[seminar] Astro Journal Club on 11 November

[Oskari Miettinen]

Dear all,

Our Astro Journal Club will be held on Wednesday at 3:00 pm (sharp) in the
seminar room F-201 of the Physics Department. This time we will discuss
about major mergers between dwarf galaxies in the Local Group.

Presenter: Monika Herceg
Paper title: Satellite Dwarf Galaxies in a Hierarchical Universe: The
Prevalence of Dwarf-Dwarf Major Mergers
Authors: Deason, A., Wetzel, A., and Garrison-Kimmel, S.

Summary:
Mergers are a common phenomenon in hierarchical structure formation,
especially for massive galaxies and clusters, but their importance for
dwarf galaxies in the Local Group remains poorly understood. We
investigate the frequency of major mergers between dwarf galaxies in the
Local Group using the ELVIS suite of cosmological zoom-in dissipationless
simulations of Milky Way- and M31-like host halos. We find that ~10
percent of satellite dwarf galaxies with M star > 1.0e6 Msun that are
within the host virial radius experienced a major merger of stellar mass
ratio closer than 0.1 since z = 1, with a lower fraction for lower mass
dwarf galaxies. Recent merger remnants are biased toward larger radial
distance and more recent virial infall times, because most recent mergers
occurred shortly before crossing within the virial radius of the host
halo. Satellite-satellite mergers also occur within the host halo after
virial infall, catalyzed by the large fraction of dwarf galaxies that fell
in as part of a group. The merger fraction doubles for dwarf galaxies
outside of the host virial radius, so the most distant dwarf galaxies in
the Local Group are the most likely to have experienced a recent major
merger. We discuss the implications of these results on observable dwarf
merger remnants, their star formation histories, the gas content of
mergers, and massive black holes in dwarf galaxies.

Link to the paper: http://adsabs.harvard.edu/abs/2014ApJ...794..115D

Hope to see you all on Wednesday!

Cheers,
Oskari