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Astron. Astrophys. 323, L1-L4 (1997)

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Letter to the Editor

X-ray detections of weak Seyfert 2's with BeppoSAX

M. Salvati 1, L. Bassani 2, R. Della Ceca 3, R. Maiolino 1, 4, G. Matt 5 and G. Zamorani 6

1 Osservatorio Astrofisico di Arcetri, L. E. Fermi 5, I-50125 Firenze, Italy
2 Istituto Tecnologie e Studio Radiazioni Extraterrestri, CNR, Via Gobetti 101, I-40129 Bologna, Italy
3 Osservatorio Astronomico di Brera, Via Brera 28, I-20121 Milano, Italy
4 MPI für Extraterrestrische Physik, Giessenbachstrasse 1, D-85748 Garching bei München, Germany
5 Dipartimento di Fisica, Università di Roma III, Via della Vasca Navale 84, I-00146 Roma, Italy
6 Osservatorio Astronomico di Bologna, Via Zamboni 33, I-40126 Bologna, Italy

Received 15 April 1997 / Accepted 2 May 1997


We report the detection in the X rays of two weak Seyfert 2's (NGC3393 and NGC4941) with the Italian-Dutch satellite BeppoSAX. These are among the first sources observed in a sample of 12 Seyfert 2's which are being studied within the BeppoSAX core program, in an effort to probe the putative torus at high X-ray energies, calibrate an isotropic luminosity indicator for absorbed nuclei, and determine the distribution of torus thicknesses, [FORMULA].

Both a Compton thick spectrum, with a reflected power law and a large equivalent width iron line, and a Compton thin spectrum, with the intrinsic power law transmitted through a large column density absorber, provide acceptable fits to both sources, with some preference for the latter model in the case of NGC4941. The high initial detection rate in our program points to a large final X-ray sample.

Key words: X-rays: galaxies – Galaxies: Seyfert – Galaxies: individual: NGC3393 – Galaxies: individual: NGC4941

Send offprint requests to: M. Salvati

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© European Southern Observatory (ESO) 1997

Online publication: June 5, 1998