SIMBAD references

2000MNRAS.318..239E - Mon. Not. R. Astron. Soc., 318, 239-249 (2000/October-2)

BeppoSAX-ROSAT PSPC observations of the Shapley supercluster: A3562.


Abstract (from CDS):

We present a combined analysis of the BeppoSAX and ROSAT PSPC observation of the cluster of galaxies A3562, a massive member of the core of the Shapley supercluster. With a complex and interacting structure composed from two groups of galaxies and A3558 to the west, the surface brightness of A3562 shows excess in the sectors to east and south when compared with an azimuthally averaged model of the emission. The emission tends to be flatter, and the distribution of the gas broader, along the merging axis and in opposition to the two groups. We present the first determination of the gradients of the gas temperature and metallicity for a cluster in the Shapley region at large distance from the cluster centre. From an analysis of the BeppoSAX data in annuli and sectors, we observe both the profiles to be flat within 8arcmin (∼0.62Mpc), with emission-weighted values of kT=5.1±0.2keV and Z=0.39±0.05Z. The value of the temperature is consistent with recent ASCA measurements and is significantly higher than previous estimates obtained from ROSAT and EXOSAT. We discuss the possible reasons for this disagreement. Between 8 and 20arcmin, the plasma temperature declines to about 3.2keV. When a polytropic profile is used to represent the gas temperature profile, the best-fitting polytropic index is 1.16±0.03. These results imply a total mass within the virial radius of {formmu1} between 40 and 80per cent lower than the optical estimate, and a gas mass fraction of about 30per cent.

Abstract Copyright: 2000, Royal Astronomical Society

Journal keyword(s): galaxies: clusters: individual: A3562 - dark matter - X-rays: galaxies

Simbad objects: 12

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