Existing models of galaxy formation have not yet explained striking correlations between structure and star formation activity in galaxies, notably the sloped and moving boundaries that divide ...star-forming from quenched galaxies in key structural diagrams. This paper uses these and other relations to "reverse engineer" the quenching process for central galaxies. The basic idea is that star-forming galaxies with larger radii (at a given stellar mass) have lower black hole (BH) masses due to lower central densities. Galaxies cross into the green valley when the cumulative effective energy radiated by their BH equals ∼4× their halo gas-binding energy. Because larger-radii galaxies have smaller BHs, one finds that they must evolve to higher stellar masses in order to meet this halo energy criterion, which explains the sloping boundaries. A possible cause of radii differences among star-forming galaxies is halo concentration. The evolutionary tracks of star-forming galaxies are nearly parallel to the green-valley boundaries, and it is mainly the sideways motions of these boundaries with cosmic time that cause galaxies to quench. BH scaling laws for star-forming, quenched, and green-valley galaxies are different, and most BH mass growth takes place in the green valley. Implications include the radii of star-forming galaxies are an important second parameter in shaping their BHs; BHs are connected to their halos but in different ways for star-forming, quenched, and green-valley galaxies; and the same BH-halo quenching mechanism has been in place since z ∼ 3. We conclude with a discussion of BH-galaxy coevolution and the origin and interpretation of BH scaling laws.
Currently-proposed galaxy quenching mechanisms predict very different behaviours during major halo mergers, ranging from significant quenching enhancement (e.g. clump-induced gravitational heating ...models) to significant star formation enhancement (e.g. gas starvation models). To test real galaxies’ behaviour, we present an observational galaxy pair method for selecting galaxies whose host haloes are preferentially undergoing major mergers. Applying the method to central L* (1010 M⊙ < M
* < 1010.5 M⊙) galaxies in the Sloan Digital Sky Survey at z < 0.06, we find that major halo mergers can at most modestly reduce the star-forming fraction, from 59 to 47 per cent. Consistent with past research, however, mergers accompany enhanced specific star formation rates for star-forming
L* centrals: ∼10 per cent when a paired galaxy is within 200 kpc (approximately the host halo's virial radius), climbing to ∼70 per cent when a paired galaxy is within 30 kpc. No evidence is seen for even extremely close pairs (<30 kpc separation) rejuvenating star formation in quenched galaxies. For galaxy formation models, our results suggest: (1) quenching in L* galaxies likely begins due to decoupling of the galaxy from existing hot and cold gas reservoirs, rather than a lack of available gas or gravitational heating from infalling clumps, (2) state-of-the-art semi-analytic models currently overpredict the effect of major halo mergers on quenching, and (3) major halo mergers can trigger enhanced star formation in non-quenched central galaxies.
ABSTRACT We have undertaken an ambitious program to visually classify all galaxies in the five CANDELS fields down to H < 24.5 involving the dedicated efforts of over 65 individual classifiers. Once ...completed, we expect to have detailed morphological classifications for over 50,000 galaxies spanning 0 < z < 4 over all the fields, with classifications from 3 to 5 independent classifiers for each galaxy. Here, we present our detailed visual classification scheme, which was designed to cover a wide range of CANDELS science goals. This scheme includes the basic Hubble sequence types, but also includes a detailed look at mergers and interactions, the clumpiness of galaxies, k-corrections, and a variety of other structural properties. In this paper, we focus on the first field to be completed-GOODS-S, which has been classified at various depths. The wide area coverage spanning the full field (wide+deep+ERS) includes 7634 galaxies that have been classified by at least three different people. In the deep area of the field, 2534 galaxies have been classified by at least five different people at three different depths. With this paper, we release to the public all of the visual classifications in GOODS-S along with the Perl/Tk GUI that we developed to classify galaxies. We present our initial results here, including an analysis of our internal consistency and comparisons among multiple classifiers as well as a comparison to the Sérsic index. We find that the level of agreement among classifiers is quite good (>70% across the full magnitude range) and depends on both the galaxy magnitude and the galaxy type, with disks showing the highest level of agreement (>50%) and irregulars the lowest (<10%). A comparison of our classifications with the Sérsic index and rest-frame colors shows a clear separation between disk and spheroid populations. Finally, we explore morphological k-corrections between the V-band and H-band observations and find that a small fraction (84 galaxies in total) are classified as being very different between these two bands. These galaxies typically have very clumpy and extended morphology or are very faint in the V-band.
We present the BoRG-JWST survey, a combination of two JWST Cycle 1 programs aimed at obtaining NIRSpec spectroscopy of representative, UV-bright \(7<z<10\) galaxy candidates across 22 independent ...sight lines selected from Hubble/WFC3 pure-parallel observations. We confirm the high-\(z\) nature of 10 out of 19 observed primary targets through low-resolution prism observations, with the rest revealing themselves unsurprisingly to be \(z\sim1-3\) interlopers, brown dwarfs, or yielding inconclusive results. From the MSA observations, we confirm an additional 9 filler sources at \(z>5\), highlighting the large abundance of high-redshift galaxies even in individual WFC3 pointings. The primary sample span an absolute magnitude range \(-20.4<M_{\rm UV}<-22.4\) mag and harbour UV continuum slopes of \(\beta\simeq-2.5\) to \(-2.0\), representing some of the most luminous \(z>7\) sources currently known and comparable to the brightest sources at \(z>10\). Prominent O III+H\(\beta\) lines are found across the full sample, while a stack of sources reveals a plethora of other rest-optical lines and additional rest-UV C III1909 Å emission. Despite their luminosities, none of the low-resolution spectra display evidence for Type 1 AGN activity based on a search for broad-line emission. Lastly, we present a spectroscopic data release of 188 confirmed \(0.5\lesssim z\lesssim5.0\) sources from filler MSA observations, highlighting the legacy value of the survey and a representative benchmark for comparisons to deep field observations.
Abstract
In 2022 November, the James Webb Space Telescope (JWST) returned deep near-infrared images of A2744—a powerful lensing cluster capable of magnifying distant, incipient galaxies beyond it. ...Together with existing Hubble Space Telescope (HST) imaging, this publicly available data set opens a fundamentally new discovery space to understand the remaining mysteries of the formation and evolution of galaxies across cosmic time. In this work, we detect and measure some 60,000 objects across the 49 arcmin
2
JWST footprint down to a 5
σ
limiting magnitude of ∼30 mag in 0.″32 apertures. Photometry is performed using circular apertures on images matched to the point-spread function (PSF) of the reddest NIRCam broad band, F444W, and cleaned of bright cluster galaxies and the related intracluster light. To give an impression of the photometric performance, we measure photometric redshifts and achieve a
σ
NMAD
≈ 0.03 based on known, but relatively small, spectroscopic samples. With this paper, we publicly release our HST and JWST PSF-matched photometric catalog with optimally assigned aperture sizes for easy use, along with single aperture catalogs, photometric redshifts, rest-frame colors, and individual magnification estimates. These catalogs will set the stage for efficient and deep spectroscopic follow up of some of the first JWST-selected samples in summer of 2023.
Abstract
The recent UNCOVER survey with the James Webb Space Telescope (JWST) exploits the nearby cluster A2744 to create the deepest view of our Universe to date by leveraging strong gravitational ...lensing. In this work, we perform photometric fitting of more than 50,000 robustly detected sources out to
z
∼ 15. We show the redshift evolution of stellar ages, star formation rates, and rest-frame colors across the full range of 0.2 ≲
z
≲ 15. The galaxy properties are inferred using the
Prospector
Bayesian inference framework using informative
Prospector
-
β
priors on the masses and star formation histories to produce joint redshift and stellar populations posteriors. Additionally, lensing magnification is performed on the fly to ensure consistency with the scale-dependent priors. We show that this approach produces excellent photometric redshifts with
σ
NMAD
∼ 0.03, of a similar quality to the established photometric redshift code
EAzY
. In line with the open-source scientific objective of this Treasury survey, we publicly release the stellar population catalog with this paper, derived from our photometric catalog adapting aperture sizes based on source profiles. This release (the catalog and all related documentation are accessible via the UNCOVER survey web page:
https://jwst-uncover.github.io/DR2.html#SPSCatalogs
with a copy deposited to Zenodo at doi:
10.5281/zenodo.8401181
) includes posterior moments, maximum likelihood spectra, star formation histories, and full posterior distributions, offering a rich data set to explore the processes governing galaxy formation and evolution over a parameter space now accessible by JWST.
ABSTRACT
Understanding how galaxies interact with the circumgalactic medium (CGM) requires determining how galaxies’ morphological and stellar properties correlate with their CGM properties. We ...report an analysis of 66 well-imaged galaxies detected in Hubble Space Telescope and Very Large Telescope MUSE observations and determined to be within ±500 km s−1 of the redshifts of strong intervening quasar absorbers at 0.2 ≲ z ≲ 1.4 with H i column densities $N_{\rm H I} \gt 10^{18}\, \rm cm^{-2}$. We present the geometrical properties (Sérsic indices, effective radii, axis ratios, and position angles) of these galaxies determined using galfit. Using these properties along with star formation rates (SFRs, estimated using the H α or O ii luminosity) and stellar masses (M* estimated from spectral energy distribution fits), we examine correlations among various stellar and CGM properties. Our main findings are as follows: (1) SFR correlates well with M*, and most absorption-selected galaxies are consistent with the star formation main sequence of the global population. (2) More massive absorber counterparts are more centrally concentrated and are larger in size. (3) Galaxy sizes and normalized impact parameters correlate negatively with NHI, consistent with higher NHI absorption arising in smaller galaxies, and closer to galaxy centres. (4) Absorption and emission metallicities correlate with M* and specific SFR, implying metal-poor absorbers arise in galaxies with low past star formation and faster current gas consumption rates. (5) SFR surface densities of absorption-selected galaxies are higher than predicted by the Kennicutt–Schmidt relation for local galaxies, suggesting a higher star formation efficiency in the absorption-selected galaxies.
Strong galactic winds are ubiquitous at \(z\gtrsim 1\). However, it is not well known where inside galaxies these winds are launched from. We study the cool winds (\(\sim 10^4\)\,K) in two spatial ...regions of a massive galaxy at \(z=1.3\), which we nickname the "Baltimore Oriole's Nest." The galaxy has a stellar mass of \(10^{10.3\pm 0.3} M_\odot\), is located on the star-forming main sequence, and has a morphology indicative of a recent merger. Gas kinematics indicate a dynamically complex system with velocity gradients ranging from 0 to 60 \(\mathrm{km}\cdot\mathrm{s}^{-1}\). The two regions studied are: a dust-reddened center (Central region), and a blue arc at 7 kpc from the center (Arc region). We measure the \ion{Fe}{2} and \ion{Mg}{2} absorption line profiles from deep Keck/DEIMOS spectra. Blueshifted wings up to 450 km\(\cdot\)s\(^{-1}\) are found for both regions. The \ion{Fe}{2} column densities of winds are \(10^{14.7\pm 0.2}\,\mathrm{cm}^{-2}\) and \(10^{14.6\pm 0.2}\,\mathrm{cm}^{-2}\) toward the Central and Arc regions, respectively. Our measurements suggest that the winds are most likely launched from both regions. The winds may be driven by the spatially extended star formation, the surface density of which is around 0.2 \(M_\odot\,\mathrm{yr}^{-1}\cdot \mathrm{kpc}^{-2}\) in both regions. The mass outflow rates are estimated to be \(4\,M_\odot\,\mathrm{yr}^{-1}\) and \(3\,M_\odot\,\mathrm{yr}^{-1}\) for the Central and Arc regions, with uncertainties of one order-of-magnitude or more. Findings of this work and a few previous studies suggest that the cool galactic winds at \(z\gtrsim 1\) might be commonly launched from the entire spatial extents of their host galaxies due to extended galaxy star formation.
We present an Atacama Large Millimeter/submillimeter Array (ALMA) survey of dust continuum emission in a sample of 70 galaxies in the redshift range z = 2-5 selected from the CANDELS GOODS-S field. ...Multi-epoch abundance matching (MEAM) is used to define potential progenitors of a z = 0 galaxy of stellar mass 1.5 × 1011 M . Gas masses are derived from the 850 m luminosity. Ancillary data from the CANDELS GOODS-S survey are used to derive the gas mass fractions. The results at z 3 are mostly in accord with expectations: The detection rates are 75% for the z = 2 redshift bin, 50% for the z = 3 bin, and 0% for z 4. The average gas mass fraction for the detected z = 2 galaxies is fgas = 0.55 0.12 and fgas = 0.62 0.15 for the z = 3 sample. This agrees with expectations for galaxies on the star-forming main sequence, and shows that gas fractions have decreased at a roughly constant rate from z = 3 to z = 0. Stacked images of the galaxies not detected with ALMA give upper limits to fgas of <0.08 and <0.15, for the z = 2 and z = 3 redshift bins. None of our galaxies in the z = 4 and z = 5 sample are detected, and the upper limit from stacked images, corrected for low metallicity, is fgas < 0.66. We do not think that lower gas-phase metallicities can entirely explain the lower dust luminosities. We briefly consider the possibility of accretion of very low-metallicity gas to explain the absence of detectable dust emission in our galaxies at z 4.
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