Issue |
A&A
Volume 449, Number 1, April I 2006
|
|
---|---|---|
Page(s) | 23 - 32 | |
Section | Cosmology (including clusters of galaxies) | |
DOI | https://doi.org/10.1051/0004-6361:20053507 | |
Published online | 16 March 2006 |
Galaxy pairs in cosmological simulations: effects of interactions on star formation
1
Consejo Nacional de Investigaciones Científicas y Técnicas, Argentina
2
Facultad de Ciencias Astronómicas y Geofísicas, La Plata, Argentina e-mail: jperez@fcaglp.unlp.edu.ar
3
Instituto de Astronomía y Física del Espacio, Argentina e-mail: patricia@iafe.uba.ar
4
Observatorio Astronómico de la Universidad Nacional de Córdoba, Argentina
Received:
24
May
2005
Accepted:
9
November
2005
We carried out a statistical analysis of galaxy pairs in hydrodynamical
ΛCDM simulations. We focus on the triggering of star formation by
interactions and analysed the enhancement of star formation activity in
terms of orbital parameters. By comparing the data to a suitable sample of simulated galaxies
without a nearby companion, we find that close
encounters ( kpc h-1) may
effectively induce star formation.
However, our results suggest that the stability properties of systems and
the spatial proximity are both relevant factors in the process of triggering
star formation by tidal interactions.
In order to assess the effects of projection and spurious pairs in
observational samples, we constructed and analysed samples of
pairs of galaxies in the simulations obtained in projection. We found a
good agreement with observational results with a threshold at
kpc h-1 for interactions to statistically enhance star formation activity.
For pairs within
kpc h-1, we estimated a
contamination by spurious pairs,
reduced to
for close
systems. We also found that spurious pairs more strongly affect high density regions, with
of spurious
pairs detected for low density regions compared to
found in high density ones.
We analysed the dependence of star formation on environment by
defining the usual projected density parameter for both pairs and isolated
galaxies in the simulations. We find the expected star formation-local density
relation for both galaxies in pairs and without a close companion, with a stronger density
dependence for close pairs which suggests a relevant role for interactions in
driving this relation.
Key words: methods: numerical / cosmology: theory / Galaxy: formation / galaxies: interactions
© ESO, 2006
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