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Astron. Astrophys. 351, L19-L22 (1999)
Letter to the Editor
The nature of the hard X-ray power-law tail in M 87
Matteo Guainazzi 1 and
Silvano Molendi 2
1 Astrophysics Division, Space Science Department of ESA, ESTEC, Postbus 299, 2200 AG Noordwijk, The Netherlands
2 Istituto di Fisica Cosmica "G.Occhialini", Via Bassini 15, 20133 Milano, Italy
Received 6 September 1999 / Accepted 13 October 1999
Abstract
Spatially-resolved spectroscopy of the elliptical galaxy M 87 with the MECS instrument on board BeppoSAX demonstrates that the hard X-ray power-law tail, originally discovered by ASCA (Matsumoto et al. 1996; Allen et al. 1999), originates in the innermost 2´. Our results are consistent with it being produced in an Accretion Dominated Flow, although a substantial jet contribution cannot be ruled out. An origin from a Seyfert-like nucleus is disfavored by our data. As a by-product of this result, we present an analysis of the thermal emission coming from the center of the Virgo cluster, which exhibits a strong positive radial temperature gradient, along with a radial decrease of the iron abundance.
Key words: accretion, accretion
disks 
galaxies:
nuclei
galaxies: individual:
M 87
galaxies: clusters: individual:
Virgo
X-rays: galaxies
Send offprint requests to: M.Guainazzi
Contents
- 1. Introduction
- 2. Observation and data reduction
- 3. Spatially-resolved spectroscopy
- 4. Discussion
- Acknowledgements
- References
© European Southern Observatory (ESO) 1999
Online publication: November 3, 1999
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