Galaxy and Mass Assembly (GAMA): active galactic nuclei in pairs of galaxies

Gordon, Yjan A.; Owers, Matt S.; Pimbblet, Kevin A.; Croom, Scott M.; Alpaslan, Mehmet; Baldry, Ivan K.; Brough, Sarah; Brown, Michael J.I.; Cluver, Michelle E.; Conselice, Christopher J.; Davies, Luke J.M.; Holwerda, Benne W.; Hopkins, Andrew M.; Gunawardhana, Madusha L.P.; Loveday, Jonathan; Taylor, Edward N.; Wang, Lingyu

Abstract

There exist conflicting observations on whether or not the environment of broad and narrow line AGN differ and this consequently questions the validity of the AGN unification model. The high spectroscopic completeness of the GAMA survey makes it ideal for a comprehensive analysis of the close environment of galaxies. To exploit this, and conduct a comparative analysis of the environment of broad and narrow line AGN within GAMA, we use a double-Gaussian emission line fitting method to model the more complex line profiles associated with broad line AGN. We select 209 type 1 (i.e., unobscured), 464 type 1.5-1.9 (partially obscured), and 281 type 2 (obscured) AGN within the GAMA II database. Comparing the fractions of these with neighbouring galaxies out to a pair separation of 350 kpch⁻¹ and Δz < 0.012 shows no difference between AGN of different type, except at separations less than 20 kpch⁻¹ where our observations suggest an excess of type 2 AGN in close pairs. We analyse the properties of the galaxies neighbouring our AGN and find no significant differences in colour or the star formation activity of these galaxies. Further to this we find that Σ₅ is also consistent between broad and narrow line AGN. We conclude that the observations presented here are consistent with AGN unification.

Citation

Gordon, Y. A., Owers, M. S., Pimbblet, K. A., Croom, S. M., Alpaslan, M., Baldry, I. K., …Wang, L. (2017). Galaxy and Mass Assembly (GAMA): active galactic nuclei in pairs of galaxies. Monthly notices of the Royal Astronomical Society, 465(3), 2671-2686. https://doi.org/10.1093/mnras/stw2925

• Journal Article Type: Article
• Acceptance Date: Nov 8, 2016
• Online Publication Date: Nov 14, 2016
• Publication Date: Mar 1, 2017
• Deposit Date: Nov 18, 2016
• Publicly Available Date: Nov 18, 2016
• Journal: Monthly notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Electronic ISSN: 1365-2966
• Publisher: Oxford University Press
• Peer Reviewed: Peer Reviewed
• Volume: 465
• Issue: 3
• Pages: 2671-2686
• DOI: https://doi.org/10.1093/mnras/stw2925
• Keywords: Galaxies -- active, Galaxies -- evolution, Galaxies -- interactions, Methods -- observational
• Public URL: https://hull-repository.worktribe.com/output/445411
• Publisher URL: http://mnras.oxfordjournals.org/content/early/2016/11/14/mnras.stw2925.abstract?sid=6ebc6ecb-3d21-4598-80b0-e674e9ded98f
• Additional Information: Copy of article first published in Monthly notices of the Royal Astronomical Society, 2017, v.465. issue3. ©: 2016 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.