Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published December 1, 2013 | Published + Submitted
Journal Article Open

HST/WFC3 Near-Infrared spectroscopy of quenched galaxies at z ~ 1.5 from the WISP Survey: Stellar population properties


We combine Hubble Space Telescope (HST) G102 and G141 near-IR (NIR) grism spectroscopy with HST/WFC3-UVIS, HST/WFC3-IR, and Spitzer/IRAC [3.6 μm] photometry to assemble a sample of massive (log (M_(star)/M_☉) ~ 11.0) and quenched (specific star formation rate <0.01 Gyr^(–1)) galaxies at z ~ 1.5. Our sample of 41 galaxies is the largest with G102+G141 NIR spectroscopy for quenched sources at these redshifts. In contrast to the local universe, z ~ 1.5 quenched galaxies in the high-mass range have a wide range of stellar population properties. We find that their spectral energy distributions (SEDs) are well fitted with exponentially decreasing star formation histories and short star formation timescales (τ ≤ 100 Myr). Quenched galaxies also show a wide distribution in ages, between 1 and 4 Gyr. In the (u – r)_0-versus-mass space quenched galaxies have a large spread in rest-frame color at a given mass. Most quenched galaxies populate the z ~ 1.5 red sequence (RS), but an important fraction of them (32%) have substantially bluer colors. Although with a large spread, we find that the quenched galaxies on the RS have older median ages (3.1 Gyr) than the quenched galaxies off the RS (1.5 Gyr). We also show that a rejuvenated SED cannot reproduce the observed stacked spectra of (the bluer) quenched galaxies off the RS. We derive the upper limit on the fraction of massive galaxies on the RS at z ~ 1.5 to be <43%. We speculate that the young quenched galaxies off the RS are in a transition phase between vigorous star formation at z > 2 and the z ~ 1.5 RS. According to their estimated ages, the time required for quenched galaxies off the RS to join their counterparts on the z ~ 1.5 RS is of the order of ~1 Gyr.

Additional Information

© 2013 American Astronomical Society. Received 2012 December 5; accepted 2013 September 10; published 2013 November 12. Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS 5-26555. The WISP survey is supported by grants HST-GO-12283 and HST-GO-12568 awarded by the Space Telescope Science Institute. C.L.M. acknowledges support from NSF grant AST- 1109288. H. A. is supported by the European Research Council (ERC) advanced grant "Light on the Dark" (LIDA).

Attached Files

Published - 0004-637X_778_2_126.pdf

Submitted - 1309.3567v1.pdf


Files (10.4 MB)
Name Size Download all
5.1 MB Preview Download
5.3 MB Preview Download

Additional details

August 22, 2023
October 25, 2023