ISSN 1990-3413, Astrophysical Bulletin, 2018, Vol. 73, No. 2, pp. 111–123.
Pleiades Publishing, Ltd., 2018.
Published in Russian in Astroﬁzicheskii Byulleten’, 2018, Vol. 73, No. 2, pp. 115–128.
The Excess Density of Field Galaxies near z ∼ 0.56 around the
Gamma-Ray Burst GRB 021004 Position
I. V. Sokolov
I. A. Solovyev
, O. V. Verkhodanov
, and V. V. S o kolov
Institute of Astronomy, Russian Academy of Sciences, Moscow, 119017 Russia
Stellar Physics Department, Institute for Astrophysics of Andalucia, Granada, 18080 Spain
Special Astrophysical Observatory, Russian Academy of Sciences, Nizhnii Arkhyz, 369167 Russia
ITMO University, St. Petersburg, 197101 Russia
Astronomical Department, St. Petersburg State University, St. Petersburg, 199034 Russia
Received June 22, 2017; in ﬁnal form, April 24, 2018
Abstract—We test for reliability any signatures of ﬁeld galaxies clustering in the GRB 021004 line of
sight. The ﬁrst signature is the GRB 021004 ﬁeld photometric redshifts distribution based on the 6-m
telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences observations
with a peak near z ∼ 0.56 estimated from multicolor photometry in the GRB direction. The second
signature is the Mg II λλ2796, 2803
A absorption doublet at z ≈ 0.56 in VLT/UVES spectra obtained
for the GRB 021004 afterglow. The third signature is the galaxy clustering in a larger (of about 3
area around GRB 021004 with an eﬀective peak near z ∼ 0.56 for both the spectral and photometric
redshifts from a few catalogs of clusters based on the Sloan Digital Sky Survey (SDSS) and Baryon
Oscillation Spectroscopic Survey (BOSS) as a part of SDSS-III. From catalog data the size of the whole
inhomogeneity in distribution of the galaxy cluster with the peak near z ≈ 0.56 was also estimated as about
or 140–190 Mpc. A possibility of inhomogeneity (a galaxy cluster) near the GRB 021004 direction
can be also conﬁrmed by an inhomogeneity in cosmic microwave background related with the Sunyaev–
Key words: cosmology: observations—large scale structure of Universe—galaxies: distances and
redshifts —gamma-ray burst: individual: GRB 021004
The main motivation in conducting this work is a
number of additional new studies on the Great Walls
in increasing order of redshift z:
• Paper  deals with the Sloan Great Wall su-
perclusters in the redshift range 0.04 <z<0.12.
The authors explore how unusual are the Shap-
ley Supercluster (with z =0.046)andtheSloan
Great Wall, considering the Sloan Great Wall as a
complex of superclusters with collapsing cores .
In these papers the distribution of galaxy groups
in the Sloan Great Wall superclusters in the sky
plane is studied in detail.
• The BOSS Great Wall superclusters in the red-
shift range 0.43 <z<0.71 were studied in pa-
The text was submitted by the authors in English.
per , it deals with discovery of a massive su-
percluster system at z ∼ 0.47. The BOSS Great
Wall consists of two walls with diameters about
186 Mpc and 173 Mpc, and two other major su-
perclusters with diameters of about 64 Mpc and
91 Mpc. This system consists of 830 galaxies with
the mean z =0.47 and with the total mass appro-
ximately 2 × 10
. The authors emphasize that
the morphology of the superclusters in the BOSS
Great Wall system is similar to the morphology of
the superclusters in the Sloan Great Wall.
• Paper  concerns some new Large Quasar Group
(Huge-LQG) at z ∼ 1.3. It was the study of sky
distribution of 73 quasars (z =1.27)ofthenew
Huge-LQG, together with that of 34 quasars of
the Clowes–Campusano Large Quasar Group
(CCLQG) with z =1.28 . Huge-LQG is the
area of about 29.5
. The members of