J/A+A/706/A362 Tracing the high-z cosmic web with Quaia (Arsenov+, 2026)
Tracing the high-z cosmic web with Quaia:
Catalogues of voids and clusters in the quasar distribution.
Arsenov N., Kovacs A., Perez Sar M., Bogdan A.Sz., Sinigaglia F.,
Kitaura F.S., Favole G., Slavcheva-Mihova L.
<Astron. Astrophys. 706, A362 (2026)>
=2026A&A...706A.362A 2026A&A...706A.362A (SIMBAD/NED BibCode)
ADC_Keywords: Surveys ; QSOs ; Redshifts ; Optical
Keywords: catalogues - surveys - large-scale structure of Universe
Abstract:
Understanding the formation and evolution of the cosmic web of
galaxies is a fundamental goal of both theoretical and observational
cosmology, using various tracers of the cosmic large-scale structure
at an ever wider range of redshifts.
Our principal aim is to advance the mapping of the cosmic web at high
redshifts using observational and synthetic catalogues of quasars
(QSOs), which offer a powerful probe of structure formation and the
validity of the concordance cosmological model at the largest scales
in the Universe.
In this analysis, we selected 708483 quasars at 0.8<z<2.2 from the
Quaia data set, allowing an extended reconstruction of the matter
density field using 24372deg2 sky area with a well-understood
selection function, and thus going beyond the capacity of previous
studies. Using the REVOLVER method, we created catalogues of voids and
clusters based on the estimation of the local density at QSO positions
with Voronoi tessellation. We tested the consistency of Quaia data and
50 realistic mock catalogues, including various parameters of the
voids and clusters in characteristic subsets of the data, and also
measurements of the density profiles of these cosmic super-structures
at R≃100h-1Mpc scales.
We identified 12820 voids and 41154 clusters in the distribution of
Quaia quasars. We found ∼5-10% level agreement between data and the
ensemble of the 50 mocks considering void and cluster radii, average
inner density, and density profiles at all redshifts. In particular,
we tested the role of survey mask proximity effects in the void and
cluster detection, which although present in the data, are consistent
in simulations and observations. Testing the extremes, the largest
voids and clusters reach Reff≃250h-1Mpc and Reff≃150h-1Mpc,
respectively, but without evidence for ultra-large cosmic structures
exceeding the dimensions of the largest structures in our mock
catalogues.
Our data-analysis results highlight the capacity of Quaia quasars to
robustly map the high-z cosmic web, further supported by the fully
consistent statistical results from 50 mock catalogues. As an
important deliverable, we share our density field estimation, void
catalogues, and cluster catalogues with the public, allowing various
additional cross-correlation probes in the high-z cosmic web
Description:
We provide three catalogues as data products to our publication. The
catalogues are based on the Quaia catalogue of quasars (Storey-Fisher
et al., 2024ApJ...964...69S 2024ApJ...964...69S, Cat. J/ApJ/964/69) in which we find voids
and clusters by using the Revolver void finder. The catalogues
presented here are: a catalogue of 12820 voids in the Quaia data, a
catalogue of the 41154 clusters and a value-added catalogue to 708483
quasars, containing their spatial properties, e.g. its belonging to a
cluster or a void, its spatial density, flag for proximity to survey
edge and others.
voids.dat: Properties of the Quaia void catalogue using the REVOLVER
method. These columns describe the voids based on their size,
position, density and other relevant parameters.
clusters.dat: Properties of the Quaia cluster catalogue using the
REVOLVER method. These columns describe the clusters based on their
size, position, density and other relevant parameters.
vaddcat.dat: Value-added catalogue, created as a main result of the
publication. For all QSOs in our target redshift range and within the
survey mask, we combine information about their object ID, position,
local density, and association with a void or cluster in Quaia.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
voids.dat 118 12820 Voids Catalogue from Quaia (table A1)
clusters.dat 104 41154 Clusters catalogue from Quaia (table A1)
vaddcat.dat 317 708483 Value-added catalogue of quasars within Quaia
quasars in our analysis (table A2)
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See also:
J/ApJ/964/69 : Quaia, the Gaia-unWISE Quasar catalog (Storey-Fisher+, 2024)
Byte-by-byte Description of file: voids.dat
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Bytes Format Units Label Explanations
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1- 5 I5 --- ID ID of void, given by ZOBOV (ID)
7- 16 F10.6 deg RAdeg Right ascension (J2000) of void centre (ra)
18- 24 F7.3 deg DEdeg Declination (J2000) of void centre (dec)
26- 30 F5.3 --- z Quaia redshift of void centre (redshift)
32- 39 F8.4 Mpc ReffMPC Effective radius of void [Mpc/h] (Reffmpc)
41- 46 F6.3 --- dext Minimun cell of Voronoi cell in void (delta_ext)
48- 56 E9.6 --- davg Average density within the void (delta_avg)
58- 68 F11.6 --- lambda Average of density fluctuation,
deltaavg*Reff(mpc)1.2 (lambda)
70- 78 F9.6 --- DensRatio Density ratio of void (DensRatio)
80- 87 F8.6 deg Thetaeff Effective angular size of void (Theta_eff)
89 I1 --- EdgeFlag [0/1] 1 if close to the survey edge, else 0
(EdgeFlag)
91- 93 I3 --- Nmembers Number of quasars in void (Nmembers)
95-104 F10.6 deg RABdeg Right ascension of void bary-centre (ravbc)
106-112 F7.3 deg DEBdeg Declination of void bary-centre (decvbc)
114-118 F5.3 --- zB Quaia redshift of void bary-centre
(redshiftvbc)
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Byte-by-byte Description of file: clusters.dat
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Bytes Format Units Label Explanations
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1- 6 I6 --- ID ID of cluster, given by ZOBOV (ID)
8- 17 F10.6 deg RAdeg Right ascension (J2000) of cluster centre (ra)
19- 28 F10.6 deg DEdeg Declination (J2000) of cluster centre (dec)
30- 37 F8.6 --- z Quaia redshift of cluster centre (redshift)
39- 48 F10.6 Mpc ReffMpc Effective radius of cluster [Mpc/h]
(Reffmpc)
50- 58 F9.6 --- dext Maximum density of Voronoi cell in cluster
(delta_ext)
60- 68 E9.6 --- davg Average density within the cluster (delta_avg)
70- 80 F11.6 --- lambda Average of density fluctuation,
deltaavg*Reff(mpc)1.6 (lambda)
82- 90 F9.6 --- DensRatio Density ratio of cluster (DensRatio)
92- 99 F8.6 deg Thetaeff Effective angular size of cluster (Theta_eff)
101 I1 --- EdgeFlag [0/1] 1 if close to the survey edge, else 0
(EdgeFlag)
103-104 I2 --- Nmembers Number of quasars in cluster (Nmembers)
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Byte-by-byte Description of file: vaddcat.dat
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Bytes Format Units Label Explanations
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1- 11 F11.7 deg RAdeg Right ascension (J2000) (ra_qso)
13- 23 E11.2 deg DEdeg Declination (J2000) (dec_qso)
25- 33 F9.7 --- zqso Quaia redshift (z_qso)
35- 42 F8.5 --- Dens Normalized density around QSO (dens)
44- 51 F8.5 --- Volcorr Voronoi volume corrected for systematics
(vol_corr)
53 I1 --- f_VolDens [0/1] If Volcorr and Dens are good: 1,
else 0 (voldensflag)
55- 61 F7.5 --- Volnocorr Raw Voronoi volume of the QSO (vol_nocorr)
63- 69 F7.5 --- selfunc Quaia selection function value (sel_func)
71- 89 I19 --- GaiaDR3 Gaia DR3 source identifier (source_id)
91-109 A19 --- unWISE unWISE DR1 source identifier (unwise_objid)
111-117 F7.1 --- IDvoid ? Void ID, if the QSO is a member (ID_v)
119-127 F9.5 deg RAVdeg ? Right ascension (J2000) of void
circumcentre (ra_v)
129-135 F7.3 deg DEVdeg ? Declination (J2000) of void circumcentre
(dec_v)
137-141 F5.3 --- zvoid ? Redshift of void circumcentre (z_v)
143-151 F9.5 deg RABdeg ? Right ascension (J2000) of void
barycentre (ravbc)
153-159 F7.3 deg DEBdeg ? Declination (J2000) of void barycentre
(decvbc)
161-165 F5.3 --- zvoidbc ? Redshift of void barycentre (zvbc)
167-174 F8.4 Mpc ReffMpcvoid ? Effective radius of the parent void
[Mpc/h] (Reffmpc_v)
176-181 F6.3 --- dminvoid ? Minimum density within the parent void
(deltaminv)
183-190 E8.5 --- daavgvoid ? Average density within the parent void
(deltaavgv)
192-201 F10.5 --- lambdavoid ? deltaavg*Reffmpc**1.2 of parent void
(lambda_v)
203-209 F7.5 deg Thetaeffvoid ? Effective angular size of void
(Thetaeffv)
211-213 F3.1 --- EdgeFlagvoid [0/1]? Void edge flag (if close to edge:
0, else: 1) (EdgeFlag_v)
215-221 F7.5 --- RoverRvoid ? Relative QSO distance to void circumcentre
(RoverRv)
223-230 F8.1 --- IDcl ? Cluster ID, if the QSO is a member (ID_c)
232-240 F9.5 deg RACdeg ? Right ascension (J2000) of cluster
circumcentre (ra_c)
242-250 F9.5 deg DECdeg ? Declination (J2000) of cluster
circumcentre (dec_c)
252-258 F7.5 --- zcl ? Redshift of cluster circumcentre (z_c)
260-268 F9.5 Mpc ReffMPCcl ? Effective radius of parent cluster
[Mpc/h] (Reffmpc_c)
270-277 F8.5 --- dmaxcl ? Maximum density of a Voronoi cell in
cluster (deltamaxc)
279-286 E8.5 --- davgcl ? Average density within the parent cluster
(deltaavgc)
288-297 F10.5 --- lambdacl ? deltaavg*Reffmpc**1.6 of parent void
(lambda_c)
299-305 F7.5 Mpc Thetaeffcl ? Effective angular size of cluster
(Thetaeffc)
307-309 F3.1 --- EdgeFlagcl [0/1]? Cluster edge flag (edgec lose: 0,
else: 1) (EdgeFlag_c)
311-317 E7.5 --- RoverRc ? Relative QSO distance to cluster
circumcentre (RoverRc)
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Acknowledgements:
Nesto Arsenov, narsenov(at)nao-rozhen.org
(End) Patricia Vannier [CDS] 11-Dec-2025