J/MNRAS/522/449 JWST properties of high-z HST-dark galaxies (Barrufet+, 2023)
Unveiling the nature of infrared bright, optically dark galaxies with early
JWST data.
Barrufet L., Oesch P.A., Weibel A., Brammer G., Bezanson R., Bouwens R.,
Fudamoto Y., Gonzalez V., Gottumukkala R., Illingworth G., Heintz K.E.,
Holden B., Labbe I., Magee D., Naidu R.P., Nelson E., Stefanon M., Smit R.,
Van Dokkum P., Weaver J.R., Williams C.C.
<Mon. Not. R. Astron. Soc. 522, 449-456 (2023)>
=2023MNRAS.522..449B 2023MNRAS.522..449B (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies ; Spectroscopy ; Photometry ; Optical ; Infrared ;
Positional data ; Redshifts ; Extinction ; Star Forming Region ;
Stars, masses
Keywords: galaxies: high-redshift - infrared: galaxies
Abstract:
Over the last few years, both Atacama Large Millimeter/submillimeter
Array (ALMA) and Spitzer observations have revealed a population of
likely massive galaxies at z > 3 that was too faint to be detected
inHubble Space Telescope (HST) rest-frame ultraviolet imaging.
However, due to the very limited photometry for individual galaxies,
the true nature of these so-called HST-dark galaxies has remained
elusive. Here, we present the first sample of such galaxies observed
with very deep, high-resolution NIRCam imaging from the Early Release
Science programme CEERS. 30 HST-dark sources are selected based on
their red colours across 1.6-4.4 µm. Their physical properties are
derived from 12-band multiwavelength photometry, including ancillary
HST imaging. We find that these galaxies are generally heavily
dust-obscured (AV ∼2 mag), massive (logM/M☉) ∼10),
star-forming sources at z ∼ 2-8 with an observed surface density
of ∼0.8 arcmin-2. This suggests that an important fraction of massive
galaxies may have been missing from our cosmic census at z > 3 all the
way into the Epoch of Reionization. The HST-dark sources lie on the
main sequence of galaxies and add an obscured star formation rate
density of 3.2+1.8-1.3 * 10-3M☉/yr/Mpc3 at z ∼ 7,
showing likely presence of dust in the Epoch of Reionization. Our
analysis shows the unique power of JWST to reveal this previously
missing galaxy population and to provide a more complete census of
galaxies at z = 2-8 based on rest-frame optical imaging.
Description:
At z > 3, the rest-frame optical light redshifts out of the view of
the Hubble Space Telescope (HST). Therefore, our understanding of
'normal' star-forming galaxies such as Lyman break galaxies (LBGs)
that were identified in HST strongly relies on rest-frame ultraviolet
(UV) observations. This can result in an incomplete galaxy census at
earlier times due to UV-faint galaxy populations such as quiescent or
dust-obscured sources. Finding and characterizing this missing galaxy
population is a key goal of extragalactic astronomy in order to inform
theoretical models of galaxy evolution. In this paper, we address this
important question with some of the first JWST NIRCam imaging from the
Early Release Science (ERS) survey CEERS. This allows us to identify
HST-dark galaxies with the same selection that has been used in the
past for HST + Spitzer samples, but now with significantly measured
multiwavelength photometry in several bands to derive their redshifts
and physical properties reliably for the first time. This follows
previous analyses with JWST data that have already revealed massive
galaxies at z > 7. In a separate paper, we also analyse the
morphologies of bright F444W-selected sources.
This analysis is based on the first four NIRCam pointings from the ERS
programme CEERS. These images include exposure sets of short- and
long-wavelength filters: F115W +F277W, F115W+ F356W, F150W + F410M,
and F200W + F444W. The typical integration time for each filter set is
0.8 h. Hence, the F115W images obtained double the exposure time
compared to the remaining filters. We also include the available
ancillary data from HST since the CEERS survey covers the previous
CANDELS/EGS field. In particular, we include a re-reduction of all the
ACS and WFC3/IR imaging taken in these fields in the five filters:
F606W, F814W, F125W, F140W, and F160W. We match the point spread
functions (PSFs) in all but the WFC3 images to the F444W filter using
the deconvolution algorithm. The multiwavelength photometric
catalogues were derived with SExtractor. The final catalogue includes
∼26000 sources with photometry in 12 bands, spanning 0.6-4.4µm.
Next, as applying selections cut detailled in section 2.2 (e.g we remove
six galaxies that are at the edge of the image and do not have a clear
detection in the longer wavelength of the wide NIRCam filters F444W,
F356W, F277W, And three more galaxies for which the photometry is
extremely noisy, likely due to remaining detector artefacts), hence,
our final sample consists of 30 HST-dark galaxies.
Hereafter, as discussed in section 3, we compute the physical
properties of the 30 HST-dark galaxies by using BAGPIPES. This code
generates a complex model galaxy spectra to fit these to arbitrary
combinations of spectroscopic and photometric data using the MultiNest
nested sampling algorithm. The main physical parameters (z, logSFR,
logM*, AV) as well as their uncertainties from distribution functions
are presented in tablea1.dat. Indeed as exposed in section 4, thanks
to the very sensitive NIRCam data, we can now for the first time
measure accurate photometric redshifts and SEDs for HST-dark galaxies.
Hence, we can now derive significantly more reliable physical
parameters such as SFRs and stellar masses compared to previous
IRAC-selected HST-dark sources.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
tablea1.dat 90 30 HST-dark galaxy sample and derived properties
by BAGPIPES code on HST/JWST/Spitzer/IRAC data
--------------------------------------------------------------------------------
See also:
J/MNRAS/496/695 : Timing the earliest quenching events (Carnall+, 2020)
J/ApJ/923/215 : MORA: ALMA 2mm survey (Casey+, 2021)
J/ApJ/876/135 : 33 Optically faint galaxies (Alcalde Pampliega+, 2019)
J/ApJ/806/110 : ALESS survey: SMGs in the ECDF-S data (da Cunha+, 2015)
J/ApJ/788/125 : An ALMA survey of ECDFS submillimeter galaxies
(Simpson+, 2014)
J/ApJS/218/33 : Spitzer-CANDELS catalog within 5 deep fields (Ashby+, 2015)
Byte-by-byte Description of file: tablea1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 I5 --- ID Identifier number of the source (ID)
7- 17 F11.7 deg RAdeg Right ascension (J2000) (RA)
19- 28 F10.7 deg DEdeg Declination (J2000) (Dec.)
30- 33 F4.2 --- z Redshift (z)
35- 38 F4.2 --- E_z Upper uncertainty of z (E_z)
40- 43 F4.2 --- e_z Lower uncertainty of z (e_z)
45- 49 F5.2 [Msun/yr] logSFR Logarithm of the star forming rate (Log_SFR)
51- 54 F4.2 [Msun/yr] E_logSFR Upper uncertainty of logSFR (ELogSFR)
56- 59 F4.2 [Msun/yr] e_logSFR Lower uncertainty of logSFR (eLogSFR)
61- 65 F5.2 [Msun] logM* Logarithm of the stellar mass (Log_Mass)
67- 70 F4.2 [Msun] E_logM* Upper uncertainty of logM* (ELogMass)
72- 75 F4.2 [Msun] e_logM* Lower uncertainty of logM* (eLogMass)
77- 80 F4.2 mag AV Extinction dust attenuation (AV)
82- 85 F4.2 mag E_AV Upper uncertainty of AV (E_AV)
87- 90 F4.2 mag e_AV Lower uncertainty of AV (e_AV)
--------------------------------------------------------------------------------
History:
From electronic version of the journal
License: CC-BY-4.0
(End) Luc Trabelsi [CDS] 19-Jun-2026