The Large-scale Environmental Effect on Galactic Conformity.
We use a volume-limited galaxy sample from the SDSS Data Release 7 to explore the environmental effect on the large-scale galactic conformity (4Mpc). We find the activity of neighbour galaxies depends more strongly on their environments than on the activity of their primary galaxies. In under-dense regions most neighbour galaxies tend to be active, while in over-dense regions neighbour galaxies are mostly passive, regardless of the activity of their primary galaxies. It is the different spatial distributions of active and passive primary galaxies that leads to the apparent strong conformity signal. The activity of neighbour galaxies in different environments can be explained by the corresponding fraction of satellite galaxies. Similar results are found for semi-analytical galaxies, suggesting no new physics is required to explain the observed large-scale conformity.
Publisher URL: http://arxiv.org/abs/1801.01617