Quenching Low-mass Satellite Galaxies: Evidence for a Threshold ICM Density
Abstract
We compile a sample of Sloan Digital Sky Survey (SDSS) galaxy clusters with high-quality Chandra X-ray data to directly study the influence of the dense intracluster medium (ICM) on the quenching of satellite galaxies. We study the quenched fractions of satellite galaxies as a function of ICM density for low- (109 ≲ M ⋆ ≲ 1010 M ⊙), intermediate- (1010 ≲ M ⋆ ≲ 1010.5 M ⊙), and high-mass (M ⋆ ≳ 1010.5 M ⊙) satellite galaxies with >3000 satellite galaxies across 24 low-redshift (z < 0.1) clusters. For low-mass galaxies we find evidence for a broken power-law trend between satellite quenched fraction and local ICM density. The quenched fraction increases modestly at ICM densities below a threshold before increasing sharply beyond this threshold toward the cluster center. We show that this increase in quenched fraction at high ICM density is well matched by a simple, analytic model of ram pressure stripping. These results are consistent with a picture where low-mass cluster galaxies experience an initial, slow-quenching mode driven by steady gas depletion, followed by rapid quenching associated with ram pressure of cold-gas stripping near (one-quarter of the virial radius, on average) the cluster center.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- March 2019
- DOI:
- 10.3847/1538-4357/ab04f7
- arXiv:
- arXiv:1902.02820
- Bibcode:
- 2019ApJ...873...42R
- Keywords:
-
- galaxies: clusters: general;
- galaxies: clusters: intracluster medium;
- galaxies: evolution;
- galaxies: star formation;
- X-rays: galaxies: clusters;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 17 pages plus appendix, 10 figures, accepted to ApJ