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: high-redshift
ACTIVE GALACTIC NUCLEI
MASSIVE DISK
ISM: jets and outflows
LUMINOUS SUBMILLIMETER
BAND BACK-END
MOLECULAR GAS-RESERVOIRS
QUASAR HOST GALAXIES
HIGH-REDSHIFT GALAXIES
GALAXIES
FORMATION HISTORY
galaxies: active
galaxies: individual: MRC 0152-209
SCALING RELATIONS
GALAXIES
STAR-FORMING GALAXIES
Author
B. Emonts
Centro de Astrobiologia (CAB)
M. Y. Mao
National Radio Astronomy Observatory
A. Stroe
Leiden University
L. Pentericci
Osservatorio Astronomico di Roma
M. Villar-Martin
Universidad Autonoma de Madrid (UAM)
Centro de Astrobiologia (CAB)
R. P. Norris
Commonwealth Scientific and Industrial Research Organisation (CSIRO)
G. Miley
Leiden University
C. De Breuck
European Southern Observatory (ESO)
G. A. van Moorsel
National Radio Astronomy Observatory
M. Lehnert
Pierre and Marie Curie University (UPMC)
C. L. Carilli
National Radio Astronomy Observatory
University of Cambridge
H. Rottgering
Leiden University
N. Seymour
University of Western Australia
E. M. Sadler
The University of Sydney
R. D. Ekers
Commonwealth Scientific and Industrial Research Organisation (CSIRO)
Guillaume Drouart
Chalmers, Earth and Space Sciences, Radio Astronomy and Astrophysics
I. Feain
The University of Sydney
L. Colina
Universidad Autonoma de Madrid (UAM)
Centro de Astrobiologia (CAB)
J. Stevens
Commonwealth Scientific and Industrial Research Organisation (CSIRO)
J. Holt
European Space Agency (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