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CO, H 2 O, H 2 O + line and dust emission in a z = 3.63 strongly lensed starburst merger at sub-kiloparsec scales

Yang, C.; Gavazzi, R.; Beelen, A.; Cox, P.; Omont, A.; Lehnert, M.D.; Gao, Y.; Ivison, R.J.; Swinbank, A.M.; Barcos-Muñoz, L.; Neri, R.; Cooray, A.; Dye, S; Eales, S.; Fu, H.; González-Alfonso, E.; Ibar, E.; Michałowski, M.J.; Nayyeri, H.; Negrello, M.; Nightingale, J.; Pérez-Fournon, I.; Riechers, D.A.; Smail, I.; Van Der Werf, P.


C. Yang

R. Gavazzi

A. Beelen

P. Cox

A. Omont

M.D. Lehnert

Y. Gao

R.J. Ivison

A.M. Swinbank

L. Barcos-Muñoz

R. Neri

A. Cooray

Associate Professor

S. Eales

H. Fu

E. González-Alfonso

E. Ibar

M.J. Michałowski

H. Nayyeri

M. Negrello

J. Nightingale

I. Pérez-Fournon

D.A. Riechers

I. Smail

P. Van Der Werf


Using the Atacama Large Millimeter/submillimeter Array (ALMA), we report high angular-resolution observations of the redshift z =3.63 galaxy H-ATLAS J083051.0+013224 (G09v1.97), one of the most luminous strongly lensed galaxies discovered by the Herschel-Astrophysical Terahertz Large Area Survey (H-ATLAS). We present 0. 2-0. 4 resolution images of the rest-frame 188 and 419 µm dust continuum and the CO(6-5), H2O(2 11-2 02) and J up = 2 H2O + line emission. We also report the detection of H 18 2 O(2 11-2 02) in this source. The dust continuum and molecular gas emission are resolved into a nearly complete ∼ 1. 5 diameter Einstein ring plus a weaker image in the center, which is caused by a special dual deflector lensing configuration. The observed line profiles of the CO(6-5), H2O(2 11-2 02) and J up = 2 H2O + lines are strikingly similar. In the source plane, we reconstruct the dust continuum images and the spectral cubes of the CO, H2O and H2O+ line emission at sub-kiloparsec scales. The reconstructed dust emission in the source plane is dominated by a compact disk with an effective radius of 0.7 ± 0.1 kpc plus an overlapping extended disk with a radius twice as large. The total intrinsic infrared luminosity, L IR , of G09v1.97 is (1.4 ± 0.7) × 10^13 L_sol and is a hyper-luminous infrared galaxy. The line emission of CO(6-5), H2O(2 11-2 02) and H2O + have similar spatial and kinematic distributions. The molecular gas and dust content reveal that G09v1.97 is a gas-rich major merger in its pre-coalescence phase, with a total molecular gas mass of ∼ 10^11 Msol. Both of the merging companions are intrinsically ultra-luminous infrared galaxies (ULIRGs) with L_IR reaching 4 × 10^12 Lsol. The approaching southern galaxy (dominating from V = −400 to −150 km/s relative to the systemic velocity) shows no obvious kinematic structure with a half-light radius Reff = 0.4 kpc, while the receding galaxy (0 to 350 km s −1) resembles a R eff = 1.2 kpc rotating disk. The two galaxies are separated by a projected distance of 1.3 kpc, bridged by weak line emission (−150 to 0 km s −1) that is co-spatially located with the cold-dust-emission peak, suggesting a large amount of cold interstellar medium (ISM) in the interacting region. As one of the most luminous star-forming dusty high-redshift galaxies, G09v1.97 is an exceptional source for understanding the ISM in gas-rich starbursting major merging systems at high-redshift.

Journal Article Type Article
Publication Date Apr 30, 2019
Journal Astronomy and Astrophysics
Electronic ISSN 1432-0746
Publisher EDP Open
Peer Reviewed Peer Reviewed
Volume 624
Issue 2019
Article Number A138
APA6 Citation Yang, C., Gavazzi, R., Beelen, A., Cox, P., Omont, A., Lehnert, M., …Van Der Werf, P. (2019). CO, H 2 O, H 2 O + line and dust emission in a z = 3.63 strongly lensed starburst merger at sub-kiloparsec scales. Astronomy and Astrophysics, 624(2019),
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