EDP Sciences
Free access
Volume 407, Number 1, August III 2003
Page(s) 41 - 50
Section Extragalactic astronomy
DOI http://dx.doi.org/10.1051/0004-6361:20030862

A&A 407, 41-50 (2003)
DOI: 10.1051/0004-6361:20030862

X-ray spectroscopy of the cluster of galaxies PKS 0745-191 with XMM-Newton

Y. Chen1, 2, Y. Ikebe2 and H. Böhringer2

1  Center of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100039, PR China
2  Max-Planck-Institut für Extraterrestrische Physik, 85740 Garching, Germany

(Received 10 July 2002 / Accepted 4 June 2003)

We present the results from XMM-Newton observations of the cluster of galaxies PKS 0745-191 . The spatially resolved spectra from the European Photon Imaging Cameras (both EPN and EMOS) can be fitted with a single temperature thermal plasma model when the interstellar column density is closer to the lower limit of the range allowed by observations. Alternatively, a two-component model can be fitted to the spectra from the inner region for slightly higher values of  $N_{\rm H}$. The temperature profile shows a drop in the center of the cluster, from about 8 keV at radii larger than ~350 kpc to about 4 keV at the center, indicating that the gas in the central region is cooling. The total cooling flow rate inferred from the spectral data is only 364 +97-94  $M_{\odot}$ yr -1, however, much smaller than the previously obtained value. The metal abundance is found to decrease from 0.5 in solar units at the center to about 0.2 at a radius of ~300 kpc. Deprojected spectra are also presented, which show a result similar to the projected spectra. The location of the X-ray emission peak is also the site of extended radio emission. Inspection of the higher resolution Chandra image of the cluster shows enhanced X-ray emission about 3 $\arcsec$ west of the center where also the radio emission is elongated. We explore possible implications on the interaction between the radio lobes and the intracluster plasma. Assuming that the gas is in hydrostatic equilibrium with the cluster potential, we find a total mass of about  $1.18\pm 0.04 \times 10^{13}$  $M_{\odot}$ within the critical radius of the observed gravitational arc, which is a factor ~2 lower, however, than that from optical lensing. We also calculated the gas mass fraction profile up to 0.63  $r_{\rm vir}$ and obtained a mean gas mass fraction $f_{\rm gas}=0.22\pm0.02$.

Key words: X-rays: galaxies -- galaxies: clusters: individual: PKS 0745-191

Offprint request: Y. Chen, ychen@mail.ihep.ac.cn

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