* Astronomy

Members Login
Post Info TOPIC: Type II Seyfert galaxies


Posts: 131433
Type II Seyfert galaxies

Title: This is not the feedback you have been looking for: nearby optical AGN rarely drive kpc-scale cold-gas outflows
Author: Borislav Nedelchev (1,2), Marc Sarzi (1), Sugata Kaviraj (1) ((1) Center for Astrophysics Research, University of Hertfordshire, College Lane, AL10 9AB Hatfield, UK, (2) European Southern Observatory, Karl-Schwarzchild-Str. 2, 85748, Garching bei München, Germany)

We study the interstellar Na I \lambda \lambda5890,5895 (Na D) absorption-line doublet in a nearly-complete sample of ~9900 nearby Seyfert 2 galaxies, in order to quantify the significance of optical AGN activity in driving kpc-scale outflows that can quench star formation. Comparison to a carefully matched sample of ~44,000 control objects indicates that the Seyfert and control population have similar Na D detection rates (~5 - 6). Only 53 Seyferts (or 0.5% of the population) are found to potentially display galactic-scale winds, compared to 0.8% of the control galaxies. While nearly a third of the Na D outflows observed in our Seyfert 2 galaxies occur around the brightest AGN, both radio and infrared data indicate that star formation could play the dominant role in driving cold-gas outflows in an even higher fraction of the Na D-outflowing Seyfert 2s. Our results indicate that galactic-scale outflows at low redshift are no more frequent in Seyferts than they are in their non-active counterparts, that optical AGN are not significant contributors to the quenching of star formation in the nearby Universe, and that star-formation may actually be the principal driver of outflows even in systems that do host an AGN. 

Read more (975kb, PDF)

Page 1 of 1  sorted by
Quick Reply

Please log in to post quick replies.

Create your own FREE Forum
Report Abuse
Powered by ActiveBoard