J/ApJ/940/L24 JWST 7.7um sources in SMACS J0723.3-7327 field (Iani+, 2022)
A first look into the nature of JWST/MIRI 7.7um sources from SMACS 0723.
Iani E., Caputi K.I., Rinaldi P., Kokorev V.I.
<Astrophys. J., 940, L24 (2022)>
=2022ApJ...940L..24I 2022ApJ...940L..24I
ADC_Keywords: Clusters, galaxy; Photometry, infrared; Photometry, HST;
Optical; Colors; Redshifts; Extinction; Galaxies, IR
Keywords: Infrared astronomy ; High-redshift galaxies ; Redshift surveys
Abstract:
Until now, our knowledge of the extragalactic universe at mid-infrared
(mid-IR) wavelengths (>5µm) was limited to rare active galactic
nuclei and the brightest normal galaxies up to z∼3. The advent of JWST
with its Mid-Infrared Instrument (MIRI) will revolutionize the ability
of the mid-IR regime as a key wavelength domain to probe the high-z
universe. In this work we present a first study of JWST MIRI 7.7µm
sources selected with >3σ significance from the lensing cluster
field SMACS J0723.3-7327. We model their spectral energy distribution
(SED) fitting with 13 JWST and Hubble Space Telescope broad bands, in
order to obtain photometric redshifts and derived physical parameters
for all these sources. We find that this 7.7µm galaxy sample is
mainly composed of normal galaxies up to z=4 and has a tail of about
2% of sources at higher redshifts to z∼9-10. The vast majority of our
galaxies have [3.6]-[7.7]<0 colors and very few of them need high dust
extinction values (AV=3-6mag) for their SED fitting. The resulting
lensing-corrected stellar masses span the range 107-1011M☉.
Overall, our results clearly show that the first MIRI 7.7µm
observations of deep fields are already useful to probe the
high-redshift universe and suggest that the deeper 7.7µm
observations to be available very soon will open up, for the first
time, the epoch of reionization at mid-IR wavelengths.
Description:
The JWST observations of SMACS J0723.3-7327 (ID proposal: 2736,
PI: K.M. Pontoppidan) were publicly released as part of the JWST Early
Release Observations (ERO) program on the 2022 July 13.
The observations were carried out with the JWST Near Infrared Camera
(NIRCam), MIRI, the Near Infrared Imager and Slitless Spectrograph,
and the Near Infrared Spectrograph (NIRSpec). In the following, we
briefly describe the MIRI and NIRCam observations we exploited in our
work.
The MIRI instrument on board of JWST observed the central region of
SMACS 0723 with the wide-band filters F770W, F1000W, F1500W, and
F1800W. The observations were carried out on the 2022 June 14, and
covered an area of 112.6"x73.5", i.e., the MIRI field-of-view. In this
work, we only make use of the F770W image. We downloaded the fully
reduced MIRI images available at the Mikulski Archive for Space
Telescopes (MAST).
A comparison between the MIRI and HST images highlighted an
astrometric offset between the two data sets. We decided to register
the MIRI observations to the HST astronomical coordinate system.
See Section 2.1.1.
The NIRCam instrument on board of JWST observed SMACS 0723 with the
wide-band filters F090W, F150W, F200W, F277W, F356W, and F444W. The
observations were carried out on the 2022 June 6. We downloaded the
fully reduced NIRCam images available at MAST. See Section 2.1.2.
SMACS 0723 was observed with HST as part of The Reionization Lensing
Cluster Survey (RELICS; Coe+ 2019, J/ApJ/884/85). The observations of
SMACS 0723 were carried out with the F435W, F606W, and F814W filters
from the Advanced Camera for Surveys (ACS), and with the F105W, F125W,
F140W, and F160W filters from the Wide Field Camera 3 (WFC3) IR
channel. We downloaded the fully reduced HST images from the RELICS
repository.
In this Letter, we adopt a flat ΛCDM cosmology with
ΩΛ=0.7, Ωm=0.3, and H0=70km/s/Mpc. All
magnitudes are in the AB photometric system.
Objects:
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RA (ICRS) DE Designation(s) (z)
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07 23 19.5 -73 27 15.6 SMACS 0723 = SMACS J0723.3-7327 (z=0.39)
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 369 341 Main properties of our sample of 7.7 micron-detected
sources at zphot>6
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See also:
J/ApJ/642/673 : IR-selected obscured AGN candidates (Polletta+, 2006)
J/ApJ/723/1110 : MIPS 24um observations of the HDFS (Huynh+, 2010)
J/ApJS/206/10 : CANDELS multiwavelength catalog (Galametz+, 2013)
J/A+A/611/A94 : 6 galaxy clusters ATCA 2.1GHz images (Martinez Aviles+, 2018)
J/ApJ/884/85 : RELICS: Reionization Lensing Cluster Survey (Coe+, 2019)
J/ApJS/257/68 : Spitzer/IRAC full-depth phot. from GREATS (Stefanon+, 2021)
J/A+A/666/L9 : SMACS J0723.3-7327 first JWST observations (Caminha+, 2022)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- Seq [2/483] Internal index number
5- 14 F10.6 deg RAdeg [110.77/110.88] Right Ascension (J2000)
16- 25 F10.6 deg DEdeg [-73.5/-73.43] Declination (J2000)
27 A1 --- l_F435W [>] Upper limit flag on F435W
29- 35 F7.2 nJy F435W [3/9839] Flux density in HST/ACS F435W band
37- 42 F6.2 nJy e_F435W [32/454]? Uncertainty in F435W
44 A1 --- l_F606W [>] Upper limit flag on F606W
46- 53 F8.2 nJy F606W [8/47291] Flux density in HST/ACS F606W band
55- 61 F7.2 nJy e_F606W [16/2178]? Uncertainty in F606W
63- 71 F9.2 nJy F814W [6/122244] Flux density in HST/ACS F814W band
73- 79 F7.2 nJy e_F814W [23/5630] Uncertainty in F814W
81- 89 F9.2 nJy F090W [0.47/159327] Flux density in JWST/NIRCam F090W
band
91- 97 F7.2 nJy e_F090W [5.9/7338] Uncertainty in F090W
99 A1 --- l_F105W [>] Upper limit flag on F105W
101- 109 F9.2 nJy F105W [10/203292]? Flux density in HST/WFC3 F105W band
111- 117 F7.2 nJy e_F105W [13/9362]? Uncertainty in F105W
119 A1 --- l_F125W [>] Upper limit flag on F125W
121- 129 F9.2 nJy F125W [9/261214]? Flux density in HST/WFC3 F125W band
131- 138 F8.2 nJy e_F125W [9/12030]? Uncertainty in F125W
140 A1 --- l_F140W [>] Upper limit flag on F140W
142- 150 F9.2 nJy F140W [10/311160]? Flux density in HST/WFC3 F140W band
152- 159 F8.2 nJy e_F140W [18/14330]? Uncertainty in F140W
161 A1 --- l_F150W [>] Upper limit flag on F150W
163- 171 F9.2 nJy F150W [22/363471]? Flux density in JWST/NIRCam F150W
band
173- 180 F8.2 nJy e_F150W [6.6/16739]? Uncertainty in F150W
182 A1 --- l_F160W [>] Upper limit flag on F160W
184- 192 F9.2 nJy F160W [8.9/346001]? Flux density in HST/WFC3 F160W
band
194- 201 F8.2 nJy e_F160W [13/15934]? Uncertainty in F160W
203- 211 F9.2 nJy F200W [11/453785] Flux density in JWST/NIRCam F200W
band
213- 220 F8.2 nJy e_F200W [5.7/20898] Uncertainty in F200W
222- 230 F9.2 nJy F277W [14/423397] Flux density in JWST/NIRCam F277W
band
232- 239 F8.2 nJy e_F277W [3.9/19499] Uncertainty in F277W
241- 249 F9.2 nJy F356W [40/266232] Flux density in JWST/NIRCam F356W
band
251- 258 F8.2 nJy e_F356W [3.6/12261] Uncertainty in F356W
260- 268 F9.2 nJy F444W [29/217443] Flux density in JWST/NIRCam F444W
band
270- 277 F8.2 nJy e_F444W [4/10014] Uncertainty in F444W
279- 287 F9.2 nJy F770W [122.9/118051] Flux density in JWST/MIRI F770W
band
289- 295 F7.2 nJy e_F770W [22.8/5437] Uncertainty in F770W
297- 301 F5.2 --- Color [-2.6/2.8] The (3.6-7.7) micron band color
303- 306 F4.2 --- e_Color [0.07/0.4] Uncertainty in Color
308- 311 F4.2 --- zBest [0/9.2] Best photometric derived redshift
313- 317 F5.2 --- zSec [0/10]? Secondary redshift solution
319- 322 F4.2 mag Av [0/6.1] The V band extinction
324- 327 F4.2 mag b_Av [0/5.91] Lower boundary on Av
329- 332 F4.2 mag B_Av [0/8.2] Upper boundary on Av
334- 338 F5.2 --- chi2 [0.07/20] Reduced chi2 value
340- 345 F6.2 --- mu [0.02/163.1]? Median magnification factor
347- 351 F5.2 --- e_mu [0.01/42.5]? Uncertainty in mu
353- 357 F5.2 [Msun] logM [4.7/13.5]? Log stellar mass
359- 363 F5.2 [Msun] b_logM [4.5/11]? Lower boundary on logM
365- 369 F5.2 [Msun] B_logM [6.5/15] Upper boundary on logM
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 13-Nov-2024