2016MNRAS.457..272D -
Mon. Not. R. Astron. Soc., 457, 272-280 (2016/March-3)
On the depletion and accretion time-scales of cold gas in local early-type galaxies.
DAVIS T.A. and BUREAU M.
Abstract (from CDS):
We consider what can be learnt about the processes of gas accretion and depletion from the kinematic misalignment between the cold/warm gas and stars in local early-type galaxies. Using simple analytic arguments and a toy model of the processes involved, we show that the lack of objects with counter-rotating gas reservoirs strongly constrains the relaxation, depletion and accretion time-scales of gas in early-type galaxies. Standard values of the accretion rate, star-formation efficiency and relaxation rate are not simultaneously consistent with the observed distribution of kinematic misalignments. To reproduce that distribution, both fast gas depletion (tdep <= 108 yr; e.g. more efficient star formation) and fast gas destruction (e.g. by active galactic nucleus feedback) can be invoked, but both also require a high rate of gas-rich mergers (>1 Gyr–1). Alternatively, the relaxation of misaligned material could happen over very long time-scales (≃100 dynamical times or ≃1-5 Gyr). We explore the various physical processes that could lead to fast gas depletion and/or slow gas relaxation, and discuss the prospects of using kinematic misalignments to probe gas-rich accretion processes in the era of large integral-field spectroscopic surveys.
Abstract Copyright:
© 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society
Journal keyword(s):
ISM: evolution - ISM: molecules - galaxies: elliptical and lenticular, cD - galaxies: evolution - galaxies: ISM - galaxies: kinematics and dynamics
Simbad objects:
3
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