J/MNRAS/439/1796 Galaxy clusters at z=0.23 and 0.45 X-ray emission (Wang+, 2014)
X-ray mapping the outer regions of galaxy clusters at z = 0.23 and 0.45.
Wang Q.D., Walker S.
<Mon. Not. R. Astron. Soc., 439, 1796-1806 (2014)>
=2014MNRAS.439.1796W 2014MNRAS.439.1796W (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, galaxy ; X-ray sources
Keywords: galaxies: clusters: general -
galaxies: clusters: individual: Abell 2246 -
galaxies: clusters: individual: GMBCG J255.34805+64.2366 -
X-rays: galaxies: clusters
Abstract:
The thermal, chemical, and kinematic properties of the potentially
multiphase circum/intergalactic medium at the virial radii of galaxy
clusters remain largely uncertain. We present an X-ray study of Abell
2246 and GMBCG J255.34805+64.23661 (z=0.23 and 0.45), two
foreground clusters of the UV-bright QSO HS 1700+6416, based on 240ks
Chandra/Advanced CCD Imaging Spectrometer observations. We
detect enhanced diffuse X-ray emission to the projected distances
beyond r200 radii of these two clusters. The large-scale X-ray
emission is consistent with being azimuthally symmetric at the
projected radii of the QSO (0.36 and 0.8 times the radii of the two
clusters). Assuming a spherical symmetry, we obtain the de-projected
temperature and density profiles of the X-ray-emitting gas. Excluding
the cool cores that are detected, we find that the mean temperature of
the hot gas is ∼4.0keV for Abell 2246 and 5.5keV for GMBCG
J255.34805+64.23661, although there are indications for temperature
drop at large radii. From these results, we can estimate the density
and pressure distributions of the hot gas along the QSO sightline. We
further infer the radial entropy profile of Abell 2246 and compare it
with the one expected from purely gravitational hierarchical structure
formation. This comparison shows that the intracluster medium in the
outer region of the clusters is likely in a clumpy and multiphased
state. These results, together with the upcoming Hubble Space
Telescope/Cosmic Origins Spectrograph observations of the QSO
sightline, will enable a comprehensive investigation of the multiphase
medium associated with the clusters.
Description:
The Chandra data used in this work were taken in nine separate
observations. We reprocess the data with the latest version of the
Chandra Interactive Analysis of Observations (CIAO; version 4.5).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 62 195 Chandra Source List
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See also:
B/chandra : The Chandra Archive Log (CXC, 1999-2014)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq Source sequential number
5- 23 A19 --- CXOU CXOU name (JHHMMSS.ss+DDMMSS.s) (1)
25- 27 F3.1 arcsec e_Pos Position uncertainty (2)
29- 33 F5.2 ct/ks CR On-axis source broad-band count rate (3)
35- 38 F4.2 ct/ks e_CR rms uncertainty on CR
40- 44 F5.2 -- HR ?=- Hardness ratio, HR=(H-S2)/(H+S2) (4)
46- 49 F4.2 -- e_HR ? rms uncertainty on HR
51- 55 F5.2 --- HR1 ?=- Hardness ratio, HR1=(S2-S1)/S (4)
57- 60 F4.2 --- e_HR1 ? rms uncertainty on HR1
62 A1 --- Flag [BSH] Mark the band in which a source is
detected with the most accurate position
that is adopted in CXOU name
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Note (1): Chandra Xray Observatory (unregistered) source name, following the
Chandra naming convention and the IAU Recommendation for Nomenclature
(e.g., http://cdsweb.u-strasbg.fr/iau-spec.html).
Note (2): Position uncertainty (1σ) calculated from the maximum likelihood
centroiding and an approximate off-axis angle (r) dependent systematic error
0.002+1.004(r/8arcmin)2 (an approximation to Fig. 4 of Feigelson et al.,
2002, Cat. J/ApJ/574/258), which are added in quadrature.
Note (3): Sum of the exposure-corrected count rates in the four bands.
Note (4): Hardness ratios listed only for values with uncertainties less
than 0.2.
Definition of the bands:
0.3-0.7 (S1), 0.7-1.5 (S2), 1.5-3 (H1), and 3-7keV (H2).
S=S1+S2, H=H1+H2, and B=S+H.
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 04-Feb-2016