X-shooter Spectroscopy and HST Imaging of 15 Massive Quiescent Galaxies at z ≳ 2
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We present a detailed analysis of a large sample of spectroscopically
confirmed massive quiescent galaxies (MQGs; log(M */M
⊙) ∼ 11.5) at z ≳ 2. This sample comprises 15
galaxies selected in the COSMOS and UDS fields by their bright K-band
magnitudes and followed up with Very Large Telescope (VLT) X-shooter
spectroscopy and Hubble Space Telescope (HST)/WFC3 H F160W
imaging. These observations allow us to unambiguously confirm their
redshifts, ascertain their quiescent nature and stellar ages, and
reliably assess their internal kinematics and effective radii. We find
that these galaxies are compact, consistent with the high-mass end of
the stellar mass–size relation for quiescent galaxies at z = 2.
Moreover, the distribution of the measured stellar velocity dispersions
of the sample is consistent with the most massive local early-type
galaxies from the MASSIVE Survey, showing that evolution in these
galaxies is dominated by changes in size. The HST images reveal, as
surprisingly high, that 40% of the sample has tidal features suggestive
of mergers and companions in close proximity, including three galaxies
experiencing ongoing major mergers. The absence of velocity dispersion
evolution from z = 2 to 0, coupled with a doubling of the stellar mass,
with a factor of 4 size increase and the observed disturbed stellar
morphologies, supports dry minor mergers as the primary drivers of the
evolution of the MQGs over the last 10 billion yr.
Originalsprog | Engelsk |
---|---|
Artikelnummer | 4 |
Tidsskrift | Astrophysical Journal |
Vol/bind | 888 |
Udgave nummer | 1 |
Antal sider | 23 |
ISSN | 0004-637X |
DOI | |
Status | Udgivet - 1 jan. 2020 |
Links
- http://adsabs.harvard.edu/abs/2020ApJ...888....4S
Forlagets udgivne version
ID: 236164757