ASTRA-DESI DR1 Release v0.7

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.

pairs/ – sparse list of target pairs used when counting neighbours.

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.

pairs/zone_REGION_pairs.fits.gz – neighbour pairs for the region.

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).

Random catalogues mirror the data counts for every tracer and random iteration.

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.

Pair catalogues (pairs/*.fits.gz)

Column
Type
Description

TARGETID1
int64
Central object in the neighbour pair.

TARGETID2
int64
Neighbour contributing to the count.

RANDITER
int32
-1 for data pairs, otherwise random catalogue index.

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.