The DESI Extragalactic Dwarf Galaxy Catalog¶
Overview¶
This catalog presents a sample of extragalactic dwarf galaxies (\(M_{\text{star}} \lesssim 10^9 M_{\text{sun}}\)) identified in DESI DR1. The catalog includes galaxies selected from BGS, ELG, and the LOW-Z Secondary Target Program, spanning a redshift range of \(0.001 < z < 0.5\). However, due to differences in target selection criteria across these samples, the catalog is not uniformly selected. Stellar masses are derived using CIGALE (Boquien et al. 2019, Siudek et al. 2024) and optical color based prescriptions (Mao et al. 2024, de lo Reyes 2024).
Various cleaning cuts are applied on the DESI photometric catalogs to identify spurious sources (e.g., shreds of larger galaxies) and then remeasure their photometry. In two forthcoming papers (Manwadkar et al. 2025a,b in preparation), details will be provided on the selection, cleaning and method for remeasuring photometry. In these papers, we will also supplement this catalog with information on spectroscopic and photometric completeness, detected anomalies in imaging/spectra, and an analysis of quenched fractions as a function of environment.
Data Access¶
Data URL: https://data.desi.lbl.gov/public/dr1/vac/dr1/extragalactic-dwarfs
NERSC access:
/global/cfs/cdirs/desi/public/dr1/vac/dr1/extragalactic-dwarfs
Documentation¶
Files¶
desi_dwarfs_y1_catalog.fits: Catalog of extragalactic dwarfs in DESI and their photometric parameters.
Data Model¶
EXTNAME = EG_DWARFS
| Name | Type | Units | Description |
|---|---|---|---|
TARGETID |
int64 | - | Unique identifier for the object |
SURVEY |
string | - | Survey name |
PROGRAM |
string | - | Program name |
HEALPIX |
int64 | - | Healpix number |
RA |
float64 | deg | Right ascension from target catalog |
DEC |
float64 | deg | Declination from target catalog |
BGS_TARGET |
int64 | - | BGS targeting bit |
SCND_TARGET |
int64 | - | Secondary targeting bit |
Z |
float64 | - | Redshift based on Redrock |
ZWARN |
int64 | - | Redrock zwarning bit |
DELTACHI2 |
float64 | - | Redrock delta-chi-squared |
SPECTYPE |
string | - | Redrock spectral classification type |
FIBERFLUX_{G,R,Z} |
float64 | nanomaggy | Fiber flux not corrected for Galactic extinction |
FLUX_{G,R,Z} |
float64 | nanomaggy | Flux corrected for Galactic extinction (AB system) |
FLUX_IVAR_{G,R,Z} |
float64 | nanomaggy^-2 | Inverse variance of flux corrected for Galactic extinction. |
MAG_{G,R,Z} |
float64 | mag | Magnitude corrected for Galactic extinction |
MAG_ERR_{G,R,Z} |
float64 | mag | magnitude error corrected for Galactic extinction |
FLUX_{W1,W2,W3,W4} |
float64 | nanomaggy | Flux corrected for Galactic extinction (AB system) |
FLUX_IVAR_{W1,W2,W3,W4} |
float64 | nanomaggy^-2 | Inverse variance of flux corrected for Galactic extinction. |
MAG_{W1,W2} |
float64 | mag | Magnitude corrected for Galactic extinction |
MAG_ERR_{W1,W2} |
float64 | mag | Magnitude error corrected for Galactic extinction |
EBV |
float64 | mag | Galactic extinction E(B-V) reddening from SFD98 |
MW_TRANSMISSION_{G,R,Z} |
float64 | - | Galactic transmission in linear units [0,1] |
MW_TRANSMISSION_{W1,W2,W3,W4} |
float64 | - | Galactic transmission in linear units [0,1] |
OBJID |
int64 | - | Catalog object number within this brick |
BRICKNAME |
string | - | Name of brick, encoding the brick sky position, eg “1126p222” near RA=112.6, Dec=+22. |
FRACFLUX_{G,R,Z} |
float64 | - | Profile-weighted fraction of the flux from other sources divided by the total flux of source |
SHAPE_R |
float64 | arcsec | Half-light radius of galaxy model |
SHAPE_R_ERR |
float64 | arcsec | Error in half-light radius of galaxy model |
MU_R |
float64 | mag/arcsec^2 | Effective surface brightness |
MU_R_ERR |
float64 | mag/arcsec^2 | Effective surface brightness error |
SERSIC |
float64 | - | Power-law index for the Sersic profile model |
SERSIC_IVAR |
float64 | - | Inverse variance of SERSIC |
BA |
float64 | - | Semi-minor to semi-major axis ratio |
TYPE |
string | - | Morphological model type |
PHI |
float64 | deg | Position angle (range of 180\(^{\circ}\)) |
FIBERMAG_R |
float64 | mag | Fiber magnitude in r-band not corrected for Galactic extinction |
LOGM_CIGALE |
float64 | log(solMass) | Stellar mass from CIGALE |
LOGM_ERR_CIGALE |
float64 | log(solMass) | Stellar mass error from CIGALE |
AGNFRAC_CIGALE |
float64 | - | Fraction of luminosity from AGN from CIGALE |
LOGSFR_CIGALE |
float64 | log(solMass/yr) | SFR form CIGALE |
LOGSFR_ERR_CIGALE |
float64 | log(solMass/yr) | Error in SFR from CIGALE |
FLAGINFRARED_CIGALE |
int64 | - | Flag indicating SNR of infrared data. AGNFRAC is well constrained if FLAGINFRARED \(\geq 3\) |
LOGM_SAGA |
float64 | log(solMass) | Stellar mass from optical-color based prescripton in Mao et al. 2024 |
SAMPLE |
string | - | Sub-sample source is part of (e.g., BGS Bright, LOW-Z) |
SGA_NORM_D26_DIST |
float64 | - | Angular distance to nearest SGA source in units of distance normalized to D26 aperture |
APERTURE_PHOTOMETRY_DONE |
int64 | - | Equal to 1 if photometry was remesured. Otherwise equal to 0. |
LOGM_SAGA_APER |
float64 | log(solMass) | Updated stellar mass after remeasuring photometry |
MAG_{G,R,Z}_APER |
float64 | mag | Remeasured magnitude from aperture photometry |
NEAREST_STAR_DIST |
float64 | arcsec | Distance to nearest star in Gaia DR2 to source. Measured only for objects whose photometry was remeasured (otherwise equal to -99) |
MAG_{G,R,Z}_UPDATED |
float64 | mag | Final magnitude for source |
Contact¶
Contact Viraj Manwadkar for questions about this catalog.