J/A+A/690/A52 AXES-SDSS galaxy groups (Damsted+, 2024)
AXES-SDSS: Comparison of SDSS galaxy groups with all-sky X-ray extended sources.
Damsted S., Finoguenov A., Lietzen H., Mamon G.A., Comparat J., Tempel E.,
Dmitrieva I., Clerc N., Collins C., Gozaliasl G., Eckert D.
<Astron. Astrophys. 690, A52 (2024)>
=2024A&A...690A..52D 2024A&A...690A..52D (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, galaxy ; X-ray sources ; Optical
Keywords: galaxies: clusters: general -
galaxies: clusters: intracluster medium - galaxies: groups: general -
cosmology: observations - large-scale structure of Universe
Abstract:
Advances in cosmological studies require us to improve our
understanding of the baryonic content of galaxy groups. The key
baryonic components of groups are galaxies and hot gas, while key
non-baryonic mass tracers are the velocity dispersion of galaxies and
the distribution of galaxies within the group. We revisit the picture
of X-ray emission of groups through the study of systematic
differences in the optical properties of groups, with and without
X-ray emission, and we study the effect of the large-scale density
field on scaling relations. We present the identification of X-ray
galaxy groups using a combination of ROSAT All Sky Survey (RASS) and
Sloan Digital Sky Survey (SDSS) data. We include a new X-ray
reanalysis of RASS, covering very extended (up to a size of half a
degree) sources, and we account for differences in the limiting
sensitivity with respect to compact and very extended X-ray emission.
We applied a screening of the identified X-ray sources, based on the
optical properties, to achieve 95% clean catalogues. We used a mock
SDSS survey to understand the performance of our FoF group finder and
applied the Clean algorithm to revise group mass estimates and achieve
a clean membership catalogue. X-ray groups exhibit less scatter in the
scaling relations and selecting the groups based on the extended X-ray
emission leads to an additional scatter reduction. Most of the scatter
for the optical groups is associated with a small (6%) fraction of
outliers, primarily associated with low optical-luminosity groups
found in dense regions of the cosmic web. These groups are primary
candidates for the contaminants in the optical group catalogues. We
find that removing only those groups from the optical group sample
using optically measured properties leads to a substantial reduction
in the scatter of the scaling relations of the optical groups. We
report a dependence of both the X-ray and optical luminosity of groups
{on large-scale density}, which we associate with the assembly bias.
These results motivate an introduction of an additional
characterisation of galaxy clusters and shed light on the physical
origin of the anomalous clustering of galaxy clusters, found by the
Dark Energy Survey (DES).
Description:
We present catalogues of SDSS groups of galaxies with extended
and compact X-ray emission and compare those to the full sample of
optical groups matched in terms of the velocity dispersion.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablec1.dat 231 8465 Clean SDSS FoF groups
tablec2.dat 134 1121 Compact X-ray catalogue of SDSS groups
tablec3.dat 148 312 Extended X-ray catalogue of SDSS groups
tablec4.dat 86 77224 Clean members of SDSS FoF groups
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See also:
IX/10 : ROSAT All-Sky Bright Source Catalogue (1RXS) (Voges+ 1999)
IX/29 : ROSAT All-Sky Survey Faint Source Catalog (Voges+ 2000)
J/A+A/461/397 : RASS-SDSS galaxy cluster survey. V. (Popesso+, 2007)
Byte-by-byte Description of file: tablec1.dat
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Bytes Format Units Label Explanations
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1- 5 I5 --- Group FoF group identification number
(GROUP_ID)
7- 24 F18.14 deg RAdeg Highest rank galaxy next X-ray
peak, right ascension (J2000)
(RA_OPT)
26- 46 F21.18 deg DEdeg Highest rank galaxy next X-ray
peak, declination (J2000)
(DEC_OPT)
48- 50 I3 --- Nmemb Number of spectroscopic members
after the cleaning (NMEM)
52- 69 F18.16 --- zsp Group redshift, assigned using
median value of clean members
(ZSPEC)
71- 89 F19.14 km/s sigmaGAP Gapper estimate of the cluster
velocity dispersion (VDISP_GAP)
91-109 F19.15 km/s e_sigmaGAP Error on sigmaGAP (EVDISP_GAP)
111-130 F20.15 km/s sigmaMAD Velocity dispersion from mean
absolute deviation (VDISP_MAD)
132-149 F18.13 kpc R200c R200c radius (R_200c)
151-170 F20.16 Lsun LR195 ?=-99 Cleaned luminosity in
r band, using Mr←19.5 galaxy
sample (z<0.06 groups)
(LR195CLEAN)
172-194 F23.19 Lsun e_LR195 ?=-99 Error on LR195
(ELR195CLEAN)
196-206 F11.8 1022700000Msun/Mpc3 D10 Large-scale density, in
0.01227*1010M_☉/Mpc3
units (D_10)
208-231 E24.16 1022700000Msun/Mpc3 e_D10 Error on D10, in
0.01227*1010M_☉/Mpc3
units (ED_10)
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Byte-by-byte Description of file: tablec2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 I5 --- Group FoF group identification number (GROUP_ID)
7- 24 F18.16 --- zsp Group redshift, assigned using median value
of clean members (ZSPEC)
26- 30 I5 --- CODEX The CODEX cluster candidate unique identifier
(CODEX)
32- 40 F9.5 deg RAdeg X-ray detection right ascension (J2000) (RA)
42- 49 F8.5 deg DEdeg X-ray detection declination (J2000) (DEC)
51- 72 E22.16 10-7W LX0124 Luminosity in the (0.1-2.4)keV band of the
cluster, aperture R500c (LX0124)
74- 95 E22.16 10-7W e_LX0124 Uncertainty on LX0124 (ELX)
97-102 F6.4 deg R200c Apparent R200c radius of the galaxy cluster
(R200C_DEG)
104-113 E10.4 mW/m2 Flux052 Galaxy cluster X-ray flux in the 0.5-2.0keV
band (FLUX052)
115-124 E10.4 mW/m2 e_Flux052 Uncertainty on FLUX052 (EFLUX052)
126-134 F9.6 arcmin RE Apparent radial extent of X-ray emission
(R_E)
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Byte-by-byte Description of file: tablec3.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 I5 --- Group FoF group identification number (GROUP_ID)
7- 24 F18.16 --- zp Group redshift, assigned using median value
of clean members (ZSPEC)
26- 33 I8 --- AXES The AXES cluster candidate unique identifier
(AXES)
35- 43 F9.5 deg RAdeg X-ray detection right ascension (J2000) (RA)
45- 52 F8.5 deg DEdeg X-ray detection declination (J2000) (DEC)
54- 75 E22.16 10-7W LX0124 Luminosity in the (0.1-2.4)keV band of the
cluster, aperture R500c (LX0124)
77- 98 E22.16 10-7W e_LX0124 Uncertainty on LX0124 (ELX)
100-105 F6.4 deg R200c Apparent R200c radius of the galaxy cluster
(R200C_DEG)
107-116 E10.4 mW/m2 Flux052 Galaxy cluster X-ray flux in the 0.5-2.0keV
band (FLUX052)
118-127 E10.4 mW/m2 e_Flux052 Uncertainty on Flux052 (EFLUX052)
129-136 F8.5 arcmin RE Apparent radial extent of X-ray emission (R_E)
138 I1 --- Flag [1/3] X-ray flux contamination flag (FLAG) (1)
140-143 F4.2 --- Acor Ratio between the extrapolated and the
measured flux (ACOR)
145-148 F4.2 --- Kcor K-correction to compute the flux in the
rest-frame 0.1-2.4keV band (KCOR)
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Note (1): X-ray flux contamination flag as follows:
1 = sources have no contamination
2 = We have either changed the flux extraction area to avoid contamination or
removed the source from the analysis in cases of strong confusion and
where the significance of flux estimate from the uncontaminated area
is low (below 95% confidence level)
3 = sources where the contamination could not be fully excluded but was
also not obvious
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Byte-by-byte Description of file: tablec4.dat
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Bytes Format Units Label Explanations
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1- 5 I5 --- Group FoF group identification number (GROUP_ID)
7- 12 I6 --- GalID FoF ID of the galaxy (GALID)
14- 32 I19 --- SpecObjID SDSS ID of the galaxy (specobjid)
34- 46 F13.9 deg RAdeg Right ascension (J2000) (RA_GAL)
48- 60 E13.5 deg DEdeg Declination (J2000) (DEC_GAL)
62- 72 F11.9 --- zsp Galaxy redshift (ZSPEC)
74- 86 E13.5 Lsun Lr r-band luminosity (L_R)
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Acknowledgements:
Alexis Finoguenov, alexis.finoguenov(at)helsinki.fi
(End) Patricia Vannier [CDS] 23-Jul-2024