Newman, AB;
Belli, S;
Ellis, RS;
(2015)
Discovery of a strongly lensed massive quiescent galaxy at z = 2.636: spatially resolved spectroscopy and indications of rotation.
The Astrophysical Journal Letters
, 813
, Article L7. 10.1088/2041-8205/813/1/L7.
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Abstract
We report the discovery of RG1M0150, a massive, recently quenched galaxy at z = 2.636 that is multiply imaged by the cluster MACSJ0150.3-1005. We derive a stellar mass of log M* = 11.49 +0.10/-0.16 and a half-light radius of Re,maj = 1.8 ± 0.4 kpc. Taking advantage of the lensing magnification, we are able to spatially resolve a remarkably massive yet compact quiescent galaxy at z > 2 in ground-based near-infrared spectroscopic observations using Magellan/FIRE and Keck/MOSFIRE. We find no gradient in the strength of the Balmer absorption lines over 0.6Re - 1.6Re which are consistent with an age of 760 Myr. Gas emission in [N ii] broadly traces the spatial distribution of the stars and is coupled with weak Hα emission (log [N ii]/Hα = 0.6 ± 0.2), indicating that OB stars are not the primary ionizing source. The velocity dispersion within the effective radius is σe, stars = 271 ± 41 km s-1. We detect rotation in the stellar absorption lines for the first time beyond z ~ 1. Using a two-integral Jeans model that accounts for observational effects, we measure a dynamical mass of log Mdyn = 11.24 ± 0.14 and V/σ = 0.70 ± 0.21. This is a high degree of rotation considering the modest observed ellipticity of 0.12 ± 0.08, but it is consistent with predictions from dissipational merger simulations that produce compact remnants. The mass of RG1M0150 implies that it is likely to become a slowly rotating elliptical. If it is typical, this suggests that the progenitors of massive ellipticals retain significant net angular momentum after quenching which later declines, perhaps through accretion of satellites.
| Type: | Article |
|---|---|
| Title: | Discovery of a strongly lensed massive quiescent galaxy at z = 2.636: spatially resolved spectroscopy and indications of rotation |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1088/2041-8205/813/1/L7 |
| Publisher version: | http://dx.doi.org/10.1088/2041-8205/813/1/L7 |
| Language: | English |
| Additional information: | Copyright © 2015. The American Astronomical Society. All rights reserved. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery.ucl.ac.uk/id/eprint/1493163 |
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