Galaxy quantities for Roman-Rubin joint simulation
Data are partitioned by (nside=32, ring ordering) healpixel. For each pixel there is a so-called “main file” (with information largely coming from the diffsky galaxy catalog), a flux file and a SED file. The flux file contains for each object only fluxes for lsst and Roman bands and the object id so it can be joined with the main file. Both it and the main file are parquet files. The SED file is in hdf5 format. The file names take the form galaxy_<hp>.parquet (main file), galaxy_flux_<hp>.parquet (flux file) and galaxy_sed_<hp>.hdf5 for SED files. In all cases <hp> is the id of the healpixel covered by the file.
Galaxy main file
Name |
Datatype |
Units |
Description |
|---|---|---|---|
galaxy_id |
int64 |
N/A |
Unique object identifier |
ra |
double |
degrees |
Object right ascension |
dec |
double |
degrees |
Object declination |
redshift |
double |
N/A |
Cosmological redshift with line-of-sight motion |
redshiftHubble |
double |
N/A |
Cosmological redshift |
peculiarVelocity |
double |
km/sec |
Peculiar velocity |
shear1 |
double |
N/A |
Shear (gamma) component 1, treecorr/Galsim convention |
shear2 |
double |
N/A |
Shear (gamma) component 2, treecorr/Galsim convention |
convergence |
double |
N/A |
Convergence (kappa) |
spheroidHalfLightRadiusArcsec |
float |
arcsec |
Bulge component half-light radius |
diskHalfLightRadiusArcsec |
float |
arcsec |
Disk component half-light radius |
diskEllipticity1 |
double |
N/A |
Ellipticity component 1 for disk, not lensed |
diskEllipticity2 |
double |
N/A |
Ellipticity component 2 for disk, not lensed |
spheroidEllipticity1 |
double |
N/A |
Ellipticity component 1 for bulge, not lensed |
spheroidEllipticity2 |
double |
N/A |
Ellipticity component 2 for bulge, not lensed |
um_source_galaxy_obs_sm |
float |
solar mass (h=0.7) |
Stellar mass |
MW_rv |
float |
N/A |
Extinction parameter |
MW_av |
float |
N/A |
Extinction parameter from F19 dust map |
Galaxy flux file
Name |
Datatype |
Units |
Description |
|---|---|---|---|
galaxy_id |
int64 |
N/A |
Unique object identifier |
lsst_flux_u |
float |
photons/sec/cm^2 |
Flux integrated over lsst u-band |
lsst_flux_g |
float |
photons/sec/cm^2 |
Flux integrated over lsst g-band |
lsst_flux_r |
float |
photons/sec/cm^2 |
Flux integrated over lsst r-band |
lsst_flux_i |
float |
photons/sec/cm^2 |
Flux integrated over lsst i-band |
lsst_flux_z |
float |
photons/sec/cm^2 |
Flux integrated over lsst z-band |
lsst_flux_y |
float |
photons/sec/cm^2 |
Flux integrated over lsst y-band |
roman_flux_W146 |
float |
photons/sec/cm^2 |
Flux integrated over roman W146-band |
roman_flux_R062 |
float |
photons/sec/cm^2 |
Flux integrated over roman R062-band |
roman_flux_Z087 |
float |
photons/sec/cm^2 |
Flux integrated over roman Z087-band |
roman_flux_Y106 |
float |
photons/sec/cm^2 |
Flux integrated over roman Y106-band |
roman_flux_J129 |
float |
photons/sec/cm^2 |
Flux integrated over roman J129-band |
roman_flux_H158 |
float |
photons/sec/cm^2 |
Flux integrated over roman H158-band |
roman_flux_F184 |
float |
photons/sec/cm^2 |
Flux integrated over roman F184-band |
roman_flux_K213 |
float |
photons/sec/cm^2 |
Flux integrated over roman K213-band |
Galaxy SED file
This file has two sections. One (meta) has an array wave_list, shape(312), of wavelengths (angstroms), which is used for SEDs of all galaxies in the file’s healpixel. The other section, galaxy, contains groups of galaxies. Each group has entries for individual galaxies, keyed by galaxy id. Such an entry is an array, shape(3, 312), consisting of SEDs for the three galaxy components (disk, bulge, knot). Units are fnu.