|
X-ray spectral complexity in Narrow-Line Seyfert 1 galaxies
Simon Vaughan (Leicester)
Narrow-line Seyfert 1 (NLS1) galaxies represent a subclass of objects
occupying one extreme of the range of optical line widths observed in
Seyfert 1s, ie: H-beta FWHM<2000 km/s. Observations with ROSAT have
shown that NLS1s frequently have stronger soft excesses and increased
variability in the 0.1-2 keV band than more normal, `broad-line'
Seyfert 1s. One possible explanation of the extreme properties of
NLS1s is that these are active galactic nuclei containing black holes
of relatively modest mass which, nevertheless, are accreting at a high
rate.
We present the results of a systematic analysis of the X-ray spectral
properties of a sample of 22 NLS1s for which data are available from
the ASCA public archive, many of which show significant spectral
complexity in the X-ray band.
|