EDP Sciences
Free access
Volume 394, Number 2, November I 2002
Page(s) 415 - 433
Section Extragalactic astronomy
DOI http://dx.doi.org/10.1051/0004-6361:20021159

A&A 394, 415-433 (2002)
DOI: 10.1051/0004-6361:20021159

Stellar envelopes as sources of broad line region emission: New possibilities allowed

G. Torricelli-Ciamponi1 and P. Pietrini2

1  Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125 Firenze, Italy
2  Dipartimento di Astronomia e Scienza dello Spazio, Università di Firenze, Largo E. Fermi 2, 50125 Firenze, Italy

(Received 19 February 2001 / Accepted 5 August 2002)

In Active Galactic Nuclei (AGNs) the presence of a star cluster around the central black hole can have several effects on the dynamics and the emission of the global system. In this paper we analyze the interaction of stellar atmospheres with a wind outflowing from the central region of the AGN nucleus. Even a small mass loss from stars, as well as possible star collisions, can give a non-negligible contribution in feeding matter into the AGN nuclear wind. Moreover, stellar mass loss can produce envelopes surrounding stars that turn out to be suitable for reproducing the observed emission from the Broad Line Region (BLR). In this framework, the envelope can be confined by the bow shock arising from the interaction between the expanding stellar atmosphere and the AGN nuclear wind.

Key words: radiation mechanisms: thermal -- ultraviolet: galaxies -- galaxies: nuclei -- galaxies: seyfert -- quasars: general

Offprint request: P. Pietrini, paola@arcetri.astro.it

© ESO 2002