J/A+A/671/A83 RV of 41 member galaxies of GrG J0330-0218 (Girardi+, 2023)
A newly identified galaxy group thanks to tidal streams of intragroup light.
Girardi M., Zarattini S., Boschin W., Nonino M., Bartalucci I.,
Mercurio A., Nocerino N., Rosati P.
<Astron. Astrophys. 671, A83 (2023)>
=2023A&A...671A..83G 2023A&A...671A..83G (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, galaxy ; Redshifts ; Spectroscopy ; Radial velocities ;
Photometry ; Optical
Keywords: galaxies: groups: individual: GrG J0330-0218 -
galaxies: groups: general -
galaxies: clusters: individual: MACS J0329-0211 -
galaxies: clusters: general - galaxies: kinematics and dynamics
Abstract:
In the accretion-driven growth scenario, part of the intracluster
light is formed in the group environment. We report the serendipitous
discovery of a group of galaxies with signs of diffuse light in the
foreground of the known galaxy cluster MACS J0329-0211 at z=0.45. Our
investigation began with the detection of diffuse light streams around
a pair of bright galaxies in the southeastern region of a Suprime-Cam
image of the galaxy cluster MACS J0329-0211. Our analysis is based on
the extended CLASH-VLT redshift catalog and on new spectroscopic data
obtained ad hoc with the Italian Telescopio Nazionale Galileo. We use
the density reconstruction method to analyze the redshift distribution
of the galaxies in the region around the galaxy pair. We also use
available photometric and X-ray data to better characterize the
properties of the group. Thanks to the large amount of redshift data
collected in this region, we have been able to discover the existence
of a group of galaxies, here called GrG J0330-0218, which is
associated with the pair of galaxies. These are the two brightest
group galaxies (BGG1 and BGG2). We extracted 41 group members from the
redshift catalog and estimate a mean redshift z=0.1537 and a
line-of-sight velocity dispersion sigmav=370km/s. In the phase-space
diagram, the distribution of the galaxies of GrG J0330-0218 follows
the characteristic trumpet-shaped pattern, which is related to the
escape velocity of galaxy clusters, suggesting that the group is a
virialized structure. Under this assumption, the mass of the group is
M200 about 6*1013M☉. We also measured a mass-to-light ratio of
130M☉/L☉ and a luminosity fraction of diffuse light of
about 20% within 0.5R200. We conjecture that galaxy pairs that are
surrounded by diffuse light, probably due to tidal interactions, can
serve as signposts for groups.
Description:
The table contains radial velocities of 41 member galaxies of the
galaxy group GrG J0330-0218 detected in the foreground of the known
galaxy cluster MACS J0329-0211. New, ad hoc spectroscopic observations
were carried out at the the Italian Telescopio Nazionale Galileo (TNG)
in Nov. and Dec. 2015 and in Jan. 2016. Other redshifts are part of
the dataset focused on MACS J0329-0211 within the ESO Large Programme
186.A-0798 "Dark Matter Mass Distributions of Hubble Treasury Clusters
and the Foundations of LambdaCDM Structure Formation Models" led by
Piero Rosati (CLASH-VLT survey) and based on observations obtained
with VIsible Multi-Object Spectrograph (VIMOS) at at the Very Large
Telescope (VLT-ESO).
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 54 41 Radial velocities of 41 member galaxies of
GrG J0330-0218
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- Seq [1/41] Sequential number (1)
6- 7 I2 h RAh Right ascension (J2000.0)
9- 10 I2 min RAm Right ascension (J2000.0)
12- 16 F5.2 s RAs Right ascension (J2000.0)
19 A1 --- DE- Declination sign (J2000.0)
20- 21 I2 deg DEd Declination (J2000.0)
23- 24 I2 arcmin DEm Declination (J2000.0)
26- 29 F4.1 arcsec DEs Declination (J2000.0)
32- 36 F5.2 mag rmag [16.68/23.53] r-band magnitudes
39 A1 --- n_rmag [ab] Origin of magnitudes (2)
42- 46 I5 km/s HRV [45269/46858] Heliocentric radial velocity
49- 51 I3 km/s e_HRV [30/171] Uncertainty on HRV
54 A1 --- n_HRV [VTM] Origin of HRV (3)
--------------------------------------------------------------------------------
Note (1): IDs. 01, 02, and 03 are BGG1, BGG2, and BGG3, respectively.
Note (2): Magnitudes are generally Pan-STARRS Kron-like r magnitudes from PS1
mean data.
References as follows:
a = obtained from PS1 stacked data
b = are obtained from Suprime-Rc catalog and
converted (r=Rc+0.25, Fukugita et al. 1995PASP..107..945F 1995PASP..107..945F)
Note (3): Origin of HRV as follows:
T = TNG
V = VLT/VIMOS
M = VLT/MUSE
--------------------------------------------------------------------------------
Acknowledgements:
Marisa Girardi, marisa.girardi(at)inaf.it
(End) Patricia Vannier [CDS] 30-Jan-2023