J/AJ/154/96 Groups of galaxies from from SDSS-DR7 (de Carvalho+, 2017)
Investigating the relation between galaxy properties and the Gaussianity of the
velocity distribution of groups and clusters.
de Carvalho R.R., Ribeiro A.L.B., Stalder D.H., Rosa R.R., Costa A.P.,
Moura T.C.
<Astron. J., 154, 96-96 (2017)>
=2017AJ....154...96D 2017AJ....154...96D (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, galaxy ; Redshifts ; X-ray sources
Keywords: evolution - galaxies: clusters: general - galaxies: formation -
galaxies: groups: general
Abstract:
We investigate the dependence of stellar population properties of
galaxies on group dynamical stage for a subsample of the Yang catalog.
We classify groups according to their galaxy velocity distribution
into Gaussian (G) and Non-Gaussian (NG). Using two totally independent
approaches, we have shown that our measurement of Gaussianity is
robust and reliable. Our sample covers Yang's groups in the redshift
range 0.03≤z≤0.1, with mass ≥1014M☉. The new method,
called Hellinger Distance, to determine whether a group has a velocity
distribution Gaussian or NG is very effective in distinguishing
between the two families. NG groups present halo masses higher than
the G ones, confirming previous findings. Examining the skewness and
kurtosis of the velocity distribution of G and NG groups, we find that
faint galaxies in NG groups are mainly infalling, for the first time,
into the groups. We show that considering only faint galaxies in the
outskirts; those in NG groups are older and more metal-rich than those
in G groups. Also, examining the Projected Phase Space of cluster
galaxies, we see that bright and faint galactic systems in G groups
are in dynamical equilibrium-which does not seem to be the case in NG
groups. These findings suggest that NG systems have a higher infall
rate, assembling more galaxies that have experienced preprocessing
before entering the group.
Description:
To study the updated group catalog of Yang et al.
(2007ApJ...671..153Y 2007ApJ...671..153Y), we select galaxies from SDSS-DR7 (see
Adelman-McCarthy et al. 2009, Cat. II/294) with 0.03≤z≤0.1 and r
magnitudes brighter than 17.78, which is the spectroscopic
completeness limit of the survey, guaranteeing that we probe the
luminosity function up to M*+1 for all systems. The lower limit in
redshift is imposed to avoid aperture effects in the stellar
population parameters measured within a fixed aperture of 3arcsec
(diameter) used in the SDSS.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 49 319 Group sample
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See also:
V/147 : The SDSS Photometric Catalogue, Release 12 (Alam+, 2015)
II/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009)
J/ApJ/776/71 : Galaxies in groups along the cosmic web. I. (Carollo+, 2013)
J/A+A/542/A36 : Rich clusters from SDSS DR8 (Einasto+, 2012)
J/A+A/540/A123 : Galaxy clusters from SDSS DR8 (Einasto+, 2012)
J/A+A/425/367 : REFLEX Galaxy Cluster Survey catalogue (Boehringer+, 2004)
J/ApJS/129/435 : NORAS galaxy cluster survey. I. (Bohringer+, 2000)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 6 I6 --- Yang [2/665] Identification number of the galaxy
group in Yang et al. 2007ApJ...671..153Y 2007ApJ...671..153Y
8- 15 F8.4 deg RAdeg Right Ascension in decimal degrees (J2000)
17- 24 F8.4 deg DEdeg Declination in decimal degrees (J2000)
26- 30 F5.3 --- [0.03/0.1] Mean redshift of the group (1)
32- 36 F5.2 [Msun] logM200 [13.3/15.8] Log of dynamical mass (M200) (2)
38- 41 F4.2 Mpc R200 [0.45/2.73] Virial radius (R200) (2)
43- 45 I3 --- N200 [20/525] Number of member galaxies within
R200, down to the limiting magnitude of the
catalog, NR200 (3)
47 A1 --- BAX [NY] Group having X-ray counterparts in BAX
(http://bax.ast.obs-mip.fr/) (4)
49 A1 --- N/R [NY] Group having X-ray counterparts in NORAS
and/or REFLEX (5)
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Note (1): As measured with the shift-gapper technique.
Note (2): As obtained through the shift-gapper algorithm and dynamical analysis.
Note (3): Only systems richer than 20 galaxies (within R200) are used in this
work (see Section 3.1 for more details on why we choose this lower limit).
Note (4): BAX is an online research database containing information on all
galaxy clusters with X-ray observations to date.
Note (5): NORAS (Northern ROSAT All-Sky; Bohringer et al. 2000,
Cat. J/ApJS/129/435), and REFLEX (ROSAT-ESO Flux-limited X-ray; Bohringer
et al. 2004, Cat. J/A+A/425/367).
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History:
From electronic version of the journal
(End) Sylvain Guehenneux [CDS] 15-Nov-2017