J/MNRAS/497/2954 2MASS redshift survey galaxy group catalogue (Lambert+, 2020)
The 2MASS redshift survey galaxy group catalogue derived from a graph-theory
based friends-of-friends algorithm.
Lambert T.S., Kraan-Korteweg R.C., Jarrett T.H., Macri L.M.
<Mon. Not. R. Astron. Soc., 497, 2954-2973 (2020)>
=2020MNRAS.497.2954L 2020MNRAS.497.2954L (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, group ; Galaxy catalogs ; Positional data ;
Velocity dispersion ; Infrared
Keywords: catalogues - surveys - large-scale structure of Universe
Abstract:
We present the galaxy group catalogue for the recently completed 2MASS
Redshift Survey (2MRS; Macri et al. 2019ApJS..245....6M 2019ApJS..245....6M, Cat.
J/ApJS/245/6) which consists of 44572 redshifts, including 1041 new
measurements for galaxies mostly located within the Zone of Avoidance.
The galaxy group catalogue is generated by using a novel, graph-theory
based, modified version of the friends-of-friends algorithm. Several
graph-theory examples are presented throughout this paper, including a
new method for identifying substructures within groups. The results
and graph-theory methods have been thoroughly interrogated against
previous 2MRS group catalogues and a Theoretical Astrophysical
Observatory (TAO) mock by making use of cutting-edge visualization
techniques including immersive facilities, a digital planetarium, and
virtual reality. This has resulted in a stable and robust catalogue
with on-sky positions and line-of-sight distances within 0.5 and 2Mpc,
respectively, and has recovered all major groups and clusters. The
final catalogue consists of 3022 groups, resulting in the most
complete 'whole-sky' galaxy group catalogue to date. We determine the
3D positions of these groups, as well as their luminosity and comoving
distances, observed and corrected number of members, richness metric,
velocity dispersion, and estimates of R200 and M200. We present
three additional data products, i.e. the 2MRS galaxies found in
groups, a catalogue of subgroups, and a catalogue of 687 new group
candidates with no counterparts in previous 2MRS-based analyses.
Description:
The Friends-of-Friends (FoF) algorithm has been the canonical method
for identifying groups in magnitude-limited redshift-surveys because
of its simplicity. Although the core algorithm remains, for the most
part, unchanged from the original formalism by Huchra & Geller
(1982ApJ...257..423H 1982ApJ...257..423H), its subsequent applications to various
redshifts surveys have varied according to their wavelength coverage,
completeness, depth, and area.
We have developed our own, graph-theory-based, modification to the
traditional FoF algorithm in order to address most of its
shortcomings.
Our final 2MRS group catalogue contains 3022 entries and is the most
complete 'whole-sky' galaxy group catalogue to date. We provide
measured and calculated group properties, such as: 3D positions,
luminosity, and comoving distances, observed and corrected number of
members, richness metric, velocity dispersion, and estimates of R200
and M200.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 102 3022 2MRS galaxy group catalogue
table2.dat 49 338 2MRS subgroup catalogue
table3.dat 74 17262 2MRS group member catalogue
table4.dat 45 841 2MRS new galaxy group catalogue
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See also:
J/ApJS/245/6 : The 2RMS catalog in the Zone of Avoidance (Macri+, 2019)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- Group 2MRS group ID as defined in this work
6- 21 A16 --- OName Name of well-known groups and clusters in
other catalogues
23- 28 F6.2 deg RAdeg Right ascension (J2000)
30- 35 F6.2 deg DEdeg Declination (J2000)
37- 42 F6.2 deg GLON Galactic longitude
44- 49 F6.2 deg GLAT Galactic latitude
51- 53 I3 --- Nmem Number of 2MRS galaxies in the group
55- 57 I3 --- Nmemcor Corrected number of members (G1)
59 A1 --- l_Rich Limit flag on Rich
61- 62 I2 --- Rich Richness (1)
64- 68 I5 km/s vcmb Recession velocity in the CMB reference
frame
70- 74 F5.1 Mpc dC Co-moving distance
76- 80 F5.1 Mpc dL Luminosity distance
82- 84 I3 km/s RMS RMS based measurement of the velocity
dispersion of the group (2)
86- 88 I3 km/s sigma Velocity dispersion given by the standard
deviation of the velocities of members of
the group (2)
90- 93 F4.2 Mpc R200 Radius of the sphere with 200 times the
critical density
95- 100 F6.1 10+11Msun M200 Mass within the R200 sphere
102 I1 --- Nsubs Number of subgroups identified within the
main group
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Note (1): We define richness as the number of galaxies within a group with
absolute magnitude of MoK←23.5. This definition is maintained up
to 100Mpc where the survey is still reasonably complete. The richness
is still calculated for groups greater than 100Mpc but this value
would represent the minimum richness possible and is reported as such
in the final catalogue.
Note (2): We use two methods for calculating the velocity dispersion, namely
the standard deviation and the root mean square (RMS) of the peculiar
velocity distribution along the line of sight, described as:
vi=c(zi-z)/(1+z), where zi, z are the velocity of galaxy i and
the mean redshift of the galaxy group, respectively (Navarro, Frenk &
White 1995MNRAS.275...56N 1995MNRAS.275...56N; Jarrett et al. 2017ApJ...836..182J 2017ApJ...836..182J).
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- Subgroup Subgroup identifier (1)
8- 11 I4 --- Group 2MRS group ID as defined in this work
13- 18 F6.2 deg RAdeg Right ascension (J2000)
20- 25 F6.2 deg DEdeg Declination (J2000)
27- 32 F6.2 deg GLON Galactic longitude
34- 39 F6.2 deg GLAT Galactic latitude
41- 45 I5 km/s vcmb Recession velocity in the CMB reference frame
47- 49 I3 --- Nmem Number of 2MRS galaxies in the subgroup
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Note (1): The subgroup ID is made up of two parts, namely the host galaxy group
ID (the group to which said subgroup belongs) and the numbered
subgroup within said host group.
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 16 A16 --- Galaxy Galaxy name (HHMMSSss+DDMMSSs)
18- 26 F9.5 deg RAdeg Right ascension (J2000)
28- 36 F9.5 deg DEdeg Declination (J2000)
38- 46 F9.5 deg GLON Galactic longitude
48- 56 F9.5 deg GLAT Galactic latitude
58- 62 I5 km/s vcmb Recession velocity in the CMB reference frame
64- 67 I4 --- Group 2MRS group ID as defined in this work
69- 74 A6 --- Subgroup Subgroup identifier
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Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- Group 2MRS group ID as defined in this work
6- 11 F6.2 deg RAdeg Right ascension (J2000)
13- 18 F6.2 deg DEdeg Declination (J2000)
20- 25 F6.2 deg GLON Galactic longitude
27- 32 F6.2 deg GLAT Galactic latitude
34- 38 I5 km/s vcmb Recession velocity in the CMB reference frame
40- 41 I2 --- Nmem Number of 2MRS galaxies in the group
43- 45 I3 --- Nmemcor Corrected number of members (G1)
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Global Notes:
Note (G1): The number of corrected group members for a given group is calculated
as : Nmem,cor=Nmem(Nv/Nv(d)), where Nmem and Nv are the
number of members found in the given group and the number of members
found in Virgo, respectively. Nv(d) is the number of group members
that Virgo would have if it were at the same distance (d) of the
given group. This is strictly dependent on the luminosity function of
Virgo.
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History:
From electronic version of the journal
(End) Ana Fiallos [CDS] 26-Jul-2023