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Astron. Astrophys. 331, 519-523 (1998)

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BeppoSAX observation of NGC 7674:
a new reflection-dominated Seyfert 2 galaxy

G. Malaguti 1, G.G.C. Palumbo 1, 2, M. Cappi 1, 3, A. Comastri 4, C. Otani 3, M. Matsuoka 3, M. Guainazzi 5, L. Bassani 1 and F. Frontera 1, 6

1 ITESRE/CNR, via Piero Gobetti 101, I-40129 Bologna, Italy
2 Dipartimento di Astronomia, Università di Bologna, via Zamboni 33, I-40126 Bologna, Italy
3 The Institute of Physical and Chemical research (RIKEN), 2-1, Hirosawa, Wako, Saitama 351-01, Japan
4 Osservatorio Astronomico di Bologna, via Zamboni 33, I-40126 Bologna, Italy
5 ASI SAX/SDC c/o Nuova Telespazio, via Corcolle 19, I-00131 Roma, Italy
6 Dipartimento di Fisica, Università di Ferrara, via Paradiso 12, I-44100 Ferrara, Italy

Received 17 October 1997 / Accepted 12 November 1997

Abstract

The Seyfert 2 galaxy NGC 7674 has been observed within the BeppoSAX Core Programme with the onboard narrow field instruments between 0.1 and 100 keV. The broad-band spectrum shows four most relevant spectral components: a) a soft excess below [FORMULA] 2 keV; b) a prominent (EW [FORMULA] 1 keV) Fe line; c) a flat ([FORMULA]) 2-10 keV continuum; d) a 4.5 [FORMULA] detection above 13 keV. The flat power law spectrum can be very well explained within the current AGN unified models assuming a steep ([FORMULA]) intrinsic spectrum scattered by warm gas for the low energy band and totally reflected by optically thick cold matter (plausibly a molecular torus) for the high energy band. The case of NGC 7674 adds to the increasing number of so called "Compton-thick" Seyfert 2 galaxies in which the direct emission is totally absorbed and the X-ray luminosity is thus at least one or two orders of magnitude larger than what inferred from the observed flux.

Key words: X-rays: galaxies – galaxies: Seyfert – galaxies: individual: NGC 7674

Send offprint requests to: G. Malaguti (malaguti@tesre.bo.cnr.it)

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© European Southern Observatory (ESO) 1998

Online publication: February 16, 1998
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