J/MNRAS/483/3545 X-ray centres of COSMOS galaxy groups (Gozaliasl+, 2019)
Chandra centres for COSMOS X-ray galaxy groups: differences in stellar
properties between central dominant and offset brightest group galaxies.
Gozaliasl G., Finoguenov A., Tanaka M., Dolag K., Montanari F.,
Kirkpatrick C.C., Vardoulaki E., Khosroshahi H.G., Salvato M., Laigle C.,
McCracken H.J., Ilbert O., Cappelluti N., Daddi E., Hasinger G., Capak P.,
Scoville N.Z., Toft S., Civano F., Griffiths R.E., Balogh M., Li Y.,
Ahoranta J., Mei S., Iovino A., Henriques B.M.B., Erfanianfar G.
<Mon. Not. R. Astron. Soc., 483, 3545-3565 (2019)>
=2019MNRAS.483.3545G 2019MNRAS.483.3545G (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, galaxy ; Galaxy catalogs ; X-ray sources ; Redshifts
Keywords: galaxies: clusters: general - galaxies: evolution -
galaxies: groups: general - galaxies: statistics -
galaxies: stellar content - X-rays: galaxies: clusters
Abstract:
We present the results of a search for galaxy clusters and groups in
the ∼2deg2 of the COSMOS field using all available X-ray
observations from the XMM-Newton and Chandra observatories. We reach
an X-ray flux limit of 3x10-16erg/cm2/s in the 0.5-2keV range, and
identify 247 X-ray groups with M200c=8x1012-3x1014M☉ at a
redshift range of 0.08=<z<1.53, using the multiband photometric
redshift and the master spectroscopic redshift catalogues of the
COSMOS. The X-ray centres of groups are determined using
high-resolution Chandra imaging. We investigate the relations between
the offset of the brightest group galaxies (BGGs) from halo X-ray
centre and group properties and compare with predictions from
semi-analytic models and hydrodynamical simulations. We find that BGG
offset decreases with both increasing halo mass and decreasing
redshift with no strong dependence on the X-ray flux and SNR. We show
that the BGG offset decreases as a function of increasing magnitude
gap with no considerable redshift-dependent trend. The stellar mass of
BGGs in observations extends over a wider dynamic range compared to
model predictions. At z<0.5, the central dominant BGGs become more
massive than those with large offsets by up to 0.3dex, in agreement
with model prediction. The observed and predicted log-normal scatter
in the stellar mass of both low- and large-offset BGGs at fixed halo
mass is ∼0.3dex.
Description:
The Cosmological Evolution Survey (COSMOS) is a deep multiband survey
centred at (Ra, Dec)=(+150.1192, +2.2058) and covering a 2deg2 area.
The full definition and survey goals can be found in Scoville et al.
(2007ApJS..172....1S 2007ApJS..172....1S).
COSMOS is the largest field that has been observed by the Hubble Space
telescope (HST) so far. In addition, COSMOS guarantees full spectral
coverage with multiwavelength imaging and spectroscopy from X-ray to
radio wavelengths by the major space-based telescopes (Hubble,
Spitzer, GALEX, XMM, Chandra, Herschel, and NuStar) and the large
ground-based observatories (Keck, Subaru, VLA, ESO-VLT, UKIRT, NOAO,
CFHT, JCMT, ALMA, and others)
The initial catalogues of the COSMOS X-ray groups were published in
Finoguenov et al. (2007ApJS..172..182F 2007ApJS..172..182F, Cat. J/ApJS/172/182) and
George et al. (2011ApJ...742..125G 2011ApJ...742..125G, Cat. J/ApJ/742/125). These
catalogues combined the available Chandra and XMM-Newton data with
developments in the photometric data sets, used for identification of
galaxy groups, with confident identification reaching a redshift of 1.
The revised catalogue of extended X-ray sources in COSMOS, released as
a part of this paper, is obtained by co-adding all the existing
Chandra and XMM-Newton data in the field. It is very similar to the
catalogue used in George et al. (2011ApJ...742..125G 2011ApJ...742..125G, Cat.
J/ApJ/742/125), but extends the list of sources beyond the redshift of
1. In addition, we are able to improve on the precision of the centres
for extended sources, using the smaller scale emission, detected by
Chandra, reducing the statistical uncertainty on the centring from
15arcsec in George et al. (2011ApJ...742..125G 2011ApJ...742..125G, Cat. J/ApJ/742/125) to
5arcsec. The scales of source confusion are also improved from 32 to
16arcsec.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 126 247 The revised catalogue of X-ray galaxy groups in
2deg2 of the COSMOS field, which was
previously presented by Finoguenov et al.
(2007ApJS..172..182F 2007ApJS..172..182F) and George et al.
(2011ApJ...742..125G 2011ApJ...742..125G)
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See also:
J/ApJS/172/182 : XMM Clusters of galaxies in COSMOS field (Finoguenov+ 2007)
J/ApJ/742/125 : Galaxies in X-ray groups. I. COSMOS memberships
(George+, 2011)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 I5 --- ID COSMOS galaxy group identification
(COSMOS NNNNN)
7- 16 F10.6 deg RAdeg Right ascension (J2000) (1)
18- 25 F8.6 deg DEdeg Declination (J2000) (1)
27- 31 F5.3 --- z Redshift
33 I1 --- Group Group's identification flags
35- 47 E13.11 Msun M200 Total mass of groups within R200 with respect
to the critical density of the Universe (2)
49- 61 E13.11 Msun e_M200 Error on M200 (1σ)
63- 71 E9.7 10-7W Lx 0.1-2.5keV rest-frame X-ray luminosity within
R500
73- 81 E9.7 10-7W e_Lx Error on Lx (1σ)
83- 88 F6.4 deg R200 Radius delimiting a sphere whose interior mean
density is 200 times the critical density of
the Universe (3)
90- 93 F4.2 keV kT IGM temperature (4)
95- 98 F4.2 keV e_kT Error on kT (1σ)
100-109 E10.8 mW/m2 Flux Group X-ray flux in the 0.5-2keV band within
R500
111-120 E10.8 mW/m2 e_Flux Error on Flux (1σ)
122-126 F5.2 --- FSig Significance of the X-ray flux estimate that is
defined as the ratio of the X-ray flux to its
error
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Note (1): Coordinates of the X-ray peak (centre)
Note (2): M200 is measured using the Lx-M200 scaling relation of
Leauthaud et al. (2010ApJ...709...97L 2010ApJ...709...97L)
Note (3): R200 is estimated using the following relation:
M200=4πx200xρxR2003/3
Where ρ is the critical density of the Universe
Note (4): Temperature obtained using the Lx-T relation
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History:
From electronic version of the journal
(End) Ana Fiallos [CDS] 28-Jul-2022