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Cold-gas outflows in typical low-redshift galaxies are driven by star formation, not AGN


Sarzi, M and Kaviraj, S and Nedelchev, B and Tiffany, J and Shabala, SS and Deller, AT and Middelberg, E, Cold-gas outflows in typical low-redshift galaxies are driven by star formation, not AGN, Monthly Notices of the Royal Astronomical Society, 456, (1) pp. L25-L29. ISSN 0035-8711 (2016) [Refereed Article]


Copyright Statement

Copyright 2015 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

DOI: doi:10.1093/mnrasl/slv165


Energetic feedback from active galactic nuclei (AGN) is an important ingredient for regulating the star formation history of galaxies in models of galaxy formation, which makes it important to study how AGN feedback actually occurs in practice. In order to catch AGNs in the act of quenching star formation, we have used the interstellar Na ɪ λλ5890, 5895(NaD) absorption lines to look for cold-gas outflows in a sample of 456 nearby galaxies for which we could unambiguously ascertain the presence of radio-AGN activity, thanks to radio imaging at milli-arcsecond scales. While compact radio emission indicating a radio AGN was found in 103 galaxies (23 per cent of the sample), and 23 objects (5 per cent) exhibited NaD absorption-line kinematics suggestive of cold-gas outflows, not one object showed evidence of a radio AGN and of a cold-gas outflow simultaneously. Radio-AGN activity was found predominantly in early-type galaxies, while cold-gas outflows were mainly seen in spiral galaxies with central star formation or composite star formation/AGN activity. Optical AGNs also do not seem capable of driving galactic winds in our sample. Our work adds to a picture of the low-redshift Universe, where cold-gas outflows in massive galaxies are generally driven by star formation and where radio-AGN activity occurs most often in systems in which the gas reservoir has already been significantly depleted.

Item Details

Item Type:Refereed Article
Keywords:galaxies: elliptical and lenticular, cD, galaxies: evolution, galaxies: nuclei, galaxies: spiral
Research Division:Physical Sciences
Research Group:Astronomical sciences
Research Field:Cosmology and extragalactic astronomy
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the physical sciences
UTAS Author:Shabala, SS (Associate Professor Stas Shabala)
ID Code:107317
Year Published:2016
Funding Support:Australian Research Council (DE130101399)
Web of Science® Times Cited:17
Deposited By:Mathematics and Physics
Deposited On:2016-03-10
Last Modified:2017-11-01
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