J/ApJ/756/139 Spectroscopic redshifts of galaxies in groups (Connelly+, 2012)
Exploring the diversity of groups at 0.1<z<0.8 with X-ray and
optically selected samples.
Connelly J.L., Wilman D.J., Finoguenov A., Hou A., Mulchaey J.S.,
McGee S.L., Balogh M.L., Parker L.C., Saglia R., Henderson R.D.E.,
Bower R.G.
<Astrophys. J., 756, 139 (2012)>
=2012ApJ...756..139C 2012ApJ...756..139C
ADC_Keywords: Galaxies, optical ; Redshifts ; Spectroscopy ; X-ray sources ;
Surveys ; Clusters, galaxy
Keywords: galaxies: groups: general; X-rays: galaxies: clusters
Abstract:
We present the global group properties of two samples of galaxy groups
containing 39 high-quality X-ray-selected systems and 38 optically
(spectroscopically) selected systems in coincident spatial regions at
0.12<z<0.79. The total mass range of the combined sample is
~(1012-5)x1014M☉. Only nine optical systems are associable
with X-ray systems. We discuss the confusion inherent in the matching
of both galaxies to extended X-ray emission and of X-ray emission to
already identified optical systems. Extensive spectroscopy has been
obtained and the resultant redshift catalog and group membership are
provided here. X-ray, dynamical, and total stellar masses of the
groups are also derived and presented. We explore the effects of
utilizing different centers and applying three different kinds of
radial cut to our systems: a constant cut of 1Mpc and two r200 cuts,
one based on the velocity dispersion of the system and the other on
the X-ray emission.
Description:
Our optical sample is selected from the Canadian Network for
Observational Cosmology Field Galaxy Redshift Survey 2 (CNOC2), a
survey consisting of four sky patches, roughly equally spaced in RA,
with a total area of about 1.5deg-2 (Carlberg et al.
1999RSPTA.357..167C 1999RSPTA.357..167C). Follow-up spectroscopy of these fields resulted
in redshifts for over 6000 galaxies with a completeness of 48% down to
Rc=21.5 (Yee et al. 2000, Cat. J/ApJS/129/475). Groups present in
the survey were then detected as pure galaxy overdensities in redshift
space. In total, over 200 groups ranging in redshift 0.12<z<0.55
were detected (Carlberg et al. 2001, Cat. J/ApJ/552/427).
Complementary to the existing spectroscopy, the GEEC (Group
Environment Evolution Collaboration) has built up a multiwavelength
data set, including HST-ACS, infrared, and UV imaging and X-ray data
(described and utilized in the present analysis), in order to study
galaxy groups in the CNOC2 fields in detail. Twenty-six of the CNOC2
groups at 0.3<z<0.55 have been actively targeted with Magellan-LDSS2
to improve the spectroscopic completeness and depth of the sample. Ten
groups (six in the RA14h field, and four in the RA21h) were observed
with VLT-FORS2 in June and July of 2005. Throughout this paper we
consider only those 38 optical groups within the regions observed by
the XMM-Newton + Chandra.
X-ray observations of two of the four CNOC2 fields were obtained and
used to identify a comparison sample of X-ray-selected galaxy groups.
These groups are selected from deep XMM-Newton + Chandra data in the
RA14h and RA21h CNOC2 patches using a wavelet algorithm. A detailed
discussion of their definition can be found in Finoguenov et al.
(2009ApJ...704..564F 2009ApJ...704..564F).
A program of targeted follow-up spectroscopy for the X-ray detected
systems was executed primarily using the VLT-FORS2 and Magellan-IMACS
spectrographs. Some additional Gemini-GMOS spectroscopy has also been
acquired.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 119 4704 Spectroscopic redshifts
table3.dat 80 67 Basic properties of X-ray-selected groups
table4.dat 106 67 Measured properties of X-ray-selected groups
table5.dat 80 38 Basic properties of optically selected groups
table6.dat 106 38 Measured properties of optically selected groups
table7.dat 146 67 Masses of X-ray-selected groups
table8.dat 146 38 Masses of optically selected groups
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See also:
III/268 : DEEP2 Redshift Survey, Data Release 4 (Matthews+ 2013)
J/ApJ/751/50 : Cat. of galaxy groups from DEEP2 Redshift Survey (Gerke+ 2012)
J/ApJS/184/218 : The zCOSMOS 10k-bright spectroscopic sample (Lilly+, 2009)
J/ApJ/658/865 : Galaxy redshifts in X-ray-luminous groups (Jeltema+, 2007)
J/ApJS/172/182 : XMM Clusters of galaxies in COSMOS field (Finoguenov+ 2007)
J/A+A/461/397 : RASS-SDSS galaxy cluster survey. V. (Popesso+, 2007)
J/ApJ/646/133 : Redshifts in X-ray-selected galaxy groups (Mulchaey+, 2006)
J/MNRAS/348/866 : 2dFGRS Percolation-Inferred Galaxy Group (2PIGG) (Eke+, 2004)
J/ApJ/565/208 : Galaxy pairs in the CNOC2 Redshift Survey (Patton+, 2002)
J/ApJ/552/427 : Galaxy groups a intermediate redshifts (Carlberg+, 2001)
J/ApJ/554/L129 : X-ray luminosity-velocity dispersion relation (Mahdavi+, 2001)
J/ApJS/129/475 : The CNOC2 survey. I. (Yee+, 2000)
J/ApJ/539/136 : Properties of poor groups of galaxies. III. (Zabludoff+, 2000)
J/ApJ/534/114 : RASSCALS: X-ray and optical study (Mahdavi+, 2000)
J/ApJ/496/39 : Properties of poor groups of galaxies. I. (Zabludoff+ 1998)
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 F10.6 deg RAdeg Right Ascension in decimal degrees (J2000)
12- 20 F9.6 deg DEdeg Declination in decimal degrees (J2000)
22- 28 F7.4 --- z [-0.0015/3.2] Redshift
30- 46 A17 --- r_z Source of z (1)
48- 78 A31 --- 1Mpc Member for 1Mpc (2)
80- 95 A16 --- r200s Member for r200,σ (2)
97-119 A23 --- r200X Member for r200,X (2)
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Note (1): Source of z as follows:
GMOS = Gemini-GMOS spectroscopy in the 5000-10000Å range (FoV: 5.5').
IMACS = Magellan-IMACS in the 5000-9500Å range (FoV: 15.5').
FORS2 = VLT-FORS2 spectrograph in the 4300-7000Å range (FoV: 6.8').
LDSS2 = Magellan-LDSS2 spectrograph
CNOC2 = Canadian Network for Observational Cosmology Field Galaxy Redshift
Survey 2 (Carlberg et al. 1999RSPTA.357..167C 1999RSPTA.357..167C;
see also Cat. J/ApJS/129/475)
HENDERSON = Henderson, R.D.E. 2010, Master's thesis , McMaster Univ.
Note (2): X-ray and/or optical group(s) for which object is a member.
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Byte-by-byte Description of file: table[35].dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- ID Group identification number for the X-ray or
optical system (XRHHhMM or OPHHhMMm)
10- 22 A13 --- Name IAU name of group (HHMMSS+DDMM.m; J2000;
only for table3)
24- 32 F9.5 deg RAdeg Right ascension of the center of the extended
X-ray emission (J2000)
34- 41 F8.5 deg DEdeg Declination of the center of the extended
X-ray emission (J2000)
43- 48 F6.4 --- z [0.1/1.02] Spectroscopic redshift
50- 52 F3.1 --- q_z [1/3.5]? Group redshift quality (1=best)
(only for table3)
54- 60 A7 --- XID X-ray group ID where there is a confident
match with optical system (for table 5 only)
62 A1 --- f_XID [a] low-significance (1)
64 A1 --- l_FX Limit flag on FX
66- 69 F4.2 10-17W/m2 FX [0.04/8.2] The total flux in the 0.5-2keV band
(10-14erg/cm2/s)
71- 74 F4.2 10-17W/m2 e_FX [0.03/0.4]? FX uncertainty
76- 80 F5.2 --- Sig [-1.5/45] Significance of the X-ray flux
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Note (1): 'a' indicates a low X-ray significance using the optical
center and aperture.
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Byte-by-byte Description of file: table[46].dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- ID Group identification number for the X-ray
or optical system (XRHHhMM or OPHHhMMm)
10- 11 I2 --- N1Mpc [1/50] Number of member galaxies within 1Mpc
13- 18 F6.2 arcsec r1Mpc [133.3/488] Radius of 1Mpc
20 A1 --- l_s1Mpc Limit flag on s1Mpc
22- 25 I4 km/s s1Mpc [72/1199]? Velocity dispersion σ
within a 1Mpc cut
27- 29 I3 km/s e_s1Mpc [31/558]? s1Mpc uncertainty
31- 34 F4.2 --- C1Mpc [0/1]? Spectroscopic completeness (to R<22)
within a 1Mpc cut
36- 40 A5 --- D1Mpc Dynamical complexity within a 1Mpc cut (2)
42- 43 I2 --- Nr2s [0/59] Number of member galaxies within a
σ-derived r200 (r200,σ)
45- 51 F7.2 arcsec rr2s [31.4/1351]? The radius r200,σ
53 A1 --- l_sr2s Limit flag on sr2s
55- 58 I4 km/s sr2s [84/1753]? velocity dispersion σ
within r200,σ
60- 62 I3 km/s e_sr2s [34/454]? sr2s uncertainty
64- 67 F4.2 --- Cr2s [0/1]? Spectroscopic completeness (to R<22)
within r200,σ
69- 73 A5 --- Dr2s Dynamical complexity within r200,σ (2)
75- 76 A2 --- l_Nr2X [≤] Limit flag on Nr2X
78- 79 I2 --- Nr2X [1/40] Number of member galaxies within an
X-ray-derived r200
81 A1 --- l_r2X Limit flag on r2X
83- 88 F6.2 arcsec r2X [60.4/313.6] The radius r200,X
90 A1 --- l_sr2X Limit flag on sr2X
92- 94 I3 km/s sr2X [64/917]? velocity dispersion within r200,X
96- 98 I3 km/s e_sr2X [16/575]? sr2X uncertainty
100-103 F4.2 --- Cr2X [0/1]? Spectroscopic completeness (to R<22)
within r200,X
105-106 A2 --- Dr2X Dynamical complexity within r200,X (2)
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Note (2): Dynamical complexity is explored in our systems in Section 8 via the
Dressler-Schectman (DS, substructure group; 1988AJ.....95..985D 1988AJ.....95..985D) and
Anderson-Darling (AD, non-Gaussian group;
See Hou et al. 2009ApJ...702.1199H 2009ApJ...702.1199H) tests.
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Byte-by-byte Description of file: table[78].dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- ID Group identification number for the X-ray
or optical system (XRHHhMM or OPHHhMMm)
10 A1 --- l_LX Limit flag on LX
12- 16 F5.2 10+39W/m2 LX [0.1/61] Rest-frame luminosity in the
0.1-2.4 keV band
18- 21 F4.2 10+39W/m2 e_LX [0.08/5]? LX uncertainty
23 A1 --- l_Mx Limit flag on Mx
25- 29 F5.2 10+13Msun Mx [0.6/14.2] Total mass estimation (3)
31- 34 F4.2 10+13Msun e_Mx [0.09/1.4]? Mx uncertainty
36 A1 --- l_Ms1 Limit flag on Ms1
38- 42 F5.2 10+11Msun Ms1 [0.2/34]? Group stellar mass within 1Mpc cut
44- 48 F5.2 10+11Msun E_Ms1 [0.05/28.5]? Positive error on Ms1
50- 54 F5.2 10+11Msun e_Ms1 [0.06/28.5]? Negative error on Ms1
56 A1 --- l_Ms2s Limit flag on Ms2s
58- 62 F5.2 10+11Msun Ms2s [0.1/36.7]? Group stellar mass using
r200,σ radial cut
64- 68 F5.2 10+11Msun E_Ms2s [0.05/13.1]? Positive error on Ms2s
70- 74 F5.2 10+11Msun e_Ms2s [0.05/10.4]? Negative error on Ms2s
76- 77 A2 --- l_Ms2x [>≤∼ ] Limit flag on Ms2x
79- 83 F5.2 10+11Msun Ms2x [0.1/52.6]? Group stellar mass using
r200,X radial cut
85- 89 F5.2 10+11Msun E_Ms2x [0.05/27.7]? Positive error on Ms2x
91- 95 F5.2 10+11Msun e_Ms2x [0.02/27.5]? Negative error on Ms2x
97 A1 --- l_Md1 Limit flag on Md1
99-105 F7.3 10+13Msun Md1 [0.4/100.3]? The dynamical (virial) mass
for 1 Mpc
107-112 F6.3 10+13Msun e_Md1 [0.4/66.2]? Md1 uncertainty
114 A1 --- l_Md2s Limit flag on Md2s
116-122 F7.3 10+13Msun Md2s [0.08/799]? The dynamical (virial) mass
for r200,σ radial cut
124-130 F7.3 10+13Msun e_Md2s [0.2/131.1]? Md2s uncertainty
132 A1 --- l_Md2x Limit flag on Md2x
134-139 F6.3 10+13Msun Md2x [0.1/36]? The dynamical (virial) mass
for r200,X radial cut
141-146 F6.3 10+13Msun e_Md2x [0.2/39.1]? Md2x uncertainty
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Note (3): Estimates of a total mass, using X-ray luminosity as a mass proxy
and a calibration of Leauthaud et al. (2010ApJ...709...97L 2010ApJ...709...97L)
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 31-Mar-2014