Herschel-ATLAS and ALMA HATLAS J142935.3-002836, a lensed major merger at redshift 1.027

Author(s)

Hugo Messias, Simon Dye, Neil Nagar, Gustavo Orellana, R. Shane Bussmann, Jae Calanog, Helmut Dannerbauer, Hai Fu, Edo Ibar, Andrew Inohara, R. J. Ivison, Mattia Negrello, Dominik A. Riechers, Yun-Kyeong Sheen, James E. Aguirre, Simon Amber, Mark Birkinshaw, Nathan Bourne, Charles M. Bradford, Dave L. Clements, Asantha Cooray, Gianfranco De Zotti, Ricardo Demarco, Loretta Dunne, Stephen Eales, Simone Fleuren, Julia Kamenetzky, Roxana E. Lupu, Steve J. Maddox, Daniel P. Marrone, Michal J. Michalowski, Eric J. Murphy, Hien T. Nguyen, Alain Omont, Kate Rowlands, Dan Smith, Matt Smith, Elisabetta Valiante, Joaquin D. Vieira

Abstract

Context. The submillimetre-bright galaxy population is believed to comprise, aside from local galaxies and radio-loud sources, intrinsically active star-forming galaxies, the brightest of which are lensed gravitationally. The latter enable studies at a level of detail beyond what is usually possible by the observation facility. Aims. This work focuses on one of these lensed systems, HATLASâ‰ J142935.3-002836 (H1429-0028), selected in the Herschel-ATLAS field. Gathering a rich, multi-wavelength dataset, we aim to confirm the lensing hypothesis and model the background source's morphology and dynamics, as well as to provide a full physical characterisation. Methods. Multi-wavelength high-resolution data is utilised to assess the nature of the system. A lensing-analysis algorithm that simultaneously fits different wavebands is adopted to characterise the lens. The background galaxy dynamical information is studied by reconstructing the 3D source plane of the ALMA COâ‰ (J:4â‰ →â‰ 3) transition. Near-IR imaging from HST and Keck-AO allows to constrain rest-frame optical photometry independently for the foreground and background systems. Physical parameters (such as stellar and dust masses) are estimated via modelling of the spectral energy distribution taking source blending, foreground obscuration, and differential magnification into account. Results. The system comprises a foreground edge-on disk galaxy (at z

_sp = 0.218) with an almost complete Einstein ring around it. The background source (at z

_sp = 1.027) is magnified by a factor of μ ~ 8-10 depending on wavelength. It is comprised of two components and a tens-of-kpc-long tidal tail resembling the Antennæ merger. As a whole, the background source is a massive stellar system (1.32

_-0.41

^{+ 0.63} × 10

¹¹ M

_⊙) forming stars at a rate of 394 ± 90 M

_⊙ yr

^-1, and it has a significant gas reservoir M

_ISM = 4.6 ± 1.7 × 10

¹⁰ M

_⊙. Its depletion time due to star formation alone is thus expected to be τ

_SF = M

_ISM/SFR = 117 ± 51 Myr. The dynamical mass of one of the components is estimated to be 5.8 ± 1.7 × 10

¹⁰ M

_⊙, and, together with the photometric total mass estimate, it implies that H1429-0028 is a major merger system (1:2.8

_-1.5

^+1.8).

Organisation(s)

Department of Astrophysics

External organisation(s)

Universidad de Concepción, Universidade do Porto, Nottingham Trent University, Harvard-Smithsonian Center for Astrophysics, Stanford University, University of California, Irvine, University of Northern Iowa, Pontificia Universidad Católica de Valparaíso, University of Edinburgh, European Southern Observatory (Germany), Instituto Nazionale die Astrofisica (INAF), University of Padova, California Institute of Technology (Caltech), Cornell University, Kutztown University of Pennsylvania, Zimbabwe Open University, University of Bristol, National Aeronautics & Space Administration (NASA), Imperial College London, University of Canterbury, Cardiff University, University of London, University of Colorado, Colorado Springs, University of Colorado, Boulder, Northern Arizona University, Centre National De La Recherche Scientifique (CNRS), Andrews University, University of Hertfordshire, Southern Illinois University, Carbondale, University of Illinois at Urbana-Champaign

Journal

Astronomy & Astrophysics

Volume

568

No. of pages

ISSN

0004-6361

DOI

https://doi.org/10.1051/0004-6361/201424410

Publication date

08-2014

Peer reviewed

Yes

Austrian Fields of Science 2012

103003 Astronomy, 103004 Astrophysics

Keywords

ASJC Scopus subject areas

Astronomy and Astrophysics, Space and Planetary Science

Portal url

https://ucrisportal.univie.ac.at/en/publications/herschelatlas-and-alma-hatlas-j1429353002836-a-lensed-major-merger-at-redshift-1027(39e489cb-1132-4495-805c-b8d4ede2d362).html

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