Bibcode
Bianconi, M.; Marleau, F. R.; Fadda, D.
Bibliographical reference
Astronomy and Astrophysics, Volume 588, id.A105, 14 pp.
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4
2016
Journal
Citations
4
Refereed citations
4
Description
Context. We present a study of star formation and central black hole
accretion activity of galaxies that are hosted in the two nearby (z ~
0.2) rich galaxy clusters Abell 983 and 1731. Aims: We aim to
quantify both the obscured and unobscured star formation rates, as well
as the presence of active galactic nuclei (AGN) as a function of the
environment in which the galaxy is located. Methods: We targeted
the clusters with unprecedented deep infrared Spitzer observations (0.2
mJy at 24 micron), near-IR Palomar imaging and optical WIYN
spectroscopy. The extent of our observations (~3 virial radii) covers
the vast range of possible environments, from the very dense cluster
centre to the very rarefied cluster outskirts and accretion regions. Results: The star-forming members of the two clusters present star
formation rates that are comparable with those measured in coeval field
galaxies. Analysis of the spatial arrangement of the spectroscopically
confirmed members reveals an elongated distribution for A1731 with
respect to the more uniform distribution of A983. The emerging picture
is compatible with A983 being a fully evolved cluster, in contrast with
the still actively accreting A1731. Conclusions: Analysis of the
specific star formation rate reveals evidence of ongoing galaxy
pre-processing along A1731's filament-like structure. Furthermore, the
decrease in the number of star-forming galaxies and AGN towards the
cluster cores suggests that the cluster environment is accelerating the
ageing process of the galaxies and blocking further accretion of the
cold gas that fuels both star formation and black hole accretion
activity.
The catalogue and the reduced images (FITS files) are only available at
the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr
(ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/588/A105