J/A+A/576/A130 Ultra-deep catalog of X-ray groups in ECDF-S (Finoguenov+, 2015)
Ultra-deep catalog of X-ray groups in the Extended Chandra Deep Field-South.
Finoguenov A., Tanaka M., Cooper M., Allevato V., Cappelluti N., Choi A.,
Heymans C., Bauer F.E., Ziparo F., Ranalli P., Silverman J., Brandt W.N.,
Xue Y.Q., Mulchaey J., Howes L., Schmid C., Wilman D., Comastri A.,
Hasinger G., Mainieri V., Luo B., Tozzi P., Rosati P., Capak P., Popesso P.
<Astron. Astrophys., 576, A130-130 (2015)>
=2015A&A...576A.130F 2015A&A...576A.130F
ADC_Keywords: Galaxy catalogs ; X-ray sources
Keywords: gravitational lensing: weak - X-rays: galaxies: clusters -
large-scale structure of Universe
Abstract:
We present the detection, identification and calibration of extended
sources in the deepest X-ray dataset to date, the Extended Chandra
Deep Field South (ECDF-S). Ultra-deep observations of ECDF-S with
Chandra and XMM-Newton enable a search for extended X-ray emission
down to an unprecedented flux of 2x10-16ergs/s/cm2. By using
simulations and comparing them with the Chandra and XMM data, we show
that it is feasible to probe extended sources of this flux level,
which is 10000 times fainter than the first X-ray group catalogs of
the ROSAT all sky survey. Extensive spectroscopic surveys at the VLT
and Magellan have been completed, providing spectroscopic
identification of galaxy groups to high redshifts. Furthermore,
available HST imaging enables a weak-lensing calibration of the group
masses. We present the search for the extended emission on spatial
scales of 32" in both Chandra and XMM data, covering 0.3 square
degrees and model the extended emission on scales of arcminutes. We
present a catalog of 46 spectroscopically identified groups, reaching
a redshift of 1.6. We show that the statistical properties of ECDF-S,
such as logN-logS and X-ray luminosity function are broadly consistent
with LCDM, with the exception that dn/dz/dΩ test reveals that a
redshift range of 0.2<z<0.5 in ECDF-S is sparsely populated. The lack
of nearby structure, however, makes studies of high-redshift groups
particularly easier both in X-rays and lensing, due to a lower level
of clustered foreground. We present one and two point statistics of
the galaxy groups as well as weak-lensing analysis to show that the
detected low-luminosity systems are indeed low-mass systems. We verify
the applicability of the scaling relations between the X-ray
luminosity and the total mass of the group, derived for the COSMOS
survey to lower masses and higher redshifts probed by ECDF-S by means
of stacked weak lensing and clustering analysis, constraining any
possible departures to be within 30% in mass. Ultra-deep X-ray surveys
uniquely probe the low-mass galaxy groups across a broad range of
redshifts. These groups constitute the most common environment for
galaxy evolution. Together with the exquisite data set available in
the best studied part of the Universe, the ECDF-S group catalog
presented here has an exceptional legacy value.
Description:
The ECDF-S area has been a frequent target of X-ray observations with
both Chandra and XMM. After the first 1Ms Chandra observation
(Giacconi et al., 2002, Cat. J/ApJS/139/369), the area was named the
Chandra Deep Field South. The extension of the CDF-S survey to 2Ms
(Luo et al., 2008, Cat. J/ApJS/179/19) and later to 4Ms of exposure
time (Xue et al., 2011, Cat. J/ApJS/195/10), via a large Director's
Discretionary Time project, has now provided our most sensitive
0.5-8keV view of the distant AGNs and galaxies. This paper does not
include the 3Ms Chandra observations of the field taken in 2014.
For cataloguing the groups, we also include the ECDF-S data (Lehmer et
al., 2005, Cat. J/ApJS/161/21), which consist of four Chandra ACIS-I
pointings, 250ks each, defining the square shape of the exposure and
sensitivity maps.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table4.dat 99 51 Catalog of the ECDF-S X-ray selected galaxy groups
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See also:
J/ApJS/139/369 : Chandra Deep Field South. 1 Ms catalog (Giacconi+, 2002)
J/ApJS/161/21 : Extended Chandra Deep Field-South survey (Lehmer+, 2005)
J/AJ/131/2373 : Extended Chandra Deep Field-South survey (Virani+, 2006)
J/ApJS/179/19 : CDFS survey: 2 Ms source catalogs (Luo+, 2008)
J/ApJS/195/10 : The CDF-S survey: 4Ms source catalogs (Xue+, 2011)
Byte-by-byte Description of file: table4.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- ID X-ray identification (number, or Kurk-N)
8- 23 A16 --- Name IAU name (JHHMMSS.s+DDMMSS)
25- 31 F7.4 deg RAdeg X-ray source right ascension (J2000)
33- 40 F8.4 deg DEdeg X-ray source declination (J2000)
42- 46 F5.3 --- z [0.07/1.61] Redshift
48- 52 F5.2 aW/m2 Flux [0.07/70] Flux in the 0.5-2keV band (1)
54- 57 F4.2 aW/m2 e_Flux rms uncertainty on Flux
59- 63 I5 ct Nct [76/18135] Total net XMM+Chandra counts
in the flux extraction region
65- 69 F5.2 10+35W LX [0.05/97] Rest-frame luminosity in the
0.1-2.4keV band, in 1042erg/s (2)
71- 75 F5.2 10+35W e_LX rms uncertainty on LX
77- 81 F5.2 10+13Msun M200 [0.28/10] Estimated total mass (3)
83- 86 F4.2 10+13Msun e_M200 rms uncertainty on M200
88- 90 F3.1 arcmin r200 [0.6/4.7] Radius corresponding to M200
92 I1 --- Qf [1/5] Quality flag (4)
94- 95 I2 --- Nz [1/49] Number of spectroscopic member
galaxies inside r200, used to evaluate the
mean spectroscopic redshift
97- 99 I3 km/s Vdisp [120/515] Predicted galaxy velocity
dispersion (5)
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Note (1): The flux (in 10-15erg/cm2/s) is extrapolated to an iteratively
determined r500 (see Finoguenov et al. 2007, J/ApJS/172/182, for details).
The aperture determining the flux has been defined by the shape of the
emission on 32" scales, unless it has been manually redefined to avoid
contamination from other extended sources (cases where this is not
possible have Qf=4).
Note (2): where the K-correction assumes the temperature from the scaling
relations adopted in Finoguenov et al. (2007ApJS..172..182F 2007ApJS..172..182F). The choice of
the energy band is driven by the available calibrations of the Lx-M relation
(Leauthaud et al. 2010ApJ...709...97L 2010ApJ...709...97L), yielding an estimated total mass M200.
Note (3): Estimated total mass, M200, defined with respect to the critical
density, with only the statistical errors quoted. Systematic errors due
to scatter in the scaling relations are ∼20% (Allevato et al.,
2012ApJ...758...47A 2012ApJ...758...47A) and the uncertainty on the calibration is 30%,
as discussed in Sects. 6 and 7.
Note (4): Flag as follows:
1 = objects of best quality, with centroids derived from the X-ray emission
and spectroscopic confirmation of the redshift
2 = objects have large uncertainties in the X-ray center (low statistics or
source confusion) with their centroids and flux extraction apertures
positioned on the associated galaxy concentration with spectroscopic
confirmation
3 = objects that still require spectroscopic confirmation
4 = objects that have more than one counterpart along the line of sight
5 = objects that have doubtful identifications and are only used to access
systematic errors in the statistical analysis associated with source
identification
Note (5): based on the Carlberg et al. (1997ApJ...476L...7C 1997ApJ...476L...7C) virial relation
using our total mass estimates.
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 05-Jun-2015