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

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 <sup>1, 6

1</sup> 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 2 keV; b) a prominent (EW 1 keV) Fe line; c) a flat () 2-10 keV continuum; d) a 4.5 detection above 13 keV. The flat power law spectrum can be very well explained within the current AGN unified models assuming a steep () 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)

SIMBAD Objects

Contents

• 1. Introduction
• 2. Observation and data reduction
• 3. Spectral analysis
  • 3.1. The 2-10 keV spectrum
  • 3.2. The soft excess
  • 3.3. The broad-band reflection-dominated spectrum
• 4. Discussion
• Acknowledgements
• References

© European Southern Observatory (ESO) 1998

Online publication: February 16, 1998
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