2001A&A...379...46L


Query : 2001A&A...379...46L

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.

Abstract Copyright:

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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Number of rows : 8
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 SAX J0122.8-3448 X 01 22 47.5 -34 48 22           ~ 1 0
2 2dFGRS TGS566Z108 G 01 22 47.663 -34 48 47.04   18.4   17.164   ~ 1 0
3 2MASS J01224824-3448575 * 01 22 48.2039223168 -34 48 57.540547188   20.1       ~ 1 0
4 NGC 526 Sy1 01 23 54.3772245792 -35 03 55.710850788   14.76 14.60 13.46   ~ 315 1
5 NGC 2110 Sy2 05 52 11.3768668776 -07 27 22.507465392   14.77 13.51 11.86   ~ 638 1
6 ESO 434-40 Sy2 09 47 40.1332188528 -30 56 55.960779696   14.10 13.69 12.44   ~ 524 0
7 NGC 4151 Sy1 12 10 32.5759813872 +39 24 21.063527532   12.18 11.48     ~ 3574 2
8 NGC 4507 Sy2 12 35 36.6338976888 -39 54 33.710416272   12.95 13.54 11.70 12.4 ~ 474 0

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2023.02.02-18:36:51

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