A sample of nine bright Seyfert 1 and NELG type galaxies, observed with BeppoSAX, is analyzed to assess on a truly broad band basis (0.1-200 keV) the issue of the spectral contributions of Compton reflection and iron line fluorescence from circumnuclear gas. The empirical description adopted for the direct continuum is the commonly used power law with an exponential cut-off. The most direct test of the theoretical predictions, namely that the equivalent width of the line, W-alpha, and the strength R of the reflection relative to the direct continuum are closely related to each other, gives a substantially positive result, that is their mean ratio is very close to expectation, and only a modest spread in the iron abundance seems implied. The existence of a steep correlation between R and the slope Gamma of the power law is not confirmed. A weak evidence is found that the existence of a very shallow trend to increase on average with cannot be altogether excluded in both R and W-alpha, but needs to be tested with a larger sample. The energy E-f in the exponential cut-off spans a range from about 80 to more than 300 keV. A possible correlation is found, with E-f increasing on average with Gamma: if ignored, for instance by keeping E-f at a fixed value in a sample study, it could be cause of artificial steepening in a correlation between R and Gamma.

Perola, G.c., Matt, G., Cappi, M., Fiore, F., Guainazzi, M., Maraschi, L., et al. (2002). Compton reflection and iron fluorescence in BeppoSAX observations of Seyfert type 1 galaxies. ASTRONOMY & ASTROPHYSICS, 389(3), 802-811 [10.1051/0004-6361:20020658].

Compton reflection and iron fluorescence in BeppoSAX observations of Seyfert type 1 galaxies

MATT, Giorgio;
2002-01-01

Abstract

A sample of nine bright Seyfert 1 and NELG type galaxies, observed with BeppoSAX, is analyzed to assess on a truly broad band basis (0.1-200 keV) the issue of the spectral contributions of Compton reflection and iron line fluorescence from circumnuclear gas. The empirical description adopted for the direct continuum is the commonly used power law with an exponential cut-off. The most direct test of the theoretical predictions, namely that the equivalent width of the line, W-alpha, and the strength R of the reflection relative to the direct continuum are closely related to each other, gives a substantially positive result, that is their mean ratio is very close to expectation, and only a modest spread in the iron abundance seems implied. The existence of a steep correlation between R and the slope Gamma of the power law is not confirmed. A weak evidence is found that the existence of a very shallow trend to increase on average with cannot be altogether excluded in both R and W-alpha, but needs to be tested with a larger sample. The energy E-f in the exponential cut-off spans a range from about 80 to more than 300 keV. A possible correlation is found, with E-f increasing on average with Gamma: if ignored, for instance by keeping E-f at a fixed value in a sample study, it could be cause of artificial steepening in a correlation between R and Gamma.
2002
Perola, G.c., Matt, G., Cappi, M., Fiore, F., Guainazzi, M., Maraschi, L., et al. (2002). Compton reflection and iron fluorescence in BeppoSAX observations of Seyfert type 1 galaxies. ASTRONOMY & ASTROPHYSICS, 389(3), 802-811 [10.1051/0004-6361:20020658].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11590/132458
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