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'.

MASSIVE DISK

BAND BACK-END

GALAXIES

HIGH-REDSHIFT GALAXIES

galaxies: individual: MRC 0152-209

galaxies: active

FORMATION HISTORY

ACTIVE GALACTIC NUCLEI

ISM: jets and outflows

galaxies: high-redshift

SCALING RELATIONS

MOLECULAR GAS-RESERVOIRS

STAR-FORMING GALAXIES

GALAXIES

QUASAR HOST GALAXIES

LUMINOUS SUBMILLIMETER

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

Centro de Astrobiologia (CAB)

Universidad Autonoma de Madrid (UAM)

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

University of Cambridge

National Radio Astronomy Observatory

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 Research and Technology Centre (ESA ESTEC)

Monthly Notices of the Royal Astronomical Society

0035-8711 (ISSN) 1365-2966 (eISSN)

Vol. 451 1 1025-1035

Subject Categories

Astronomy, Astrophysics and Cosmology

DOI

10.1093/mnras/stv930

More information

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