64 / array data type
NAXIS = 4 / number of array dimensions
NAXIS1 = 4563 / flux
NAXIS2 = 8 / x array (low-mass IMF slope s)
NAXIS3 = 9 / metallicity array
NAXIS4 = 24 / age array
PCOUNT = 0 / number of parameters
GCOUNT = 1 / number of groups
EXTNAME = ‘FLUX_MATRIX’ / extension name
Z_GRID = 9 / -2.25,-1.8,-1.35,-1,-0.7,-0.33,0,0.2,0.35
T_GRID = 24 / 0.1-1.0 (steps of 0.1), 1-15 (steps of 1)
X_GRID = 8 / 0.3, 0.8, 1.3, 1.8, 2.35, 2.8, 3.3, 3.8
Z_UNIT = ‘dex ‘ / unit of metallicity
T_UNIT = ‘Gyr ‘ / unit of age
F_UNIT = ‘erg/s/A/Msun’ / unit of flux
STEL_PAR= ’empirical’ / stellar parameter calculations
STEL_REF= ‘Chen et al (2020)’ / reference
END
