J/MNRAS/496/695 Timing the earliest quenching events (Carnall+, 2020)
Timing the earliest quenching events with a robust sample of massive quiescent
galaxies at 2<z<5.
Carnall A.C., Walker S., McLure R.J., Dunlop J.S., McLeod D.J., Cullen F.,
Wild V., Amorin R., Bolzonella M., Castellano M., Cimatti A., Cucciati O.,
Fontana A., Gargiulo A., Garilli B., Jarvis M.J., Pentericci L.,
Pozzetti L., Zamorani G., Calabro A., Hathi N.P., Koekemoer A.M.
<Mon. Not. R. Astron. Soc., 496, 695-707 (2020)>
=2020MNRAS.496..695C 2020MNRAS.496..695C (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies ; Redshifts ; Star Forming Region ; Infrared
Keywords: methods: statistical - galaxies: evolution - galaxies: star formation
Abstract:
We present a sample of 151 massive (M*>1010M☉) quiescent
galaxies at 2<z<5, based on a sophisticated Bayesian spectral energy
distribution fitting analysis of the CANDELS UDS and GOODS-South
fields. Our sample includes a robust sub-sample of 61 objects for
which we confidently exclude low-redshift and star-forming solutions.
We identify 10 robust objects at z>3, of which 2 are at z>4. We report
formation redshifts, demonstrating that the oldest objects formed at
z>6; however, individual ages from our photometric data have
significant uncertainties, typically ∼0.5Gyr. We demonstrate that the
UVJ colours of the quiescent population evolve with redshift at z>3,
becoming bluer and more similar to post-starburst galaxies at lower
redshift. Based upon this, we construct a model for the time evolution
of quiescent galaxy UVJ colours, concluding that the oldest objects
are consistent with forming the bulk of their stellar mass at z∼6-7
and quenching at z∼5. We report spectroscopic redshifts for two of our
objects at z=3.440 and 3.396, which exhibit extremely weak Lyα
emission in ultra-deep VANDELS spectra. We calculate star formation
rates based on these line fluxes, finding that these galaxies are
consistent with our quiescent selection criteria, provided their
Lyα escape fractions are >3 and >10 per cent, respectively. We
finally report that our highest redshift robust object exhibits a
continuum break at λ∼7000Å in a spectrum from VUDS,
consistent with our photometric redshift of
zphot=4.72+0.06-0.04. If confirmed as quiescent, this object
would be the highest redshift known quiescent galaxy. To obtain
stronger constraints on the times of the earliest quenching events,
high-SNR spectroscopy must be extended to z≳3 quiescent objects.
Description:
In this work, we analyse data from CANDELS UDS and GOODS-South, two of
the best-studied extragalactic legacy fields. Both have deep
near-ultraviolet to near-infrared Hubble Space Telescope (HST) data
from CANDELS (Grogin et al. 2011ApJS..197...35G 2011ApJS..197...35G; Koekemoer et al.
2011ApJS..197...36K 2011ApJS..197...36K) and other programmes, as well as a wide range of
ground-based and Spitzer-IRAC multiwavelength ancillary data. Full
details of the catalogues used can be found in Galametz et al.
(2013ApJS..206...10G 2013ApJS..206...10G, Cat. J/ApJS/206/10) and Guo et al.
(2013ApJS..207...24G 2013ApJS..207...24G, Cat. J/ApJS/207/24) for UDS and GOODS-S,
respectively.
These two fields in particular were chosen for this work due to the
availability of ultra-deep K-band imaging from the Hawk-I UDS and
GOODS Survey (HUGS; Fontana et al. 2014A&A...570A..11F 2014A&A...570A..11F, Cat.
J/A+A/570/A11). At z≳3, the Balmer/4000Å break falls between the H
and K bands, meaning the extremely deep imaging in these bands
provided by CANDELS and HUGS, respectively, is critical for the robust
identification of older stellar populations at these redshifts. For
this reason, we supplement the Guo et al. (2013ApJS..207...24G 2013ApJS..207...24G, Cat.
J/ApJS/207/24) GOODS-S catalogue with additional, deeper K-band data
from the final HUGS data release.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 143 151 Coordinates, magnitudes, and BAGPIPES physical
parameters for our parent z>2 massive quiescent
galaxy sample
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See also:
J/ApJS/206/10 : CANDELS multiwavelength catalog (Galametz+, 2013)
J/ApJS/207/24 : GOODS-S CANDELS multiwavelength catalog (Guo+, 2013)
J/A+A/570/A11 : The Hawk-I UDS and GOODS Survey (HUGS) (Fontana+, 2014)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- Name Source identifier
14- 22 F9.6 deg RAdeg Right ascension (J2000)
24- 33 F10.6 deg DEdeg Declination (J2000)
35- 38 F4.1 mag F160Wmag F160W-band magnitude
40- 43 F4.1 mag Ksmag Ks-band magnitude
45- 48 F4.2 --- z2.5 2.5 percentile of the redshift
50- 53 F4.2 --- z16 16 percentile of the redshift
55- 58 F4.2 --- z50 50 percentile of the redshift
60- 63 F4.2 --- z84 84 percentile of the redshift
65- 68 F4.2 --- z97.5 97.5 percentile of the redshift
70- 73 F4.2 Gyr t16 16 percentile of the formation time
75- 78 F4.2 Gyr t50 50 percentile of the formation time
80- 83 F4.2 Gyr t84 84 percentile of the formation time
85- 89 F5.2 [Msun] logMass16 Logarithm of the 16 percentile of the
stellar mass
91- 95 F5.2 [Msun] logMass50 Logarithm of the 50 percentile of the
stellar mass
97- 101 F5.2 [Msun] logMass84 Logarithm of the 84 percentile of the
stellar mass
103- 108 F6.2 [Msun/yr] logSFR16 Logarithm of the 16 percentile of the
specific star formation rate
110- 115 F6.2 [Msun/yr] logSFR50 Logarithm of the 50 percentile of the
specific star formation rate
117- 122 F6.2 [Msun/yr] logSFR84 Logarithm of the 84 percentile of the
specific star formation rate
124- 127 F4.2 mag Av16 16 percentile of the dust reddening
129- 132 F4.2 mag Av50 50 percentile of the dust reddening
134- 137 F4.2 mag Av84 84 percentile of the dust reddening
139- 143 A5 --- robust [True /False] Indicates if the source
belongs to the robust sub-sample (1)
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Note (1): Objects in our robust sub-sample are required to have >97.5 per cent
of their specific star formation rate posterior below sSFR=0.2/tH
and <2.5 per cent of their redshift posterior below z=2. These
criteria correspond to 2σ upper and lower limits, respectively,
for a Gaussian posterior distribution.
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History:
From electronic version of the journal
(End) Ana Fiallos [CDS] 27-Jun-2023