BeppoSAX observation of the rich cluster of galaxies Abell 85

Free access article

Issue		A&A Volume 368, Number 2, March III 2001


Page(s)		440 - 450
Section		Extragalactic astronomy
DOI		http://dx.doi.org/10.1051/0004-6361:20010017

A&A 368, 440-450 (2001)
DOI: 10.1051/0004-6361:20010017

BeppoSAX observation of the rich cluster of galaxies Abell 85

G. B. Lima Neto^{1, 2}, V. Pislar^{2, 3} and J. Bagchi⁴

¹ Instituto Astronômico e Geofísico/USP, Av. Miguel Stefano 4200, 04301-904 São Paulo/S.P., Brazil
² Institut d'Astrophysique de Paris, CNRS, 98bis Bd. Arago, 75014 Paris, France
³ Université du Havre, 25 rue Philippe Lebon, 76600 Le Havre, France
⁴ Inter-University Centre for Astronomy and Astrophysics (IUCAA), Post Bag 4, Ganeshkhind, Pune 411007, India

(Received 23 June 2000 / Accepted 15 December 2000 )

Abstract
We report the observation of the Intra-Cluster Medium (ICM) of Abell 85 by the X-ray satellite BeppoSAX. We have analysed both the spectrum obtained in the central 8 arcmin circular region centred on the Very Steep Spectrum Radio Source (VSSRS) and the spectra from a number of sub-regions. Analysis of the spectra allowed us to independently obtain new estimates of the temperature, metallicity and line-of-sight hydrogen density column, both globally ( $T=6.6\pm0.3$ keV, $Z = 0.38\pm0.06 Z_{\odot}$ and $N_{\rm H} = 5.5^{+0.9}_{-0.7} 10^{20}$ cm^-2) and locally. These measures are in good agreement with previous measures based on ROSAT and ASCA data. In the region of the VSRSS, we attempted to discriminate between thermal and non-thermal X-ray emission. Although we could not do this unambiguously, we have nonetheless estimated the extended magnetic field using the radio spectrum available for this region. We obtain a lower limit intensity of $0.9 \mu$ G, consistent with our previous estimate. We also derive $\alpha$ -elements/iron abundance ratios that turn out to be higher than 1. Such a result tends to support the burst model for elliptical galaxies, where a strong galactic wind develops early in the galaxy history and type II supernovae (SN) may be the major contributors to the enrichment of the ICM. A two-temperature ICM model was fitted in the central region, yielding a main component with roughly the mean cluster temperature and a cooler component with temperature less than 0.1 keV.

Key words: galaxies: clusters: Abell 85 -- galaxies: magnetic fields -- X-rays: galaxies -- galaxies: abundances -- radio continuum: galaxies

Offprint request: G. B. Lima Neto, gastao@iagusp.usp.br

SIMBAD Objects

What is OpenURL?

The OpenURL standard is a protocol for transmission of metadata describing the resource that you wish to access. An OpenURL link contains article metadata and directs it to the OpenURL server of your choice. The OpenURL server can provide access to the resource and also offer complementary services (specific search engine, export of references...). The OpenURL link can be generated by different means.

If your librarian has set up your subscription with an OpenURL resolver, OpenURL links appear automatically on the abstract pages.
You can define your own OpenURL resolver with your EDPS Account. In this case your choice will be given priority over that of your library.
You can use an add-on for your browser (Firefox or I.E.) to display OpenURL links on a page (see http://www.openly.com/openurlref/). You should disable this module if you wish to use the OpenURL server that you or your library have defined.