Issue |
A&A
Volume 438, Number 1, July IV 2005
|
|
---|---|---|
Page(s) | 87 - 101 | |
Section | Extragalactic astronomy | |
DOI | https://doi.org/10.1051/0004-6361:20052753 | |
Published online | 06 July 2005 |
Star formation rates and mass distributions in interacting galaxies
Institut für Astrophysik, Leopold-Franzens-Universität Innsbruck, Technikerstr. 25, 6020 Innsbruck, Austria e-mail: wolfgang.e.kapferer@uibk.ac.at
Received:
24
January
2005
Accepted:
22
March
2005
We present a systematic investigation of the star
formation rate (hereafter SFR) in interacting disk galaxies. We
determine the dependence of the overall SFR on different spatial
alignments and impact parameters of more than 50 different
configurations in combined N-body/hydrodynamic simulations. We
also show mass profiles of the baryonic components. We find that
galaxy–galaxy interactions can enrich the surrounding intergalatic
medium with metals very efficiently up to distances of several 100 kpc. This enrichment can be explained in terms of indirect processes like thermal-driven galactic winds or direct processes
like “kinetic” spreading of baryonic matter. In the case of equal
mass mergers the direct–kinetic- redistribution of gaseous matter
(after 5 Gyr) is less efficient than the environmental enrichment
of the same isolated galaxies by a galactic wind. In the case of
non-equal mass mergers however, the direct–kinetic- process
dominates the redistribution of gaseous matter. Compared to the
isolated systems, the integrated star formation rates (ISFRs)
() in the
modelled interacting galaxies are in extreme cases a factor of 5 higher and on average a factor of 2 higher in interacting galaxies. Co-rotating and counter-rotating interactions do not
show a common trend for the enhancement of the ISFRs depending on
the interaction being edge-on or face-on. The latter case shows an
increase of the ISFRs for the counter-rotating system of about 100%, whereas the edge-on counter-rotating case results in a lower increase (~10%). An increase in the minimum
separation yields only a very small decrease in the ISFR after the
first encounter. If the minimum separation is larger than ~
the disk scale length Rd the second encounter does not provide an enhancement for the ISFR.
Key words: hydrodynamics / methods: numerical / galaxies: interactions / galaxies: general / intergalactic medium / galaxies: evolution
© ESO, 2005
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