The formation and evolution of ultra diffuse galaxies in the field and in galaxy groups

by Fangzhou Jiang

at Astrophysics and Cosmology Seminar

Wed, 23 May 2018, 11:15
Physics building (#54) room 207

Abstract

Ultra diffuse galaxies UDGs have been detected in both dense environments and in the field Their halo mass range and formation mechanisms are currently under debate We analyze UDGs in cosmological zoom in simulations of galaxies in the field and in galaxies groups with an emphasis on their shape evolution and formation mechanisms We confirm the result of Di Cintio et al that UDGs in the field prefer a specific halo mass range of 10 10 11 Msun and we find that their host halos have typical spin but relatively low concentration Although the UDGs have Sersic indices of order unity in agreement with observations their shapes are generally more prolate than galaxies of similar halo mass and stellar mass The formation of UDGs in the field is fairly recent below z 0 3 and usually associated with bursty star formation histories supporting the scenario that they were puffed up by repeated supernovae outflows In galaxy groups UDGs are more quiescent towards the center in agreement with observations Interestingly a significant fraction of group UDGs were normal dwarf galaxies at accretion and became UDGs after the first pericenter where they were puffed up by tidal shocks losing most of their cold gas due to ram pressure and becoming quiescent Finally we characterize the survivability of UDGs that formed in the field in a cluster environment with a semi analytic model of satellite evolution

Created on 20-05-2018 by Bar Lev, Yevgeny (ybarlev)
Updaded on 20-05-2018 by Bar Lev, Yevgeny (ybarlev)