Galaxy quantities for ops-rehearsals 3 and 4
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 cosmodc2 galaxy catalog) and a flux file. The latter contains for each object only fluxes for lsst bands and the object id so it can be joined with the main file. Both are parquet files. The main file can be rather large (over 3 Gbytes) so, depending on your application, you may want to iterate over row groups rather than reading it all in at once.
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 |
redshift_hubble |
double |
N/A |
Cosmological redshift |
peculiar_velocity |
double |
km/sec |
Peculiar velocity |
shear_1 |
double |
N/A |
Shear (gamma) component 1, treecorr/Galsim convention |
shear_2 |
double |
N/A |
Shear (gamma) component 2, treecorr/Galsim convention |
convergence |
double |
N/A |
Convergence (kappa) |
size_bulge_true |
float |
arcsec |
Bulge half-light radius (major axis) not lensed |
size_minor_bulge_true |
float |
arcsec |
Bulge half-light radius (minor axis) not lensed |
sersic_bulge |
float |
N/A |
Sersic index of bulge light profile |
size_disk_true |
float |
arcsec |
Disk half-light radius (major axis) not lensed |
size_disk_bulge_true |
float |
arcsec |
Disk half-light radius (minor axis) not lensed |
sersic_disk |
float |
N/A |
Sersic index of disk light profile |
ellipticity_1_disk_true |
double |
N/A |
Ellipticity component 1 for disk, not lensed |
ellipticity_2_disk_true |
double |
N/A |
Ellipticity component 2 for disk, not lensed |
ellipticity_1_bulge_true |
double |
N/A |
Ellipticity component 1 for bulge, not lensed |
ellipticity_2_bulge_true |
double |
N/A |
Ellipticity component 2 for bulge, not lensed |
sed_val_bulge |
list(double) |
4.4659e13 W/Hz |
Integrated rest-frame AB luminosities for tophat filters (bulge component) |
sed_val_disk |
list(double) |
4.4659e13 W/Hz |
Like sed_val_bulge |
bulge_magnorm |
double |
N/A |
Normalization for SED |
disk_magnorm |
double |
N/A |
Normalization for SED |
MW_rv |
float |
N/A |
Extinction parameter |
MW_av |
float |
N/A |
Extinction parameter from F19 dust map |
sed_val_knots |
list(double) |
4.4659e13 W/Hz |
Like sed_val_bulge |
n_knots |
float |
N/A |
Number of knots |
knots_magnorm |
double |
N/A |
Normalization for SED |
NOTE: For tophat definitions (start and width in units of angstroms) see yaml config file associated with the data.
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 |