The pre-processing of subhaloes in SDSS groups and clusters
Abstract
We investigate pre-processing using the observed quenched fraction of group and cluster galaxies in the Yang et al. Sloan Digital Sky Survey (SDSS)-seventh data release (DR7) group catalogue in the redshift range of 0.01 < z < 0.045. We categorize group galaxies as virialized, infall or backsplash and we apply a combination of the Dressler-Shectman statistic and group member velocities to identify subhaloes. On average, the fraction of galaxies that reside in subhaloes is a function of host halo mass, where more massive systems have a higher fraction of subhalo galaxies both in the overall galaxy and infall populations. Additionally, we find that within the range 2 ≲ r200 < 3 the quiescent fraction is higher in the subhalo population with respect to both the field and non-subhalo populations. At these large radii (2 ≲ r200 < 3), the majority of galaxies (∼80 per cent) belong to the infall population and therefore, we attribute the enhanced quenching to infalling subhalo galaxies, indicating that pre-processing has occurred in the subhalo population. We conclude that pre-processing plays a significant role in the observed quiescent fraction, but only for the most massive (Mhalo > 1014.5 M⊙) systems in our sample.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- July 2014
- DOI:
- 10.1093/mnras/stu829
- arXiv:
- arXiv:1404.7504
- Bibcode:
- 2014MNRAS.442..406H
- Keywords:
-
- galaxies: clusters: general;
- galaxies: formation;
- galaxies: groups: general;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 14 pages, 11 figures, accepted for publication in MNRAS