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New insights into the narrow-line Seyfert 1 phenomenon

Mathur, Smita

I briefly review the X/UV absorber models and show that the observations of NLS1s are generally consistent with the models. The covering factor of absorbers in NLS1s is likely to be high and there is some evidence of super-solar metallicities. I argue that NLS1s may be active galaxies in the early stage of their evolution and as such, may be low l…

V751 Cyg and V Sge as transient supersoft X-ray sources

Greiner, Jochen

I review the observational evidence for luminous, soft X-ray emission during optical low-states in the two cataclysmic variables V751 Cyg and V Sge, and discuss the possible link to the canonical supersoft X-ray sources.

The UV spectra of NLS1s - implications for their broad line regions

Brandt, W. N.; Vestergaard, M.; Mathur, S. +3 more

We study the UV spectra of NLS1 galaxies and compare them with typical Seyfert 1 galaxies and quasars. The NLS1 spectra show narrower UV lines as well as weaker CIV λ1549 and CIII] λ1909 emission. We show that these line properties are due to a lower ionization parameter and somewhat higher BLR cloud densities. These modified conditions can be exp…