As part of the JWST Advanced Deep Extragalactic Survey (JADES), NIRSpec has spectroscopically confirmed four young and metal-poor galaxies at redshift 10.3-13.2, from an early epoch of galaxy formation.

Surveys with the James Webb Space Telescope (JWST) have discovered candidate galaxies in the first 400 Myr of cosmic time. Preliminary indications have suggested these candidate galaxies may be more massive and abundant than previously thought. However, without confirmed distances, their inferred properties remain uncertain. Here we identify four galaxies located in the JWST Advanced Deep Extragalactic Survey Near-Infrared Camera imaging with photometric redshifts z of roughly 10-13. These galaxies include the first redshift z > 12 systems discovered with distances spectroscopically confirmed by JWST in a companion paper. Using stellar population modelling, we find the galaxies typically contain 100 million solar masses in stars, in stellar populations that are less than 100 million years old. The moderate star-formation rates and compact sizes suggest elevated star-formation rate surface densities, a key indicator of their formation pathways. Taken together, these measurements show that the first galaxies contributing to cosmic reionization formed rapidly and with intense internal radiation fields.

The abundance of carbon relative to oxygen (C/O) is a promising probe of star formation history in the early universe, as the ratio changes with time due to production of these elements by different nucleosynthesis pathways. We present a measurement of log(C/O) = -1.01 +/- 0.12 (stat) +/- 0.15 (sys) in a z = 6.23 galaxy observed as part of the GLASS-JWST Early Release Science Program. Notably, we achieve good precision thanks to the detection of the rest-frame ultraviolet O III], CIII], and C IV emission lines delivered by JWST/NIRSpec. The C/O abundance is similar to 0.8 dex lower than the solar value and is consistent with the expected yield from core-collapse supernovae, indicating that longer-lived intermediate-mass stars have not fully contributed to carbon enrichment. This in turn implies rapid buildup of a young stellar population with age less than or similar to 100 Myr in a galaxy seen similar to 900 Myr after the big bang. Our chemical abundance analysis is consistent with spectral energy distribution modeling of JWST/NIRCam photometric data, which indicates a current stellar mass log M-star/M-circle dot = 8.4(-0.2)(+0.4) and specific star formation rate similar or equal to 20 Gyr(-1). These results showcase the value of chemical abundances and C/O in particular to study the earliest stages of galaxy assembly.

JWST has revolutionized the field of extragalactic astronomy with its sensitive and high-resolution infrared view of the distant Universe. Adding to the new legacy of JWST observations, we present the first NIRCam imaging data release from the JWST Advanced Deep Extragalactic Survey (JADES), providing nine filters of infrared imaging of similar to 25 arcmin2 covering the Hubble Ultra Deep Field and portions of Great Observatories Origins Deep Survey South. Utilizing 87 on-sky dual-filter hours of exposure time, these images reveal the deepest ever near-infrared view of this iconic field. We supply carefully constructed nine-band mosaics of the JADES bands, as well as matching reductions of five additional bands from the JWST Extragalactic Medium-band Survey. Combining with existing Hubble Space Telescope imaging, we provide 23-band space-based photometric catalogs and photometric redshifts for approximate to 47,500 sources. To promote broad engagement with JADES, we have created an interactive FitsMap website to provide an interface for professional researchers and the public to experience these JWST data sets. Combined with the first JADES NIRSpec data release, these public JADES imaging and spectroscopic data sets provide a new foundation for discoveries of the infrared Universe by the worldwide scientific community.

The gravitationally lensed supernova Refsdal appeared in multiple images produced through gravitational lensing by a massive foreground galaxy cluster. After the supernova appeared in 2014, lens models of the galaxy cluster predicted that an additional image of the supernova would appear in 2015, which was subsequently observed. We use the time delays between the images to perform a blinded measurement of the expansion rate of the Universe, quantified by the Hubble constant (H-0). Using eight cluster lens models, we infer H-0 = 64:8(+4:4) (-4:3) kilometers per second per megaparsec. Using the two models most consistent with the observations, we find H-0 = 66:6(+4:1) (-3:3) kilometers per second per megaparsec. The observations are best reproduced by models that assign dark-matter halos to individual galaxies and the overall cluster.

In the first billion years after the Big Bang, sources of ultraviolet (UV) photons are believed to have ionized intergalactic hydrogen, rendering the Universe transparent to UV radiation. Galaxies brighter than the characteristic luminosity L* (refs. 1,2) do not provide enough ionizing photons to drive this cosmic reionization. Fainter galaxies are thought to dominate the photon budget; however, they are surrounded by neutral gas that prevents the escape of the Lyman-alpha photons, which has been the dominant way to identify them so far. JD1 was previously identified as a triply-imaged galaxy with a magnification factor of 13 provided by the foreground cluster Abell 2744 (ref. 3), and a photometric redshift of z approximate to 10. Here we report the spectroscopic confirmation of this very low luminosity (approximate to 0.05 L*) galaxy at z = 9.79, observed 480 Myr after the Big Bang, by means of the identification of the Lyman break and redward continuum, as well as multiple greater than or similar to 4 sigma emission lines, with the Near-InfraRed Spectrograph (NIRSpec) and Near-InfraRed Camera (NIRCam) instruments. The combination of the James Webb Space Telescope (JWST) and gravitational lensing shows that this ultra-faint galaxy (M-UV = -17.35)-with a luminosity typical of the sources responsible for cosmic reionization-has a compact (approximate to 150 pc) and complex morphology, low stellar mass (10(7.19) M circle dot) and subsolar (approximate to 0.6 Z(circle dot)) gas-phase metallicity.

Context. The space density of X-ray-luminous, blindly selected active galactic nuclei (AGN) traces the population of rapidly accreting super-massive black holes through cosmic time. It is encoded in the X-ray luminosity function, whose bright end remains poorly constrained in the first billion years after the Big Bang as X-ray surveys have thus far lacked the required cosmological volume. With the eROSITA Final Equatorial-Depth Survey (eFEDS), the largest contiguous and homogeneous X-ray survey to date, X-ray AGN population studies can now be extended to new regions of the luminosity-redshift space (L2 - 10 keV > 10(45) erg s(-1) and z > 6).Aims. The current study aims at identifying luminous quasars at z > 5.7 among X-ray-selected sources in the eFEDS field in order to place a lower limit on black hole accretion well into the epoch of re-ionisation. A secondary goal is the characterisation of the physical properties of these extreme coronal emitters at high redshifts.Methods. Cross-matching eFEDS catalogue sources to optical counterparts from the DESI Legacy Imaging Surveys, we confirm the low significance detection with eROSITA of a previously known, optically faint z = 6.56 quasar from the Subaru High-z Exploration of Low-luminosity Quasars (SHELLQs) survey. We obtained a pointed follow-up observation of the source with the Chandra X-ray telescope in order to confirm the low-significance eROSITA detection. Using new near-infrared spectroscopy, we derived the physical properties of the super-massive black hole. Finally, we used this detection to infer a lower limit on the black hole accretion density rate at z > 6.Results. The Chandra observation confirms the eFEDS source as the most distant blind X-ray detection to date. The derived X-ray luminosity is high with respect to the rest-frame optical emission of the quasar. With a narrow MgII line, low derived black hole mass, and high Eddington ratio, as well as its steep photon index, the source shows properties that are similar to local narrow-line Seyfert 1 galaxies, which are thought to be powered by young super-massive black holes. In combination with a previous high-redshift quasar detection in the field, we show that quasars with L2 - 10 keV > 10(45) erg s(-1) dominate accretion onto super-massive black holes at z similar to 6.

In November 2020, a new, bright object, eRASSt J234402.9 - 352640, was discovered in the second all-sky survey of SRG/eROSITA. The object brightened by a factor of at least 150 in 0.2-2.0 keV flux compared to an upper limit found six months previous, reaching an observed peak of 1.76(+0:03) (-0:24) x 10(-11) erg cm(-2) s(-1). The X-ray ignition is associated with a galaxy at z = 0.10, making the peak luminosity log(10)( L(0.2-2)keV=[ergs(-1)]) = 44.7 +/- 0.1. Around the time of the rise in X-ray flux, the nucleus of the galaxy brightened by approximately 3 mag. in optical photometry, after correcting for the host contribution. We present X-ray follow-up data from Swift, XMM-Newton, and NICER, which reveal a very soft spectrum as well as strong 0.2-2.0 keV flux variability on multiple timescales. Optical spectra taken in the weeks after the ignition event show a blue continuum with broad, asymmetric Balmer emission lines, and high-ionisation ([OIII] lambda lambda 4959,5007) and low-ionisation ([NII]lambda 6585, [SII]lambda lambda 6716,6731) narrow emission lines. Following the peak in the optical light curve, the X-ray, UV, and optical photometry all show a rapid decline. The X-ray light curve shows a decrease in luminosity of similar to 0.45 over 33 days and the UV shows a drop of similar to 0.35 over the same period. eRASSt J234402.9 352640 also shows a brightening in the mid-infrared, likely powered by a dust echo of the luminous ignition. We find no evidence in Fermi-LAT gamma-ray data for jet-like emission. The event displays characteristics of a tidal disruption event (TDE) as well as of an active galactic nucleus (AGN), complicating the classification of this transient. Based on the softness of the X-ray spectrum, the presence of high-ionisation optical emission lines, and the likely infrared echo, we find that a TDE within a turned-o ff AGN best matches our observations.

We report on multiwavelength observations of the tidal disruption event (TDE) candidate eRASSt J074426.3 + 291606 (J0744), located in the nucleus of a previously quiescent galaxy at z = 0.0396. J0744 was first detected as a new, ultra-soft X-ray source (photon index similar to 4) during the second SRG/eROSITA All-Sky Survey (eRASS2), where it had brightened in the 0.3-2 keV band by a factor of more than similar to 160 relative to an archival 3 sigma upper limit inferred from a serendipitous Chandra pointing in 2011. The transient was also independently found in the optical by the Zwicky Transient Facility (ZTF), with the eRASS2 detection occurring only similar to 20 d after the peak optical brightness, suggesting that the accretion disc formed promptly in this TDE. Continued X-ray monitoring over the following similar to 400 d by eROSITA, NICER XTI and Swift XRT showed a net decline by a factor of similar to 100, albeit with large amplitude X-ray variability where the system fades, and then rebrightens, in the 0.3-2 keV band by a factor similar to 50 during an 80-d period. Contemporaneous Swift UVOT observations during this extreme X-ray variability reveal a relatively smooth decline, which persists over similar to 400 d post-optical peak. The peak observed optical luminosity (absolute g-band magnitude similar to-16.8 mag) from this transient makes J0744 the faintest optically detected TDE observed to date. However, contrasting the known set of 'faint and fast' TDEs, the optical emission from J0744 decays slowly (exponential decay time-scale similar to 120 d), making J0744 the first member of a potential new class of 'faint and slow' TDEs.