Nina Bonaventura

We present the UV-to-near-IR (NIR) size evolution of a sample of 161 quiescent galaxies with M _* > 10 ¹⁰ M _⊙ 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 μ m. On average, we find that quiescent galaxies are 45% (15%) more compact at rest-frame 1 μ m than they are at 0.3 μ m (0.5 μ 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 _⊙ , the evolution follows R _e ∝ (1 + z ) ^−1.1 , whereas it becomes steeper, following R _e ∝ (1 + z ) ^−1.7 , for higher-mass quiescent galaxies with M _* > 10 ^10.6 M _⊙ . 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 ∝ ( 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 Σ _e ≳ 10 ¹⁰ M _⊙ 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 ∼ 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 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 hr 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 ∼42 arcmin ² with over 100 hr of exposure time spread over nine NIRCam filters, including two medium-band filters. This is extended at medium depth in GOODS-S and GOODS-N with NIRCam imaging of ∼167 arcmin ² , averaging 25 hr of exposure over 8–10 filters. In both fields, we conduct extensive NIRSpec multiobject spectroscopy, including two deep pointings of 55 hr exposure time, 14 medium pointings of ∼12 hr, and 15 shallower pointings of ∼4 hr, targeting over 5000 Hubble Space Telescope– and JWST-detected faint sources with five low-, medium-, and high-resolution dispersers covering 0.6–5.3 μ m. Finally, JADES extends redward via coordinated parallels with the JWST Mid-Infrared Instrument, featuring ∼10 arcmin ² with 43 hr of exposure at 7.7 μ m and thrice that area with 1.4–6.8 hr of exposure at 12.8 and 15 μ m. For nearly 30 yr, 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 JWST's legacy in these fields.

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 .

In Paper I, we exploited the unsurpassed resolution and depth of JWST/NIRCam imagery to investigate the relationship between active galactic nuclei (AGN) and host-galaxy properties in the JWST era, finding a correlation between the level of spatial disturbance (as measured by shape asymmetry, A _S ) and obscuration ( N _H ). Here in Paper II, we report an expansion of our X-ray and infrared analysis of Seyfert-luminosity host galaxies with four additional metrics to the single-metric morphology analysis of Paper I, as well as new samples of inactive control galaxies. This expanded study of one of the largest and most complete, multiwavelength samples of AGN detected at 0.6 < z < 3.8 in the GOODS-South and -North fields, confirms that mergers surprisingly play a significant role in obscured, subquasar AGN host galaxies. Additionally, the pattern of morphological disturbances observed amongst the X-ray- and mid-IR-selected AGN suggests that these represent different phases of AGN evolution tied to a major-merger timeline, as opposed to distinct populations of AGN. These results indicate that mergers are important in triggering subquasar AGN at these redshifts.

We summarize the properties and initial data release of the JADES Origins Field (JOF), the longest single pointing yet imaged with the James Webb Space Telescope (JWST). This field falls within the GOODS-S region about 8′ southwest of the Hubble Ultra Deep Field (HUDF), where it was formed initially in Cycle 1 as a parallel field of HUDF spectroscopic observations within the JWST Advanced Deep Extragalactic Survey (JADES). This imaging was greatly extended in Cycle 2 program 3215, which observed the JOF for 5 days in six medium-band filters, seeking robust candidates for z > 15 galaxies. This program also includes ultradeep parallel NIRSpec spectroscopy (up to 91 hr on source, summing over the dispersion modes) on the HUDF. Cycle 3 observations from program 4540 added 20 hr of NIRCam slitless spectroscopy and F070W imaging to the JOF. With these three campaigns, the JOF was observed for 380 open-shutter hours with NIRCam using 15 imaging filters and two grism bandpasses. Further, parts of the JOF have deep 43 hr MIRI observations in F770W. Taken together, the JOF is one of the most compelling deep fields available with JWST and a powerful window into the early Universe. This paper presents the second data release from JADES, featuring the imaging and catalogs from the year 1 JOF observations.

We analyze 99 photometrically selected Little Red Dots (LRDs) at z ≈ 4–8 in the GOODS fields, leveraging ultradeep JADES NIRCam short-wavelength (SW) data. Among the 99 selected LRDs, we examine the morphology of 30. The remaining 69 appear predominantly compact, with sizes ≲400 pc and no extended components even in stacked SW images. However, their unresolved nature may partly reflect current depth limitations, which could prevent the detection of faint diffuse components. Among the 30 morphologically analyzed LRDs, 50% show multiple associated components, while the rest exhibit highly asymmetric structures, despite appearing as single sources. This diversity in rest-frame UV morphologies may point to interactions or strong internal feedback. We find median stellar masses of log 10 ( M ⋆ / M ⊙ ) = 9.0 7 − 0.08 + 0.11 for pure stellar models with A V ≈ 1.1 6 − 0.21 + 0.11 mag, and log 10 ( M ⋆ / M ⊙ ) = 9.6 7 − 0.27 + 0.17 for models including active galactic nuclei (AGNs) with A V ≈ 2.7 4 − 0.71 + 0.55 mag, in line with recent studies suggesting higher masses and dust content for AGN-fitted LRDs. NIRSpec spectra are available for 15 sources, six of which are also in the morphological sample. Broad Hα is detected in 40% (FWHM = 1200–2900 km s⁻¹), and one source shows broad Hβ emission. Emission line ratios indicate a composite nature, consistent with both AGN and stellar processes. Altogether, these results suggest that LRDs are a mixed population, and their rest-frame UV morphology reflects this complexity. Morphological studies of larger samples could provide a new way to understand what drives their properties and evolution.

We observed the gravitationally lensed (μ = 9.6 ± 0.19) galaxy A1689-zD1 at z = 7.1 in bands 3, 6, and 8 of the Atacama Large Millimeter/submillimeter Array. These high-resolution observations (≈200 pc) enabled us to separate the source into five components in the [C II] 158 μm and [O III] 88 μm emission lines within a projected distance of 2 kpc. Even though these components appear to vary strongly from one another in both their line, continuum, and optical characteristics, the assembly of components do not show ordered rotation and appear consistent with simulations of a galaxy system undergoing the process of assembly. The total dynamical mass of the galaxy (2 × 10¹⁰ M_⊙) is an order of magnitude larger than the spectrally estimated stellar mass, suggesting a near-complete optical obscuration of the bulk of the stellar component. Comparing the line ratios as well as the line properties to other properties such as the star formation rate, we find that A1689-zD1 is consistent with the relations derived from local star-forming galaxies. Even though A1689-zD1 lies on local star formation scaling relations and has a high dust and stellar mass estimate, the kinematics suggest it is in an early assembly stage, which could lead to it becoming a disk galaxy at a later stage.

We explore the accretion rates of supermassive black holes (SMBHs) in late-stage galaxy mergers by observing three ultraluminous infrared galaxies (ULIRGs), IRAS 14378-3651, IRAS 17208-0014 and IRAS 23365+3604, using the JWST/MIRI Medium Resolution Spectrometer and JWST/NIRSpec integral field unit. In all three cases, we fail to detect [Ne vi] λ7.65 μm, a robust active galactic nuclei (AGN) tracer lying in a low-opacity interstellar window, nor do we detect any other lines that might indicate AGNs. The only detected high-excitation emission line, [Mg iv] (λ4.488 μm), arises from shocks associated with supernovae. Our new, deep flux limits on AGN tracers in the near- and mid-infrared indicate that the nuclear obscuration of any purported AGNs in our sample is isotropic, i.e., the far-infrared luminosities of these galaxies are unlikely to be driven by escaping AGN power. This allows us to show that the Eddington ratios of their SMBHs are low. We then assemble an unbiased sample of 19 ULIRGs (from the IRAS Bright Galaxy Sample with L(TIR) ≥ 10¹² L _⊙) in late-stage mergers and show that their dynamically measured black hole masses are consistent with the values from scaling from their stellar masses. On this basis, we show that the Eddington ratios of any AGNs in 15 of these galaxies are also very low, ≲10%. This indicates that any black holes are in a relatively quiescent state. That is, high levels of accretion are found in only a minority of late-merger-phase ULIRGs.

The topology of reionization and the environments where galaxies efficiently produce ionizing photons are key open questions. For the first time, we investigate the trend between ionizing photon production efficiency, ξ _ion, and galaxy overdensity, log ( 1 + δ ) . We analyze the ionizing properties of 79 galaxies between 1.0 < z < 5.2 using JWST NIRSpec medium-resolution spectra from the Systematic Mid-infrared Instrument Legacy Extragalactic Survey (SMILES) program. Among these, 67 galaxies have Hα coverage, spanning 1.0 < z < 3.1. The galaxy overdensity, log ( 1 + δ ) , is measured using the JADES photometric catalog, which covers the SMILES footprint. For the subset with Hα coverage, we find that log ξ ion is positively correlated with log ( 1 + δ ) , with a slope of 0.9 4 − 0.46 + 0.46 . Additionally, the mean ξ _ion for galaxies in overdense regions ( log ( 1 + δ ) > 0.1 ) is 2.43 times that of galaxies in lower density regions ( log ( 1 + δ ) < 0.1 ). This strong trend is found to be independent of redshift evolution. Furthermore, our results confirm the robust correlations between ξ _ion and the rest-frame equivalent widths of the [O iii] or Hα emission lines. Our results suggest that galaxies in high-density regions are efficient producers of ionizing photons.