EDP Sciences Journals List
Advanced Search
Subscriber Authentication Point
Home All issues Volume 414/3 Article
Free access article

Issue A&A
Volume 414, Number 3, February II 2004
Page(s) L41 - L44
Section Letters
DOI http://dx.doi.org/10.1051/0004-6361:20031749



A&A 414, L41-L44 (2004)
DOI: 10.1051/0004-6361:20031749

Letter

Is there a hard tail in the Coma Cluster X-ray spectrum?

M. Rossetti1, 2 and S. Molendi1

1  Istituto di Astrofisica Spaziale e Fisica Cosmica, via Bassini 15, 20133 Milano, Italy
2  Università degli Studi di Milano, Dip. di Fisica, via Celoria 16, 20133 Milano, Italy

(Received 30 September 2003 / Accepted 17 December 2003)

Abstract
We report results from a re-analysis of the BeppoSAX observation of Coma and from the analysis of a second, yet unpublished observation of the same object. From our re-analysis of the first observation we find that the statistical evidence for a hard tail is about 2 $\sigma$. From the analysis of the second observation which, thanks to the lower background and the longer exposure time, is characterized by a larger signal-to-noise we find no evidence for a hard tail. From the upper limit on the flux of the hard tail, using the standard Inverse Compton formulae, we derive a lower limit for the magnetic of ${\sim} 0.2{-}0.4\ \mu\rm {Gauss}$ consistent with Faraday rotation measurements.


Key words: cosmic microwave background -- galaxies: clusters: individual: Coma -- magnetic field -- radiation mechanism: non-thermal -- X-rays: galaxies: clusters

Offprint request: M. Rossetti, rossetti@mi.iasf.cnr.it

SIMBAD Objects



© ESO 2004


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.