Smaller stellar disc scale lengths in rich environments

Abstract

We investigate the dependence of stellar disc scale lengths on environment for a sample of Sloan Digital Sky Survey Data Release 7 galaxies with published photometric bulge-disc decompositions. We compare disc scale lengths at fixed bulge mass for galaxies in an isolated field environment to galaxies in X-ray rich and X-ray poor groups. At low bulge mass, stellar disc scale lengths in X-ray rich groups are smaller compared to discs in both X-ray poor groups and in isolated field environments. This decrease in disc scale length is largely independent of halo mass, though shows some dependence on group-centric distance. We also find that stellar disc scale lengths are smaller in X-ray rich environments for a subset of starforming galaxies and for galaxies of different morphological types. We note that disc scale lengths of low mass galaxies are known to have large systematic uncertainties, however we focus on differences between samples with the same measurement biases. Our results show that stellar disc scale lengths depend on X-ray brightness, a tracer of IGM density, suggesting a role for hydrodynamic processes such as ram-pressure stripping and/or starvation.

Exponential galaxy discs as the quasi-stationary distribution in a Markov chain model simulating stellar scattering

“…When the disc radius 𝑅 doubles, the scale length ℎ will double if 𝑝/𝑞 ≈ 1 or if the radial bin size 𝑑 doubles with 𝑅. This scaling relation between 𝑅 and ℎ qualitatively agrees with results from observations (Demers et al 2019). Given 𝑅, the variation in quasi-stationary scale length due to a fixed change in the radial scattering bias 𝑝/𝑞 becomes less as 𝑑 increases.…”

“…The observation of real galactic discs shows that the exponential scale length of spiral galaxies increases with the total stellar mass in the disc (Jaffé et al 2018;Demers et al 2019). Particularly, Figure 4 of Demers et al (2019) shows that the disc scale length roughly doubles when the stellar mass goes from 10 10.0 𝑀 to 10 10.9 𝑀 .…”

“…The observation of real galactic discs shows that the exponential scale length of spiral galaxies increases with the total stellar mass in the disc (Jaffé et al 2018;Demers et al 2019). Particularly, Figure 4 of Demers et al (2019) shows that the disc scale length roughly doubles when the stellar mass goes from 10 10.0 𝑀 to 10 10.9 𝑀 . If we assume that the stellar mass is proportional to the cube of the model disc edge, a mass change from 10 10.0 𝑀 to 10 10.9 𝑀 corresponds to a twofold increase in the model disc edge.…”

The galaxy mass-size relation in CARLA clusters and proto-clusters at 1.4 < z < 2.8: Larger cluster galaxy sizes

“…In another work, Huang et al (2018) find that massive galaxies in clusters are as much as 20%-40% larger than in the field based on deep observations with the Hyper Suprime-Cam (see also Yoon et al 2017). For spiral galaxies, the environmental dependence of the MSR is more pronounced: its scatter is much larger (Maltby et al 2010;Cappellari 2013;Lange et al 2015) and disks are smaller in clusters (Kuchner et al 2017;Demers et al 2019). This means that dense environments either destroy disks or inhibit their growth, for example through tidal interactions, rampressure, and/or strangulation (Boselli & Gavazzi 2006).…”

Star-clump scattering and the formation of exponential density profiles in galactic disks

“…The observation of real galactic discs shows that the exponential scale length of spiral galaxies increases with the total stellar mass in the disc (Jaffé et al, 2018;Demers et al, 2019).…”