ALMA [N ii] 205 μm Imaging Spectroscopy of the Lensed Submillimeter Galaxy ID 141 at Redshift 4.24
Abstract We present an Atacama Large Millimeter/submillimeter Array observation of the Submillimeter galaxy ID 141 at z = 4.24 in the [N ii ] 205 μ m line (hereafter [N ii ] ) and the underlying continuum at (rest-frame) 197.6 μ m. Benefiting from lensing magnification by a galaxy pair at z = 0.59...
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Published in | The Astrophysical journal Vol. 898; no. 1; p. 33 |
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Main Authors | , , , , , , , , , , , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
Philadelphia
IOP Publishing
01.07.2020
|
Subjects | |
Online Access | Get full text |
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Summary: | Abstract
We present an Atacama Large Millimeter/submillimeter Array observation of the Submillimeter galaxy ID 141 at
z
= 4.24 in the [N
ii
] 205
μ
m line (hereafter [N
ii
] ) and the underlying continuum at (rest-frame) 197.6
μ
m. Benefiting from lensing magnification by a galaxy pair at
z
= 0.595, ID 141 is one of the brightest
SMGs. At the angular resolutions of
–1.″5 (1″ ∼6.9 kpc), our observation clearly separates and moderately resolves the two lensed images in both continuum and line emission at a signal-to-noise ratio >5. Our continuum-based lensing model implies an averaged amplification factor of ∼5.8 and reveals that the delensed continuum image has a Sérsic index
and Sérsic radius of ∼0.″18 (∼1.24 kpc). Furthermore, the reconstructed [N
ii
] velocity field in the source plane is dominated by a rotation component with a maximum velocity of ∼300 km s
−1
at large radii, indicating a dark matter halo mass of ∼10
. This, together with the reconstructed velocity dispersion field being smooth and modest in value (<100 km s
−1
) over much of the outer parts of the galaxy, favors the interpretation of ID 141 being a disk galaxy dynamically supported by rotation. The observed [N
ii
] /CO (7−6) and [N
ii
] /[C
ii
] 158
μ
m line-luminosity ratios, which are consistent with the corresponding line ratio versus far-infrared color correlation from local luminous infrared galaxies, imply a delensed star formation rate of (1.8
yr
−1
and provide an independent estimate of the size of the star-forming region
kpc in radius. |
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ISSN: | 0004-637X 1538-4357 |
DOI: | 10.3847/1538-4357/ab980b |