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J/A+A/585/A130    X-ray halo of 33 clusters of galaxies images  (Hofmann+, 2016)

Thermodynamic perturbations in the X-ray halo of 33 clusters of galaxies observed with Chandra ACIS. Hofmann F., Sanders J.S., Nandra K., Clerc N., Gaspari M. <Astron. Astrophys. 585, A130 (2016)> =2016A&A...585A.130H (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, galaxy ; X-ray sources Keywords: galaxies: clusters - X-rays: galaxies: clusters - turbulence Abstract: In high-resolution X-ray observations of the hot plasma in clusters of galaxies significant structures caused by AGN feedback, mergers, and turbulence can be detected. Many clusters have been observed by Chandra in great depth and at high resolution. Using archival data taken with the Chandra ACIS instrument the aim was to study thermodynamic perturbations of the X-ray emitting plasma and to apply this to better understand the thermodynamic and dynamic state of the intra cluster medium (ICM). We analyzed deep observations for a sample of 33 clusters with more than 100ks of Chandra exposure each at distances between redshift 0.025 and 0.45. The combined exposure of the sample is 8Ms. Fitting emission models to different regions of the extended X-ray emission we searched for perturbations in density, temperature, pressure, and entropy of the hot plasma. For individual clusters we mapped the thermodynamic properties of the ICM and measured their spread in circular concentric annuli. Comparing the spread of different gas quantities to high-resolution 3D hydrodynamic simulations, we constrain the average Mach number regime of the sample to Mach1D ∼0.16±0.07. In addition we found a tight correlation between metallicity, temperature and redshift with an average metallicity of Z∼0.3±0.1 Z(solar). This study provides detailed perturbation measurements for a large sample of clusters which can be used to study turbulence and make predictions for future X-ray observatories like eROSITA, Astro-H, and Athena. Description: For a sample of 33 clusters of galaxies all available Chandra X-ray observations were merged and thermodynamic 2D maps of the ICM were calculated. Based on these maps deviations from spherical symmetry were calculated for each thermodynamic property. The pixlist<cluster><S/N>.fits files list the properties of each pixel in the 2D maps for each cluster with a fixed signal-to- noise ratio (S/N) in each 2D spatial bin. The <cluster>int5.fits files contain the spread measurements of temperature, density, pressure, and entropy in five concentric circular annuli. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 165 33 Sample properties and fits files informations images/* 0 33 Individual fits images tables/* 0 66 Individual fits tables
Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 18 A18 --- Name Cluster name (1) 20- 28 A9 --- cluster Abbreviate name of cluster, used for the fits file names 30- 34 F5.3 10+22cm-2 nH Hydrogen column density 36- 39 F4.1 keV <Tmap> Mean map temperature 41- 45 F5.3 keV e_<Tmap> rms uncertainty on <Tmap> 47- 50 F4.2 Mpc rFOV Maximum radius (from X-ray peak) covered in our analysis 52- 55 F4.2 Mpc r500 Overdensity radius (2) 57- 60 F4.2 Mpc e_r500 rms uncertainty on r500 (2) 62- 65 F4.1 10+14Msun M500 Oversensity mass (2) 67- 69 F3.1 10+14Msun e_M500 rms uncertainty on M500 (2) 71- 75 F5.3 --- rFOV/r500 Radius ratio 78- 86 F9.5 deg RAdeg Right ascension of image center (J2000) 87- 95 F9.5 deg DEdeg Declination of image center (J2000) 97-118 A22 --- Image Name of the fits image in subdirectory images 120-139 A20 --- Int5 Name of the fits file (asymmetry measured in 5 annuli) in subdirectory tables (3) 141-165 A25 --- Pixlist Name of the fits file (pixel by pixel thermodynamic map) in subdirectory tables (4)
Note (1): Most commonly used cluster name and abbreviated catalogue names of clusters, sorted on descending mass (M500). Note (2): Overdensity radii r500 and M500 were calculated using the mass-temperature scaling relation from Vikhlinin et al. (2009ApJ...692.1033V) for an estimate on the r500 fraction covered in each object. We used <Tmap> as input for the scaling relation and estimated errors assuming a 0.5keV systematic uncertainty (see scatter in Fig. 4). Note (3): Content of clusterint5.fits files (asymmetry measured in 5 annuli) ------------------------------------------------------------------------------ Row Units Label Explanations ------------------------------------------------------------------------------ 1 kpc rr average radius of annulus (1) 2 keV T average temperature 3 keV Te T uncertainty 4 --- Z average metallicity (2) 5 --- Ze Z uncertainty 6 --- dP frac. spread in pressure (3) 7 --- dP_eu dP positive uncertainty 8 --- dP_el dP negative uncertainty 9 --- dS frac. spread in entropy (3) 10 --- dS_eu dS positive uncertainty 11 --- dS_el dS negative uncertainty 12 --- dn frac. spread in density (3) 13 --- dn_eu dn positive uncertainty 14 --- dn_el dn negative uncertainty 15 --- dT frac. spread in temperature (3) 16 --- dT_eu dP positive uncertainty 17 --- dT_el dP negative uncertainty ---------------------------------------------------------------------------- Note (1): all asymmetry measurements were taken in circular concentric annuli around the cluster center. confidence ranges are on the 1 sigma level. Note (2): metallicity is given as a fraction of solar metallicity. Note (3): fractional intrinsic spread measurements of properties. ----------------------------------------------------------------------------- Note (4): Content of pixlistclusterint_NN.fits files (pixel by pixel thermodynamic map) ------------------------------------------------------------------------------ Row Units Label Explanations ------------------------------------------------------------------------------ 1 pixel x x pixel coordinate (1) 2 pixel y y pixel coordinate (1) 3 --- binnum Bin number (2) 4 --- cts Counts in observation 5 --- bgcts Counts in background observation 6 cm2s*cts*photon-1 exp Effective exposure (3) 7 keV T Temperature (4) 8 keV Tup T upper limit (4) 9 keV Tlo T lower limit (4) 10 Sun Z Solar metallicity fraction (4) 11 Sun Zup Z upper limit (4) 12 Sun Zlo Z lower limit (4) 13 cm-5 norm Normalization of spectrum (4) 14 cm-5 normup Norm upper limit (4) 15 cm-5 normlo Norm lower limit (4) 16 --- redshift Fixed redshift of the cluster 17 1022cm-2^ NH Foreground column density 18 pixel cen_dist Distance from cluster center 19 rad cen_angl Angle measured from dir. west 20 arcsec rad_arcsec Distance from cluster center 21 kpc rad_kpc Distance from cluster center 22 keV*cm-5/2*arcsec-1 P Pseudo pressure 23 keV*cm5/3*arcsec2/3 S Pseudo entropy 24 cm-5/2*arcsec-1 n Pseudo density 25 keV*cm-5/2*arcsec-1 P_err Symmetric P uncertainty 26 keV*cm5/3*arcsec2/3 S_err Symmetric S uncertainty 27 cm-5/2*arcsec-1 n_err Symmetric n uncertainty -------------------------------------------------------------------------------- Note (1): pixelsize∼1arcsecond Note (2): Number of the spatial bin the pixel belongs to. Pixels with the same bin number have the same spectral values. Only their coordinates differ. Note (3): effective exposure of the observation in Chandra default units of exposure (cm2s*count/photon). Note that background observation exposure will differ. Note (4): values obtained from fitting an absorbed XSPEC apec model for collisionally ionized plasma to the spectrum extracted in one spatial bin. All confidence ranges are on the 1 sigma level. Note (5): properties calculated from spectral fits. See publication for details.
Acknowledgements: Florian Hofmann, fhofmann(at)mpe.mpg.de
(End) Florian Hofmann [MPE,Germany], Patricia Vannier [CDS] 30-Oct-2015
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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