The formation of ultra-diffuse galaxies in cored dark matter haloes through tidal stripping and heating

Abstract

We propose that the Ultra-Diffuse Galaxy (UDG) population represents a set of satellite galaxies born in ∼ 10 10 − 10 11 M halos, similar to field dwarfs, which suffer a dramatic reduction in surface brightness due to tidal stripping and heating. This scenario is observationally motivated by the radial alignment of UDGs in Coma as well as the significant dependence of UDG abundance on cluster mass. As a test of this formation scenario, we apply a semi-analytic model describing the change in stellar mass and half-light radius of dwarf satellites, occupying either cored or cuspy halos, to cluster subhalos in the Illustris-dark simulation. Key to this model are results from simulations which indicate that galaxies in cored dark-matter halos expand significantly in response to tidal stripping and heating, whereas galaxies in cuspy halos experience limited size evolution. Our analysis indicates that a population of tidallystripped dwarf galaxies, residing in cored halos (like those hosting low-surface brightness field dwarfs), is able to reproduce the observed sizes and stellar masses of UDGs in clusters remarkably well.

One Hundred SMUDGes in S-PLUS: Ultra-diffuse Galaxies Flourish in the Field

“…The detection of populations of UDGs in galaxy clusters (e.g. van Dokkum et al 2015;Mihos et al 2015;van der Burg et al 2016;Venhola et al 2017;Shi et al 2017) led to the exploration of a possible evolutionary link between these galaxies and their harsh environment (Safarzadeh & Scannapieco 2017;Conselice 2018;Ogiya 2018;Bennet et al 2018;Carleton et al 2019). However, UDGs were also found in less dense environments, such as filaments (e.g.. Martínez-Delgado et al 2016), groups (e.g.…”

Ultra-diffuse galaxies in the Auriga simulations

“…Amorisco & Loeb 2016;Leisman et al 2017;Rong et al 2017;Spekkens & Karunakaran 2018) or feedback outflows (Di Cintio et al 2017;Chan et al 2018), and (iii) tidal galaxies (e.g. Venhola et al 2017;Carleton et al 2019;Toloba et al 2018).…”

Ultra-diffuse galaxies without dark matter

“…The allegedly dark matter-deficient UDGs are relatively luminous for low surface brightness dwarfs, and one might also consider initial conditions as a formation pathway, due to high initial spin (Amorisco & Loeb 2016). Their ultra-diffuse nature may also be due to tidal heating (Carleton et al 2019) or to early supernova-driven gas outflows (Di Cintio et al 2019). However these mechanisms do not obviously account for the dark matter deficiency, nor most significantly for the bright globular clusters.…”