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

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Version 2 2024-04-18, 05:27
Version 1 2023-05-18, 17:45
journal contribution
posted on 2024-04-18, 05:27 authored by M Sarzi, S Kaviraj, B Nedelchev, J Tiffany, Stanislav ShabalaStanislav Shabala, AT Deller, E Middelberg
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.

Funding

Australian Research Council

History

Publication title

Monthly Notices of the Royal Astronomical Society

Volume

456

Issue

1

Pagination

L25-L29

ISSN

0035-8711

Department/School

School of Natural Sciences

Publisher

Blackwell Publishing Ltd

Publication status

  • Published

Place of publication

9600 Garsington Rd, Oxford, England, Oxon, Ox4 2Dg

Rights statement

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

Socio-economic Objectives

280120 Expanding knowledge in the physical sciences

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