J/ApJ/876/135 33 Optically faint galaxies (Alcalde Pampliega+, 2019)
Optically faint massive Balmer break galaxies at z > 3 in the
CANDELS/GOODS fields.
Alcalde Pampliega B., Perez-Gonzalez P.G., Barro G., Dominguez Sanchez H.,
Eliche-Moral M.C., Cardiel N., Hernan-caballero A., Rodriguez-Munoz L.,
Sanchez Blazquez P., Esquej P.
<Astrophys. J., 876, 135-135 (2019)>
=2019ApJ...876..135A 2019ApJ...876..135A (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, photometry ; Redshifts ; Colors ; Extinction
Keywords: galaxies: evolution - galaxies: high-redshift -
galaxies: star formation - infrared: galaxies
Abstract:
We present a sample of 33 Balmer break galaxies (BBGs) selected as
Hubble Space Telescope/F160W dropouts in the deepest CANDELS/GOODS
fields (H≥27.3mag) but relatively bright in Spitzer/IRAC
([3.6], [4.5] <24.5mag), implying red colors (median and quartiles:
<H-[3.6]≥3.12.83.4mag). Half of these BBGs are newly identified
sources. Our BBGs are massive (<log(M/M☉)≥10.810.411.0),
high-redshift (=4.84.45.1), dusty (<A(V)≥2.01.52.0mag)
galaxies. The spectral energy distributions (SEDs) of half of our
sample indicate that they are star-forming galaxies with typical
specific star formation rates (SFRs) of 0.5-1.0Gyr-1, qualifying
them as main-sequence (MS) galaxies at 3<z<6. One-third of these SEDs
indicate the presence of prominent emission lines (Hβ+[OIII],
Hα+[NII]) boosting the IRAC fluxes and red colors. Approximately
20% of the BBGs are very dusty (A(V)∼2.5mag) starbursts with strong
mid-to-far-infrared detections and extreme SFRs (SFR>103M☉/yr)
that place them above the MS. The rest, 30%, are post-starbursts or
quiescent galaxies located >2σ below the MS with mass-weighted
ages older than 700Myr. Only two of the 33 galaxies are X-ray-detected
active galactic nuclei (AGNs) with optical/near-infrared SEDs
dominated by stellar emission, but the presence of obscured AGNs in
the rest of the sources cannot be discarded. Our sample accounts for
8% of the total number density of log(M/M☉)>10 galaxies at z>3,
but it is a significant contributor (30%) to the general population of
red log(M/M☉)> 11 galaxies at 4<z<6. Finally, our results point
out that one of every 30 massive log(M/M☉)> 11 galaxies in the
local universe was assembled in the first 1.5Gyr after the big bang, a
fraction that is not reproduced by state-of-the-art galaxy formation
simulations.
Description:
Our catalog is composed by as a sample of BBG candidates (selected as
H-band dropouts) in two of the deepest cosmological fields, namely,
GOODS-N and GOODS-S. We limit our search for BBGs to the area surveyed
by CANDELS, from the UV to the FIR and millimeter. In total, we work
with a sky region of 330-arcmin2 (160-arcmin2 in GOODS-N and
170-arcmin2 in GOODS-S).
Our selection technique is based on two conditions. The BBG candidates
are required to be bright in the first two channels of IRAC, [3.6] and
[4.5]< 24.5 mag, and they must be undetected (dropouts) in the
HST/F160W (H≳27mag) mosaics (according to publicly available
catalogs).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table.dat 245 33 Galaxy properties for the sample of 33 galaxies
(table1 and table3)
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Byte-by-byte Description of file: table.dat
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Bytes Format Units Label Explanations
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2- 10 A9 --- ID ID (BBG_GDNNN or BBG_GDSNN)
13- 24 F12.8 deg RAdeg Rigth ascension (J2000)
27- 38 F12.8 deg DEdeg Declination (J2000)
41- 43 F3.1 --- z Photometric redshift
46- 50 F5.2 mag F160W Photometry HST/WFC3_F160W (AB)
53- 56 F4.2 mag e_F160W Photometric error in HST/WFC3_F160W (AB)
59- 63 F5.2 mag [3.6] Photometry IRAC CH1 (AB)
66- 69 F4.2 mag e_[3.6] Photometric error in IRAC CH1 (AB)
72- 76 F5.2 mag [4.5] Photometry IRAC CH2 (AB)
79- 82 F4.2 mag e_[4.5] Photometric error in IRAC CH2 (AB)
85- 90 F6.2 mag [5.8] ?=-99 Photometry IRAC CH3 (AB)
93- 96 F4.2 mag e_[5.8] ?=0 Photometric error in IRAC CH3 (AB)
99-104 F6.2 mag [8.0] ?=-99 Photometry IRAC CH4 (AB)
107-110 F4.2 mag e_[8.0] ?=0 Photometric error in IRAC CH4 (AB)
113-120 F8.3 Msun/yr SFR SFR_total if IR-detected:
SFRUV+SFRIR, otherwise: SFRsed
123-129 F7.3 Msun/yr SFRsed SFR from SED fitting
132-139 F8.3 Msun/yr SFRUV SFR UV, computed from rest-frame UV
luminosity, uncorrected for attenuation
142-150 F9.3 Msun/yr SFRIR ?=0 SFR IR, computed from IR luminosity
153-157 F5.2 [Msun] logM Stellar mass
160-164 F5.2 [Msun] e_logM Error on logM (lower value)
167-171 F5.2 [Msun] E_logM Error on logM (upper value)
174-176 F3.1 [Sun] Z Metallicity
179-185 F7.3 Myr Tau Star formation time-scale
188-194 F7.3 Myr e_Tau Error on tau (lower value)
197-203 F7.3 Myr E_Tau Error on tau (upper value)
206-210 F5.3 Gyr Age Best-fitting age
213-217 F5.3 Gyr e_Age Error on age (lower value)
220-224 F5.3 Gyr E_Age Error on age (upper value)
227-231 F5.3 mag Av Dust attenuation
234-238 F5.3 mag e_Av Error on Av (lower value)
241-245 F5.3 mag E_Av Error on Av (upper value)
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Acknowledgements:
Belen Alcalde Pampliega, belenalc(at)ucm.es, belen.alcalde(at)eso.org
(End) Belen Alcalde Pampliega [ESO], Patricia Vannier [CDS] 23-Aug-2022