Narrow Line Seyfert 1 galaxies at hard X-rays

Details Narrow Line Seyfert 1 galaxies at hard X-rays Narrow Line Seyfert 1 galaxies at hard X-rays

2011-06-15

arxiv.org/abs/1106.3023v1

Astronomy and Astrophysics

Astrophysics

High Energy Astrophysical Phenomena

Accepted to MNRAS, June, 15, 2011. 15 pages, 6 figures and 7 tables

Scientific paper

Narrow Line Seyfert 1 (NLSy1) galaxies are a peculiar class of type 1 AGN (BLSy1). The X-ray properties of individual objects belonging to this class are often extreme and associated with accretion at high Eddington ratios. Here we present a study on a sample of 14 NLSy1 galaxies selected at hard X-rays (> 20 keV) from the fourth INTEGRAL/IBIS catalogue. The 20-100 keV IBIS spectra show hard X-ray photon indeces flatly distributed (Gamma_{20-100 keV} ranging from ~1.3 to ~3.6) with an average value of = 2.3+/-0.7, compatible with a sample of hard X-ray BLSy1 average slope. Instead, NLSy1 show steeper spectral indeces with respect to BLSy1 when broad-band spectra are considered. Indeed, we combine XMM-Newton and Swift/XRT with INTEGRAL/IBIS data sets to obtain a wide energy spectral coverage (0.3-100 keV). A constraint on the high energy cut-off and on the reflection component is achieved only in one source, Swift J2127.4+5654 (E_{cut-off} ~ 50 keV, R=1.0{+0.5}_{-0.4}). Hard X-ray selected NLSy1 do not display particularly strong soft excess emission, while absorption fully or partially covering the continuum is often measured as well as Fe line emission features. Variability is a common trait in this sample, both at X-ray and at hard X-rays. The fraction of NLSy1 in the hard X-ray sky is likely to be ~15%, in agreement with estimates derived in optically selected NLSy1 samples. We confirm the association of NLSy1 with small black hole masses with a peak at 10^{7} M_{dot} in the distribution, however hard X-ray NLSy1 seem to occupy the lower tail of the Eddington ratios distribution of classical NLSy1.

Affiliated with

Also associated with

No associations

Rating

Narrow Line Seyfert 1 galaxies at hard X-rays does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Narrow Line Seyfert 1 galaxies at hard X-rays, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Narrow Line Seyfert 1 galaxies at hard X-rays will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-659203