EDP Sciences
Free access
Volume 366, Number 3, February II 2001
Page(s) 788 - 795
Section Extragalactic astronomy
DOI http://dx.doi.org/10.1051/0004-6361:20000334

A&A 366, 788-795 (2001)
DOI: 10.1051/0004-6361:20000334

BeppoSAX observation of Hercules A and MRC 0625-536

E. Trussoni1, L. Feretti2, S. Massaglia3 and P. Parma2

1  Osservatorio Astronomico di Torino, Strada Osservatorio 20, 10025 Pino Torinese, Italy
2  Istituto di Radioastronomia del CNR, Via Gobetti 101, 40129 Bologna, Italy
3  Dipartimento di Fisica Generale dell'Università, Via Pietro Giuria 1, 10125 Torino, Italy

(Received 12 September 2000 / Accepted 23 November 2000)

We present BeppoSAX observations of the two FR I type radio galaxies Hercules A (3C 348) and MRC 0625-536 in the energy range 0.2-200 keV. Data analysis shows that the X-ray flux from Hercules A is consistent with a diffuse thermal plasma emitting at $T \approx 4$-5 keV with a possible, but somewhat uncertain, contribution of a softer component at $T \approx 3 $ keV. The non thermal emission from the active nucleus must be significantly smaller than the thermal one, and no indication of relevant core obscuration by a surrounding torus was detected. The flux from MRC 0625-536 originates from an extended region and has been fitted to a thermal law with $T \approx
5.7$ keV and with a column density consistent with the galactic absorption. A spatially resolved spectral analysis does not show a relevant variation of the temperature and of the metallicity across the diffuse emission zone. A non thermal spectral component, related to the nuclear activity, may be present in the innermost region with some possible amount of local obscuration, contributing $\mathrel{\mathchoice {\vcenter{\offinterlineskip\halign{\hfil
$\displaystyle ...10% to the total luminosity. Hard X-ray emission from MRC 0625-536 has been detected in the PDS (15-200 keV) that may be related either to its galactic core or to the intracluster region.

Key words: galaxies: active -- galaxies: clusters: individual: A 3391 -- galaxies: individual: Hercules A; MRC 0625-536 -- galaxies: nuclei -- X-rays: galaxies

Offprint request: E. Trussoni, trussoni@to.astro.it

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