Contatto di riferimento: Donatella Romano
Partecipanti: Nick Devereux*, (Embry-Riddle Aeronautical University, Prescott, US)
Abstract
Hubble Space Telescope (HST) spectroscopy has revealed a remarkable population of dwarf Seyferts with an unusually large broad-line region (BLR). These objects are remarkable for two reasons. Firstly, the size of the BLR can, in some cases, rival those seen in the most luminous quasars. Secondly, the size of the BLR is not correlated with the AGN luminosity, an observation that distinguishes them from reverberating active galactic nuclei. Collectively, these early results suggest that non-reverberating dwarf Seyferts are a very heterogeneous group, and not simply scaled versions of their reverberating counterparts. Close inspection with HST reveals broad H Balmer emission lines with single peaks, double peaks, and a combination of the two, suggesting that the broad emission lines are produced in kinematically distinct regions centered on the black hole (BH). Since the gravitational field strength is already known for these objects, by virtue of knowing their BH mass, the relationship between velocity, and radius may be established, given a kinematic model for the BLR gas. In this way, one can determine the inner, and outer radii of the BLRs by modeling the shape of their broad emission line profiles. High quality spectra obtained with the Space Telescope Imaging Spectrograph will be presented for M81, NGC 3998, NGC 4203, NGC 3227, NGC 4051, and NGC 3516 enabling a determination of the size, structure, and ionization of the BLR in these dwarf Seyfert galaxies. See you on thursday in the seminars' room, floor -1, via Ranzani 1, on time at 14h.
Next seminars:
* June 11th, at 14:00
Marco Ajello (Clemson University, US)
* June 18th, at 14:00
Elena Pancino (INAF-OABo)
* June 25th, at 14:00
Brian Lemaux (LAM Marseille, FR)
* July 2nd, at 14:00
Helena Dominguez Sanchez (Universidad Complutense Madrid, E)
The complete list of seminars is available at:
http://davide2.bo.astro.it/?page_id=4531
The organizers of seminars:
Cristian Vignali cristian.vignali@unibo.it
Donatella Romano donatella.romano@oabo.inaf.it