A CO-rich merger shaping a powerful and hyperluminous infrared radio galaxy at z=2: the Dragonfly Galaxy
Journal article, 2015
In the low-redshift Universe, the most powerful radio sources are often associated with gasrich galaxy mergers or interactions. We here present evidence for an advanced, gas-rich ('wet') merger associated with a powerful radio galaxy at a redshift of z similar to 2. This radio galaxy, MRC 0152-209, is the most infrared-luminous high-redshift radio galaxy known in the Southern hemisphere. Using the Australia Telescope Compact Array, we obtained highresolution CO(1-0) data of cold molecular gas, which we complement with Hubble Space Telescope (HS7)IWide Field Planetaiy Camera 2 (WFPC2) imaging and William Herschel Telescope long-slit spectroscopy. We find that, while roughly M-H2 x 10(10) Me of molecular gas coincides with the central host galaxy, another M-H2 similar to 3 x 10(10) Me is spread across a total extent of'-60 kpc. Most of this widespread CO(1-0) appears to follow prominent tidal features visible in the rest-frame near-UV HSTIWFPC2 imaging. Lya emission shows an excess over He II, but a deficiency over LIR, which is likely the result of photoionization by enhanced but very obscured star formation that was triggered by the merger. In terms of feedback, the radio source is aligned with widespread CO(1-0) emission, which suggests that there is a physical link between the propagating radio jets and the presence of cold molecular gas on scales of the galaxy's halo. Its optical appearance, combined with the transformational stage at which we witness the evolution of MRC 0152-209, leads us to adopt the name 'Dragonfly Galaxy'.
GALAXIES
STAR-FORMING GALAXIES
MOLECULAR GAS-RESERVOIRS
LUMINOUS SUBMILLIMETER
galaxies: active
MASSIVE DISK
galaxies: high-redshift
galaxies: individual: MRC 0152-209
ISM: jets and outflows
GALAXIES
FORMATION HISTORY
BAND BACK-END
HIGH-REDSHIFT GALAXIES
QUASAR HOST GALAXIES
SCALING RELATIONS
ACTIVE GALACTIC NUCLEI
Author
B. Emonts
CSIC-INTA - Centro de Astrobiologia (CAB)
M. Y. Mao
National Radio Astronomy Observatory
A. Stroe
Leiden Observatory Research Institute
L. Pentericci
Osservatorio Astronomico di Roma
M. Villar-Martin
Universidad Autonoma de Madrid
CSIC-INTA - Centro de Astrobiologia (CAB)
R. P. Norris
Australia Telescope National Facility
G. Miley
Leiden Observatory Research Institute
C. De Breuck
European Southern Observatory
G. A. van Moorsel
National Radio Astronomy Observatory
M. Lehnert
Universite Pierre et Marie Curie
C. L. Carilli
National Radio Astronomy Observatory
University of Cambridge
H. Rottgering
Leiden Observatory Research Institute
N. Seymour
University of Western Australia
E. M. Sadler
The University of Sydney
R. D. Ekers
Australia Telescope National Facility
Guillaume Drouart
Chalmers, Earth and Space Sciences, Radio Astronomy and Astrophysics
I. Feain
The University of Sydney
L. Colina
Universidad Autonoma de Madrid
CSIC-INTA - Centro de Astrobiologia (CAB)
J. Stevens
Australia Telescope National Facility
J. Holt
European Space Research and Technology Centre/ESA
Monthly Notices of the Royal Astronomical Society
0035-8711 (ISSN) 1365-2966 (eISSN)
Vol. 451 1 1025-1035Subject Categories (SSIF 2011)
Astronomy, Astrophysics and Cosmology
DOI
10.1093/mnras/stv930