ELVES Surveys

ELVES-Dwarf · Public data

Data documentation

Documentation for the public ELVES-Dwarf data products, with guidance on file contents, data access and usage, and definitions of all columns and fields.

Back to ELVES-Dwarf
Release
v1
Date
2026-08-30
Products
3
Cite
Li et al. 2026, in prep.

Learn with the data

Tutorial notebooks

Short, reproducible examples that use the same public files documented below. Read the executed notebook on this site, download it, or open it in Google Colab.

Calculate satellite quenched fraction

Build a confirmed-satellite sample, apply the color--magnitude quenching criterion, and calculate binned quenched fractions with Jeffreys binomial intervals.

View notebook Download .ipynb Open in Colab

Catalog

Host catalog

Properties of the ELVES-Dwarf host galaxies. Please see Table 1 of Li et al. 2026 for the description and the full reference list.

Format
FITS binary table
Rows
39
Columns
21
File size
17 KB
Download
Download file ELVES-Dwarf_host_cat_v1.fits 
from astropy.table import Table

cat = Table.read("ELVES-Dwarf_host_cat_v1.fits")
print(cat.colnames)

Columns

Column Type Unit Description
name string (10 chars) — Host galaxy name.
ra float64 deg Right ascension (J2000).
dec float64 deg Declination (J2000).
isolated boolean — True if the host passes the ELVES-Dwarf isolation criterion.
has_isolation boolean — True if the host galaxy has tidal indices from Karachentsev (2013).
dist_mpc float64 Mpc Adopted host distance.
dist_err_mpc float64 Mpc Uncertainty on the adopted distance.
dist_method string (4 chars) — Distance indicator used. Values: TRGB, SBF, Ceph.
v_h_km_s float64 km/s Heliocentric radial velocity.
theta1 float64 — Tidal index, considering the influence of the most dominant perturber. Negative values indicate that the host is isolated.
theta5 float64 — Tidal index, considering the influence of the five most dominant perturbers. Negative values indicate that the host is isolated.
log_l_ks_lsun float64 dex (L_sun) Log of the K_s-band luminosity.
M_V float64 mag Absolute V-band magnitude.
g_r_0 float64 mag Extinction-corrected g - r color.
log_mstar_msun float64 dex (M_sun) Log stellar mass.
log_mstar_err float64 dex Uncertainty on the log stellar mass.
rvir_kpc float64 kpc Adopted virial radius.
area_deg2 float64 deg2 Sky area searched around the host.
frac_unmasked float64 — Fraction of the searched area left unmasked.
data_source string (32 chars) — Provenance of the imaging or of the literature satellite list.
reference string (36 chars) — Reference for the adopted host distance.

Catalog

Satellite candidate catalog

Catalog of all satellite candidates in ELVES-Dwarf. Please see Table 3 of Li et al. 2026 for the description and the full reference list.

Format
FITS binary table
Rows
207
Columns
34
File size
177 KB
Download
Download file ELVES-Dwarf_master_cat_v1.fits 
from astropy.table import Table

cat = Table.read("ELVES-Dwarf_master_cat_v1.fits")
print(cat.colnames)

Columns

Column Type Unit Description
name string (13 chars) — Satellite candidate name.
ra float64 deg Right ascension (J2000).
dec float64 deg Declination (J2000).
host string (10 chars) — Host galaxy name; joins to "name" in the host catalog.
host_dist float64 Mpc Distance of the host galaxy.
followup string (9 chars) — Follow-up data used to decide membership. Values: TRGB, Velocity, HSC-LA, HSC-SMOKA, CFHT, GMOS, IMACS, None
distance float64 Mpc Measured distance of the candidate, where available. For SBF, this is the median of the posterior distribution.
status string (12 chars) — Membership classification. Values: Confirmed, Rejected, Unconfirmed, Not Observed
reff_sersic float64 arcsec Sersic effective radius.
err_reff_sersic float64 arcsec Uncertainty on the Sersic effective radius.
m_g_sersic float64 mag Sersic apparent g-band magnitude.
err_m_g_sersic float64 mag Uncertainty on the Sersic g-band magnitude.
m_V_sersic float64 mag Sersic apparent V-band magnitude.
err_m_V_sersic float64 mag Uncertainty on the Sersic V-band magnitude.
mu_eff_g float64 mag/arcsec2 Mean g-band surface brightness within the effective radius.
mu_0_V float64 mag/arcsec2 Central V-band surface brightness.
gr_sersic float64 mag Sersic g - r color.
err_gr_sersic float64 mag Uncertainty on the Sersic g - r color.
gi_sersic float64 mag Sersic g - i color.
n_sersic float64 — Sersic index.
ell_sersic float64 — Ellipticity, 1 - b/a.
log_m_star float64 dex (M_sun) Log stellar mass.
err_log_m_star float64 dex Uncertainty on the log stellar mass.
velocity float64 km/s Radial velocity, where available.
dist_1sigma float64 array (2) Mpc Lower and upper bounds of the 68% distance interval.
dist_2sigma float64 array (2) Mpc Lower and upper bounds of the 95% distance interval.
dist_SNR float64 — Signal-to-noise of the distance measurement.
dist_comment string (454 chars) — Free-text note on the distance measurement.
dist_method string (4 chars) — Distance indicator used. Values: TRGB, SBF, Vel, Ceph
ang_proj_kpc float64 kpc Projected separation from the host.
ang_proj_Rvir float64 — Projected separation in units of the host virial radius.
Psat float64 — Satellite probability (see paper for details).
completeness float64 — Estimated detection completeness.
reference string (35 chars) — Literature reference(s) for the candidate.

File set

Survey footprints

Sky coverage of the imaging searched around each ELVES-Dwarf host, as a polygon per host. Provided both as GeoJSON (for programmatic use) and as a DS9 region file (for overlaying on images).

Format
GeoJSON + DS9 region
Hosts
32
File size
49 KB (64 files)
Download
Download file ELVES-Dwarf_survey_footprint_v1.zip 
import json

with open("DDO046_survey_footprint.geojson") as f:
    fp = json.load(f)

print(fp["metadata"])
ring = fp["features"][0]["geometry"]["coordinates"][0]  # [[ra, dec], ...]

Footprint viewer

Loading…
  • Search footprint
  • Virial radius
  • Host
  • Confirmed
  • Unconfirmed
  • Rejected

Files

File Format Description
<host>_survey_footprint.geojson GeoJSON (ICRS / fk5, degrees) FeatureCollection with a "metadata" block and one Polygon feature per contributing survey; ring coordinates are [RA, Dec] pairs in degrees.
<host>_survey_footprint.reg DS9 region file (fk5) The same polygons as DS9 regions, with the metadata repeated in header comment lines. Loads directly in DS9, and readable with the "regions" package.

GeoJSON metadata

Field Type Unit Description
host string — Host galaxy name; joins to "name" in the host catalog.
ra float deg Right ascension of the host (J2000).
dec float deg Declination of the host (J2000).
bands array of string — Imaging bands covering the footprint (e.g. ["g", "r"]).
r_ang_deg float deg Angular radius of the search region around the host.
distance_Mpc float Mpc Adopted host distance used to set the search radius.
surveys array of string — Imaging surveys contributing to the footprint.
Individual files (32 hosts)

General

Notes