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Titolo:
BeppoSAX view of NGC 526A: A Seyfert 1.9 galaxy with a flat spectrum
Autore:
Landi, R; Bassani, L; Malaguti, G; Cappi, M; Comastri, A; Dadina, M; Di Cocco, G; Fabian, AC; Palazzi, E; Palumbo, GGC; Trifoglio, M;
Indirizzi:
Univ Bologna, Dipartmento Fis, I-40127 Bologna, Italy Univ Bologna Bologna Italy I-40127 partmento Fis, I-40127 Bologna, Italy CNR, ITeSRE, I-40129 Bologna, Italy CNR Bologna Italy I-40129CNR, ITeSRE, I-40129 Bologna, Italy Osservatorio Astron Bologna, I-40127 Bologna, Italy Osservatorio Astron Bologna Bologna Italy I-40127 I-40127 Bologna, Italy Univ Cambridge, Inst Astron, Cambridge CB3 0HA, England Univ Cambridge Cambridge England CB3 0HA ron, Cambridge CB3 0HA, England Univ Bologna, Dipartimento Astron, I-40127 Bologna, Italy Univ Bologna Bologna Italy I-40127 imento Astron, I-40127 Bologna, Italy
Titolo Testata:
ASTRONOMY & ASTROPHYSICS
fascicolo: 1, volume: 379, anno: 2001,
pagine: 46 - 53
SICI:
1432-0746(200111)379:1<46:BVON5A>2.0.ZU;2-5
Fonte:
ISI
Lingua:
ENG
Soggetto:
RAY ASTRONOMY SATELLITE; ACTIVE GALACTIC NUCLEI; ASCA OBSERVATIONS; ON-BOARD; LINE;
Keywords:
X-rays : galaxies; galaxies : Seyfert; galaxies : individual : NGC 526A;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
32
Recensione:
Indirizzi per estratti:
Indirizzo: Landi, R Univ Bologna, Dipartmento Fis, Via Irnerio 46, I-40127 Bologna, Italy Univ Bologna Via Irnerio 46 Bologna Italy I-40127 Bologna, Italy
Citazione:
R. Landi et al., "BeppoSAX view of NGC 526A: A Seyfert 1.9 galaxy with a flat spectrum", ASTRON ASTR, 379(1), 2001, pp. 46-53

Abstract

In the present work we report the BeppoSAX observation of the Seyfert 1.9 galaxy NGC 526A in the band 0.1-150 keV. The high energy instrument onboard, PDS, has succeeded in measuring for the first time the spectrum of this source in the 13-150 keV range. The combined analysis of all Narrow Field Instruments provides a power law spectral index of similar or equal to1.6 andconfirms the at spectral nature of this source. Although NGC 526A varies strongly in the 2-10 keV range over a period of months/years, its spectral shape remains constant over these timescales. An Fe-K alpha 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 N-H similar to 10(22) cm(-2), but most likely originates by reflection in an accretion disk viewed at an intermediate inclination angle of similar to 42 degrees. The reflection component is however small (R less than or equal to 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 at power law spectrum cut-off at around 100 keV plus a small reflection component which could explainthe 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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Documento generato il 26/09/17 alle ore 09:14:03