TY - JOUR
T1 - Merger-driven star formation activity in Cl J1449+0856 at z = 1.99 as seen by ALMA and JVLA
AU - Coogan, R. T.
AU - Daddi, E.
AU - Sargent, M. T.
AU - Strazzullo, V.
AU - Valentino, F.
AU - Gobat, R.
AU - Magdis, G.
AU - Bethermin, M.
AU - Pannella, M.
AU - Onodera, M.
AU - Liu, D.
AU - Cimatti, A.
AU - Dannerbauer, H.
AU - Carollo, M.
AU - Renzini, A.
AU - Tremou, E.
N1 - Funding Information:
We thank the referee for their feedback and suggestions. We also thank Frederic Bournaud for his help and discussion on deriving dynamical masses. RTC acknowledges support from the Science and Technology Facilities Council grant ST/N504452/1. MTS was supported by a Royal Society Leverhulme Trust Senior Research Fellowship (LT150041). GEM acknowledges support from the Carlsberg Foundation, the ERC Consolidator Grant funding scheme (project ConTExt, grant number No. 648179), and a research grant (13160) from VillumFonden. AC acknowledges the grants ASI n.I/023/12/0 ‘Attivit relative alla fase B2/C per la mis-sione Euclid’ and PRIN MIUR 2015 ‘Cosmology and Fundamental Physics: illuminating the Dark Universe with Euclid’. HD acknowledges financial support from the Spanish Ministry of Economy and Competitiveness (MINECO) under the 2014 Ramn y Cajal program MINECO RYC-2014-15686. ET acknowledges financial support from the UnivEarthS Labex program of Sorbonne Paris Cité (ANR-10-LABX-0023 and ANR-11-IDEX-0005-02).
Publisher Copyright:
© 2018 The Author(s). Published by Oxford University Press on behalf of The Royal Astronomical Society.
PY - 2018/9/1
Y1 - 2018/9/1
N2 - 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 τ dep < 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.
AB - 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 τ dep < 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.
KW - Galaxies evolution
KW - Galaxies: ISM
KW - Galaxies: clusters: individual: Cl J1449+0856
KW - Galaxies: star formation
KW - Galaxies:high-redshift
UR - http://www.scopus.com/inward/record.url?scp=85050775806&partnerID=8YFLogxK
U2 - 10.1093/mnras/sty1446
DO - 10.1093/mnras/sty1446
M3 - Article
AN - SCOPUS:85050775806
VL - 479
SP - 703
EP - 729
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
SN - 0035-8711
IS - 1
ER -