X-ray spectral complexity in narrow-line Seyfert 1 galaxies
| dc.creator | Vaughan, S. | |
| dc.creator | Reeves, J. | |
| dc.creator | Warwick, R. | |
| dc.creator | R | |
| dc.creator | Edelson | |
| dc.date | 1999-05-25 | |
| dc.date.accessioned | 2026-07-07T10:51:30Z | |
| dc.date.available | 2026-07-07T10:51:30Z | |
| dc.description | We present a systematic analysis of the X-ray spectral properties of a sample of 22 ``narrow-line'' Seyfert 1 galaxies for which data are available from the ASCA public archive. Many of these sources, which were selected on the basis of their relatively narrow H-beta line width (FWHM <= 2000 km/s), show significant spectral complexity in the X-ray band. Their measured hard power-law continua have photon indices spanning the range 1.6 - 2.5 with a mean of 2.1, which is only slightly steeper than the norm for ``broad-line'' Seyfert 1s. All but four of the sources exhibit a soft excess, which can be modelled as blackbody emission (T_{bb} ~ 100 - 300 eV) superposed on the underlying power-law. This soft component is often so strong that, even in the relatively hard bandpass of ASCA, it contains a significant fraction, if not the bulk, of the X-ray luminosity, apparently ruling out models in which the soft excess is produced entirely through reprocessing of the hard continuum. Most notably, 6 of the 22 objects show evidence for a broad absorption feature centred in the energy range 1.1 - 1.4 keV, which could be the signature of resonance absorption in highly ionized material. A further 3 sources exhibit ``warm absorption'' edges in the 0.7 - 0.9 keV bandpass. Remarkably, all 9 ``absorbed'' sources have H-beta line widths below 1000 km/s, which is less than the median value for the sample taken as a whole. This tendency for very narrow line widths to correlate with the presence of ionized absorption features in the soft X-ray spectra of NLS1s, if confirmed in larger samples, may provide a further clue in the puzzle of active galactic nuclei. | |
| dc.description | 13 pages, 5 figures, accepted for publication in MNRAS | |
| dc.identifier | https://arxiv.org/abs/astro-ph/9905323 | |
| dc.identifier | http://arxiv.org/abs/astro-ph/9905323 | |
| dc.identifier | AIPConf.Proc.599:995-998,1999 | |
| dc.identifier | doi:10.1063/1.1434793 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/184841 | |
| dc.subject | Astrophysics | |
| dc.title | X-ray spectral complexity in narrow-line Seyfert 1 galaxies | |
| dc.type | text |