Speaker
Karen Knierman
(Arizona State University)
Description
While major mergers and their tidal debris are well studied, equal mass galaxy
mergers are relatively rare compared to minor mergers (mass ratio <0.3).
Minor mergers are less energetic than major mergers, but more common in the
observable universe, and thus likely played a pivotal role in the formation of most
large galaxies. Tidal debris regions have large amounts of neutral gas but a lower
gas density and may have higher turbulence. We use star formation tracers such as
young star cluster populations and H-alpha and CII emission to determine the
different factors that may influence star formation in tidal debris. These tracers
were compared to the reservoirs of molecular and neutral gas available for star
formation to estimate the star formation efficiency (SFE). The SFR in tidal debris
can reach up to 50% of the total star formation in the system. The SFE of tidal
tails in minor mergers can range over orders of magnitude on both local and global
scales. From the tidal debris environments in our study, this variance appears to
stem from the formation conditions of the debris. Current surveys of the 2.12
micron line of molecular hydrogen, CO(1-0), and HI for 15 minor mergers, are
providing a larger sample of environments to study the threshold for star formation
that can inform star formation models, particularly at low densities.
Primary author
Karen Knierman
(Arizona State University)
