Bibcode
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.
Bibliographical reference
Astronomy and Astrophysics, Volume 624, id.A138, 23 pp.
Advertised on:
4
2019
Journal
Citations
35
Refereed citations
34
Description
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(211-202), and
Jup = 2 H2O+ line emission. We also
report the detection of H2O(211-202) 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(211-202), and
Jup = 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. While the
average magnification for the dust continuum is μ ˜ 10-11, the
magnification of the line emission varies from 5 to 22 across different
velocity components. The line emission of CO(6-5),
H2O(211-202), 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 ˜1011 M⊙. Both of
the merging companions are intrinsically ultra-luminous infrared
galaxies (ULIRGs) with infrared luminosities LIR reaching
≳4 × 1012 L⊙, and the total
LIR of G09v1.97 is (1.4 ± 0.7)×1013
L⊙. The approaching southern galaxy (dominating from V =
-400 to -150 km s-1 relative to the systemic velocity) shows
no obvious kinematic structure with a semi-major half-light radius of
as = 0.4 kpc, while the receding galaxy (0 to 350 km
s-1) resembles an as = 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.
Reduced images and datacubes are only available at the CDS via anonymous
ftp to http://cdsarc.u-strasbg.fr
(ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/624/A138
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Formation and Evolution of Galaxies: Observations in Infrared and other Wavelengths
This IAC research group carries out several extragalactic projects in different spectral ranges, using space as well as ground-based telescopes, to study the cosmological evolution of galaxies and the origin of nuclear activity in active galaxies. The group is a member of the international consortium which built the SPIRE instrument for the
Ismael
Pérez Fournon