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This paper gives an overview of Targeting Extremely Magnified Panchromatic Lensed Arcs and Their Extended Star formation (TEMPLATES), a JWST Early Release Science program that targeted four extremely bright, gravitationally lensed galaxies, two extremely dusty and two with low attenuation, as templates for galaxy evolution studies with JWST. TEMPLATES obtains a common set of spectral diagnostics for these 1.3 ≤ z ≤ 4.2 galaxies, in particular H α , Paschen α , and the rest-frame optical and near-infrared continua. In addition, two of the four targets have JWST coverage of [O iii ] 5007 Å and H β ; the other two targets have JWST coverage of polycyclic aromatic hydrocarbon 3.3 μ m and complementary Atacama Large Millimeter/submillimeter Array data covering the [C ii ] 158 μ m emission line. The science goals of TEMPLATES are to demonstrate attenuation-robust diagnostics of star formation, map the distribution of star formation, compare the young and old stellar populations, and measure the physical conditions of star formation and their spatial variation across the galaxies. In addition, TEMPLATES has the technical goal to establish best practices for the integral field units within the NIRSpec and MIRI instruments, both in terms of observing strategy and in terms of data reduction. The paper describes TEMPLATES’s observing program, scientific and technical goals, data reduction methods, and deliverables, including high-level data products and data reduction cookbooks.

We present JWST and Atacama Large Millimeter/submillimeter Array (ALMA) imaging for the lensing system SPT0418−47, which includes a strongly lensed, dusty, star-forming galaxy at redshift z = 4.225 and an associated multiply imaged companion. The JWST NIRCam and MIRI imaging observations presented in this paper were acquired as part of the Early Release Science program Targeting Extremely Magnified Panchromatic Lensed Arcs and Their Extended Star formation (TEMPLATES). This data set provides robust mutiwavelength detections of stellar light in both the main (SPT0418A) and companion (SPT0418B) galaxies, while the ALMA detection of [C ii ] emission confirms that SPT0418B lies at the same redshift as SPT0418A. We infer that the projected physical separation of the two galaxies is 4.42 ± 0.05 kpc. We derive total magnifications of μ = 29 ± 1 and μ = 4.1 ± 0.7 for SPT0418A and SPT0418B, respectively. We use both prospector and cigale to derive stellar masses. We find that SPT0418A has a stellar mass of ${M}_{* }={3.4}_{-0.6}^{+1.1}\times {10}^{10}{M}_{\odot }$ from prospector or M _* = 1.5 ± 0.3 × 10 ^10 M _⊙ from cigale . The stellar mass ratio of SPT0418A and SPT0418B is roughly between 4 and 7 ( ${4.2}_{-1.6}^{+1.9}$ for prospector and 7.5 ± 3.7 for cigale ). We see evidence of extended structure associated with SPT0418A that is suggestive of a tidal feature. These features, along with the close projected proximity, imply that the system is interacting. Interestingly, the star formation rates and stellar masses of both galaxies are consistent with the main sequence of star-forming galaxies at this epoch, indicating that this ongoing interaction has not noticeably elevated the star formation levels.

Using integrated spectra for two gravitationally lensed galaxies from the JWST TEMPLATES Early Release Science program, we analyze faint auroral lines, which provide direct measurements of the gas-phase chemical abundance. For the brighter galaxy, SGAS1723+34 ( z = 1.3293), we detect the [O iii ] λ 4363, [S iii ] λ 6312, and [O ii ] λ λ 7320, 7330 auroral emission lines, and set an upper limit for the [N ii ] λ 5755 line. For the second galaxy, SGAS1226+21 ( z = 2.925), we do not detect any auroral lines, and report upper limits. With these measurements and upper limits, we constrain the electron temperatures in different ionization zones within both of these galaxies. For SGAS1723+34, where auroral lines are detected, we calculate direct oxygen and nitrogen abundances, finding an N/O ratio consistent with observations of nearby ( z ∼ 0) galaxies. These observations highlight the potent combination of JWST and gravitational lensing to measure faint emission lines in individual distant galaxies and to directly study the chemical abundance patterns in those galaxies.

Using a combination of Hubble Space Telescope (HST), JWST, and Atacama Large Millimeter/submillimeter Array (ALMA) data, we perform spatially resolved spectral energy distributions (SED) fitting of fourteen 4 < z < 6 ultraviolet (UV)-selected main-sequence galaxies targeted by the ALMA Large Program [C ii ] Resolved ISM in Star-forming Galaxies. We consistently model the emission from stars and dust in ∼0.5–1 kpc spatial bins to obtain maps of their physical properties. We find no offsets between the stellar masses ( M _* ) and star formation rates (SFRs) derived from their global emission and those from adding up the values in our spatial bins, suggesting there is no bias of outshining by young stars on the derived global properties. We show that ALMA observations are important to derive robust parameter maps because they reduce the uncertainties in L _dust (hence, A _V and SFR). Using these maps, we explore the resolved star-forming main sequence for z ∼ 5 galaxies, finding that this relation persists in typical star-forming galaxies in the early Universe. We find less obscured star formation where the M _* (and SFR) surface densities are highest, typically in the central regions, contrary to the global relation between these parameters. We speculate this could be caused by feedback driving gas and dust out of these regions. However, more observations of IR luminosities with ALMA are needed to verify this. Finally, we test empirical SFR prescriptions based on the UV+IR and [C ii ] line luminosity, finding they work well at the scales probed (approximately kiloparsec). Our work demonstrates the usefulness of joint HST-, JWST-, and ALMA-resolved SED modeling analyses at high redshift.

The James Webb Space Telescope Time-Domain Field (JWST-TDF) is an ∼14′ diameter field near the North Ecliptic Pole that will be targeted by one of the JWST Guaranteed Time Observations programs. Here, we describe our James Clerk Maxwell Telescope SCUBA-2 850 μ m imaging of the JWST-TDF and present the submillimeter source catalog and properties. We also present a catalog of radio sources from Karl J. Jansky Very Large Array 3 GHz observations of the field. These observations were obtained to aid JWST's study of dust-obscured galaxies that contribute significantly to cosmic star formation at high redshifts. Our deep 850 μ m map covers the JWST-TDF at a noise level of σ _850 _µ _m = 1.0 mJy beam ^−1 , detecting 83/31 sources in the main/supplementary signal-to-noise ratio (S/N > 4 / S/N = 3.5–4) sample, respectively. The 3 GHz observations cover a 24′ diameter field with a 1 σ noise of 1 μ Jy beam ^−1 at a 0.″7 FWHM. We identified eighty-five 3 GHz counterparts to sixty-six 850 μ m sources and then matched these with multiwavelength data from the optical to the mid-infrared wave bands. We performed spectral energy distribution fitting for 61 submillimeter galaxies (SMGs) matched with optical/near-infrared data, and found that SMGs at S/N > 4 have a median value of z _phot = 2.22 ± 0.12, star formation rates of 300 ± 40 M _⊙ yr ^−1 (Chabrier initial mass function), and typical cold dust masses of 5.9 ± 0.7 × 10 ^8 M _⊙ , in line with bright SMGs from other surveys. The large cold dust masses indicate correspondingly large cool gas masses, which we suggest are a key factor necessary to drive the high star formation rates seen in this population.

We present the initial results of an ongoing survey with the Karl G. Jansky Very Large Array targeting the CO( J = 1–0) transition in a sample of 30 submillimeter-selected, dusty star-forming galaxies (SFGs) at z = 2–5 with existing mid- J CO detections from the Atacama Large Millimeter/submillimeter Array and NOrthern Extended Millimeter Array, of which 17 have been fully observed. We detect CO(1–0) emission in 11 targets, along with three tentative (∼1.5 σ –2 σ ) detections; three galaxies are undetected. Our results yield total molecular gas masses of 6–23 × 10 ^10 ( α _CO /1) M _⊙ , with gas mass fractions, f _gas = M _mol /( M _* + M _mol ), of 0.1–0.8 and a median depletion time of (140 ± 70) Myr. We find median CO excitation ratios of r _31 = 0.75 ± 0.39 and r _41 = 0.63 ± 0.44, with significant scatter. We find no significant correlation between the excitation ratio and a number of key parameters such as redshift, CO(1–0) line width, or Σ _SFR . We only find a tentative positive correlation between r _41 and the star-forming efficiency, but we are limited by our small sample size. Finally, we compare our results to predictions from the SHARK semi-analytical model, finding a good agreement between the molecular gas masses, depletion times, and gas fractions of our sources and their SHARK counterparts. Our results highlight the heterogeneous nature of the most massive SFGs at high redshift, and the importance of CO(1–0) observations to robustly constrain their total molecular gas content and interstellar medium properties.

We present the first spatially resolved maps of gas-phase metallicity for two dust-obscured star-forming galaxies at z ∼ 4, from the JWST TEMPLATES Early Release Science program, derived from NIRSpec integral field unit spectroscopy of the H α and [N ii ] emission lines. Empirical optical line calibrations are used to determine that the sources are globally enriched to near-solar levels. While one source shows elevated [N ii ]/H α ratios and broad H α emission consistent with the presence of an active galactic nucleus in a ≳1 kpc region, we argue that both systems have already undergone significant metal enrichment as a result of their extremely high star formation rates. Utilizing Atacama Large Millimeter/submillimeter Array rest-frame 380 μ m continuum and [C i ]( ^3 P _2 – ^3 P _1 ) line maps we compare the spatial variation of the metallicity and gas-to-dust ratio in the two galaxies, finding the two properties to be anticorrelated on highly resolved spatial scales, consistent with various literature studies of z ∼ 0 galaxies. The data are indicative of the enormous potential of JWST to probe the enrichment of the interstellar medium on ∼kpc scales in extremely dust-obscured systems at z ∼ 4 and beyond.