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Astron. Astrophys. 351, 937-944 (1999)

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X-ray spectral components from a broad band BeppoSAX observation of the Seyfert galaxy IC 4329A

G.C. Perola 1, G. Matt 1, M. Cappi 2, D. Dal Fiume 2, F. Fiore 3, M. Guainazzi 4, T. Mineo 5, S. Molendi 6, F. Nicastro 7, L. Piro 8 and G. Stirpe 9

1 Dipartimento di Fisica, Università degli Studi "Roma Tre", Via della Vasca Navale 84, 00146 Roma, Italy
2 Istituto Tecnologie e Studio Radiazioni Extraterrestri, CNR, Via Gobetti 101, 40129 Bologna, Italy
3 Osservatorio Astronomico di Roma, Via dell'Osservatorio, 00044 Monteporzio Catone, Italy
4 Astrophysics Division, Space Science Department of ESA, ESTEC, Postbus 299, 2200 AG Noordwijk, The Netherlands
5 Istituto di Fisica Cosmica ed Applicazioni all'Informatica, C.N.R., Via U. La Malfa 153, 90146 Palermo, Italy
6 Istituto di Fisica Cosmica "G. Occhialini", C.N.R., Via Bassini 15, 20133 Milano, Italy
7 Harvard-Smithsonian Center for Astrophysics, 60 Garden st., Cambridge, MA 02138, USA
8 Istituto di Astrofisica Spaziale, C.N.R., Via Fosso del Cavaliere, 00133 Roma, Italy
9 Osservatorio Astronomico di Bologna, Viale Berti Pichat 6/2, 40127 Bologna, Italy

Received 11 May 1999 / Accepted 27 September 1999


From the spectral analysis of a broadband (0.1-200 keV) BeppoSAX observation of the Seyfert 1 galaxy IC 4329A, the main results obtained are: a) the amount of reflection, together with the intensity of the iron K line, indicate a geometry with a solid angle substantially less than 2[FORMULA]; b) the power law is affected by a cut off with e-folding energy about 270 keV, the fourth individual object so far where this property has been firmly detected; c) two absorption features at about 0.7 and 1 keV are found, the first corresponding to a blend of O VI and O VII , the other to a combination of FeL and NeK edges. Compared to an earlier ASCA observation, when the source was 30% fainter, the values of both the relative amount of reflection and the warm absorber ionization degree are significantly lower: the comparison is suggestive of sizeable delay effects in this object, due to geometrical factors in the reflection, and to relaxation to equilibrium states in the ionization of the absorber.

Key words: galaxies: individual: IC 4329A – galaxies: Seyfert – X-rays: galaxies

Send offprint requests to: G.C. Perola (perola@fis.uniroma3.it)

© European Southern Observatory (ESO) 1999

Online publication: November 16, 1999