J/A+A/567/A89 Swift X-ray Telescope Cluster Survey. II. (Tozzi+, 2014)
The Swift X-ray Telescope Cluster Survey. II. X-ray spectral analysis.
Tozzi P., Moretti A., Tundo E., Liu T., Rosati P., Borgani S.,
Tagliaferri G., Campana S., Fugazza D., D'Avanzo P.
<Astron. Astrophys., 567, A89-89 (2014)>
=2014A&A...567A..89T 2014A&A...567A..89T
ADC_Keywords: Clusters, galaxy ; X-ray sources
Keywords: galaxies: clusters: general - galaxies: high-redshift -
cosmology: observations - X-rays: galaxies: clusters -
intergalactic medium
Abstract:
We present a spectral analysis of a new, flux-limited sample of 72
X-ray selected clusters of galaxies identified with the X-ray
Telescope (XRT) on board the Swift satellite down to a flux limit of
∼10-14erg/s/cm2 (SWXCS). We carry out a detailed X-ray spectral
analysis with the twofold aim of measuring redshifts and
characterizing the properties of the intracluster medium (ICM) for the
majority of the SWXCS sources.
Optical counterparts and spectroscopic or photometric redshifts for
some of the sources are obtained with a cross-correlation with the
NASA/IPAC Extragalactic Database. Additional photometric redshifts are
computed with a dedicated follow-up program with the Telescopio
Nazionale Galileo and a cross-correlation with the SDSS. In addition,
we also blindly search for the Hydrogen-like and He-like iron
Kα emission line complex in the X-ray spectrum. We detect the
iron emission lines in 35% of the sample, and hence obtain a robust
measure of the X-ray redshift zX with typical rms error 1-5%. We use
zX whenever the optical redshift is not available. Finally, for all
the sources with measured redshift, background-subtracted spectra are
fitted with a single-temperature mekal model to measure global
temperature, X-ray luminosity and iron abundance of the ICM. We
perform extensive spectral simulations to accounts for fitting bias,
and to assess the robustness of our results. We derive a criterion to
select reliable best-fit models and an empirical formula to account
for fitting bias. The bias-corrected values are then used to
investigate the scaling properties of the X-ray observables.
Description:
In Paper I we considered the Swift/XRT archive from February 2005 to
April 2010, including 336 fields in the corresponding GRB positions,
with Galactic latitude |b|>20°, to avoid crowded fields and
strong Galactic absorption. We followed a standard data reduction
procedure by means of the xrtpipeline task of the current release of
the HEADAS software (version v6.8) with the most updated calibration
(CALDB version 20111031, Nov. 2011). Then, we proceeded with a
customized data reduction, aimed at optimizing our data to the
detection of extended sources. The most important aspect of this step
is the reduction of the background thanks to the exclusion of the
intense GRB emission at the beginning of each observation, after a
careful investigation of the background light curves.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 155 89 Cluster sample
table2.dat 175 46 Results of X-ray spectral analysis
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See also:
J/A+A/528/A122 : SwiftFT catalog (Puccetti+, 2011)
J/A+A/547/A57 : Swift X-ray Telescope Cluster Survey (Tundo+, 2012)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 5 A5 --- --- [SWXCS]
7- 20 A14 --- SWXCS SWXCS designation (JHHMMSS+DDMM.m) (1)
21 A1 --- n_SWXCS [*] Several possible counterparts (2)
22- 29 F8.6 --- z1 ? Optical redshift from cross-correlation
with NED
31- 38 F8.6 --- e_z1 ? rms uncertainty on z1
40 A1 --- f_z1 [ps] photometric or spectroscopic redshift
42- 45 F4.2 --- z2 ? Optical redshift from follow-up with TNG
47- 50 F4.2 --- E_z2 ? Error on z2 (upper value)
52- 55 F4.2 --- e_z2 ? Error on z2 (lower value)
56 A1 --- r_z2 [*] * for redshift obtained with VLT
archival data
58- 62 F5.3 --- zX ? X-ray redshift
64- 68 F5.3 --- E_zX ? Error on z2 (upper value)
70- 74 F5.3 --- e_zX ? Error on z2 (lower value)
76- 81 A6 --- Srv Reference for optical redshift (survey name)
82- 83 I2 --- r_Srv ? Reference for redshift from literature (3)
85-113 A29 --- OCl Optical counterpart (cluster)
115-138 A24 --- OGal Optical counterpart (galaxy)
140-141 A2 --- --- [SW]
142-155 A14 --- Name Name of the X-ray source in paper I
(JHHMMSS+DDMMSS; cat. J/A+A/547/A57)
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Note (1): The format of the name of the sources is SWXCS JHHMMSS+DDMM.m. This
new designation supersedes that used in Paper I, and it has been officially
accepted by the IAU register of acronym.
Note (2): The source marked with * has two other cluster counterparts at
distances larger than 1-arcmin from the X-ray centroid: ZwCl 1234.0+2916 and
WHL J123620.6+285756. These counterparts are not considered here.
Note (3): References for the redshifts from the literature as follows:
1 = Shectman et al. (1996ApJ...470..172S 1996ApJ...470..172S, Cat. VII/203)
2 = Colless et al. (2001MNRAS.328.1039C 2001MNRAS.328.1039C, Cat. VII/226)
3 = Adelman-McCarthy et al. (2006ApJS..162...38A 2006ApJS..162...38A, Cat. II/267)
4 = Wen et al. (2010, ApJS, 187, 272, Cat. J/ApJS/183/197)
5 = Adelman-McCarthy et al. (2008ApJS..175..297A 2008ApJS..175..297A, Cat. II/282)
6 = Koester et al. (2007ApJ...660..239K 2007ApJ...660..239K, Cat. J/ApJ/660/239)
7 = Abazajian et al. (2005AJ....129.1755A 2005AJ....129.1755A, Cat. II/259)
8 = Hao et al. (2010ApJS..191..254H 2010ApJS..191..254H, Cat. J/ApJS/191/254)
9 = von der Linden et al. (2007MNRAS.379..867V 2007MNRAS.379..867V, Cat. J/MNRAS/379/867)
10 = Huchra et al. (2012ApJS..199...26H 2012ApJS..199...26H, Cat. J/ApJS/199/26)
11 = Gal et al. (2003AJ....125.2064G 2003AJ....125.2064G, Cat. J/AJ/125/2064)
12 = Adelman-McCarthy et al. (2007ApJS..172..634A 2007ApJS..172..634A, Cat. II/276)
13 = Estrada et al. (2007ApJ...660.1176E 2007ApJ...660.1176E)
14 = Owen et al. (1995AJ....109...14O 1995AJ....109...14O, Cat. J/AJ/109/14)
15 = Struble & Rood (1999ApJS..125...35S 1999ApJS..125...35S)
16 = Schwope et al. (2000AN....321....1S 2000AN....321....1S, Cat. IX/32)
17 = di Nella et al. (1996MNRAS.283..367D 1996MNRAS.283..367D, Cat. J/MNRAS/283/367)
18 = redshift obtained from Literature by the NED Team prior to November 1992
19 = Szabo et al. (2011ApJ...736...21S 2011ApJ...736...21S, Cat. J/ApJ/736/21)
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 5 A5 --- --- [SWXCS]
7- 20 A14 --- SWXCS SWXCS designation (JHHMMSS+DDMM.m)
22- 25 F4.2 arcmin Rext Radius of the circular region used for
spectroscopic analysis
27- 30 F4.2 keV kT Temperature directly obtained from the
spectral analysis
32- 35 F4.2 keV E_kT Error on kT (upper value)
37- 40 F4.2 keV e_kT Error on kT (lower value)
42- 45 F4.2 keV kTc Temperature corrected for fitting bias
47- 50 F4.2 keV E_kTc Error on kTc (upper value)
52- 55 F4.2 keV e_kTc Error on kTc (lower value)
57 A1 --- l_Z Limit flag on Z
58- 61 F4.2 Sun Z Iron abundance directly obtained from the
spectral analysis
63- 66 F4.2 Sun E_Z ? Error on Z (upper value)
68- 71 F4.2 Sun e_Z ? Error on Z (lower value)
73 A1 --- l_Zc Limit flag on Zc
74- 78 F5.3 Sun Zc ?=- Iron abundance corrected for the
fitting bias
80- 83 F4.2 Sun E_Zc ? Error on Zc (upper value)
85- 88 F4.2 Sun e_Zc ? Error on Zc (lower value)
90- 97 E8.3 mW/m2 FS Soft (0.5-2keV) band flux measured within Rext
99-103 F5.3 10+37W LS X-ray luminosity in the soft (0.5-2keV) band
measured within Rext (in 1044erg/s)
105-110 F6.3 10+37W Lbol Bolometric X-ray luminosity
measured within Rext (in 1044erg/s)
112-118 F7.1 ct Cts Net counts in the soft (0.5-2keV) band
120-123 I4 kpc R500l Estimated R500 in kpc (1)
125-127 I3 kpc e_R500l rms uncertainty on R500 in arcmin
129-133 F5.2 arcmin R500 Estimated R500 in arcmin (1)
135-138 F4.2 arcmin e_R500 rms uncertainty on R500 in arcmin
140-144 F5.3 10+37W LS2 Estinated X-ray luminosity in the 0.5-2keV band
within R500 (in 1044erg/s)
146-150 F5.3 10+37W E_LS2 Error on LS2 (upper value)
152-156 F5.3 10+37W e_LS2 Error on LS2 (lower value)
158-163 F6.3 10+37W Lbol2 Estimated bolometric X-ray luminosity
within R500 (in 1044erg/s)
165-169 F5.3 10+37W E_Lbol2 Error on Lbol2 (upper value)
171-175 F5.3 10+37W e_Lbol2 Error on Lbol2 (lower value)
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Note (1): R500 defined as the radius within which the average density
contrast is 500.
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History:
From electronic version of the journal
References:
Tundo et al., Paper I 2012A&A...547A..57T 2012A&A...547A..57T, Cat. J/A+A/547/A57
Liu et al., Paper III 2015ApJS..216...28L 2015ApJS..216...28L, Cat. J/ApJS/216/28
(End) Patricia Vannier [CDS] 22-Sep-2014