Cold molecular gas and free-free emission from hot, dust-obscured galaxies at z similar to 3
Journal article, 2020
We report on observations of redshifted CO(1-0) line emission and observed-frame similar to 30 GHz radio continuum emission from five ultra-luminous, mid-IR selected hot, Dust-Obscured Galaxies (Hot DOGs) at z greater than or similar to 3 using the Karl G. Jansky Very Large Array. We detect CO(1-0) line emission in all five Hot DOGs, with one of them at high signal-to-noise ratio. We analyse FIR-radio spectral energy distributions, including dust, free-free, and synchrotron emission for the galaxies. We find that most of the 115 GHz rest-frame continuum is mostly due to synchrotron or free-free emission, with only a potentially small contribution from thermal emission. We see a deficit in the rest-frame 115 GHz continuum emission compared to dusty star-forming galaxies and sub-millimetre galaxies (SMGs) at high redshift, suggesting that Hot DOGs do not have similar cold gas reserves compared with star-forming galaxies. One target, W2305-0039, is detected in the FIRST 1.4 GHz survey, and is likely to possess compact radio jets. We compare to the FIR-radio correlation, and find that at least half of the Hot DOGs in our sample are radio-quiet with respect to normal galaxies. These findings suggest that Hot DOGs have comparably less cold molecular gas than star-forming galaxies at lower, z similar to 2 redshifts, and are dominated by powerful, yet radio-quiet AGN.
galaxies: evolution
galaxies: active
radio lines: galaxies
Author
Penney
University Of Leicester
A. W. Blain
University Of Leicester
R. J. Assef
Diego Portales University
T. Diaz-Santos
Diego Portales University
Foundation for Research and Technology Hellas (FORTH)
Chinese Academy of Sciences
J. Gonzalez-Lopez
Diego Portales University
Carnegie Institution for Science
C-W Tsai
Chinese Academy of Sciences
M. Aravena
Diego Portales University
P. R. M. Eisenhardt
California Institute of Technology (Caltech)
Suzy Jones
Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics
H. D. Jun
Korea Institute for Advanced Study
M. Kim
Kyungpook National University
D. Stern
California Institute of Technology (Caltech)
J. Wu
Chinese Academy of Sciences
Monthly Notices of the Royal Astronomical Society
0035-8711 (ISSN) 1365-2966 (eISSN)
Vol. 496 2 1565-1578Subject Categories
Analytical Chemistry
Astronomy, Astrophysics and Cosmology
Atom and Molecular Physics and Optics
DOI
10.1093/MNRAS/STAA1582