J/ApJ/946/L40 Galaxies in JWST obs. of SMACS J0723.3-7327 (Langeroodi+, 2023)
PAH emission from star-forming galaxies in JWST mid-infrared imaging of the
lensing cluster SMACS J0723.3-7327.
Langeroodi D., Hjorth J.
<Astrophys. J., 946, L40 (2023)>
=2023ApJ...946L..40L 2023ApJ...946L..40L
ADC_Keywords: Galaxies, photometry; Colors; Infrared; Cross identifications;
Redshifts
Keywords: Polycyclic aromatic hydrocarbons ; Galaxy photometry ; Galaxy colors ;
James Webb Space Telescope
Abstract:
The mid-infrared spectra of star-forming galaxies (SFGs) are
characterized by characteristic broad polycyclic aromatic hydrocarbon
(PAH) emission features at 3-20µm. As these features are
redshifted, they are predicted to dominate the flux at specific
mid-infrared wavelengths, leading to substantial redshift-dependent
color variations in broadband photometry. The advent of JWST for the
first time allows the study of this effect for normal SFGs. Based on
spectral energy distribution templates, we here present tracks in mid-
infrared (4.4, 7.7, 10, 15, and 18µm) color-color diagrams
describing the redshift dependence of SFG colors. In addition, we
present simulated color-color diagrams by populating these tracks
using the cosmic star formation history and the star formation rate
function. Depending on redshift, we find that SFGs stand out in the
color-color diagrams by several magnitudes. We provide the first
observational demonstration of this effect for galaxies detected in
the JWST Early Release Observations of the field toward the lensing
cluster SMACS J0723.3-7327. While the distribution of detected
galaxies is consistent with the simulations, the numbers are
substantially boosted by lensing effects. The PAH emitter with the
highest spectroscopic redshift, detected in all bands, is a multiply
imaged galaxy at z=1.45. There is also a substantial number of cluster
members that do not exhibit PAH emission except for one SFG at z=0.38.
Future wider-field observations will further populate mid-infrared
color-color diagrams and provide insight into the evolution of typical
SFGs.
Description:
We analyze the JWST NIRCam and MIRI Early Release Observations of the
SMACS J0723.3-7327 field (PID 2736, PI: Pontoppidan). The broadband
imaging consists of six overlapping NIRCam images in the F090W, F150W,
F200W, F277W, F356W, and F444W filters reaching a point-source
sensitivity of AB∼29.8mag and four overlapping MIRI images in the
F770W, F1000W, F1500W, and F1800W filters reaching 5σ depths of
AB∼26.3, 25.1, 24.0, and 23.0mag, respectively. For each filter, we
acquire the photometry- and astrometry-calibrated data products from
the Mikulski Archive for Space Telescopes (MAST).
Where available, we assign spectroscopic redshifts to the detected
galaxies. The SMACS J0723 field was observed under the MUSE
0102.A-0718 program (Caminha+ 2022, J/A+A/666/L9), resulting in a
spectroscopic redshift catalog containing 78 secure redshift
measurements of Hubble Space Telescope (HST)-detected (Reionization
Lensing Cluster Survey program; RELICS, Coe+ 2019, J/ApJ/884/85) sources.
See Section 4.
Objects:
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RA (ICRS) DE Designation(s)
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07 23 13.29 -73 27 25.1 SMACS J0723.3-7327 = PSZ1 G284.97-23.69
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 134 172 *Measured photometry of the sources plotted in
Figures 2, 3, and 4
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Note on table1.dat: We only plot the galaxies (CLASS_STAR<0.5) where the
estimated error of aperture photometry (MAGERR_APER) is below 0.2mag
(i.e., a ∼5σ detection) in F356W, F444W and F770W bands.
See Section 4.
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See also:
J/ApJ/656/770 : Mid-IR spectrum of star-forming galaxies (Smith+, 2007)
J/ApJ/705/885 : PAH in galaxies at z∼0.1 (O'Dowd+, 2009)
J/ApJS/182/628 : Spitzer quasar and ULIRG evolution study (Veilleux+, 2009)
J/ApJ/719/1191 : Mid-IR indicators of SF and AGN in galaxies (Treyer+, 2010)
J/ApJ/723/895 : IR luminosities and aromatic features of 5MUSES (Wu+, 2010)
J/ApJ/759/139 : Herschel + MIPS phot. of GOODS sources (Kirkpatrick+, 2012)
J/ApJS/212/18 : An atlas of UV-to-MIR galaxy SEDs (Brown+, 2014)
J/ApJ/790/124 : Dust and gas physics of the GOALS sample (Stierwalt+, 2014)
J/A+A/617/A130 : Luminous infrared galaxies AKARI 2.5-5um data (Inami+, 2018)
J/ApJ/884/85 : RELICS: Reionization Lensing Cluster Survey (Coe+, 2019)
J/ApJ/884/136 : PAH features of star-forming gal. using IRS (Xie+, 2019)
J/A+A/666/L9 : SMACS J0723.3-7327 first JWST observations (Caminha+, 2022)
J/ApJ/946/L35 : High-z galaxies from JWST ERO (Morishita+, 2023)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- ID [2/554] Sequential identifier used in this work
5- 15 F11.7 deg RAdeg [110.7/111] Right Ascension (J2000)
17- 27 F11.7 deg DEdeg [-73.5/-73.4] Declination (J2000)
29- 35 F7.4 mag F356W [18.73/25] JWST/NIRCam F356W band AB magnitude
37- 42 F6.4 mag e_F356W [0.0001/0.008] Uncertainty in F356W
44- 50 F7.4 mag F444W [19.07/25.3] JWST/NIRCam F444W band AB magnitude
52- 57 F6.4 mag e_F444W [0.0001/0.02] Uncertainty in F444W
59- 65 F7.4 mag F770W [19.24/25.2] JWST/MIRI F770W band AB magnitude
67- 72 F6.4 mag e_F770W [0.001/0.15] Uncertainty in F770W
74- 80 F7.4 mag F1000W [17.99/25.4] JWST/MIRI F1000W band AB magnitude
82- 87 F6.4 mag e_F1000W [0.0004/0.2] Uncertainty in F1000W
89- 95 F7.4 mag F1500W [18.2/28.4]?=99 JWST/MIRI F1500W band AB magnitude
97-103 F7.4 mag e_F1500W [0.0008/9.2]?=99 Uncertainty in F1500W
105-111 F7.4 mag F1800W [18/29.7]?=99 JWST/MIRI F1800W band AB magnitude
113-119 F7.4 mag e_F1800W [0.0015/86.4]?=99 Uncertainty in F1800W
121-122 I2 --- [CSM2022] [21/76]? Literature ID from
Caminha+ 2022, J/A+A/666/L9
124-127 I4 --- [CBM2023] [9483]? ID for zspec from
Carnall+ 2023MNRAS.518L..45C 2023MNRAS.518L..45C
129-134 F6.4 --- zspec [0.32/1.5]? MUSE/NIRSpec spectroscopic redshift
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 10-Mar-2025