Search

We report the discovery of Cerberus, an extremely red object detected with the MIRI Deep Imaging Survey (MIDIS) observations in the F1000W filter of the Hubble Ultra Deep Field. The object is detected at signal-to-noise ratio (S/N) ∼ 6, with F1000W ∼ 27 mag, and undetected in the NIRCam data gathered by the JWST Advanced Deep Extragalactic Survey (JADES), fainter than the 30.0–30.5 mag 5 σ detection limits in individual bands, as well as in the MIDIS F560W ultradeep data (∼29 mag, 5 σ ). Analyzing the spectral energy distribution built with low-S/N (

We present the construction of a deep multiwavelength point-spread-function-matched photometric catalog in the Ultra-Deep Survey (UDS) field following the final UKIDSS UDS release. The catalog includes photometry in 24 filters, from the MegaCam- uS 0.38 μ m band to the Spitzer-IRAC 8 μ m band, over ∼0.9 deg ^2 and with a 5 σ depth of 25.3 AB in the K -band detection image. The catalog, containing ≈188,564 (136,235) galaxies at 0.2 < z < 8.0 with stellar mass $\mathrm{log}({M}_{* }/{M}_{\odot })\gt 8$ and K -band total magnitude K < 25.2 (24.3) AB, enables a range of extragalactic studies. We also provide photometric redshifts, corresponding redshift probability distributions, and rest-frame absolute magnitudes and colors derived using the template-fitting code eazy-py . Photometric redshift errors are less than 3%−4% at z < 4 across the full brightness range in the K band and stellar mass range $8\lt \mathrm{log}({M}_{* }/{M}_{\odot })\lt 12$ . Stellar population properties (e.g., stellar mass, star formation rate, dust extinction) are derived from the modeling of the spectral energy distributions using the codes FAST and Dense Basis.

We present deep James Webb Space Telescope (JWST)/Mid-Infrared Instrument (MIRI) F560W observations of a flux-limited, Atacama Large Millimeter/submillimeter Array (ALMA)-selected sample of 28 galaxies at z = 0.5–3.7 in the Hubble Ultra Deep Field (HUDF). The data from the MIRI Deep Imaging Survey (MIDIS) reveal the stellar structure of the HUDF galaxies at rest-frame wavelengths of λ > 1 μ m for the first time. We revise the stellar mass estimates using new JWST photometry and find good agreement with pre-JWST analyses; the few discrepancies can be explained by blending issues in the earlier lower-resolution Spitzer data. At z ∼ 2.5, the resolved rest-frame near-infrared (1.6 μ m) structure of the galaxies is significantly more smooth and centrally concentrated than seen by the Hubble Space Telescope at rest-frame 450 nm (F160W), with effective radii of R _e (F560W) = 1–5 kpc and Sérsic indices mostly close to an exponential (disk-like) profile ( n ≈ 1), up to n ≈ 5 (excluding active galactic nuclei). We find an average size ratio of R _e (F560W)/ R _e (F160W) ≈ 0.7 that decreases with stellar mass. The stellar structure of the ALMA-selected galaxies is indistinguishable from a HUDF reference sample of all galaxies with a MIRI flux density greater than 1 μ Jy. We supplement our analysis with custom-made, position-dependent, empirical point-spread function models for the F560W observations. The results imply that a smoother stellar structure is in place in massive gas-rich, star-forming galaxies at “Cosmic Noon,” despite a more clumpy rest-frame optical appearance, placing additional constraints on galaxy formation simulations. As a next step, matched-resolution, resolved ALMA observations will be crucial to further link the mass- and light-weighted galaxy structures to the dusty interstellar medium.

We study 31 little red dots (LRD) detected by JADES/NIRCam and covered by the SMILES/MIRI survey, of which ∼70% are detected in the two bluest MIRI bands and 40% in redder MIRI filters. The median/quartiles redshifts are $z={6.9}_{5.9}^{7.7}$ (55% spectroscopic). The spectral slopes flatten in the rest-frame near-infrared, consistent with a 1.6 μ m stellar bump but bluer than direct pure emission from active galactic nuclei (AGN) tori. The apparent dominance of stellar emission at these wavelengths for many LRDs expedites stellar mass estimation: the median/quartiles are $\mathrm{log}{M}_{\star }/{M}_{\odot }={9.4}_{9.1}^{9.7}$ . The number density of LRDs is 10 ^−4.0±0.1 Mpc ^−3 , accounting for 14% ± 3% of the global population of galaxies with similar redshifts and masses. The rest-frame near-/mid-infrared (2–4 μ m) spectral slope reveals significant amounts of warm dust (bolometric attenuation ∼3–4 mag). Our spectral energy distribution modeling implies the presence of 10 mag. We find a wide variety in the nature of LRDs. However, the best-fitting models for many of them correspond to extremely intense and compact starburst galaxies with mass-weighted ages 5–10 Myr, very efficient in producing dust, with their global energy output dominated by the direct (in the flat rest-frame ultraviolet and optical spectral range) and dust-recycled emission from OB stars with some contribution from an obscured AGN (in the infrared).

We study the stellar population properties of 182 spectroscopically confirmed (MUSE/VLT) Ly α emitters (LAEs) and 450 photometrically selected Lyman-break galaxies (LBGs) at z = 2.8–6.7 in the Hubble Extreme Deep Field. Leveraging the combined power of Hubble Space Telescope and JWST NIRCam and MIRI observations, we analyze their rest-frame UV-through-near-IR spectral energy distributions, with MIRI playing a crucial role in robustly assessing the LAEs’ stellar masses and ages. Our LAEs are low-mass objects $({{\rm{log}}}_{10}({M}_{\star }/{M}_{\odot })\simeq 7.5)$ with little or no dust extinction ( E ( B − V ) ≃ 0.1) and a blue UV continuum slope ( β ≃ −2.2). While 75% of our LAEs are young (

We present the ultraviolet luminosity function and an estimate of the cosmic star formation rate density at 8 < z < 13 derived from deep NIRCam observations taken in parallel with the MIRI Deep Survey of the Hubble Ultra Deep Field (HUDF), NIRCam covering the parallel field 2. Our deep (40 hr) NIRCam observations reach an F277W magnitude of 30.8 (5 σ ), more than 2 mag deeper than JWST public data sets already analyzed to find high-redshift galaxies. We select a sample of 44 z > 8 galaxy candidates based on their dropout nature in the F115W and/or F150W filters, a high probability for their photometric redshifts, estimated with three different codes, being at z > 8, good fits based on χ ^2 calculations, and predominant solutions compared to z < 8 alternatives. We find mild evolution in the luminosity function from z ∼ 13 to z ∼ 8, i.e., only a small increase in the average number density of ∼0.2 dex, while the faint-end slope and absolute magnitude of the knee remain approximately constant, with values α = − 2.2 ± 0.1, and M ^* = − 20.8 ± 0.2 mag. Comparing our results with the predictions of state-of-the-art galaxy evolution models, we find two main results: (1) a slower increase with time in the cosmic star formation rate density compared to a steeper rise predicted by models; (2) nearly a factor of 10 higher star formation activity concentrated in scales around 2 kpc in galaxies with stellar masses ∼10 ^8 M _⊙ during the first 350 Myr of the universe, z ∼ 12, with models matching better the luminosity density observational estimations ∼150 Myr later, by z ∼ 9.

Lyman-break galaxy (LBG) candidates at z ≳ 10 are rapidly being identified in James Webb Space Telescope (JWST)/NIRCam observations. Due to the (redshifted) break produced by neutral hydrogen absorption of rest-frame UV photons, these sources are expected to drop out in the bluer filters while being well detected in redder filters. However, here we show that dust-enshrouded star-forming galaxies at lower redshifts ( z ≲ 7) may also mimic the near-infrared (near-IR) colors of z > 10 LBGs, representing potential contaminants in LBG candidate samples. First, we analyze CEERS-DSFG-1, a NIRCam dropout undetected in the F115W and F150W filters but detected at longer wavelengths. Combining the JWST data with (sub)millimeter constraints, including deep NOEMA interferometric observations, we show that this source is a dusty star-forming galaxy (DSFG) at z ≈ 5.1. We also present a tentative 2.6 σ SCUBA-2 detection at 850 μ m around a recently identified z ≈ 16 LBG candidate in the same field and show that, if the emission is real and associated with this candidate, the available photometry is consistent with a z ∼ 5 dusty galaxy with strong nebular emission lines despite its blue near-IR colors. Further observations on this candidate are imperative to mitigate the low confidence of this tentative submillimeter emission and its positional uncertainty. Our analysis shows that robust (sub)millimeter detections of NIRCam dropout galaxies likely imply z ∼ 4–6 redshift solutions, where the observed near-IR break would be the result of a strong rest-frame optical Balmer break combined with high dust attenuation and strong nebular line emission, rather than the rest-frame UV Lyman break. This provides evidence that DSFGs may contaminate searches for ultra-high redshift LBG candidates from JWST observations.

The new capabilities that JWST offers in the near- and mid-infrared (IR) are used to investigate in unprecedented detail the nature of optical/near-IR-faint, mid-IR-bright sources, with HST-dark galaxies among them. We gather JWST data from the CEERS survey in the Extended Groth Strip, jointly with HST data, and analyze spatially resolved optical-to-mid-IR spectral energy distributions to estimate photometric redshifts in two dimensions and stellar population properties on a pixel-by-pixel basis for red galaxies detected by NIRCam. We select 138 galaxies with F150W − F356W > 1.5 mag and F356W < 27.5 mag. The nature of these sources is threefold: (1) 71% are dusty star-forming galaxies (SFGs) at 2 < z < 6 with $9\lt \mathrm{log}{M}_{\star }/{M}_{\odot }\lt 11$ and a variety of specific SFRs (100 Gyr ^−1 ); (2) 18% are quiescent/dormant (i.e., subject to reignition/rejuvenation) galaxies (QGs) at 3 < z < 5, with $\mathrm{log}{M}_{\star }/{M}_{\odot }\sim 10$ and poststarburst mass-weighted ages (0.5–1.0 Gyr); and (3) 11% are strong young starbursts with indications of high equivalent width emission lines (typically, [O iii ]+H β ) at 6 < z < 7 (XELG- z 6) and $\mathrm{log}{M}_{\star }/{M}_{\odot }\sim 9.5$ . The sample is dominated by disk-like galaxies with remarkable compactness for XELG- z 6 (effective radii smaller than 0.4 kpc). Large attenuations in SFGs, 2 < A ( V ) < 5 mag, are found within 1.5 times the effective radius, approximately 2 kpc, while QGs present A ( V ) ∼ 0.2 mag. Our SED-fitting technique reproduces the expected dust emission luminosities of IR-bright and submillimeter galaxies. This study implies high levels of star formation activity between z ∼ 20 and z ∼ 10, where virtually 100% of our galaxies had already formed 10 ^8 M _⊙ , 60% had assembled 10 ^9 M _⊙ , and 10% up to 10 ^10 M _⊙ (in situ or ex situ).

We report the discovery of a candidate galaxy with a photo- z of z ∼ 12 in the first epoch of the James Webb Space Telescope (JWST) Cosmic Evolution Early Release Science Survey. Following conservative selection criteria, we identify a source with a robust z _phot = ${11.8}_{-0.2}^{+0.3}$ (1 σ uncertainty) with m _F200W = 27.3 and ≳7 σ detections in five filters. The source is not detected at λ < 1.4 μ m in deep imaging from both Hubble Space Telescope (HST) and JWST and has faint ∼3 σ detections in JWST F150W and HST F160W, which signal a Ly α break near the red edge of both filters, implying z ∼ 12. This object (Maisie’s Galaxy) exhibits F115W − F200W > 1.9 mag (2 σ lower limit) with a blue continuum slope, resulting in 99.6% of the photo- z probability distribution function favoring z > 11. All data-quality images show no artifacts at the candidate’s position, and independent analyses consistently find a strong preference for z > 11. Its colors are inconsistent with Galactic stars, and it is resolved ( r _h = 340 ± 14 pc). Maisie’s Galaxy has log M _* / M _⊙ ∼ 8.5 and is highly star-forming (log sSFR ∼ −8.2 yr ^−1 ), with a blue rest-UV color ( β ∼ −2.5) indicating little dust, though not extremely low metallicity. While the presence of this source is in tension with most predictions, it agrees with empirical extrapolations assuming UV luminosity functions that smoothly decline with increasing redshift. Should follow-up spectroscopy validate this redshift, our universe was already aglow with galaxies less than 400 Myr after the Big Bang.

We present new Spitzer Infrared Array Camera (IRAC) 3.6 and 4.5 μ m mosaics of three fields, E-COSMOS, DEEP2-F3, and ELAIS-N1. Our mosaics include both new IRAC observations as well as reprocessed archival data in these fields. These fields are part of the HSC-Deep grizy survey and have a wealth of additional ancillary data. The addition of these new IRAC mosaics is critical in allowing for improved photometric redshifts and stellar population parameters at cosmic noon and earlier epochs. The total area mapped by this work is ∼17 deg ^2 with a mean integration time of ≈1200s, providing a median 5 σ depth of 23.7(23.3) at 3.6(4.5) μ m in AB. We perform SExtractor photometry both on the combined mosaics as well as the single-epoch mosaics taken ≈6 months apart. The resultant IRAC number counts show good agreement with previous studies. In combination with the wealth of existing and upcoming spectrophotometric data in these fields, our IRAC mosaics will enable a wide range of galactic evolution and AGN studies. With that goal in mind, we make the combined IRAC mosaics and coverage maps of these three fields publicly available.

We investigate the star formation main sequence (MS; SFR– M _⋆ ) down to 10 ^8−9 M _⊙ using a sample of 34,061 newly discovered ultrafaint (27 mag ≲ i ≲ 30 mag) galaxies at 1 < z < 3 detected in the GOODS-N field. Virtually none of these galaxies are contained in previous public catalogs, effectively doubling the number of known sources in the field. The sample was constructed by stacking the optical broadband observations taken by the HST/GOODS-CANDELS surveys, as well as the 25 ultradeep medium-band images gathered by the GTC/SHARDS project. Our sources are faint (average observed magnitudes 〈 i 〉 ∼ 28.2 and 〈 H 〉 ∼ 27.9 mag), blue (UV slope 〈 β 〉 ∼ −1.9), star-forming (rest-frame colors 〈 U − V 〉 ∼ 0.10 and 〈 V − J 〉 ∼ 0.17 mag) galaxies. These observational characteristics are identified with young (mass-weighted age 〈 t _M _− _w 〉 ∼ 0.014 Gyr) stellar populations subject to low attenuations (〈 A ( V )〉 ∼ 0.30 mag). Our sample allows us to probe the MS down to 10 ^8.0 M _⊙ at z = 1 and 10 ^8.5 M _⊙ at z = 3, around 0.6 dex deeper than previous analyses. In the low-mass galaxy regime, we find an average value for the slope of 0.97 at 1 < z < 2 and 1.12 at 2 < z < 3. Nearly 60% of our sample presents stellar masses in the range 10 ^6-8 M _⊙ at 1 < z

We use the Illustris-1 simulation to explore the capabilities of the Hubble Space Telescope (HST) and James Webb Space Telescope (JWST) data to analyze the stellar populations in high-redshift galaxies, taking advantage of the combined depth, spatial resolution, and wavelength coverage. For that purpose, we use simulated broadband ACS, WFC3, and NIRCam data and two-dimensional stellar population synthesis (2D-SPS) to derive the integrated star formation history (SFH) of massive ( M _* > 10 ^10 M _⊙ ) simulated galaxies at 1 < z < 4 that evolve into a local M _* > 10 ^11 M _⊙ galaxy. In particular, we explore the potential of HST and JWST data sets reaching a depth similar to those of the CANDELS and ongoing CEERS observations, respectively, and concentrate on determining the capabilities of this data set for characterizing the first episodes in the SFH of local M _* > 10 ^11 M _⊙ galaxies by studying their progenitors at z > 1. The 2D-SPS method presented in this paper has been calibrated to robustly recover the cosmic times when the first star formation episodes occurred in massive galaxies, i.e., the first stages in their integrated SFHs. In particular, we discuss the times when the first 1%–50% of their total stellar mass formed in the simulation. We demonstrate that we can recover these ages with typical median systematic offset of less than 5% and scatter around 20%–30%. According to our measurements on Illustris data, we are able to recover that local M _* > 10 ^11 M _⊙ galaxies would have started their formation by z = 16, forming the first 5% of their stellar mass present at z ∼ 1 by z = 4.5, 10% by z = 3.7, and 25% by z = 2.7.

The IRAC mapping of the NMBS-II fields program is an imaging survey at 3.6 and 4.5 μm with the Spitzer Infrared Array Camera (IRAC). The observations cover three Canada–France–Hawaii Telescope Legacy Survey Deep (CFHTLS-D) fields, including one also imaged by AEGIS, and two MUSYC fields. These are then combined with archival data from all previous programs into deep mosaics. The resulting imaging covers a combined area of about 3 deg2, with at least ∼2 hr integration time for each field. In this work, we present our data reduction techniques and document the resulting coverage maps at 3.6 and 4.5 μm. All of the images are W-registered to the reference image, which is either the z-band stack image of the 25% best-seeing images from the CFHTLS-D for CFHTLS-D1, CFHTLS-D3, and CFHTLS-D4, or the K-band images obtained at the Blanco 4-m telescope at CTIO for MUSYC1030 and MUSYC1255. We make all images and coverage maps described here publicly available via the Spitzer Science Center. [ABSTRACT FROM AUTHOR]