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Published April 6, 2026 | Version v11
Dataset Open

ASTRA-DESI DR1 Release v0.11

Authors/Creators

  • 1. Universidad Nacional de Colombia
  • 2. Universidad de Antioquia
  • 3. Universidad de los Andes

Description

ASTRA-DESI Data Release 1 (DR1)

This record bundles the ASTRA-DESI DR1 products for the two DESI survey regions (NGC1 and NGC2). Every catalogue is delivered as a compressed FITS binary table (.fits.gz) whose first extension (HDU 1) contains the data. File headers store the keywords RELEASE=DR1 and the corresponding ZONE label for quick checks.

The regions follow the sky boxes defined by Hou et al. (2025, arXiv:2508.09070):

  • NGC1 covers 110 ° < RA < 260 ° and -10 ° < DEC < 8 °;
  • NGC2 covers 180 ° < RA < 260 ° and 30 ° < DEC < 40 °.
Tracer Number of objects
BGS 240,986
LRG 102,199
ELG 67,456
QSO 87,307

Directory layout

The archive preserves the NERSC production tree. Top-level folders contain:

  • raw/ – merged real and random catalogues per region.
  • classification/ – neighbour count summaries per tracer and random iteration.
  • probabilities/ – web-type membership probabilities derived from the classification counts.
  • groups/ – watershed groups for a given tracer and region (NGC1 or NGC2).

Naming conventions

  • raw/zone_REGION.fits.gz – Region NGC1 or NGC2.
  • classification/zone_REGION_classified.fits.gz – combined tracer summary for the region.
  • probabilities/zone_REGION_probability.fits.gz – per-object web-type probabilities.
  • groups/TYPE_TRACER_REGION.fits.gz – per-object web-type groups.

Column reference

Raw catalogues (raw/*.fits.gz)

Column Type Description
TARGETID int64 DESI target identifier.
RA float64 Right ascension in degrees.
DEC float64 Declination in degrees.
Z float64 Spectroscopic redshift.
XCART, YCART, ZCART float64 Comoving Cartesian coordinates (Mpc) computed with the Planck18 cosmology.
TRACERTYPE string Tracer label with suffix _DATA or _RAND (BGS_BRIGHT, ELG, LRG, QSO).
RANDITER int32 -1 for real objects, otherwise the random iteration index (0–99).
SED_SFR float64 Star formation rate derived from SED fitting.
SED_MASS float64 Stellar mass derived from SED fitting.
FLUX_G float64 Observed flux in the g photometric band.
FLUX_R float64 Observed flux in the r photometric band.

Each raw file merges all tracers for its zone. Random catalogues mirror the data counts for every tracer and random iteration. 

Additional columns SED_SFR, SED_MASS, FLUX_G, and FLUX_R were incorporated from the DESI EDR value-added catalogues associated with the emission-line sample: https://data.desi.lbl.gov/doc/releases/dr1/vac/stellar-mass-emline/. These quantities are derived via SED fitting using CIGALE (Zou et al. 2024).

Classification catalogues (classification/*.fits.gz)

Column Type Description
TARGETID int64 Identifier of the central object.
RANDITER int32 -1 for data rows, otherwise the random catalogue index.
ISDATA bool True for data rows; False for random iterations.
NDATA int32 Number of neighbour pairs built from data tracers for this target.
NRAND int32 Number of neighbour pairs contributed by random tracers.
TRACERTYPE string Tracer family (BGS_BRIGHT, ELG, LRG, QSO).

Probability catalogues (probabilities/*.fits.gz)

Column Type Description
TARGETID int64 Identifier of the object.
TRACERTYPE string Tracer family.
PVOID float32 Probability of the object being a void class.
PSHEET float32 Probability of the sheet class.
PFILAMENT float32 Probability of the filament class.
PKNOT float32 Probability of the knot class.

Watershed group catalogues

Each file contains a primary header plus two binary-table extensions:

  • HDU 1: VOIDS (one row per retained group).
  • HDU 2: POINT_MEMBERSHIP (one row per data/random point).

Primary-header keywords include TRACER, CAP, NVOIDS, H, OMEGA_M, RTHRESH, and WMODE.

- Group catalogues (VOIDS, HDU 1)

Column Type Description
VOID_ID int32 Group identifier.
N_DATA_IN_GROUP int32 Number of data members in the group.
N_RAND_IN_GROUP int32 Number of random members in the group.
RA float64 Group center right ascension (deg).
DEC float64 Group center declination (deg).
REDSHIFT float64 Redshift of the group center from comoving-distance inversion.
X, Y, Z float64 Group center Cartesian coordinates (Mpc/h).
R_EFF float64 Effective RMS radius of members around the group center (Mpc/h).
SEMI_AXIS_A, SEMI_AXIS_B, SEMI_AXIS_C float64 Principal semi-axes from the inertia tensor (Mpc/h).
ELLIP float32 Ellipticity, defined as 1 - C/A.

- Point membership (POINT_MEMBERSHIP, HDU 2)

Column Type Description
NODE_INDEX int32 Internal index in the combined data+random graph.
TARGETID int64 DESI target identifier.
IS_DATA int8 1 for data rows, 0 for random rows.
GROUPID int32 Assigned watershed group ID; -1 means unassigned.
VOID_CLASS_ID int8 Reserved class field (default -1).
VOID_CLASS string Reserved class label (default unknown).
R float32 Local contrast statistic.
N_DATA int32 Number of data neighbours.
N_RAND int32 Number of random neighbours.
RA, DEC, Z float64 Sky coordinates and redshift of each point.
X_CART, Y_CART, Z_CART float64 Cartesian coordinates (Mpc/h).

Using the catalogues

  • All FITS tables are compressed with gzip.
  • Random catalogues use RANDITER values 0–99; filtering on RANDITER >= 0 isolates the random iterations.
  • The Cartesian coordinates assume the Planck18 cosmology provided by astropy.cosmology.Planck18.

Files

Files (3.5 GB)

Name Size
md5:1f79871682804b366f80a8f1edb287e1
776.8 MB Download
md5:ba144757e152b57aebf72ebd2c52e637
60.0 MB Download
md5:74c154d45d9669c0cdc4086255d6a8bf
4.8 MB Download
md5:13ded32c924725ac0ebc11c6e13f4d48
2.7 GB Download

Additional details

Related works

Cites
Journal article: 10.1093/rasti/rzaf032 (DOI)
Preprint: arXiv:2604.01456 (arXiv)
Is supplemented by
Preprint: arXiv:2503.14745 (arXiv)

Software

Repository URL
https://github.com/forero/ASTRA-DESI
Programming language
Python , Shell
Development Status
Active