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| Paper: |
Near-Infrared Spectroscopy of Passively Evolving Galaxies at z > 1.4 with Subaru/MOIRCS |
| Volume: |
458, Galactic Archaeology: Near-Field Cosmology and the Formation of the Milky Way |
| Page: |
337 |
| Authors: |
Onodera, M. |
| Abstract: |
We present the results of near-IR spectroscopic observations of passive galaxies at z ≥ 1.4 in the COSMOS field.
The observations have been conducted with Subaru/MOIRCS,
and have resulted in absorption lines and/or continuum detection for
16 out of 17 objects down to KAB = 21 (18 of 34 in total),
then allowing us the measurement of their spectroscopic redshifts.
COSMOS photometric redshifts are found in fair agreement overall with the spectroscopic redshifts,
with a standard deviation of ≈ 0.05, but including ∼ 30% of outliers
for which they are systematically underestimated. All galaxies fall in four distinct redshift spikes at z = 1.43, 1.53, 1.67 and 1.82,
with this latter one including 7 galaxies.
SED fits to broad-band fluxes indicate stellar masses in the range of ∼ 4 – 40 × 1010 M☉,
and that star formation was quenched ∼ 1 Gyr before the cosmic epoch at which they are observed.
The spectra of individual galaxies have allowed us to measure HδF indices
and the strength of the 4000 Å break, which confirms the passive nature of the program galaxies. |
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