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Discovery of a Strongly Lensed Massive Quiescent Galaxy at z = 2.636: Spatially Resolved Spectroscopy and Indications of Rotation

Newman, Andrew B. and Belli, Sirio and Ellis, Richard S. (2015) Discovery of a Strongly Lensed Massive Quiescent Galaxy at z = 2.636: Spatially Resolved Spectroscopy and Indications of Rotation. Astrophysical Journal, 813 (1). Art. No. L7. ISSN 0004-637X. https://resolver.caltech.edu/CaltechAUTHORS:20151204-140128583

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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_(-0.16)^(+0.10) and a half-light radius of R_(e,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 0.6R_e - 1.6R_e, 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]/Hɑ = 0.6 ± 0.2, indicating that OB stars are not the primary ionizing source. The velocity dispersion within the effective radius is σ_(e,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 M_(dyn) = 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.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1088/2041-8205/813/1/L7DOIArticle
http://iopscience.iop.org/article/10.1088/2041-8205/813/1/L7PublisherArticle
http://arxiv.org/abs/1509.04345arXivDiscussion Paper
ORCID:
AuthorORCID
Newman, Andrew B.0000-0001-7769-8660
Belli, Sirio0000-0002-5615-6018
Ellis, Richard S.0000-0001-7782-7071
Additional Information:© 2015 American Astronomical Society. Received 2015 September 16; accepted 2015 October 12; published 2015 October 23. We thank Dan Kelson for expertise reducing the FourStar data and insightful discussions. It is a pleasure to acknowledge helpful conversations with Adam Muzzin and Sune Toft, as well as the referee for a prompt and thoughtful report. The authors acknowledge the very significant cultural role that the summit of Mauna Kea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain.
Subject Keywords:galaxies: elliptical and lenticular, cD; galaxies: kinematics and dynamics; gravitational lensing: strong
Issue or Number:1
Record Number:CaltechAUTHORS:20151204-140128583
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20151204-140128583
Official Citation:Andrew B. Newman et al 2015 ApJ 813 L7
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:62623
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:08 Dec 2015 17:51
Last Modified:03 Oct 2019 09:20

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