The Large-scale Effect of Environment on Galactic Conformity

Sun, S.; Guo, Q.; Wang, L.; Wang, J.; Gao, L.; Lacey, C.G.; Pan, J.

Abstract

We use a volume-limited galaxy sample from the Sloan Digital Sky Survey Data Release 7 to explore the dependence of galactic conformity on the large-scale environment, measured on ∼4 Mpc scales. We find that the star formation activity of neighbour galaxies depends more strongly on the environment than on the activity of their primary galaxies. In underdense regions most neighbour galaxies tend to be active, while in overdense regions neighbour galaxies are mostly passive, regardless of the activity of their primary galaxies. At a given stellar mass, passive primary galaxies reside in higher density regions than active primary galaxies, leading to the apparently strong conformity signal. The dependence of the activity of neighbour galaxies on environment can be explained by the corresponding dependence of the fraction of satellite galaxies. Similar results are found for galaxies in a semi-analytical model, suggesting that no new physics is required to explain the observed large-scale conformity.

Citation

Sun, S., Guo, Q., Wang, L., Wang, J., Gao, L., Lacey, C., & Pan, J. (2018). The Large-scale Effect of Environment on Galactic Conformity. Monthly Notices of the Royal Astronomical Society, 477(3), 3136-3144. https://doi.org/10.1093/mnras/sty832

• Journal Article Type: Article
• Acceptance Date: Mar 28, 2018
• Online Publication Date: Apr 4, 2018
• Publication Date: Jul 1, 2018
• Deposit Date: May 16, 2018
• Publicly Available Date: May 16, 2018
• Journal: Monthly Notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Electronic ISSN: 1365-2966
• Publisher: Royal Astronomical Society
• Peer Reviewed: Peer Reviewed
• Volume: 477
• Issue: 3
• Pages: 3136-3144
• DOI: https://doi.org/10.1093/mnras/sty832