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Stefano Carniani

Publications and source records attributed to Stefano Carniani.

At least 163 records · Page 9Linked to original sources
arXiv2024

Building the First Galaxies -- Chapter 2. Starbursts Dominate The Star Formation Histories of 6 < z <12 Galaxies

We use SEDz* -- a code designed to chart star formation histories (SFHs) of 6<z<12 galaxies -- to analyze the SEDs of 894 galaxies with deep JWST/NIRCam imaging by JADES in the GOODS-S field. We show how SEDz* matches observed SEDs using stellar-population templates, graphing the contribution of each epoch-by-epoch to confirm the robustness of the technique. Very good SED fits for most SFHs demonstrates the compatibility of the templates with stars in the first galaxies -- as expected, because their light is primarily from main-sequence A-stars, free of post-main-sequence complexity and insensitive to heavy-element compositions. We confirm earlier results from Dressler(2023): (1) Four types of star formation histories: SFH1 -- burst; SFH2 -- stochastic; SFH3 -- `contiguous' (3-epochs); and SFH4 -- `continuous' (4-6 epochs); (2) Starbursts -- both single and multiple -- are predominate (~70%) in this critical period of cosmic history, although longer SFHs (0.5-1.0 Gyr) contribute one-third of the accumulated stellar mass. These 894 SFHs contribute log M/Msun = 11.14, 11.09, 11.00, and 10.60 for SFH1-4, respectively, adding up to 4x10^11 Msun by z=6 for this field. We suggest that the absence of rising SFHs could be explained as an intense dust-enshrouded phase of star formation lasting tens of Myr that preceded each of the SFHs we measure. We find no strong dependencies of SFH type with the large-scale environment, however, the discovery of a compact group of 30 galaxies, 11 of which had first star formation at z=11-12, suggests that long SFHs could dominate in rare, dense environments.

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arXiv2024

The ALPINE-ALMA [C II] survey: Characterisation of Spatial Offsets in Main-Sequence Galaxies at $z \sim$ 4-6

Galaxy morphology is shaped by stellar activity, feedback, gas and dust properties, and interactions with surroundings, and can therefore provide insight into these processes. In this paper, we study the spatial offsets between stellar and interstellar medium emission in a sample of 54 main-sequence star-forming galaxies at $z\sim4-6$ observed with the Atacama Large Millimeter/submillimeter Array (ALMA) and drawn from the ALMA Large Program to INvestigate C$^+$ at Early times (ALPINE). We find no significant spatial offset for the majority ($\sim$ 70 percent) of galaxies in the sample among any combination of [C II], far-infrared continuum, optical, and ultraviolet emission. However, a fraction of the sample ($\sim$ 30 percent) shows offsets larger than the median by more than 3$σ$ significance (compared to the uncertainty on the offsets), especially between [C II] and ultraviolet emission. We find that these significant offsets are of the order of $\sim$0.5-0.7 arcsec, corresponding to $\sim$3.5-4.5 kiloparsecs. The offsets could be caused by a complex dust geometry, strong feedback from stars and active galactic nuclei, large-scale gas inflow and outflow, or a combination of these phenomena. However, our current analysis does not definitively constrain the origin. Future, higher resolution ALMA and JWST observations may help resolve the ambiguity. Regardless, since there exist at least some galaxies that display such large offsets, galaxy models and spectral energy distribution fitting codes cannot assume co-spatial emission in all main-sequence galaxies, and must take into account that the observed emission across wavelengths may be spatially segregated.

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arXiv2024

A small and vigorous black hole in the early Universe

Multiple theories have been proposed to describe the formation of black hole seeds in the early Universe and to explain the emergence of very massive black holes observed in the first billion years after Big Bang. Models consider different seeding and accretion scenarios, which require the detection and characterisation of black holes in the first few hundred million years after Big Bang to be validated. Here we present an extensive analysis of the JWST-NIRSpec spectrum of GN-z11, an exceptionally luminous galaxy at z=10.6, revealing the detection of the [NeIV]2423 and CII*1335 transitions (typical of Active Galactic Nuclei, AGN), as well as semi-forbidden nebular lines tracing gas densities higher than 10^9 cm-3, typical of the Broad Line Region of AGN. These spectral features indicate that GN-z11 hosts an accreting black hole. The spectrum also reveals a deep and blueshifted CIV1549 absorption trough, tracing an outflow with velocity 800-1000 km/s, likely driven by the AGN. Assuming local virial relations, we derive a black hole mass of log(M_BH/Msun) = 6.2 +- 0.3, accreting at about 5 times the Eddington rate. These properties are consistent with both heavy seeds scenarios, or scenarios envisaging intermediate/light seeds experiencing episodic super-Eddington phases. Our finding naturally explains the high luminosity of GN-z11 and can also provide an explanation for its exceptionally high nitrogen abundance.

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arXiv2024

JADES: The emergence and evolution of Ly$α$ emission and constraints on the IGM neutral fraction

The rest-frame UV recombination emission line Ly$α$ can be powered by ionising photons from young massive stars in star forming galaxies, but its ability to be resonantly scattered by neutral gas complicates its interpretation. For reionization era galaxies, a neutral intergalactic medium (IGM) will scatter Ly$α$ from the line of sight, making Ly$α$ a useful probe of the neutral fraction evolution. Here, we explore Ly$α$ in JWST/NIRSpec spectra from the ongoing JADES programme, which targets hundreds of galaxies in the well-studied GOODS-S and GOODS-N fields. These sources are UV-faint ($-20.4<\rm M_{\rm UV}<-16.4$), and thus represent a poorly-explored class of galaxies. The low spectral resolution ($R\sim100$) spectra of a subset of 84 galaxies in GOODS-S with $z_{spec}>5.6$ (as derived with optical lines) are fit with line and continuum models, in order to search for significant line emission. Through exploration of the R100 data, we find evidence for Ly$α$ in 17 sources. This sample allows us to place observational constraints on the fraction of galaxies with Ly$α$ emission in the redshift range $5.6<z<7.5$, with a decrease from $z=6$ to $z=7$. We also find a positive correlation between Ly$α$ equivalent width and M$_{UV}$, as seen in other samples. These results are used to estimate the neutral gas fraction at $z\sim7$, agreeing with previous results ($X_{HI}\sim0.5-0.9$).

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arXiv2024

The Cosmos in its Infancy: JADES Galaxy Candidates at z > 8 in GOODS-S and GOODS-N

We present a catalog of 717 candidate galaxies at $z > 8$ selected from 125 square arcminutes of NIRCam imaging as part of the JWST Advanced Deep Extragalactic Survey (JADES). We combine the full JADES imaging dataset with data from the JEMS and FRESCO JWST surveys along with extremely deep existing observations from HST/ACS for a final filter set that includes fifteen JWST/NIRCam filters and five HST/ACS filters. The high-redshift galaxy candidates were selected from their estimated photometric redshifts calculated using a template fitting approach, followed by visual inspection from seven independent reviewers. We explore these candidates in detail, highlighting interesting resolved or extended sources, sources with very red long-wavelength slopes, and our highest redshift candidates, which extend to $z_{phot} = 18$. We also investigate potential contamination by stellar objects, and do not find strong evidence from SED fitting that these faint high-redshift galaxy candidates are low-mass stars. Over 93\% of the sources are newly identified from our deep JADES imaging, including 31 new galaxy candidates at $z_{phot} > 12$. Using 42 sources in our sample with measured spectroscopic redshifts from NIRSpec and FRESCO, we find excellent agreement to our photometric redshift estimates, with no catastrophic outliers and an average difference of $\langle Δz = z_{phot}- z_{spec} \rangle= 0.26$. These sources comprise one of the most robust samples for probing the early buildup of galaxies within the first few hundred million years of the Universe's history.

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arXiv2024

Inside the bubble: exploring the environments of reionisation-era Lyman-$α$ emitting galaxies with JADES and FRESCO

We present a study of the environments of 17 Lyman-$α$ (Ly$α$) emitting galaxies (LAEs) in the reionisation era ($5.8 < z < 8$) identified by JWST/NIRSpec as part of the JWST Advanced Deep Extragalactic Survey (JADES). Unless situated in sufficiently (re)ionised regions, Ly$α$ emission from these galaxies would be strongly absorbed by neutral gas in the intergalactic medium (IGM). We conservatively estimate sizes of the ionised regions required to reconcile the relatively low Ly$α$ velocity offsets ($Δv_\text{Ly$α$}<300\,\mathrm{km\,s^{-1}}$) with moderately high Ly$α$ escape fractions ($f_\mathrm{esc,\,Lyα}>5\%$) observed in our sample of LAEs, suggesting the presence of ionised hydrogen along the line of sight towards at least eight out of 17 LAEs. We find minimum physical `bubble' sizes of the order of $R_\text{ion}\sim0.1$-$1\,\mathrm{pMpc}$ are required in a patchy reionisation scenario where ionised bubbles containing the LAEs are embedded in a fully neutral IGM. Around half of the LAEs in our sample are found to coincide with large-scale galaxy overdensities seen in FRESCO at $z \sim 5.8$-$5.9$ and $z\sim7.3$, suggesting Ly$α$ transmission is strongly enhanced in such overdense regions, and underlining the importance of LAEs as tracers of the first large-scale ionised bubbles. Considering only spectroscopically confirmed galaxies, we find our sample of UV-faint LAEs ($M_\text{UV}\gtrsim-20\,\mathrm{mag}$) and their direct neighbours are generally not able to produce the required ionised regions based on the Ly$α$ transmission properties, suggesting lower-luminosity sources likely play an important role in carving out these bubbles. These observations demonstrate the combined power of JWST multi-object and slitless spectroscopy in acquiring a unique view of the early Universe during cosmic reionisation via the most distant LAEs.

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arXiv2023

Ionised gas kinematics and dynamical masses of $z\gtrsim6$ galaxies from JADES/NIRSpec high-resolution spectroscopy

We explore the kinematic gas properties of six $5.5 1$ thus far. The cold gas masses implied by the observed star formation rates are $\sim 10\times$ larger than the stellar masses. We find that their ionised gas is spatially resolved by JWST, with evidence for broadened lines and spatial velocity gradients. Using a simple thin-disc model, we fit these data with a novel forward modelling software that accounts for the complex geometry, point spread function, and pixellation of the NIRSpec instrument. We find the sample to include both rotation- and dispersion-dominated structures, as we detect velocity gradients of $v(r_{\rm e})\approx100-150\,{\rm km\,s^{-1}}$, and find velocity dispersions of $σ_0\approx 30-70\,{\rm km\,s^{-1}}$ that are comparable to those at cosmic noon. The dynamical masses implied by these models ($M_{\rm dyn}\sim10^{9-10}\,{\rm M_\odot}$) are larger than the stellar masses by up to a factor 40, and larger than the total baryonic mass (gas + stars) by a factor of $\sim 3$. Qualitatively, this result is robust even if the observed velocity gradients reflect ongoing mergers rather than rotating discs. Unless the observed emission line kinematics is dominated by outflows, this implies that the centres of these galaxies are dark-matter dominated or that star formation is $3\times$ less efficient, leading to higher inferred gas masses.

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arXiv2023

JADES: Carbon enrichment 350 Myr after the Big Bang in a gas-rich galaxy

Finding the emergence of the first generation of metals in the early Universe, and identifying their origin, are some of the most important goals of modern astrophysics. We present deep JWST/NIRSpec spectroscopy of GS-z12, a galaxy at z=12.5, in which we report the detection of C III]$λλ$1907,1909 nebular emission. This is the most distant detection of a metal transition and the most distant redshift determination via emission lines. In addition, we report tentative detections of [O II]$λλ$3726,3729 and [Ne III]$λ$3869, and possibly O III]$λλ$1661,1666. By using the accurate redshift from C III], we can model the Ly$α$ drop to reliably measure an absorbing column density of hydrogen of $N_{HI} \approx 10^{22}$ cm$^{-2}$ - too high for an IGM origin and implying abundant ISM in GS-z12 or CGM around it. We infer a lower limit for the neutral gas mass of about $10^7$ MSun which, compared with a stellar mass of $\approx4 \times 10^7$ MSun inferred from the continuum fitting, implies a gas fraction higher than about 0.1-0.5. We derive a solar or even super-solar carbon-to-oxygen ratio, tentatively [C/O]>0.15. This is higher than the C/O measured in galaxies discovered by JWST at z=6-9, and higher than the C/O arising from Type-II supernovae enrichment, while AGB stars cannot contribute to carbon enrichment at these early epochs and low metallicities. Such a high C/O in a galaxy observed 350 Myr after the Big Bang may be explained by the yields of extremely metal poor stars, and may even be the heritage of the first generation of supernovae from Population III progenitors.

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arXiv2023

The galaxies missed by Hubble and ALMA: the contribution of extremely red galaxies to the cosmic census at 3<z<8

Using deep JWST imaging from JADES, JEMS and SMILES, we characterize optically-faint and extremely red galaxies at $z>3$ that were previously missing from galaxy census estimates. The data indicate the existence of abundant, dusty and post-starburst-like galaxies down to $10^8$M$_\odot$, below the sensitivity limit of Spitzer and ALMA. Modeling the NIRCam and HST photometry of these red sources can result in extreme, high values for both stellar mass and star formation rate (SFR); however, including 7 MIRI filters out to 21$μ$m results in decreased mass (median 0.6 dex for log$_{10}$M$^*$/M$_{\odot}>$10), and SFR (median 10$\times$ for SFR$>$100 M$_{\odot}$/yr). At $z>6$, our sample includes a high fraction of little red dots (LRDs; NIRCam-selected dust-reddened AGN candidates). We significantly measure older stellar populations in the LRDs out to rest-frame 3$μ$m (the stellar bump) and rule out a dominant contribution from hot dust emission, a signature of AGN contamination to stellar population measurements. This allows us to measure their contribution to the cosmic census at $z>3$, below the typical detection limits of ALMA ($L_{\rm IR}<10^{12}L_\odot$). We find that these sources, which are overwhelmingly missed by HST and ALMA, could effectively double the obscured fraction of the star formation rate density at $4<z<6$ compared to some estimates, showing that prior to JWST, the obscured contribution from fainter sources could be underestimated. Finally, we identify five sources with evidence for Balmer breaks and high stellar masses at $5.5<z<7.7$. While spectroscopy is required to determine their nature, we discuss possible measurement systematics to explore with future data.

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arXiv2023

Dynamically cold disks in the early Universe: myth or reality?

Theoretical models struggle to reproduce dynamically cold disks with significant rotation-to-dispersion support($V_{\rm{rot}}/σ$) observed in star-forming galaxies in the early Universe, at redshift $z>4$. We aim to explore the possible emergence of dynamically cold disks in cosmological simulations and to understand if different kinematic tracers can help reconcile the tension between theory and observations. We use 3218 galaxies from the SERRA suite of zoom-in simulations, with $8<\log(M_*/M_{\odot})<10.3$ and SFR$<128\,M_{\odot}{yr}^{-1}$, within $4 10^9\,M_{\odot}$ galaxies, for which $σ_{Hα}>2σ_{CII}$ for a significant fraction of the sample. Regardless of the tracer, our predictions suggest the existence of massive ($M_*>10^{10}M_{\odot}$) galaxies with $V_{rot}/σ>10$ at $z>4$, maintaining cold disks for >10 orbital periods (200Myr). Furthermore, we do not find any significant redshift dependence for $V_{rot}/σ$ ratio in our sample. Our simulations predict the existence of dynamically cold disks in the early Universe. However, different tracers are sensitive to different kinematic properties. While [CII] effectively traces the thin, gaseous disk of galaxies, H$α$ includes the contribution from ionized gas beyond the disk, characterized by prevalent vertical or radial motions that may be associated with outflows. The presence of H$α$ halos could be a signature of such galactic outflows. This emphasizes the importance of combining ALMA and JWST/NIRspec studies of high-z galaxies.

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arXiv2023

JWST CEERS & JADES Active Galaxies at z = 4-7 Violate the Local $M_\bullet-M_\star$ Relation at $>3σ$: Implications for Low-Mass Black Holes and Seeding Models

JWST is revolutionizing our understanding of the high-$z$ Universe by expanding the black hole horizon, looking farther and to smaller masses, and revealing the stellar light of their hosts. By examining JWST galaxies at $z=4-7$ that host H$α$-detected black holes, we investigate (i) the high-$z$ $M_\bullet-M_\star$ relation and (ii) the black hole mass distribution, especially in its low-mass range ($M_\bullet \lesssim 10^{6.5} M_\odot$). With a detailed statistical analysis, our findings conclusively reveal a high-$z$ $M_\bullet-M_\star$ relation that deviates at $>3σ$ confidence level from the local relation. The high-$z$ relation is: $\log(M_\bullet/M_\odot) = -2.43^{+0.83}_{-0.83} + 1.06^{+0.09}_{-0.09} \log(M_\star/M_\odot)$. Black holes are overmassive by $\sim 10-100\times$ compared to their low-$z$ counterparts in galactic hosts of the same stellar mass. This fact is not due to a selection effect in surveys. Moreover, our analysis predicts the possibility of detecting in high-$z$ JWST surveys $5-15\times$ more black holes with $M_\bullet \lesssim 10^{6.5} M_\odot$, and $10-30\times$ more with $M_\bullet \lesssim 10^{8.5} M_\odot$, compared to local relation's predictions. The lighter black holes preferentially occupy galaxies with a stellar mass of $\sim 10^{7.5}-10^8 M_\odot$. We have yet to detect these sources because (i) they may be inactive (duty cycles $1\%-10\%$), (ii) the host overshines the AGN, or (iii) the AGN is obscured and not immediately recognizable by line diagnostics. A search of low-mass black holes in existing JWST surveys will further test the $M_\bullet-M_\star$ relation. Current JWST fields represent a treasure trove of black hole systems at $z = 4-7$; their detection will provide crucial insights into their early evolution and co-evolution with their galactic hosts.

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arXiv2023

Spatially resolved Kennicutt-Schmidt relation at z~7 and its connection with the interstellar medium properties

We exploit moderately resolved [OIII], [CII] and dust continuum ALMA observations to derive the gas density ($n$), the gas-phase metallicity ($Z$) and the deviation from the Kennicutt-Schmidt (KS) relation ($κ_s$) on ~sub-kpc scales in the interstellar medium (ISM) of five bright Lyman Break Galaxies at the Epoch of Reionization ($z\approx 7$). To do so, we use GLAM, a state-of-art, physically motivated Bayesian model that links the [CII] and [OIII] surface brightness ($Σ_{\rm [CII]}$, $Σ_{\rm [OIII]}$) and the SFR surface density ($Σ_{\rm SFR}$) to $n$, $κ_s$, and $Z$. All five sources are characterized by a central starbursting region, where the $Σ_{\rm gas}$ vs $Σ_{\rm SFR}$ align ~10x above the KS relation ($κ_s\approx10$). This translates into gas depletion times in the range $t_{\rm dep}\approx 80-250$ Myr. The inner starbursting centers are characterized by higher gas density ($\log (n/{\rm cm^{-3}}) \approx 2.5-3.0$) and higher metallicity ($\log (Z/Z_{\odot}) \approx -0.5$) than the galaxy outskirts. We derive marginally negative radial metallicity gradients ($\nabla \log Z \approx -0.03 \pm 0.07$dex/kpc), and a dust temperature ($T_d\approx$32-38 K) that anticorrelates with the gas depletion time.

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arXiv2023

JADES: Discovery of extremely high equivalent width Lyman-alpha emission from a faint galaxy within an ionized bubble at z=7.3

We report the discovery of a remarkable Ly$α$ emitting galaxy at z = 7.2782, JADES-GS-z7-LA, with EW$_0$(Ly$α$) $= 388.0 \pm 88.8$Åand UV magnitude -17.0. The spectroscopic redshift is confirmed via rest-frame optical lines [O II], H$β$ and [O III] in its JWST/NIRSpec Micro-Shutter Assembly (MSA) spectrum. The Ly$α$ line is detected in both lower resolution PRISM as well as medium resolution G140M grating spectra. The LSF-deconvolved Ly$α$ FWHM in the grating is $383.9 \pm 56.2$ km/s and the Ly$α$ velocity offset compared to the systemic redshift is $113.3 \pm 80.0$ km/s, indicative of very little neutral gas or dust within the galaxy. We estimate the Ly$α$ escape fraction to be >70%. JADES-GS-z7-LA has a O32 ratio of $11.1 \pm 2.2$ and a R23 ratio of $11.2 \pm 2.6$, consistent with low metallicity and high ionization parameters. Deep NIRCam imaging also revealed a close companion source (separated by 0.23"), which exhibits similar photometry to that of JADES-GS-z7-LA, with a photometric excess in the F410M NIRCam image consistent with [O III]+H$β$ emission at the same redshift. The spectral energy distribution of JADES-GS-z7-LA indicates a "bursty" star formation history, with a low stellar mass of $\approx 10^7$ $M_\odot$. Assuming that the Ly$α$ transmission through the intergalactic medium is the same as its measured escape fraction, an ionized region of size > 1.5 pMpc is needed to explain the high Ly$α$ EW and low velocity offset compared to systemic seen in JADES-GS-z7-LA. Owing to its UV-faintness, we show that it is incapable of single-handedly ionizing a region large enough to explain its Ly$α$ emission. Therefore, we suggest that JADES-GS-z7-LA (and possibly the companion source) may be a part of a larger overdensity, presenting direct evidence of overlapping ionized bubbles at $z>7$.

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arXiv2023

JADES: Insights on the low-mass end of the mass--metallicity--star-formation rate relation at $3 < z < 10$ from deep JWST/NIRSpec spectroscopy

We analyse the gas-phase metallicity properties of a sample of low stellar mass (log M*/M_sun <= 9) galaxies at 3 < z < 10, observed with JWST/NIRSpec as part of the JADES programme in its deep GOODS-S tier. By combining this sample with more massive galaxies at similar redshifts from other programmes, we study the scaling relations between stellar mass, oxygen abundance (O/H), and star-formation rate (SFR) for 146 galaxies, spanning across three orders of magnitude in stellar mass and out to the epoch of early galaxy assembly. We find evidence for a shallower slope at the low-mass-end of the mass-metallicity relation (MZR), with 12 + log(O/H) = (7.72+-0.02) + (0.17+-0.03) log(M* / 10^8 M_sun), in good agreement with the MZR probed by local analogues of high-redshift systems like 'Green Pea' and 'Blueberry' galaxies. The inferred slope is well matched by models including 'momentum-driven' SNe winds, suggesting that feedback mechanisms in dwarf galaxies (and at high-z) might be different from those in place at higher masses. The evolution in the normalisation is observed to be relatively mild compared to previous determinations of the MZR at z~3 (~ 0.1 - 0.2 dex across the explored mass regime). We observe a deviation from the local fundamental metallicity relation (FMR) for our sample at high redshift, especially at z > 6, with galaxies significantly less enriched (with a median offset in log(O/H) of ~ 0.5 dex, significant at ~ 5 sigma) than predicted given their M* and SFR. These observations are consistent with an enhanced stochasticity in the star-formation history, and/or with an increased efficiency in metal removals by outflows, prompting us to reconsider the nature of the relationship between M*, O/H, and SFR in the early Universe.

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arXiv2023

Are there more galaxies than we see around high-$z$ quasars?

Whether or not $z \gtrsim 6$ quasars lie in the most massive dark-matter halos of the Universe is still a subject of dispute. While most theoretical studies support this scenario, current observations yield discordant results when they probe the halo mass through the detection rate of quasar companion galaxies. Feedback processes from supermassive black holes and dust obscuration have been blamed for this discrepancy, but the impact of these effects is complex and far from being clearly understood. This paper aims to improve the interpretation of current far-infrared observations by taking into account the cosmological volume probed by the Atacama Large Millimeter/submillimeter Array Telescope and to explain the observational discrepancies. We statistically investigate the detection rate of quasar companions in current observations and verify if they match the expected distribution from various theoretical models, once convolved with the ALMA field-of-view, through the use of Monte Carlo simulations. We demonstrate that the telescope geometrical bias is fundamental and can alone explain the scatter in the number of detected satellite galaxies in different observations. We conclude that the resulting companion densities depend on the chosen galaxy distributions. According to our fiducial models, current data favour a density scenario where quasars lie in dark-matter halos of viral mass $M_{\rm vir} \gtrsim 10^{12}~{\rm M_{\odot}}$, in agreement with most theoretical studies. According to our analysis, each quasar has about 2 companion galaxies, with a [CII] luminosity $L_{\rm [CII]} \gtrsim 10^8~{\rm L}_{\odot}$, within a distance of about 1~Mpc from the quasar.

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arXiv2023

JADES Initial Data Release for the Hubble Ultra Deep Field: Revealing the Faint Infrared Sky with Deep JWST NIRCam Imaging

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 9 filters of infrared imaging of $\sim$25 arcmin$^2$ covering the Hubble Ultra Deep Field and portions of Great Observatories Origins Deep Survey (GOODS) 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 9-band mosaics of the JADES bands, as well as matching reductions of 5 additional bands from the JWST Extragalactic Medium-band Survey (JEMS). Combining with existing HST imaging, we provide 23-band space-based photometric catalogs and photometric redshifts for $\approx47,500$ sources. To promote broad engagement with the JADES survey, we have created an interactive {\tt FitsMap} website to provide an interface for professional researchers and the public to experience these JWST datasets. Combined with the first JADES NIRSpec data release, these public JADES imaging and spectroscopic datasets provide a new foundation for discoveries of the infrared universe by the worldwide scientific community.

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arXiv2023

Quiescent low-mass galaxies observed by JWST in the Epoch of Reionization

The surprising JWST discovery of a quiescent, low-mass ($M_\star=10^{8.7} \rm M_\odot$) galaxy at redshift $z=7.3$ (JADES-GS-z7-01-QU) represents a unique opportunity to study the imprint of feedback processes on early galaxy evolution. We build a sample of 130 low-mass ($M_\star\lesssim 10^{9.5} \rm M_\odot$) galaxies from the SERRA cosmological zoom-in simulations, which show a feedback-regulated, bursty star formation history (SFH). The fraction of time spent in an active phase increases with the stellar mass from $f_{duty}\approx 0.6$ at $M_\star\approx 10^{7.5} \rm M_\odot$ to $\approx 0.99$ at $M_\star\geq 10^{9} \rm M_\odot$, and it is in agreement with the value $f_{duty}\approx 0.75$ estimated for JADES-GS-z7-01-QU. On average, 30% of the galaxies are quiescent in the range $6 < z < 8.4$; they become the dominant population at $M_\star\lesssim 10^{8.3} \rm M_\odot$. However, none of these quiescent systems matches the Spectral Energy Distribution of JADES-GS-z7-01-QU, unless their SFH is artificially truncated a few Myr after the main star formation peak. As supernova feedback can only act on a longer timescale ($\gtrsim 30 \rm \, Myr$), this implies that the observed abrupt quenching must be caused by a faster physical mechanism, such as radiation-driven winds.

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