出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：Narrow Line Seyfert 1 galaxies are among the most interesting class of active nuclei. Their observational properties suggest that they are high accretion rate systems probably associated with relatively small black hole masses compared to classical Seyfert 1 galaxies. However, the number of known NLSy1 detected above 10 keV is small notwithstanding the importance of the high energy data to discriminate between the major competig models. Here we present a detailed study of a sample of 14 NLSy1 detected above 10 keV by INTEGRAL/IBIS, through an accurate broad-band analysis using INTEGRAL data combined with XMM-Newton and Swift/XRT data. The high energy spectral properties of our sample have been related to their accretion parameters in order to unveil the nature of these extreme AGN. We have estimated the fraction of NLSy1 in the hard X-ray sky to be nearly 15%, in agreement with the estimate derived from optically selected NLSy1 samples.
