Bussmann, R. S., Gurwell, M. A., Fu, Hai, Smith, D. J. B., Dye, S., Auld, Robbie Richard, Baes, M., Baker, A. J., Bonfield, D., Cava, A., Clements, D. L., Cooray, A., Coppin, K., Dannerbauer, H., Dariush, A., De Zotti, G., Dunne, Loretta ![]() ![]() ![]() ![]() |
Abstract
We present high-spatial resolution imaging obtained with the Submillimeter Array (SMA) at 880 μm and the Keck adaptive optics (AO) system at the K S-band of a gravitationally lensed submillimeter galaxy (SMG) at z = 4.243 discovered in the Herschel Astrophysical Terahertz Large Area Survey. The SMA data (angular resolution ≈0farcs6) resolve the dust emission into multiple lensed images, while the Keck AO K S-band data (angular resolution ≈0farcs1) resolve the lens into a pair of galaxies separated by 0farcs3. We present an optical spectrum of the foreground lens obtained with the Gemini-South telescope that provides a lens redshift of z lens = 0.595 ± 0.005. We develop and apply a new lens modeling technique in the visibility plane that shows that the SMG is magnified by a factor of μ = 4.1 ± 0.2 and has an intrinsic infrared (IR) luminosity of L IR = (2.1 ± 0.2) × 1013 L ☉. We measure a half-light radius of the background source of r s = 4.4 ± 0.5 kpc which implies an IR luminosity surface density of ΣIR = (3.4 ± 0.9) × 1011 L ☉ kpc–2, a value that is typical of z > 2 SMGs but significantly lower than IR luminous galaxies at z ~ 0. The two lens galaxies are compact (r lens ≈ 0.9 kpc) early-types with Einstein radii of θE1 = 0.57 ± 0.01 and θE2 = 0.40 ± 0.01 that imply masses of M lens1 = (7.4 ± 0.5) × 1010 M ☉ and M lens2 = (3.7 ± 0.3) × 1010 M ☉. The two lensing galaxies are likely about to undergo a dissipationless merger, and the mass and size of the resultant system should be similar to other early-type galaxies at z ~ 0.6. This work highlights the importance of high spatial resolution imaging in developing models of strongly lensed galaxies discovered by Herschel.
Item Type: | Article |
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Date Type: | Publication |
Status: | Published |
Schools: | Physics and Astronomy |
Subjects: | Q Science > QB Astronomy |
Uncontrolled Keywords: | galaxies: evolution; galaxies: fundamental parameters; galaxies: high-redshift; gravitational lensing: strong |
Publisher: | IOP Science |
ISSN: | 0004-637X |
Last Modified: | 25 Oct 2022 08:37 |
URI: | https://orca.cardiff.ac.uk/id/eprint/53743 |
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