ALMA Lensing Cluster Survey: An ALMA Galaxy Signposting a MUSE Galaxy Group at z=4.3 Behind "El Gordo"
Journal article, 2021
We report the discovery of a Multi Unit Spectroscopic Explorer (MUSE) galaxy group at z = 4.32 lensed by the massive galaxy cluster ACT-CL J0102-4915 (aka El Gordo) at z = 0.87, associated with a 1.2 mm source that is at a 2.07 0.88 kpc projected distance from one of the group galaxies. Three images of the whole system appear in the image plane. The 1.2 mm source has been detected within the Atacama Large Millimetre/submillimetre Array (ALMA) Lensing Cluster Survey (ALCS). As this ALMA source is undetected at wavelengths lambda < 2 mu m, its redshift cannot be independently determined, however, the three lensing components indicate that it belongs to the same galaxy group at z = 4.32. The four members of the MUSE galaxy group have low to intermediate stellar masses (similar to 10(7)-10(10) M) and star formation rates (SFRs) of 0.4-24 M yr(-1), resulting in high specific SFRs (sSFRs) for two of them, which suggest that these galaxies are growing fast (with stellar mass doubling times of only similar to 2 x 10(7) yr). This high incidence of starburst galaxies is likely a consequence of interactions within the galaxy group, which is compact and has high velocity dispersion. Based on the magnification-corrected sub-/millimeter continuum flux density and estimated stellar mass, we infer that the ALMA source is classified as an ordinary ultra-luminous infrared galaxy (with associated dust-obscured SFR similar to 200-300 M yr(-1)) and lies on the star formation main sequence. This reported case of an ALMA/MUSE group association suggests that some presumably isolated ALMA sources are in fact signposts of richer star-forming environments at high redshifts.
Starburst galaxies
Submillimeter astronomy
High-redshift galaxies
Galaxy groups
Author
K. I. Caputi
University of Copenhagen
University of Groningen
G. B. Caminha
University of Groningen
S. Fujimoto
University of Copenhagen
K. Kohno
University of Tokyo
F. Sun
University of Arizona
E. Egami
University of Arizona
S. Deshmukh
University of Groningen
F. Tang
University of Groningen
Y. Ao
University of Science and Technology of China
Chinese Academy of Sciences
L. Bradley
Space Telescope Science Institute (STScI)
D. Coe
Space Telescope Science Institute (STScI)
D. Espada
SKA Organisation
C. Grillo
Istituto nazionale di astrofisica (INAF)
University of Milan
University of Copenhagen
B. Hatsukade
University of Tokyo
Kirsten Kraiberg Knudsen
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
M. M. Lee
Max Planck Society
G. E. Magdis
University of Copenhagen
Technical University of Denmark (DTU)
K. Morokuma-Matsui
University of Tokyo
P. Oesch
University of Geneva
M. Ouchi
National Astronomical Observatory of Japan
University of Tokyo
P. Rosati
University of Ferrara
Istituto nazionale di astrofisica (INAF)
H. Umehata
University of Tokyo
RIKEN
F. Valentino
University of Copenhagen
E. Vanzella
Istituto nazionale di astrofisica (INAF)
W. -H. Wang
Academia Sinica
J. F. Wu
Space Telescope Science Institute (STScI)
A. Zitrin
Ben-Gurion University of the Negev
Astrophysical Journal
0004-637X (ISSN) 1538-4357 (eISSN)
Vol. 908 2 146Subject Categories
Astronomy, Astrophysics and Cosmology
Geophysics
Computer Vision and Robotics (Autonomous Systems)
DOI
10.3847/1538-4357/abd4d0