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The triggering of local AGN and their role in regulating star formation
Citation
Kaviraj, S and Shabala, SS and Deller, AT and Middelberg, E, The triggering of local AGN and their role in regulating star formation, Monthly Notices of the Royal Astronomical Society, 452, (1) pp. 774-783. ISSN 0035-8711 (2015) [Refereed Article]
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Copyright Statement
Copyright 2015 The Authors
DOI: doi:10.1093/mnras/stv1329
Abstract
We explore the processes that trigger local AGN and the role of these AGN in regulating star formation, using ∼550 nearby
galaxies observed by the mJy Imaging VLBA Exploration at 20 cm (mJIVE) survey. The ≳107 K brightness temperature required for an mJIVE detection cannot be achieved via star formation alone, allowing us to unambiguously
detect nearby radio AGN and study their role in galaxy evolution. Radio AGN are an order of magnitude more common in early-type
galaxies (ETGs) than in their late-type counterparts. The VLBI-detected ETGs in this study have a similar stellar mass distribution
to their undetected counterparts, are typically not the central galaxies of clusters and exhibit merger fractions that are
significantly higher than in the average ETG. This suggests that these radio AGN (which have VLBI luminosities >1022 W Hz−1) are primarily fuelled by mergers, and not by internal stellar mass-loss or cooling flows. Our radio AGN are a factor of
∼3 times more likely to reside in the UV–optical red sequence than the average ETG. Furthermore, typical AGN lifetimes (a
few 107 yr) are much shorter than the transit times from blue cloud to red sequence (∼1.5 Gyr). This indicates that nearby (merger-triggered)
AGN appear several dynamical time-scales into the associated star formation episode. This implies that such AGN typically
couple only to residual gas, at a point where star formation has already declined significantly, and are, therefore, unlikely
to play a significant role in regulating the star formation episode.
Item Details
| Item Type: | Refereed Article |
|---|---|
| Keywords: | galaxies: elliptical and lenticular, cD– galaxies: evolution – galaxies: formation – galaxies: interactions |
| Research Division: | Physical Sciences |
| Research Group: | Astronomical and Space 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 (Dr Stas Shabala) |
| ID Code: | 102554 |
| Year Published: | 2015 |
| Funding Support: | Australian Research Council (DE130101399) |
| Web of Science® Times Cited: | 25 |
| Deposited By: | Mathematics and Physics |
| Deposited On: | 2015-08-28 |
| Last Modified: | 2017-11-03 |
| Downloads: | 145 View Download Statistics |
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