HDU1
XTENSION= ‘IMAGE ‘ / Image extension
BITPIX = -64 / array data type
NAXIS = 4 / number of array dimensions
NAXIS1 = 3 / parameters (age, metallicity, IMF slope s)
NAXIS2 = 8 / s array (low-mass IMF slope)
NAXIS3 = 9 / metallicity array
NAXIS4 = 24 / age array
PCOUNT = 0 / number of parameters
GCOUNT = 1 / number of groups
EXTNAME = ‘PARA_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)
S_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
END
