Our understanding of the physical properties of star-forming galaxies during the Epoch of Reionization (EoR; at z > 6) suffers from degeneracies among the apparent properties of the stars, nebular gas, and dust. These degeneracies are most prominent with photometry, which has insufficient (1) spectral resolution and (2) rest-frame spectral coverage. We explore ways to break these degeneracies with a sample of N = 22 high-redshift star-forming galaxies at 7 < z(phot) <= 9, using some of the deepest existing imaging from JWST/NIRCam and JWST/MIRI with JADES. Key to this study is the imaging from JWST/MIRI at 7.7 mu m, which provides coverage of the rest-frame I band at the observed redshifts. We infer stellar population properties and rest-frame colors using a variety of filter sets and star formation history (SFH) assumptions to explore the impact of these choices. Evaluating these quantities both with and without the 7.7 mu m data point shows that dense spectral coverage with JWST/NIRCam (eight or more filters, including at least one medium-band at lambda(obs) approximate to 4-5 mu m) can compensate for lacking the rest-frame I-band coverage for the vast majority (approximate to 80%) of our sample. Furthermore, these galaxy properties are most consistently determined by assuming the delayed-tau SFH, which provides the smallest offsets and scatters around these offsets when including JWST/MIRI. Within extragalactic surveys like JADES and CEERS, our findings suggest that robust characterization of the stellar population properties and rest-frame colors for typical high-redshift star-forming galaxies (i.e., galaxies with M-UV approximate to -20 and beta(UV) approximate to -2) is possible with JWST/NIRCam alone at z approximate to 8.

One of the most surprising results of early James Webb Space Telescope (JWST) observations is the discovery of an abundance of red, compact, broad-line objects dubbed "little red dots" (LRDs) at z>4. Their spatial density (∼10^-4-10^-5 cMpc^-3) is 100 times more abundant than UV-selected quasars at those redshift if one extrapolates the quasar luminosity function (QLF) down to the LRD regime. However, whether LRDs dominate black hole accretion at quasar-like luminosities (L_bol≳ 10^45-46 erg s^-1) remains unanswered, as probing the bright end of the LRD luminosity function requires a much larger area than those able to be surveyed by JWST. In this work, we present our search for the brightest LRDs (K<23.7) at 4.5<z<4.9 using wide-area multiwavelength imaging surveys from the near-UV to the infrared bands. With over 15 square degrees of sky coverage, we only identify one single LRD candidate at z_phot≈4.6, which translates into a spatial density of n(M_5100<-23.5)≈10^-8 cMpc^-3 – this is nearly 10 times less abundant than the UV-selected quasars at similar optical luminosity. When combined with the LRD sample identified by JWST at the same redshift range, we find a sharp cutoff in the optical luminosity function at λL_5100≈2.5×10^44 erg s^-1, while the QLF turnover occurs at ≳20 times higher luminosity. We therefore confirm the exclusively low-luminosity nature of LRDs, ruling out that LRDs are the counter parts of quasars. Furthermore, we speculate that, if the shape of the luminosity function holds up, it points to LRDs being powered by low-mass black holes with a narrow range of Eddington-level accretion rates.

Models predict that chemical enrichment and gas redistribution should proceed rapidly once star formation begins, yet direct observational constraints at the earliest cosmic epochs have been scarce. Here we present evidence that metal-enriched gas in multiple ionic phases was already present around galaxies before the midpoint of cosmic reionization. Using JWST/NIRSpec rest-frame ultraviolet spectroscopy of three galaxies at redshifts z=7.2-9.3, we detect blueshifted metal absorption in all three systems; across the sample, the detected transitions span neutral, low-ionization, and high-ionization species, including O I, Si II, C II, Si IV, and C IV. These absorption features show velocity offsets of order |Δv| ∼ 50–250 km s^-1, predominantly blueshifted relative to the systemic redshifts of the host galaxies derived from nebular emission lines. This ionic coexistence within a broadly shared velocity structure, together with the observed equivalent-width ratios, is consistent with outflowing or otherwise kinematically disturbed galaxy-associated gas, similar to that seen at lower redshift. The observations therefore indicate that metal-enriched gas associated with galaxies was already kinematically disturbed at very early times, requiring rapid metal production in the early generations of stars. These results show that key conditions for baryon cycling were established in at least a subset of luminous galaxies within the first several hundred million years of cosmic time, well before the completion of reionization.

JWST is beginning to uncover a population of extremely metal-poor galaxies (EMPGs, Z < 1% Z_⊙) at z > 3, mostly through serendipitous NIRSpec discoveries and blind slitless spectroscopy. To accelerate our understanding of pristine star formation, we further develop a methodology to identify EMPG candidates from photometry, using the extensive deep medium-band imaging from JADES. Our EMPG candidates at 2.5 < z < 6.5 exhibit strong photometric boosts by Hα, yet correspondingly weak boosts by [O III] + Hβ, likely indicating extremely low metallicity to explain their lack of [O III] emission. We further demand our EMPG candidates to have strong Balmer jumps, as revealed by medium-band imaging, to ensure that they are young starbursts, as opposed to broad-line AGN/LRDs, though contamination by dusty/dense-gas starbursts and highly-obscured AGN remains a concern. SED-fitting with near-pristine models (∼0.1-1% Z_⊙) indicates that our 22 EMPG candidates are low-mass (median M_* ≈ 10^6.7 M_⊙), faint dwarf galaxies (M_UV≈ -16.6), with high ionizing photon production efficiencies (log (ξ_ion, obs/(Hz erg^-1)) ≈ 26.0). Hence these are plausible sites of near-pristine star formation, comprising ∼0.04-0.6% of 2.5 < z < 6.5 galaxies at -19 < M_UV < -16. We discuss this extremely metal-poor extension to the mass-metallicity relation. We forecast that deep (∼28 h) NIRCam slitless spectroscopy can identify bright EMPGs through strong Hβ but lack of [O III] emission, or secure the redshifts of fainter systems through Hα detections. Highly-multiplexed NIRSpec spectroscopy offers an alternate route to discovering the faintest pristine galaxies out to z=10, without requiring deep medium-band/MIRI imaging to identify secure candidates.

We report the confirmation of a HeIIλ1640 emitter located at 3 pkpc from the galaxy GN-z11, at z=10.6. The detection, based on JWST NIRSpec-IFU high-resolution spectroscopy, confirms a previous claim based on medium-resolution spectroscopy. The HeIIλ1640 identification is further supported by the independent detection of Hγ obtained by Übler et al. (2026) at the same location. The HeII emission is spectrally resolved in two components separated by 120 km/s. The Equivalent Width of the HeII emission is extremely high (>20 A). No metal lines are detected. Population III stars appear to be the most plausible explanation for the observed HeII emission. We argue that Population III stars are the most plausible explanation for the observed He II emission, with no satisfactory alternative from other classes of sources or mechanisms.

We exploit a new sample of around 400 bright dusty galaxies from the Atacama Large Millimeter/submillimeter Array (ALMA) CHAMPS Large Program, together with the rich JWST multiband data products in the COSMOS field, to explore and validate new selection methods for identifying dusty star-forming galaxies (DSFGs). Here we present an effective empirical selection criterion based on a newly defined parameter: I-star equivalent to log(10)(M-star)xlog(10)(SFR) . Incorporating the m277W - m444W color as a second parameter further improves the purity of the selection. We then apply this method to the COSMOS2025 catalog to search for fainter dusty galaxy candidates below the ALMA CHAMPS detection limit and, through a stacking technique, identify a population of high-redshift DSFG candidates with an average flux density of S-1.2mm approximate to 150 mu Jy and a space density of similar to 6 x 10(-6) Mpc(-3). Three of these galaxies have been spectroscopically confirmed at z(spec) = 7.20, 5.85, and 5.04. This faint population seems to have been missed by most of the previous submillimeter/millimeter surveys and ground- and space-based UV-near-IR observations. We then show evidence of a possible evolutionary connection between the z > 10 UV-bright galaxies recently discovered by JWST, the faint dusty z approximate to 6-8 galaxies identified here, and the population of z approximate to 3-5 massive quiescent galaxies; all of them are potentially linked as progenitor-descendant populations based on their abundance, redshifts, and stellar masses. Future spectroscopic campaigns will be essential to confirm the redshifts and physical properties of these massive, faint, high-redshift DSFG candidates.

We present the second data release of the Systematic Mid-Infrared Instrument Legacy Extragalactic Survey (SMILES), focusing on JWST/NIRSpec medium-resolution spectroscopy of galaxies across cosmic time. This release includes spectroscopic observations of 166 galaxies spanning 0 < z < 7.5, sampling star-forming galaxies, quiescent systems, and active galactic nuclei (AGNs), with an emphasis on galaxies at cosmic noon ( z ∼ 1–3). We describe the target selection strategy, the observational setup with the G140M/F100LP and G235M/F170LP gratings, and the data calibration process. The final data products include the reduced spectra, redshift catalog, emission-line catalogs produced with GELATO for emission-line galaxies and pPXF fits for quiescent systems, and ancillary spectral energy distribution fit results derived from multiband photometry. The SMILES NIRSpec dataset enables investigations of obscured AGNs, multiphase outflows, ionizing properties, and the role of environment in galaxy evolution. All data products are publicly available through STScI/MAST at https://archive.stsci.edu/hlsp/smiles .

We present the UV-to-near-IR (NIR) size evolution of a sample of 161 quiescent galaxies with M-* > 10(10)M(circle dot)over 0.5 < z < 5. With deep multiband NIRCam images in GOODS-South from JADES, we measure the effective radii (R-e) of the galaxies at rest-frame 0.3, 0.5, and 1 mu m. On average, we find that quiescent galaxies are 45% (15%) more compact at rest-frame 1 mu m than they are at 0.3 mu m (0.5 mu m). Regardless of wavelengths, the R-e of quiescent galaxies strongly evolves with redshift, and this evolution depends on stellar mass. For lower-mass quiescent galaxies with M-* = 10(10)-10(10.6)M(circle dot), the evolution follows R-e proportional to (1 + z)(-1.1), whereas it becomes steeper, following R-e proportional to (1 + z)(-1.7), for higher-mass quiescent galaxies with M-* > 10(10.6)M(circle dot). To constrain the physical mechanisms driving the apparent size evolution, we study the relationship between R-e and the formation redshift (z(form)) of quiescent galaxies. For lower-mass quiescent galaxies, this relationship is broadly consistent with R-e proportional to(1+z(form))(-1) , in line with the expectation of the progenitor effect. For higher-mass quiescent galaxies, the relationship between R-e and z(form) depends on stellar age. Older quiescent galaxies have a steeper relationship between R-e and z(form) than that expected from the progenitor effect alone, suggesting that mergers and/or post-quenching continuous gas accretion drive additional size growth in very massive systems. We find that the z > 3 quiescent galaxies in our sample are very compact, with mass surface densities Sigma(e) greater than or similar to 10(10)M(circle dot) kpc(-2), and their R-e are possibly even smaller than anticipated from the size evolution measured for lower-redshift quiescent galaxies. Finally, we take a close look at the structure of GS-9209, one of the earliest confirmed massive quiescent galaxies at z(spec) similar to 4.7. From UV to NIR, GS-9209 becomes increasingly compact, and its light profile becomes more spheroidal, showing that the color gradient is already present in this earliest massive quiescent galaxy.

We study the luminosity function (LF) and clustering properties of 888 H alpha emitters (HAEs) at 3.75 < z < 6 in the GOODS-N field. The sample, built from JWST CONGRESS and FRESCO NIRCam grism surveys using a novel redshift assignment algorithm, spans similar to 62 arcmin(2) and reaches L-H alpha similar to 10(41.2) erg s(-1). We identify two prominent filamentary protoclusters at z approximate to 4.41 and z approximate to 5.19, hosting 98 and 144 HAEs, respectively. The observed H alpha LFs show similar shallow faint-end slopes for both protocluster and field galaxies at 3.75 < z < 5, and for the protocluster at 5 < z < 6 (alpha approximate to -1.2 to -1.3). In contrast, the field LF at 5 < z < 6 has a much steeper slope ( alpha=-1.87(-0.23)(+0.30)), suggesting that protocluster galaxies at z > 5 are more evolved, resembling the populations at 3.75 < z < 5. The observed star formation rate density from H alpha integrated down to 0.45 M-circle dot yr(-1), is 0.050(-0.003)(+0.002)M(circle dot)yr(-1)Mpc(-3) at 3.75 < z < 5 and 0.046(-0.004)(+0.006)M(circle dot)yr(-1)Mpc(-3) at 5 < z < 6, with protoclusters contributing about 25% and 55%, respectively. This implies a large fraction of star formation at z > 4 occurs in protoclusters. For the first time, we conduct the star formation-rate-limited three-dimensional clustering analysis at z > 4. We find that the filamentary geometry of protoclusters flattens the power-law shape of the HAE autocorrelation functions, with slopes much shallower than the typically assumed value. The autocorrelation function of field HAEs has a correlation length of r(0)=4.61(-0.68)(+1.00)h(-1)Mpc at z approximate to 4-5 and r0(=)6.23(-1.13)(+1.68)h(-1)Mpc at z approximate to 5-6. Comparing the observed correlation functions with the UniverseMachine simulation, we infer the dark matter (sub-)halo masses of HAEs to be log(M-h/M-circle dot)=11.0-11.2 at z approximate to 4-6, with a scatter of 0.4 dex.

We present COSMOS2025, the COSMOS-Web catalog of photometry, morphology, photometric redshifts, and physical parameters for more than 700 000 galaxies in the Cosmic Evolution Survey (COSMOS) field. This catalog is based on our James Webb Space Telescope 255 h COSMOS-Web program, which provides deep near-infrared imaging in four NIRCam (F115W, F150W, F277W, F444W) and one MIRI (F770W) filter over the central similar to 0.54 deg(2) (similar to 0.2 deg(2) for MIRI) in COSMOS. These data are combined with ground- and space-based data to derive photometric measurements of NIRCam-detected sources using both fixed-aperture photometry (on the space-based bands) and a profile-fitting technique on all 37 bands spanning 0.3 mu m to 8 mu m. We provide morphology for all sources from complementary techniques including profile fitting and machine-learning classification. We derive photometric redshifts, physical parameters, and non-parametric star formation histories from spectral energy distribution (SED) fitting. The catalog has been extensively validated against previous COSMOS catalogs and other surveys. Photometric redshift accuracy measured using spectroscopically confirmed galaxies out to z similar to 9 reaches sigma(MAD) = 0.012 at m(F444W) < 28 and remains at sigma(MAD) less than or similar to 0.03 as a function of magnitude, color, and galaxy type. This represents a factor of similar to 2 improvement at 26 AB mag compared to COSMOS2020. The catalog is approximately 80% complete at log(M-star/M-circle dot) similar to 9 at z similar to 10 and at log(M-star/M-circle dot) similar to 7 at z similar to 0.2, representing a gain of 1 dex compared to COSMOS2020. COSMOS2025 represents the definitive COSMOS-Web catalog. It is provided with complete documentation, together with redshift probability distributions, and it is ready for scientific exploitation today.

We present JADES-GS 209777, previously cataloged as CANDELS J033238.02-274626.2, hereafter "the Hatchling," a red quasar at $z=3.711$. While the source has been reported in earlier deep-field catalogs, our multiwavelength analysis reveals a visible active nucleus still embedded in a dense gas- and dust-rich environment. Red quasar continua are often attributed to dust attenuation, including non-standard extinction curves, but the highly comprehensive multiwavelength data for this source provide direct constraints on the material being cleared. Using JWST/NIRSpec, NIRCam, MIRI, HST, MUSE, Chandra, ALMA, and VLA data, we detect broad emission lines and strong X-ray emission, showing that the active nucleus is at least partially exposed. We also detect H$α$ and He I absorption, indicating dense gas close to the nucleus. Kinematically disturbed O I, Mg II, Na D, and [O III] features, together with extended Ly$α$ emission over $\gtrsim 20$ kpc, further show that multiphase gas is being accelerated from the nuclear region into the host-galaxy environment. The ALMA detection reveals strong dust emission, with the inferred infrared luminosity placing the system in the ULIRG regime. The continuum is red and sharply declining toward the rest-frame UV, resembling compact red AGNs, and may reflect extreme dust attenuation, gas reprocessing, possible BAL-like absorption, or a combination of these effects. Regardless of which mechanism dominates the continuum shape, the line diagnostics show that the visible nucleus remains partially obscured by nearby material. The Hatchling therefore represents a unique opportunity to explore a poorly known transition phase in which feedback is likely clearing an enshrouded quasar and allowing it to emerge toward a more unobscured active nucleus.

ABSTRACT Understanding how galaxies assemble their mass during the first billion years of cosmic time is a central goal of extragalactic astrophysics, yet joint constraints on their sizes and kinematics remain scarce. We present one of the first statistical studies of the $\mathrm{H}\alpha$ size–mass relation at high redshift with a sample of 213 galaxies at spectroscopic redshifts of $z\approx 4-6$ from the FRESCO and CONGRESS NIRCam grism surveys. We measure the $\mathrm{H}\alpha$ morphology and kinematics of our sample using the novel forward modelling Bayesian inference tool geko, and complement them with stellar continuum sizes in the rest-frame far ultraviolet (FUV), near ultraviolet (NUV), and optical, obtained from modelling of imaging data from the JADES survey with Pysersic. At $z\approx 5$, we find that the average H $\alpha$ sizes are larger than the stellar continuum (FUV, NUV, and optical), with $r_{\rm e, \mathrm{H}\alpha } = 1.17 \pm 0.05$ kpc and $r_{\rm e,cont} \approx 0.9$ kpc for galaxies with $\log (M_{\star } \rm [{\rm M}_{\odot } ]) = 9.5$. However, we find no significant differences between the stellar continuum sizes at different wavelengths, suggesting that galaxies are not yet steadily growing inside–out at these epochs. Instead, we find that the ratio $r_{\rm e, \mathrm{H}\alpha }/r_{\rm e, NUV}$ increases with the distance above the star-forming main sequence ($\Delta \rm MS$), consistent with an expansion of H $\alpha$ sizes during episodes of enhanced star formation caused by an increase in ionizing photons. As galaxies move above the star-forming main sequence, we find an increase of their rotational support $\text{v}/\sigma _0$, which could be tracing accreting gas illuminated by the $\mathrm{H}\,\alpha$ emission. Finally, we find that about half of the elongated systems ($b/a\lt 0.5$) are not rotationally supported, indicating a potential flattened/prolate galaxy population at high redshift.

James Webb Space Telescope (JWST)/NIRCam slitless spectroscopy enables dynamical mass measurementsfor typical starforming galaxies only a billion years after the big bang. We model the H alpha morpho-kinematics of 163 galaxies at redshift z approximate to 4-6 from FRESCO and CONGRESS (with JADES imaging), using the geko code, and infer rotational velocities and dispersions within r(e). Our sample spans log M-star approximate to 7-10 and log M-dyn approximate to 9-11. Gas masses are inferred from empirical scaling relations and combined with stellar massesto yield baryonic masses. The resulting median inferred gas-to-baryonic mass fraction is < f(gas)> = 0.77. Using these baryonic masses together with the dynamical masses, we derive dark-matter fractions f(DM)(r < r(e) ) within the H alpha half-light radius, and find a high median value of < f(DM)> = 0.73, where f(DM) is defined relative to the total (DM + baryonic) mass. About two-thirds of systems are DM-dominated within r(e) similar to 0.5-1 kpc. We find that f(DM) decreases with stellar mass, consistent with predictionsfrom simulations. The stellar Tully-Fisher relation shows a tentative offset to higher v(circ) at fixed M-star and substantial intrinsic scatter, suggesting that the relation is only beginning to emerge at z similar to 5. We measure a negative correlation between f(DM) and baryonic surface density Sigma(bar), weaker but broadly consistent with trends at cosmic noon and at z similar to 0. Qualitatively comparing with modified NFW profiles coupled to an empirical stellar-to-halo mass relation suggests that the lowest f(DM) (less than or similar to 0.4) require cored inner DM profiles, while the highest fractions favour cuspier profiles, potentially reflecting adiabatic contraction. Overall, the elevated f(gas) and f(DM) at z greater than or similar to 4 are compatible with progenitors of baryon-dominated systems at z similar to 2 and naturally anticipate overmassive black holes at fixed M-star.

We report the discovery of a galaxy proto-cluster candidate (dubbed MACS0416-OD-z8p5) at a spectroscopic redshift of z∼8.47, dating back to ∼550Myr after the Big Bang. The observations are part of the JWST Cycle-3 treasury program, Slitless Areal Pure-Parallel HIgh-Redshift Emission Survey (SAPPHIRES) with NIRCam-grism. Using wide field slitless spectroscopy (WFSS) obtained in the MACS0416 parallel field, we robustly confirm nine galaxies at z_ spec∼8.47 via emission line detections of [OIII]5008A (with >5 σ) and tentatively confirm one additional galaxy (at ∼3 σ). This discovery represents the highest-redshift, spectroscopically confirmed galaxy over-density known to date, which is ∼6–8 times more dense than the average volume density of galaxies at the same redshift. Furthermore, a galaxy hosting a low-mass active galactic nucleus (“Little-Red-Dot”) is found as a member, suggesting an early emergence of active, massive black holes and feedback between these black holes and their surrounding environments. We also discuss the spatial structures connecting the galaxy over-density to nearby massive star-forming galaxies (separated by ∼ 5pMpc, including MACS0416-Y1 and MACS0416-JD. This finding of a massive dark matter halo hosting a galaxy over-density at z∼8.5 is surprising given that our survey covered only a small, random field (16.5 arcmin^2) as part of a pure parallel observation. The comparison with cosmological simulations shows that the likelihood of finding such a large-scale structure is <5 % under the current galaxy formation scenario and the observed survey volume. Our results demonstrate the power of WFSS observations to build a complete line-emitter sample and suggest an important role for over-densities in enhancing galaxy formation by funneling large-scale gas supplies into small cosmological volumes.

Little Red Dots (LRDs) have emerged as a key population linked to early black hole growth, yet photometric selections have predominantly targeted only the most extreme red systems, thereby shaping our current understanding of this new population of objects. In this work, we deliberately explore a broad range of optical redness while enforcing stringent compactness and visual inspection to ensure robustness and minimize contamination. Leveraging the depth and multiwavelength coverage of the JWST Advanced Deep Extragalactic Survey (JADES) data in the GOODS-North and GOODS-South fields, we construct the largest photometric census of LRDs to date in these fields, comprising 412 sources over z≈2–11 across ≈349.6 arcmin^2. We show that classic extreme color cuts isolate only a minor fraction of this population (≲25%), while the majority of LRDs span a broader, largely unexplored parameter space. We quantify how selection strategies impact UV and optical luminosity functions and number density evolution, finding that current demographic trends of LRDs are strongly driven by selection biases and further limited by incomplete identification at both high and low redshift. Spectroscopically confirmed LRDs reveal a continuous range of spectral shapes, consistent with varying Active Galactic Nucleus (AGN) and host contributions in agreement with recent findings. Our results demonstrate that commonly adopted, purity-driven selections bias current demographic constraints toward the most extreme systems, potentially misrepresenting the diversity and evolution of the LRD population. Accounting for these selection effects is essential for interpreting LRDs and their role in early black hole growth.

Transient astronomy of the early Universe (z greater than or similar to 2) remains largely unexplored, lying beyond the rest-frame optical spectroscopic reach of most current observatories. Yet this regime promises transformative insights, with high-redshift transients providing direct access to the early Universe and enabling studies of how stellar populations and cosmology evolve over cosmic time. JWST is uniquely equipped to probe these redshifts efficiently in the rest-frame optical and near-IR. We present results from an initial pathfinder search, covering an area of similar to 133 arcmin(2) (similar to 0.037 deg(2)) independently imaged by the PRIMER and COSMOS-Web extragalactic surveys. Although neither program was designed for time-domain astronomy, combining their data results in difference images separated by roughly 1 yr, leading to the discovery of 68 supernovae (SNe) with host photometric redshifts reaching z less than or similar to 5. For most SNe, only a single epoch is available, but the combination of host redshift, classification, color, and magnitude enables us to prioritize candidates for detailed photometric and spectroscopic follow-up. Among the most notable sources are a relatively bright, blue core-collapse SN at z > 3 (SN 2023aeab) and a young, normal Type Ia SN at z > 2 (SN 2023aeax). The sample distribution highlights the increasing likelihood that a wide-area JWST program can uncover younger, bluer, and potentially more extreme explosions. While this pathfinder effort is limited in cadence and number of filters, it demonstrates the strong potential of a dedicated, well-planned, time-domain survey with JWST to obtain the sample sizes and rate measurements needed to chart SN populations deep into the early Universe.

Understanding how galaxies ignite and extinguish their star formation remains a cornerstone question in modern astrophysics. Recent JWST surveys have revealed an overabundance of massive quiescent galaxies in the first billion years of the Universe, challenging current models of galaxy evolution. In the nearby Universe, ram pressure stripping (RPS) is a major environmental mechanism capable of rapidly shutting down star formation, yet direct observation remains scarce at redshift z≳1, and its role at z>2 is even poorly constrained by simulations. Here, we utilize JWST and ALMA observations to present direct evidence of RPS in the post-starburst galaxy A2744-JF-z3, residing in a galaxy group at redshift 3.06, the earliest such detection to date. Spectroscopic diagnostics and spectral energy distribution modeling reveal the ongoing removal of cold gas and dust, coincident with the abrupt cessation of star formation. Contrary to hydrodynamical simulations that predict a reduced incidence of RPS at high redshift, our results instead imply that RPS can operate at z>3, suggesting a highly stochastic and impulsive stripping within a clumpy, filamentary intra-group and circumgalactic medium. These observations extend environmental quenching well into the epoch of galaxy assembly, highlighting RPS as a previously overlooked decisive pathway to rapid quenching in nascent groups and protoclusters in the early Universe.

Ly-alpha emission is widely used to trace cosmic reionization, but its interpretation depends on how Ly-alpha visibility varies with galaxy environment. We use deep JWST/NIRSpec observations from Deep Insights into UV Spectroscopy at the Epoch of Reionization (DIVER) in GOODS-N to measure Ly-alpha visibility for 250 galaxies at 4.825 A. We combine these measurements with H-alpha and [O III] emitters from JWST/NIRCam wide-field slitless spectroscopy to map the density field around each DIVER galaxy. Galaxies with high Ly-alpha equivalent widths (W_Lyalpha>25 A) or high effective Ly-alpha escape fractions (f_esc,Lyalpha^eff>0.05) tend to lie farther from nearby H-alpha and [O III] emitters than galaxies with lower Ly-alpha visibility. The clearest signal occurs near the prominent GOODS-N overdensity at z 5.2, where fewer than 15

We present an overview of the James Webb Space Telescope (JWST) Advanced Deep Extragalactic Survey (JADES), an ambitious program of infrared imaging and spectroscopy in the GOODS-S and GOODS-N deep fields, designed to study galaxy evolution from high redshift to cosmic noon. JADES uses about 770 hours of Cycle 1 guaranteed time largely from the Near-Infrared Camera (NIRCam) and Near-Infrared Spectrograph (NIRSpec) instrument teams. In GOODS-S, in and around the Hubble Ultra Deep Field and Chandra Deep Field South, JADES produces a deep imaging region of ~45 arcmin$^2$ with an average of 130 hrs of exposure time spread over 9 NIRCam filters. This is extended at medium depth in GOODS-S and GOODS-N with NIRCam imaging of ~175 arcmin$^2$ with an average exposure time of 20 hrs spread over 8-10 filters. In both fields, we conduct extensive NIRSpec multi-object spectroscopy, including 2 deep pointings of 55 hrs exposure time, 14 medium pointings of ~12 hrs, and 15 shallower pointings of ~4 hrs, targeting over 5000 HST and JWST-detected faint sources with 5 low, medium, and high-resolution dispersers covering 0.6-5.3 microns. Finally, JADES extends redward via coordinated parallels with the JWST Mid-Infrared Instrument (MIRI), featuring ~9 arcmin$^2$ with 43 hours of exposure at 7.7 microns and twice that area with 2-6.5 hours of exposure at 12.8 microns For nearly 30 years, the GOODS-S and GOODS-N fields have been developed as the premier deep fields on the sky; JADES is now providing a compelling start on the JWST legacy in these fields.

We present a catalogue of spectroscopically selected [O III ]+H β emitters at 6.75 < z < 9.05 and the resulting [O III ] 5008 Å luminosity function (LF) in the COSMOS field. We leveraged the 0.33 deg 2 covered by COSMOS-3D using NIRCam/WFSS F444W to perform the largest spectroscopic search for [O III ] emitters at 6.75 < z < 9.05. We present our catalogue of 249 [O III ] emitters and their associated completeness function. The inferred constraints on the [O III ] LF enabled us to characterise the knee of the [O III ] 5008 Å LF, resulting in improved [O III ] 5008 Å LF constraints at z ∼ 7, 8. Notably, we find evidence for a decline of the [O III ] luminosity density between z ∼ 6 − 8, which could be expected if the metallicity of [O III ] emitters, as well as the cosmic star-formation rate density, is declining at these redshifts. We find that theoretical models that reproduce the z ∼ 7, 8 [O III ] 5008 Å LF do not reproduce well the [O III ] equivalent width distribution, pointing to potential challenges in the modelling of [O III ] and other nebular lines in the early Universe. Finally, we provide the first constraints on the cosmic variance of [O III ] emitters, estimating at 15% the fractional uncertainty for the z ∼ 7, 8 [O III ] 5008 Å LF in the 0.33 deg 2 field. This estimate is in good agreement with that inferred from clustering, and it shows that the [O III ] 5008 Å LF derived from smaller extragalactic legacy fields is strongly affected by cosmic variance. Our results highlight the fundamental role that wide-area JWST slitless surveys play to map the galaxy large-scale structure down into the reionisation era, serving as a springboard for a variety of science cases.