J/ApJS/174/117 Properties and metal abundances of clusters (Maughan+, 2008)
Images, structural properties, and metal abundances of galaxy clusters observed
with Chandra ACIS-I at 0.1<z<1.3.
Maughan B.J., Jones C., Forman W., Van Speybroeck L.
<Astrophys. J. Suppl. Ser., 174, 117-135 (2008)>
=2008ApJS..174..117M 2008ApJS..174..117M
ADC_Keywords: Clusters, galaxy ; X-ray sources ; Abundances
Keywords: cosmology: observations - galaxies: clusters: general -
galaxies: high-redshift - intergalactic medium - X-rays: galaxies
Abstract:
We have assembled a sample of 115 galaxy clusters at 0.1<z<1.3 with
archived Chandra ACIS-I observations. We present X-ray images of the
clusters and make available region files containing contours of the
smoothed X-ray emission. The structural properties of the clusters
were investigated, and we found a significant absence of relaxed
clusters (as determined by centroid shift measurements) at z>0.5.
The slope of the surface brightness profiles at large radii were
steeper on average by 15% than the slope obtained by fitting a simple
β-model to the emission. This slope was also found to be correlated
with cluster temperature, with some indication that the correlation is
weaker for the clusters at z>0.5. We measured the mean metal
abundance of the cluster gas as a function of redshift and found
significant evolution, with the abundances dropping by 50% between
z=0.1 and z∼1. This evolution was still present (although less
significant) when the cluster cores were excluded from the abundance
measurements, indicating that the evolution is not solely due to the
disappearance of relaxed, cool core clusters (which are known to have
enhanced core metal abundances) from the population at z≳0.5.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 71 148 Summary of the observations used
table2.dat 62 115 Structural properties of the clusters
table3.dat 130 115 Summary of the cluster properties
--------------------------------------------------------------------------------
See also:
J/A+A/396/397 : Deep cluster survey in Chandra archival data (Boschin+, 2002)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 17 A17 --- Name Cluster identification (1)
19- 22 I4 --- ObsID Chandra observation identifier (NNNN)
24- 25 I2 h RAh ICRS hour of right ascension of the X-ray
centroid (J2000)
27- 28 I2 min RAm ICRS minute of right ascension (J2000)
30- 34 F5.2 s RAs ICRS second of right ascension (J2000)
36 A1 --- DE- Sign of declination (J2000)
37- 38 I2 deg DEd ICRS degree of declination (J2000)
40- 41 I2 arcmin DEm ICRS arcminute of declination (J2000)
43- 46 F4.1 arcsec DEs ICRS arcsecond of declination (J2000)
48- 52 F5.3 --- z Redshift of the cluster (2)
54- 63 A10 "YYYY/MM/DD" ObsDate Observation date
65 A1 --- BG [BCD] "Blank-sky" background period
corresponding for each observation
67- 71 F5.1 ks ExpTime Cleaned exposure time of each observation
--------------------------------------------------------------------------------
Note (1): Clusters identified as <[MJF2008] JHHMMSS.ss+DDMMSS.s> in Simbad.
Note (2): Redshifts are taken from NED or BAX, the X-Rays Clusters Database
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 17 A17 --- Name Cluster identification
19- 22 F4.2 --- Ell Ellipticity: e=(1-b/a) where a and b are the
semimajor and -minor axes respectively
24- 27 F4.2 --- E_Ell Positive error on ellipticity
29- 32 F4.2 --- e_Ell Negative error on ellipticity
34- 37 F4.2 --- W Centroid shift , in hundredths of R500 (1)
39- 42 F4.2 --- e_W Error on Centroid shift (1)
44- 47 F4.2 --- Rw Maximum radius within which the centroid shift
could be measured (in units of R500)
49- 52 F4.2 [---] b500 ?=- Logarithmic slope of the surface
brightness profile at radius R500 (3)
54- 57 F4.2 [---] E_b500 ? Positive error on b500
59- 62 F4.2 [---] e_b500 ? Negative error on b500
--------------------------------------------------------------------------------
Note (1): defined as the standard deviation of the projected separation
between the peak and centroid; it is expressed in 10-2R500 units
(approximately 0.005 virial radius). The errors quoted for the are
the statistical uncertainties on a standard deviation calculated from
n measurements [/(2n-2)].
Note (3): b500 is defined with b500 = 1/6.(1-dlog(Sx)/dlog(r)) at r=R500.
For 6 clusters, the emission was not detected to a large enough radius
to measure β500.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 17 A17 --- Name Cluster identification
19- 22 F4.2 Mpc R500 Radius R500 (1)
24- 27 F4.1 keV kT Temperature for r<R500
29- 32 F4.1 keV E_kT Positive error on kT
34- 36 F3.1 keV e_kT Negative error on kT
38- 42 F5.1 10+37W LX X-ray luminosity for r<R500 (4)
44- 46 F3.1 10+37W e_LX Error on LX
48- 51 F4.2 Sun Z Metal abundance for r<R500
53- 56 F4.2 Sun E_Z Positive error on Z
58- 61 F4.2 Sun e_Z Negative error on Z
63- 67 F5.2 10+13solMass Mgas Gas Mass for r<R500
69- 72 F4.2 10+13solMass E_Mgas Positive error on Mass (2)
74- 77 F4.2 10+13solMass e_Mgas Negative error on Mass (2)
79- 82 F4.1 keV kT2 ?=- Temperature for 0.15<(r/R500)<1 (3)
84- 86 F3.1 keV E_kT2 ? Positive error for kT2
88- 90 F3.1 keV e_kT2 ? Negative error for kT2
92- 95 F4.1 10+37W LX2 X-ray luminosity for (0.15<r<1)R500 (4)
97- 99 F3.1 10+37W e_LX2 Error on LX2
101-104 F4.2 Sun Z2 ?=- Metal abundance 0.15<(r/R500)<1 (3)
106-109 F4.2 Sun E_Z2 ? Positive error on Z2
111-114 F4.2 Sun e_Z2 ? Negative error on Z2
116-120 F5.1 10+13solMass.keV YX YX = gas mass times mean X-ray spectral
temperature (from Kravtsov et al.,
2006ApJ...650..128K 2006ApJ...650..128K)
122-125 F4.1 10+13solMass.keV E_YX Positive error on YX
127-130 F4.1 10+13solMass.keV e_YX Negative error on YX
--------------------------------------------------------------------------------
Note (1): This radius corresponds to approximately half of the virial radius.
Note (2): Uncertainties determined from Monte Carlo randomizations of the
observed emission measure profiles
Note (3): 4 clusters were too faint to permit a full spectral fit in the
(0.15<r<1)R500 aperture and have no measurments for kT and Z2. For
these clusters YX was derived using the temperature measured in the
r<R_500- aperture, and LX was measured by a spectral fit in the
(0.15<r<1)R500 aperture with kT fixed at the global temperature.
Note (4): in units of 1044erg/s = 1037W
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Emmanuelle Perret [CDS] 12-Jun-2009