Galaxy And Mass Assembly (GAMA) : the bright void galaxy population in the optical and mid-IR

Penny, Samantha J.; Brown, Michael J. I.; Pimbblet, Kevin A.; Cluver, Michelle E.; Croton, D. J.; Owers, Matt S.; Lange, Rebecca; Alpaslan, Mehmet; Baldry, Ivan K.; Bland-Hawthorn, J. (Joss); Brough, Sarah; Driver, Simon P.; Holwerda, Benne Willem, 1976-; Hopkins, Andrew M.; Jarrett, T. H.; Jones, D. Heath; Kelvin, Lee S.; Lara-López, Maritza A.; Liske, Jochen; López-Sánchez, Ángel R.; Loveday, Jon; Meyer, M. J.; Norberg, Peder; Robotham, Aaron S. G.; Rodrigues, M

Department of Physics and Mathematics
Galaxies -- evolution; Galaxies -- general
November 2015

Journal article


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

We examine the properties of galaxies in the Galaxies and Mass Assembly (GAMA) survey located in voids with radii >10 h−1 Mpc. Utilizing the GAMA equatorial survey, 592 void galaxies are identified out to z ≈ 0.1 brighter than Mr = −18.4, our magnitude completeness limit. Using the WHα versus [N II]/Hα (WHAN) line strength diagnostic diagram, we classify their spectra as star forming, AGN, or dominated by old stellar populations. For objects more massive than 5 × 109 M⊙, we identify a sample of 26 void galaxies with old stellar populations classed as passive and retired galaxies in the WHAN diagnostic diagram, else they lack any emission lines in their spectra. When matched to Wide-field Infrared Survey Explorer mid-IR photometry, these passive and retired galaxies exhibit a range of mid-IR colour, with a number of void galaxies exhibiting [4.6] − [12] colours inconsistent with completely quenched stellar populations, with a similar spread in colour seen for a randomly drawn non-void comparison sample. We hypothesize that a number of these galaxies host obscured star formation, else they are star forming outside of their central regions targeted for single-fibre spectroscopy. When matched to a randomly drawn sample of non-void galaxies, the void and non-void galaxies exhibit similar properties in terms of optical and mid-IR colour, morphology, and star formation activity, suggesting comparable mass assembly and quenching histories. A trend in mid-IR [4.6] − [12] colour is seen, such that both void and non-void galaxies with quenched/passive colours <1.5 typically have masses higher than 1010 M⊙, where internally driven processes play an increasingly important role in galaxy evolution.

Publisher
The University of Hull
Peer reviewed
Yes
Language
English
Extent
11 MB
Identifier
hull:11560

Journal

Journal title
Monthly notices of the Royal Astronomical Society
Publication date
November 2015
Publisher
Oxford University Press
DOI
10.1093/mnras/stv1926
ISSN (Print)
0035-8711
ISSN (Electronic)
1365-2966
Volume
453
Issue
4
Start page
3519
End page
3539
Notes

This article has been accepted for publication in Monthly notices of the Royal Astronomical Society Letters ©: 2015 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

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