Bibcode
Coogan, R. T.; Daddi, E.; Sargent, M. T.; Strazzullo, V.; Valentino, F.; Gobat, R.; Magdis, G.; Bethermin, M.; Pannella, M.; Onodera, M.; Liu, D.; Cimatti, A.; Dannerbauer, H.; Carollo, M.; Renzini, A.; Tremou, E.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 479, Issue 1, p.703-729
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9
2018
Citations
72
Refereed citations
63
Description
We use Atacama Large Millimetre Array and Jansky Very Large Array
observations of the galaxy cluster Cl J1449+0856 at z = 1.99, in order
to study how dust-obscured star formation, interstellar medium content,
and active galactic nuclei activity are linked to environment and galaxy
interactions during the crucial phase of high-z cluster assembly. We
present detections of multiple transitions of 12CO, as well
as dust continuum emission detections from 11 galaxies in the core of Cl
J1449+0856. We measure the gas excitation properties, star formation
rates, gas consumption timescales, and gas-to-stellar mass ratios for
the galaxies. We find evidence for a large fraction of galaxies with
highly excited molecular gas, contributing >50 per cent to the total
star formation rate (SFR) in the cluster core. We compare these results
with expectations for field galaxies, and conclude that environmental
influences have strongly enhanced the fraction of excited galaxies in
this cluster. We find a dearth of molecular gas in the galaxies' gas
reservoirs, implying a high star formation efficiency (SFE) in the
cluster core, and find short gas depletion timescales
τdep < 0.1-0.4 Gyr for all galaxies. Interestingly, we
do not see evidence for increased specific SFRs (sSFRs) in the cluster
galaxies, despite their high SFEs and gas excitations. We find evidence
for a large number of mergers in the cluster core, contributing a large
fraction of the core's total star formation compared with expectations
in the field. We conclude that the environmental impact on the galaxy
excitations is linked to the high rate of galaxy mergers, interactions,
and active galactic nuclei in the cluster core.
Related projects
Molecular Gas and Dust in Galaxies Across Cosmic Time
Two of the most fundamental questions in astrophysics are the conversion of molecular gas into stars and how this physical process is a function of environments on all scales, ranging from planetary systems, stellar clusters, galaxies to galaxy clusters. The main goal of this internal project is to get insight into the formation and evolution of
Helmut
Dannerbauer