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Abstract 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 Hα, Paschenα, and the rest-frame optical and near-infrared continua. In addition, two of the four targets have JWST coverage of [Oiii] 5007 Å and Hβ; the other two targets have JWST coverage of polycyclic aromatic hydrocarbon 3.3μm and complementary Atacama Large Millimeter/submillimeter Array data covering the [Cii] 158μm 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. 

ABSTRACT We present the spatially resolved measurements of a cool galactic outflow in the gravitationally lensed galaxy RCS0327 at z ≈ 1.703 using VLT/MUSE IFU observations. We probe the cool outflowing gas, traced by blueshifted Mg ii and Fe ii absorption lines, in 15 distinct regions of the same galaxy in its image-plane. Different physical regions, 5 – 7 kpc apart within the galaxy, drive the outflows at different velocities (Vout ∼ −161 to −240 km s−1), and mass outflow rates ($$\dot{M}_{out} \sim 183$$ – 527 $${\rm M}_{\odot }\, \mathrm{yr}^{-1}$$). The outflow velocities from different regions of the same galaxy vary by 80 km s−1, which is comparable to the variation seen in a large sample of star-burst galaxies in the local universe. Using multiply lensed images of RCS0327, we probe the same star-forming region at different spatial scales (0.5–25 kpc2), we find that outflow velocities vary between ∼ −120 and −242 km s−1, and the mass outflow rates vary between ∼37 and 254 $${\rm M}_{\odot }\, \mathrm{yr}^{-1}$$. The outflow momentum flux in this galaxy is ≥ 100% of the momentum flux provided by star formation in individual regions, and outflow energy flux is ≈ 10% of the total energy flux provided by star formation. These estimates suggest that the outflow in RCS0327 is energy driven. This work shows the importance of small scale variations of outflow properties due to the variations of local stellar properties of the host galaxy in the context of galaxy evolution. 

Abstract The environments where galaxies reside crucially shape their star formation histories. We investigate a large sample of 1626 cluster galaxies located within 105 galaxy clusters spanning a large range in redshift (0.26 <z< 1.13). The galaxy clusters are massive (M₅₀₀≳ 2 × 10¹⁴M_⊙) and uniformly selected from the SPT and ACT Sunyaev–Zel’dovich surveys. With spectra in hand for thousands of cluster members, we use the galaxies’ position in projected phase space as a proxy for their infall times, which provides a more robust measurement of environment than quantities such as projected clustercentric radius. We find clear evidence for a gradual age increase of the galaxy’s mean stellar populations (∼0.71 ± 0.4 Gyr based on a 4000 Å break, D_n4000) with the time spent in the cluster environment. This environmental quenching effect is found regardless of galaxy luminosity (faint or bright) and redshift (low or high-z), although the exact stellar age of galaxies depends on both parameters at fixed environmental effects. Such a systematic increase of D_n4000 with infall proxy would suggest that galaxies that were accreted into hosts earlier were quenched earlier due to longer exposure to environmental effects such as ram pressure stripping and starvation. Compared to the typical dynamical timescales of 1–3 Gyr of cluster galaxies, the relatively small age increase (∼0.71 ± 0.4 Gyr) found in our sample galaxies seems to suggest that a slow environmental process such as starvation is the dominant quenching pathway. Our results provide new insights into environmental quenching effects spanning a large range in cosmic time (∼5.2 Gyr,z= 0.26–1.13) and demonstrate the power of using a kinematically derived infall time proxy. 

Abstract We present the first spatially resolved maps of gas-phase metallicity for two dust-obscured star-forming galaxies atz∼ 4, from the JWST TEMPLATES Early Release Science program, derived from NIRSpec integral field unit spectroscopy of the Hαand [Nii] 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]/Hαratios and broad Hαemission 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 380μm continuum and [Ci](³P₂–³P₁) 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 ofz∼ 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 atz∼ 4 and beyond. 

We present a Hubble Space Telescope (HST) weak gravitational lensing study of nine distant and massive galaxy clusters with redshifts 1.0 ≲  z  ≲ 1.7 ( z median  = 1.4) and Sunyaev Zel’dovich (SZ) detection significance ξ  > 6.0 from the South Pole Telescope Sunyaev Zel’dovich (SPT-SZ) survey. We measured weak lensing galaxy shapes in HST/ACS F 606 W and F 814 W images and used additional observations from HST/WFC3 in F 110 W and VLT/FORS2 in U HIGH to preferentially select background galaxies at z  ≳ 1.8, achieving a high purity. We combined recent redshift estimates from the CANDELS/3D-HST and HUDF fields to infer an improved estimate of the source redshift distribution. We measured weak lensing masses by fitting the tangential reduced shear profiles with spherical Navarro-Frenk-White (NFW) models. We obtained the largest lensing mass in our sample for the cluster SPT-CL J2040−4451, thereby confirming earlier results that suggest a high lensing mass of this cluster compared to X-ray and SZ mass measurements. Combining our weak lensing mass constraints with results obtained by previous studies for lower redshift clusters, we extended the calibration of the scaling relation between the unbiased SZ detection significance ζ and the cluster mass for the SPT-SZ survey out to higher redshifts. We found that the mass scale inferred from our highest redshift bin (1.2 <  z  < 1.7) is consistent with an extrapolation of constraints derived from lower redshifts, albeit with large statistical uncertainties. Thus, our results show a similar tendency as found in previous studies, where the cluster mass scale derived from the weak lensing data is lower than the mass scale expected in a Planckν ΛCDM (i.e. ν Λ cold dark matter) cosmology given the SPT-SZ cluster number counts. 

Abstract Using stellar population synthesis models to infer star formation histories (SFHs), we analyze photometry and spectroscopy of a large sample of quiescent galaxies that are members of Sunyaev–Zel’dovich (SZ)-selected galaxy clusters across a wide range of redshifts. We calculate stellar masses and mass-weighted ages for 837 quiescent cluster members at 0.3 < z < 1.4 using rest-frame optical spectra and the Python-based Prospector framework, from 61 clusters in the SPT-GMOS Spectroscopic Survey (0.3 < z < 0.9) and three clusters in the SPT Hi-z cluster sample (1.25 < z < 1.4). We analyze spectra of subpopulations divided into bins of redshift, stellar mass, cluster mass, and velocity-radius phase-space location, as well as by creating composite spectra of quiescent member galaxies. We find that quiescent galaxies in our data set sample a diversity of SFHs, with a median formation redshift (corresponding to the lookback time from the redshift of observation to when a galaxy forms 50% of its mass, t 50 ) of z = 2.8 ± 0.5, which is similar to or marginally higher than that of massive quiescent field and cluster galaxy studies. We also report median age–stellar mass relations for the full sample (age of the universe at t 50 (Gyr) = 2.52 (±0.04)–1.66 (±0.12) log 10 ( M /10 11 M ⊙ )) and recover downsizing trends across stellar mass; we find that massive galaxies in our cluster sample form on aggregate ∼0.75 Gyr earlier than lower-mass galaxies. We also find marginally steeper age–mass relations at high redshifts, and report a bigger difference in formation redshifts across stellar mass for fixed environment, relative to formation redshifts across environment for fixed stellar mass. 

Abstract The gravitationally lensed star WHL 0137–LS, nicknamed Earendel, was identified with a photometric redshift z phot = 6.2 ± 0.1 based on images taken with the Hubble Space Telescope. Here we present James Webb Space Telescope (JWST) Near Infrared Camera images of Earendel in eight filters spanning 0.8–5.0 μ m. In these higher-resolution images, Earendel remains a single unresolved point source on the lensing critical curve, increasing the lower limit on the lensing magnification to μ > 4000 and restricting the source plane radius further to r < 0.02 pc, or ∼4000 au. These new observations strengthen the conclusion that Earendel is best explained by an individual star or multiple star system and support the previous photometric redshift estimate. Fitting grids of stellar spectra to our photometry yields a stellar temperature of T eff ≃ 13,000–16,000 K, assuming the light is dominated by a single star. The delensed bolometric luminosity in this case ranges from log ( L ) = 5.8 to 6.6 L ⊙ , which is in the range where one expects luminous blue variable stars. Follow-up observations, including JWST NIRSpec scheduled for late 2022, are needed to further unravel the nature of this object, which presents a unique opportunity to study massive stars in the first billion years of the universe.