SAX J0122.8-3448 , the SIMBAD biblio

2001A&A...379...46L - Astronomy and Astrophysics, volume 379, 46-53 (2001/11-3)

BeppoSAX view of NGC 526A: A Seyfert 1.9 galaxy with a flat spectrum.

LANDI R., BASSANI L., MALAGUTI G., CAPPI M., COMASTRI A., DADINA M., DI COCCO G., FABIAN A.C., PALAZZI E., PALUMBO G.G.C. and TRIFOGLIO M.

Abstract (from CDS):

In the present work we report the BeppoSAX observation of the Seyfert 1.9 galaxy NGC 526A in the band 0.1-150keV. The high energy instrument onboard, PDS, has succeeded in measuring for the first time the spectrum of this source in the 13-150keV range. The combined analysis of all Narrow Field Instruments provides a power law spectral index of ≃1.6 and confirms the flat spectral nature of this source. Although NGC 526A varies strongly in the 2-10keV range over a period of months/years, its spectral shape remains constant over these timescales. An Fe line, characterized by a complex structure, has been detected in the 6-7 keV range. The line, which has an equivalent width of 120 eV, is not compatible with being produced in an absorbing medium with NH∼1022cm–2, but most likely originates by reflection in an accretion disk viewed at an intermediate inclination angle of ∼42°. The reflection component is however small i (R≤0.7) and so it is not sufficient to steepen the spectrum to photon index values more typical of AGNs. Instead, we find that the data are more consistent with a flat power law spectrum cut-off at around 100keV plus a small reflection component which could explain the observed iron line. Thus NGC 526A is the only bona-fide Seyfert 2 galaxy which maintains a ``flat spectrum'' even when broad band data are considered: in this sense its properties, with respect to the general class of Seyfert 2's, are analogous to those of NGC 4151 with respect to the vast majority of Seyfert 1's.

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Journal keyword(s): X-rays: galaxies - galaxies: Seyfert - galaxies: individual: NGC 526A

Nomenclature: Table 2: [LBM2001b] N (Nos 1-2).

Simbad objects: 8

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