Team Papers
Hidden giants in JWST's PEARLS: An ultra-massive z=4.26 sub-millimeter galaxy that is invisible to HST
Ian Smail & the PEARLS team.
Submitted to ApJ, available at ADS
We present a multi-wavelength analysis using SMA, JCMT, NOEMA, JWST, HST, and SST of two dusty strongly star-forming galaxies, 850.1 and 850.2, seen through the massive cluster lens A1489. These SMA-located sources both lie at z=4.26 and have bright dust continuum emission, but 850.2 is a UV-detected Lyman-break galaxy, while 850.1 is undetected at <2um, even with deep JWST/NIRCam observations. We investigate their stellar, ISM, and dynamical properties, including a pixel-level SED analysis to derive sub-kpc-resolution stellar-mass and Av maps. We find that 850.1 is one of the most massive and highly obscured, Av~5, galaxies known at z>4 with M*~10^11.8 Mo (likely forming at z>6), and 850.2 is one of the least massive and least obscured, Av~1, members of the z>4 dusty star-forming population. The diversity of these two dust-mass-selected galaxies illustrates the incompleteness of galaxy surveys at z>3-4 based on imaging at <2um, the longest wavelengths feasible from HST or the ground. The resolved mass map of 850.1 shows a compact stellar mass distribution, Re(mass)~1kpc, but its expected evolution to z~1.5 and then z~0 matches both the properties of massive, quiescent galaxies at z~1.5 and ultra-massive early-type galaxies at z~0. We suggest that 850.1 is the central galaxy of a group in which 850.2 is a satellite that will likely merge in the near future. The stellar morphology of 850.1 shows arms and a linear bar feature which we link to the active dynamical environment it resides within.
EPOCHS Paper II: The Ultraviolet Luminosity Function from 7.5<z<13.5 using 110 square arcminutes of deep, blank-field data from the PEARLS Survey and Public Science Programmes
Nathan Adams & the PEARLS team.
Submitted to ApJ, available at ADS
We present an analysis of the ultraviolet luminosity function (UV LF) and star formation rate density of distant galaxies (7.5<z<13.5) in the `blank' fields of the Prime Extragalactic Areas for Reionization Science (PEARLS) survey combined with Early Release Science (ERS) data from the CEERS, GLASS and NGDEEP surveys/fields. We use a combination of SED fitting tools and quality cuts to obtain a reliable selection and characterisation of high-redshift (z>6.5) galaxies from a consistently processed set of deep, near-infrared imaging. Within an area of 110 arcmin sq., we identify 214 candidate galaxies at redshifts z>6.5 and we use this sample to study the ultraviolet luminosity function (UV LF) in four redshift bins between 7.5<z<13.5. The measured number density of galaxies at z=8 and z=9 match those of past observations undertaken by the em Hubble Space Telescope (HST). However, towards higher redshifts we find that the evolution of the UV LF is mild, resulting in higher measured number densities of UV luminous galaxies at z=10.5 and z=12.5 compared to predictions from simulations and past HST observations. When examining the star formation rate density of galaxies at this time period, our observations are still consistent with a constant star formation efficiency, are slightly lower than previous early estimations using JWST and support galaxy driven reionization at z∼8.
Are JWST/NIRCam color gradients in the lensed z=2.3 dusty star-forming galaxy El Anzuelo due to central dust attenuation or inside-out galaxy growth?
Patrick Kamieneski & the PEARLS team.
Submitted to ApJ, available at ADS
Gradients in the mass-to-light ratio of distant galaxies impede our ability to characterize their size and compactness. The long-wavelength filters of
JWST's NIRCam offer a significant step forward. For galaxies at Cosmic Noon (z∼2), this regime corresponds to the rest-frame near-infrared, which is less biased towards young stars and captures emission from the bulk of a galaxy's stellar population. We present an initial analysis of an extraordinary lensed dusty star-forming galaxy (DSFG) at z=2.3 behind the El Gordo cluster (z=0.87), named El Anzuelo ("The Fishhook") after its partial Einstein-ring morphology. The FUV-NIR SED suggests an intrinsic star formation rate in line with other DSFGs on the star-forming main sequence. We develop a parametric lens model to reconstruct the source-plane structure of dust imaged by the Atacama Large Millimeter/submillimeter Array, far-UV to optical light from Hubble, and near-IR imaging with 8 filters of JWST/NIRCam, as part of the Prime Extragalactic Areas for Reionization and Lensing Science (PEARLS) program. The source-plane half-light radius is remarkably consistent from ∼1−4.5 μm, despite a clear color gradient where the inferred galaxy center is redder than the outskirts. We interpret this to be the result of both a radially-decreasing gradient in attenuation and substantial spatial offsets between UV- and IR-emitting components. A spatial decomposition of the SED reveals modestly suppressed star formation in the inner kiloparsec, which suggests that we are witnessing the early stages of inside-out quenching.
PEARLS: Low Stellar Density Galaxies in the El Gordo Cluster Observed with JWST
Tim Carleton & the PEARLS team.
Submitted to ApJ, available at ADS
A full understanding of how unusually large "Ultra Diffuse Galaxies" (UDGs) fit into our conventional understanding of dwarf galaxies remains elusive, despite the large number of objects identified locally. A natural extension of UDG research is the study of similar galaxies at higher redshift to establish how their properties may evolve over time. However, this has been a challenging task given how severely systematic effects and cosmological surface brightness dimming inhibit our ability to study low-surface brightness galaxies at high-z. Here, we present an identification of low stellar surface density galaxies (LDGs), likely the progenitors of local UDGs, at moderate redshift with deep near-IR observations of the El Gordo cluster at z=0.87 with JWST. By stacking 8 NIRCAM filters, we are able to achieve an apparent surface brightness sensitivity faint enough to be complete to the bright end of the LDG population. Our analysis identifies significant differences between this population and local UDGs, such as their color and size distributions, which suggest that UDG progenitors are bluer and more extended at high-z than at z=0. This suggests that multiple mechanisms are responsible for UDG formation and that prolonged transformation of cluster dwarfs is not a primary UDG formation mechanism at high-z. Furthermore, we find a slight overabundance of LDGs in El Gordo, and, in contrast to findings in local clusters, our analysis does not show a deficit of LDGs in the center of El Gordo, implying that tidal destruction of LDGs is significant.
The JWST PEARLS View of the El Gordo Galaxy Cluster and of the Structure It Magnifies
Brenda Frye & the PEARLS team.
Accepted by ApJ, available at ADS
The massive galaxy cluster El Gordo (z=0.87) imprints multitudes of gravitationally lensed arcs onto James Webb Space Telescope (JWST) Near-Infrared Camera (NIRCam) images. Eight bands of NIRCam imaging were obtained in the ``Prime Extragalactic Areas for Reionization and Lensing Science'' (``PEARLS'') program. PSF-matched photometry across Hubble Space Telescope (HST) and NIRCam filters supplies new photometric redshifts. A new light-traces-mass lens model based on 56 image multiplicities identifies the two mass peaks and yields a mass estimate within 500 kpc of ~(7.0 +/- 0.30) x 10^14 Msun. A search for substructure in the 140 cluster members with spectroscopic redshifts confirms the two main mass components. The southeastern mass peak that contains the BCG is more tightly bound than the northwestern one. The virial mass within 1.7 Mpc is (5.1 +/- 0.60) x 10^14 Msun, lower than the lensing mass. A significant transverse velocity component could mean the virial mass is underestimated. We contribute one new member to the previously known z=4.32 galaxy group. Intrinsic (delensed) positions of the five secure group members span a physical extent of ~60 kpc. Thirteen additional candidates selected by spectroscopic/photometric constraints are small and faint with a mean intrinsic luminosity ~2.2 mag fainter than L*. NIRCam imaging admits a fairly wide range of brightnesses and morphologies for the group members, suggesting a more diverse galaxy population in this galaxy overdensity.
JWST's PEARLS: TNJ1338−1942 - I. Extreme jet triggered star-formation in a z=4.11 luminous radio galaxy
Ken Duncan & the PEARLS team.
Published in MNRAS 522, 3, 4548-4564, available at ADS Link
We present the first JWST observations of the z=4.11 luminous radio galaxy TN J1338−1942. Our NIRCam observations, designed to probe the key rest-frame optical continuum and emission line features at this redshift, enable resolved spectral energy distribution modelling that incorporates both a range of stellar population assumptions and radiative shock models. With an estimated stellar mass of log10(M/M⊙)∼10.9 , TN J1338−1942 is confirmed to be one of the most massive galaxies known at this epoch. Our observations also reveal extremely high equivalent-width nebular emission coincident with the luminous AGN jets that is consistent with radiative shocks surrounded by extensive recent star-formation. We estimate the total star-formation rate (SFR) could be as high as ∼1800M⊙yr−1, with the SFR that we attribute to the jet induced burst conservatively ≳500M⊙yr−1 . The mass-weighted age of the star-formation, tmass<4 Myr, is consistent with the likely age of the jets responsible for the triggered activity and significantly younger than that measured in the core of the host galaxy. The extreme scale of the potential jet-triggered star-formation activity indicates the potential importance of positive AGN feedback in the earliest stages of massive galaxy formation, with our observations also illustrating the extraordinary prospects for detailed studies of high-redshift galaxies with JWST.
JWST's PEARLS: A JWST/NIRCam view of ALMA sources
Cheng Cheng, Haojing Yan & the PEARLS team.
Published in ApJ 942 L19, available at ADS Link
We report the results of James Webb Space Telescope/NIRCam observations of 19 (sub)millimeter sources detected by the Atacama Large Millimeter Array (ALMA). The accurate ALMA positions allowed unambiguous identifications of their NIRCam counterparts. Taking gravitational lensing into account, these represent 16 distinct galaxies in three fields and constitute the largest sample of its kind to date. The counterparts' spectral energy distributions from rest-frame ultraviolet to near infrared provide photometric redshifts, stellar masses and star formation rates. The deep NIRCam data allow us to study the rest-frame near-IR morphologies. Excluding two multiply imaged systems and one quasar, the majority of the remaining sources are disk-like and show either little or no disturbance. This suggests that secular growth is a potential route for the assembly of high-mass disk galaxies.
JWST's PEARLS: a new lens model for ACT-CL J0102−4915, “El Gordo”, and the first red supergiant star at cosmological distances discovered by JWST
Jose Diego & the PEARLS team.
Published in A&A 672, A3, 22, available at ADS Link
The first JWST data on the massive colliding cluster El Gordo confirm 23 known families of multiply lensed images and identify 8 new members of these families. Based on these families, we derived an initial lens model which guided the identification of 37 additional families of multiply lensed galaxies, among which 28 are entirely new systems, and 9 were previously known. The initial lens model determined geometric redshifts for the 37 new systems. The derived dark-matter distribution confirms the double-peak configuration of mass found by earlier work with the southern and northern clumps having similar masses. We confirm that El Gordo is the most massive known cluster at z>0.8. The JWST images also show several candidate caustic-crossing events. One of them is likely a red supergiant star at z=2.1878. This would be the first red supergiant found at cosmological distances.
JWST's PEARLS: Prime Extragalactic Areas for Reionization and Lensing Science: Project Overview and First Results
Rogier Windhorst & the PEARLS team.
Published in ApJ 165, 13, available at ADS Link
We give an overview and describe the rationale, methods, and first results from NIRCam images of the JWST "Prime Extragalactic Areas for Reionization and Lensing Science" ("PEARLS") project. This paper presents our first PEARLS observations, their NIRCam data reduction and analysis, our first object catalogs, the 0.9-4.5 μm galaxy counts and Integrated Galaxy Light. We assess the JWST sky brightness in 13 NIRCam filters, yielding our first constraints to diffuse light at 0.9-4.5 μm. PEARLS is designed to be of lasting benefit to the community.
JWST's PEARLS: Bright 1.5-2.0 micron Dropouts in the Spitzer/IRAC Dark Field
Haojing Yan & the PEARLS team.
Published in ApJ 942 L8, available at ADS Link
Using the first epoch of our observations in the Spitzer IRAC Dark Field, we search for F150W and F200W dropouts following the conventional dropout method to select candidate objects at z>11. In 14.2 arcmin^2, we have found 13 F150W dropouts and 8 F200W dropouts, all brighter than 27.5 mag in the band to the red side of the break signature. Most notably, some of these objects are as bright as ~24 mag, which corresponds to MUV<-23 mag at z>11. These objects may be either z>11 galaxies with evolved stellar populations or old galaxies at z ~ 3 to 8. Spectroscopic identifications of such objects are urgently needed.
JWST's PEARLS: Dust Attenuation and Gravitational Lensing in the Backlit-galaxy System VV 191
Bill Keel & the PEARLS team.
Published in AJ, 165, 4,166
We derive the spatial and wavelength behavior of dust attenuation in the multiple-armed spiral galaxy VV 191b using backlighting by the superimposed elliptical system VV 191a in a pair with an exceptionally favorable geometry for this measurement. Imaging using the James Webb Space Telescope and Hubble Space Telescope spans the wavelength range 0.3-4.5 μm with high angular resolution, tracing the dust in detail from 0.6-1.5 μm. Distinct dust lanes continue well beyond the bright spiral arms, and trace a complex web, with a very sharp radial cutoff near 1.7 Petrosian radii. We present attenuation profiles and coverage statistics in each band at radii 14-21 kpc. We derive the attenuation law with wavelength; the data both within and between the dust lanes clearly favor a stronger reddening behavior (R = A V /E B-V ≈ 2.0 between 0.6 and 0.9 μm, approaching unity by 1.5 μm) than found for starbursts and star-forming regions of galaxies. Power-law extinction behavior ∝λ -β gives β = 2.1 from 0.6-0.9 μm. R decreases at increasing wavelengths (R ≈ 1.1 between 0.9 and 1.5 μm), while β steepens to 2.5. Mixing regions of different column density flattens the wavelength behavior, so these results suggest a different grain population than in our vicinity. The NIRCam images reveal a lens arc and counterimage from a background galaxy at z ≈ 1, spanning 90° azimuthally at 2.″8 from the foreground elliptical-galaxy nucleus, and an additional weakly lensed galaxy. The lens model and imaging data give a mass/light ratio M/L B = 7.6 in solar units within the Einstein radius 2.0 kpc.
PEARLS team papers can be found in this ADS library.
This work is based on observations made with the NASA/ESA/CSA James Webb Space Telescope. The data were obtained from the Mikulski Archive for Space Telescopes at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-03127 for JWST. These observations are associated with JWST programs 1176 and 2738.