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The redshift-dependent relation between galaxy stellar mass and star formation rate (the Star-Forming Sequence, or SFS) is a key observational yardstick for galaxy assembly. We use the SAGAbg-A sample of background galaxies from the Satellites Around Galactic Analogs (SAGA) Survey to model the low-redshift evolution of the low-mass SFS. The sample is comprised of 23258 galaxies with H$\alpha$-based star formation rates (SFRs) spanning $6<\log_{10}(\rm M_\star/[M_\odot])<10$ and $z<0.21$ ($t<2.5$ Gyr). Although it is common to bin or stack galaxies at $z \lesssim 0.2$ for galaxy population studies, the difference in lookback time between $z=0$ and $z=0.21$ is comparable to the time between $z=1$ to $z=2$. We develop a model to account for both the physical evolution of low-mass SFS and the selection function of the SAGA survey, allowing us to disentangle redshift evolution from redshift-dependent selection effects across the SAGAbg-A redshift range. Our findings indicate significant evolution in the SFS over the last 2.5 Gyr, with a rising normalization: $\langle {\rm SFR}({\rm M_\star=10^{8.5} M_\odot)}\rangle(z)=1.24^{+0.25}_{-0.23}\ {\rm z} -1.47^{+0.03}_{-0.03}$. We also identify the redshift limit at which a static SFS is ruled out at the 95% confidence level, which is $z=0.05$ based on the precision of the SAGAbg-A sample. Comparison with cosmological hydrodynamic simulations reveals that some contemporary simulations under-predict the recent evolution of the low-mass SFS. This demonstrates that the recent evolution of the low-mass SFS can provide new constraints on the assembly of the low-mass Universe and highlights the need for improved models in this regime., Comment: 20 pages, 7 figures. Submitted to ApJ

Accurate chemical compositions of star-forming regions are a critical diagnostic tool to characterize the star formation history and gas flows which regulate galaxy formation. However, the abundance discrepancy factor (ADF) between measurements from the "direct" optical electron temperature ($T_e$) method and from the recombination lines (RL) represents $\sim0.2$ dex systematic uncertainty in oxygen abundance. The degree of uncertainty for other elements is unknown. We conduct a comprehensive analysis of O$^{++}$ and N$^+$ ion abundances using optical and far-infrared spectra of a star-forming region within the nearby dwarf galaxy Haro 3, which exhibits a typical ADF. Assuming homogeneous conditions, the far-IR emission indicates an O abundance which is higher than the $T_e$ method and consistent with the RL value, as would be expected from temperature fluctuations, whereas the N abundance is too large to be explained by temperature fluctuations. Instead a component of highly obscured gas is likely required to explain the high far-IR to optical flux ratios. Accounting for this obscured component reduces both the IR-based metallicities and the inferred magnitude of temperature fluctuations, such that they cannot fully explain the ADF in Haro 3. Additionally, we find potential issues when predicting the RL fluxes from current atomic data. Our findings underscore the critical importance of resolving the cause of abundance discrepancies and understanding the biases between different metallicity methods. This work represents a promising methodology, and we identify further approaches to address the current dominant uncertainties., Comment: 18 pages, 7 figures, and 2 tables. Submitted to ApJ

Environment plays a critical role in shaping the assembly of low-mass galaxies. Here, we use the UniverseMachine (UM) galaxy-halo connection framework and the Data Release 3 of the Satellites Around Galactic Analogs (SAGA) Survey to place dwarf galaxy star formation and quenching into a cosmological context. UM is a data-driven forward model that flexibly parameterizes galaxy star formation rates (SFR) using only halo mass and assembly history. We add a new quenching model to UM, tailored for galaxies with stellar masses $\lesssim 10^9$ solar masses, and constrain the model down to a stellar mass $\gtrsim 10^7$ solar masses using new SAGA observations of 101 satellite systems around Milky Way (MW)-mass hosts and a sample of isolated field galaxies in a similar mass range from the Sloan Digital Sky Survey (SDSS). The new best-fit model, 'UM-SAGA,' reproduces the satellite stellar mass functions, average SFRs, and quenched fractions in SAGA satellites while keeping isolated dwarfs mostly star forming. The enhanced quenching in satellites relative to isolated field galaxies leads the model to maximally rely on halo assembly to explain the observed environmental quenching. Extrapolating the model down to a stellar mass $\sim 10^{6.5}$ solar masses yields a quenched fraction of $\gtrsim$ 30% for isolated field galaxies and $\gtrsim$ 80% for satellites of MW-mass hosts at this stellar mass. This specific prediction can soon be tested by spectroscopic surveys to reveal the relative importance of internal feedback, cessation of mass and gas accretion, satellite-specific gas processes, and reionization for the evolution of faint low-mass galaxies., Comment: 33 pages, 14 figures, 2 tables. This paper is part of the SAGA Survey Data Release 3. Survey website: https://sagasurvey.org

We present the star-forming properties of 378 satellite galaxies around 101 Milky Way analogs in the Satellites Around Galactic Analogs (SAGA) Survey, focusing on the environmental processes that suppress or quench star formation. In the SAGA stellar mass range of 10^6 to 10^10 solar masses, we present quenched fractions, star-forming rates, gas-phase metallicities, and gas content. The fraction of SAGA satellites that are quenched increases with decreasing stellar mass and shows significant system-to-system scatter. SAGA satellite quenched fractions are highest in the central 100 kpc of their hosts and decline out to the virial radius. Splitting by specific star formation rate (sSFR), the least star-forming satellite quartile follows the radial trend of the quenched population. The median sSFR of star-forming satellites increases with decreasing stellar mass and is roughly constant with projected radius. Star-forming SAGA satellites are consistent with the star formation rate--stellar mass relationship determined in the Local Volume, while the median gas-phase metallicity is higher and median HI gas mass is lower at all stellar masses. We investigate the dependence of the satellite quenched fraction on host properties. Quenched fractions are higher in systems with larger host halo mass, but this trend is only seen in the inner 100 kpc; we do not see significant trends with host color or star formation rate. Our results suggest that lower mass satellites and satellites inside 100 kpc are more efficiently quenched in a Milky Way-like environment, with these processes acting sufficiently slowly to preserve a population of star-forming satellites at all stellar masses and projected radii., Comment: 25 pages, 13 figures, 2 tables. Accepted by ApJ. This paper is part of the SAGA Survey Data Release 3. Data and notebooks are available on the survey website: https://sagasurvey.org

We present the third Data Release (DR3) of the Satellites Around Galactic Analogs (SAGA) Survey, a spectroscopic survey characterizing satellite galaxies around Milky Way (MW)-mass galaxies. The SAGA Survey DR3 includes 378 satellites identified across 101 MW-mass systems in the distance range 25-40.75 Mpc, and an accompanying redshift catalog of background galaxies (including about 46,000 taken by SAGA) in the SAGA footprint of 84.7 sq. deg. The number of confirmed satellites per system ranges from zero to 13, in the stellar mass range 10^6 to 10^10 solar masses. Based on a detailed completeness model, this sample accounts for 94% of the true satellite population down to a stellar mass of 10^7.5 solar masses. We find that the mass of the most massive satellite in SAGA systems is the strongest predictor of satellite abundance; one-third of the SAGA systems contain LMC-mass satellites, and they tend to have more satellites than the MW. The SAGA satellite radial distribution is less concentrated than the MW, and the SAGA quenched fraction below 10^8.5 solar masses is lower than the MW, but in both cases, the MW is within 1 sigma of SAGA system-to-system scatter. SAGA satellites do not exhibit a clear corotating signal as has been suggested in the MW/M31 satellite systems. Although the MW differs in many respects from the typical SAGA system, these differences can be reconciled if the MW is an older, slightly less massive host with a recently accreted LMC/SMC system., Comment: 38 pages, 23 figures, 7 tables. Accepted by ApJ. This paper is part of the SAGA Survey Data Release 3. Data and notebooks will be available on the survey website: https://sagasurvey.org

In Chen et al., 2023 (C23; arXiv:2304.09898), we introduced a new method to directly measure temperature fluctuations and applied it to a nearby dwarf galaxy, Mrk 71, finding a temperature fluctuation parameter $t^2 = 0.008\pm 0.043$. This result is lower by $\sim 2\sigma$ than the value required to explain the abundance discrepancy (AD) in this object. In the Matters Arising article submitted by Mendez-Delgado et al. (arXiv:2310.01197), the authors claim that using the same data presented in C23 in a different way, it is possible to conclude that the measurements are consistent with a larger $t^2 \simeq 0.1$ inferred indirectly from recombination lines (RLs). However, this requires a higher density such that the infrared [O III] 52 $\mu$m and [O III] 88 $\mu$m lines -- which form the basis of the direct measurement method -- are mutually inconsistent. Moreover, to reach agreement between the direct $t^2$ measurement and the larger $t^2$ value inferred from RLs requires systematically varying four parameters by $\sim 1\sigma$ from their best-determined values, which collectively amount to a $\sim2\sigma$ difference, consistent with the significance ($\sim 2 \sigma$) originally reported in C23. Therefore, we conclude that the results of C23 hold, and that the combined optical and infrared [O III] data disfavour $t^2 \simeq 0.1$ at the $\approx2\sigma$ level in Mrk 71. Future work is nonetheless warranted to better understand the AD associated with both optical and infrared emission line analysis., Comment: Response requested by the editorial board. Peer-reviewed version published in Nature Astronomy

Measuring the relation between star formation and galactic winds is observationally difficult. In this work we make an indirect measurement of the mass loading factor (the ratio between mass outflow rate and star formation rate) in low-mass galaxies using a differential approach to modeling the low-redshift evolution of the star-forming main sequence and mass-metallicity relation. We use the SAGA (Satellites Around Galactic Analogs) background galaxies, those spectra observed by the SAGA survey that are not associated with the main SAGA host galaxies, to construct a sample of 11925 spectroscopically confirmed low-mass galaxies from $0.01\lesssim z \leq 0.21$ and measure a auroral line metallicity for 120 galaxies. The crux of the method is to use the lowest redshift galaxies as the boundary condition of our model, and to infer a mass-loading factor for the sample by comparing the expected evolution of the low redshift reference sample in stellar mass, gas-phase metallicity, and star formation rate against the observed properties of the sample at higher redshift. We infer a mass-loading factor of $\eta_{\rm m}=0.92^{+1.76}_{-0.74}$, which is in line with direct measurements of the mass-loading factor from the literature despite the drastically different set of assumptions needed for each approach. While our estimate of the mass-loading factor is in good agreement with recent galaxy simulations that focus on resolving the dynamics of the interstellar medium, it is smaller by over an order of magnitude than the mass-loading factor produced by many contemporary cosmological simulations., Comment: 37 pages, 19 figures, accepted to ApJ

We present the star-formation-rate -- stellar-mass (SFR-M$_\ast$) relation for galaxies in the CEERS survey at $4.5\leq z\leq 12$. We model the \jwst\ and \hst\ rest-UV and rest-optical photometry of galaxies with flexible star-formation histories (SFHs) using \bagpipes. We consider SFRs averaged from the SFHs over 10~Myr (\sfrten) and 100~Myr (\sfrcen), where the photometry probes SFRs on these timescales, effectively tracing nebular emission lines in the rest-optical (on $\sim10$~Myr timescales) and the UV/optical continuum (on $\sim100$ Myr timescales). We measure the slope, normalization and intrinsic scatter of the SFR-M$_\ast$ relation, taking into account the uncertainty and the covariance of galaxy SFRs and $M_\ast$. From $z\sim 5-9$ there is larger scatter in the $\sfrten-M_\ast$ relation, with $\sigma(\log \sfrcen)=0.4$~dex, compared to the $\sfrcen-M_\ast$ relation, with $\sigma(\log \sfrten)=0.1$~dex. This scatter increases with redshift and increasing stellar mass, at least out to $z\sim 7$. These results can be explained if galaxies at higher redshift experience an increase in star-formation variability and form primarily in short, active periods, followed by a lull in star formation (i.e. ``napping'' phases). We see a significant trend in the ratio $R_\mathrm{SFR}=\log(\sfrten/\sfrcen)$ in which, on average, $R_\mathrm{SFR}$ decreases with increasing stellar mass and increasing redshift. This yields a star-formation ``duty cycle'' of $\sim40\%$ for galaxies with $\log M_\ast/M_\odot\geq 9.3$, at $z\sim5$, declining to $\sim20\%$ at $z\sim9$. Galaxies also experience longer lulls in star formation at higher redshift and at higher stellar mass, such that galaxies transition from periods of higher SFR variability at $z\gtrsim~6$ to smoother SFR evolution at $z\lesssim~4.5$., Comment: 28 pages, 12 figures, 2 Appendix figures

We present a novel approach to extracting dwarf galaxies from photometric data to measure their average halo mass profile with weak lensing. We characterise their stellar mass and redshift distributions with a spectroscopic calibration sample. Using the ${\sim}5000\mathrm{deg}^2$ multi-band photometry from Dark Energy Survey and redshifts from the Satellites Around Galactic Analogs (SAGA) survey with an unsupervised machine learning method, we select a low-mass galaxy sample spanning redshifts $z{<}0.3$ and divide it into three mass bins. From low to high median mass, the bins contain [146 420, 330 146, 275 028] galaxies and have median stellar masses of $\log_{10}(M_*/M_{\odot})= [8.52^{+0.57}_{-0.76}, 9.02^{+0.50}_ {-0.64}, 9.49^{+0.50}_{-0.58}]$. We measure the stacked excess surface mass density profiles, $\Delta\Sigma(R)$, of these galaxies using galaxy--galaxy lensing with a signal-to-noise of [14, 23, 28]. Through a simulation-based forward-modelling approach, we fit the measurements to constrain the stellar-to-halo mass relation and find the median halo mass of these samples to be $\log_{10}(M_{\rm halo}/M_{\odot})$ = [$10.67\substack{+0.2\\-0.4}$, $11.01\substack{+0.14 \\ -0.27}$,$11.40\substack{+0.08\\-0.15}$]. The CDM profiles are consistent with NFW profiles over scales ${\lesssim}0.15 \rm{h}^{-1}$Mpc. We find that ${\sim}20$ per cent of the dwarf galaxy sample are satellites. This is the first measurement of the halo profiles and masses of such a comprehensive, low-mass galaxy sample. The techniques presented here pave the way for extracting and analysing even lower-mass dwarf galaxies and for more finely splitting galaxies by their properties with future photometric and spectroscopic survey data., Comment: Measurements available at: https://github.com/aamon/Dwarf-Lensing ; 22 pages, 16 figures

The astronomical community is grappling with the increasing volume and complexity of data produced by modern telescopes, due to difficulties in reducing, accessing, analyzing, and combining archives of data. To address this challenge, we propose the establishment of a coordinating body, an "entity," with the specific mission of enhancing the interoperability, archiving, distribution, and production of both astronomical data and software. This report is the culmination of a workshop held in February 2023 on the Future of Astronomical Data Infrastructure. Attended by 70 scientists and software professionals from ground-based and space-based missions and archives spanning the entire spectrum of astronomical research, the group deliberated on the prevailing state of software and data infrastructure in astronomy, identified pressing issues, and explored potential solutions. In this report, we describe the ecosystem of astronomical data, its existing flaws, and the many gaps, duplication, inconsistencies, barriers to access, drags on productivity, missed opportunities, and risks to the long-term integrity of essential data sets. We also highlight the successes and failures in a set of deep dives into several different illustrative components of the ecosystem, included as an appendix., Comment: 59 pages; please send comments and/or questions to foadi@googlegroups.com

We present high-cadence photometric and spectroscopic observations of SN~2023axu, a classical Type II supernova with an absolute $V$-band peak magnitude of $-16.5 \pm 0.1$ mag. SN~2023axu was discovered by the Distance Less Than 40 Mpc (DLT40) survey within 1 day of the last non-detection in the nearby galaxy NGC 2283 at 13.7 Mpc. We modeled the early light curve using a recently updated shock cooling model that includes the effects of line blanketing and found the explosion epoch to be MJD 59971.48 $\pm$ 0.03 and the probable progenitor to be a red supergiant with a radius of 417 $\pm$ 28 $R_\odot$. The shock cooling model cannot match the rise of observed data in the $r$ and $i$ bands and underpredicts the overall UV data which points to possible interaction with circumstellar material. This interpretation is further supported by spectral behavior. We see a ledge feature around 4600 \AA\ in the very early spectra (+1.1 and +1.5 days after the explosion) which can be a sign of circumstellar interaction. The signs of circumstellar material are further bolstered by the presence of absorption features blueward of H$\alpha$ and H$\beta$ at day $>$40 which is also generally attributed to circumstellar interaction. Our analysis shows the need for high-cadence early photometric and spectroscopic data to decipher the mass-loss history of the progenitor., Comment: 18 pages, 12 figures, to be submitted to the AAS Journals

The Nancy Grace Roman Space Telescope is capable of delivering an unprecedented all-sky, high-spatial resolution, multi-epoch infrared map to the astronomical community. This opportunity arises in the midst of numerous ground- and space-based surveys that will provide extensive spectroscopy and imaging together covering the entire sky (such as Rubin/LSST, Euclid, UNIONS, SPHEREx, DESI, SDSS-V, GALAH, 4MOST, WEAVE, MOONS, PFS, UVEX, NEO Surveyor, etc.). Roman can uniquely provide uniform high-spatial-resolution (~0.1 arcsec) imaging over the entire sky, vastly expanding the science reach and precision of all of these near-term and future surveys. This imaging will not only enhance other surveys, but also facilitate completely new science. By imaging the full sky over two epochs, Roman can measure the proper motions for stars across the entire Milky Way, probing 100 times fainter than Gaia out to the very edge of the Galaxy. Here, we propose NANCY: a completely public, all-sky survey that will create a high-value legacy dataset benefiting innumerable ongoing and forthcoming studies of the universe. NANCY is a pure expression of Roman's potential: it images the entire sky, at high spatial resolution, in a broad infrared bandpass that collects as many photons as possible. The majority of all ongoing astronomical surveys would benefit from incorporating observations of NANCY into their analyses, whether these surveys focus on nearby stars, the Milky Way, near-field cosmology, or the broader universe., Comment: Submitted to the call for white papers for the Roman Core Community Survey (June 16th, 2023), and to the Bulletin of the AAS

We present findings of the detection of Magnesium II (Mg II, {\lambda} = 2796, 2803 {\AA}) absorbers from the early data release of the Dark Energy Spectroscopic Instrument (DESI). DESI is projected to obtain spectroscopy of approximately 3 million quasars (QSOs), of which over 99% are anticipated to be at redshifts greater than z > 0.3, such that DESI would be able to observe an associated or intervening Mg II absorber illuminated by the background QSO. We have developed an autonomous supplementary spectral pipeline that detects these systems through an initial line-fitting process and then confirms the line properties using a Markov Chain Monte Carlo sampler. Based upon a visual inspection of the resulting systems, we estimate that this sample has a purity greater than 99%. We have also investigated the completeness of our sample in regard to both the signal-to-noise properties of the input spectra and the rest-frame equivalent width (W0) of the absorber systems. From a parent catalog containing 83,207 quasars, we detect a total of 23,921 Mg II absorption systems following a series of quality cuts. Extrapolating from this occurrence rate of 28.8% implies a catalog at the completion of the five-year DESI survey that will contain over eight hundred thousand Mg II absorbers. The cataloging of these systems will enable significant further research because they carry information regarding circumgalactic medium environments, the distribution of intervening galaxies, and the growth of metallicity across the redshift range 0.3 < z < 2.5., Comment: 17 pages, 8 figures

Quiescent galaxies having more compact morphologies than star-forming galaxies has been a consistent result in the field of galaxy evolution. What is not clear is at what point this divergence happens, i.e. when do quiescent galaxies become compact, and how big of a role does the progenitor effect play in this result? Here we aim to model the morphological and star-formation histories of high redshift (0.8 $<$ z $<$ 1.65) massive galaxies (log(M/M$\odot$) $>$ 10.2) with stellar population fits using HST/WFC3 G102 and G141 grism spectra plus photometry from the CLEAR (CANDELS Lyman-alpha Emission at Reionization) survey, constraining the star-formation histories for a sample of $\sim$ 400 massive galaxies using flexible star-formation histories. We develop a novel approach to classifying galaxies by their formation activity in a way that highlights the green valley population, by modeling the specific star-formation rate distributions as a function of redshift and deriving the probability that a galaxy is quiescent (PQ). Using PQ and our flexible star-formation histories we outline the evolutionary paths of our galaxies in relation to stellar mass, Sersic index, $R_{eff}$, and stellar mass surface density. We find that galaxies show no appreciable stellar mass growth after entering the green valley (a net decrease of 4$\%$) while their stellar mass surface densities increase by $\sim$ 0.25 dex. Therefore galaxies are becoming compact during the green valley and this is due to increases in Sersic index and decreases in $R_{eff}$., Comment: 17 pages, 10 figures, submitted to ApJ

The heavy element content ("metallicity") of the Universe is a record of the total star formation history. Gas-phase metallicity in galaxies, as well as its evolution with time, is of particular interest as a tracer of accretion and outflow processes. However, metallicities from the widely-used electron temperature ($T_e$) method are typically ~2x lower than the values based on the recombination line method. This "abundance discrepancy factor" (ADF) is well known and is commonly ascribed to bias due to temperature fluctuations. We present a measurement of oxygen abundance in the nearby (3.4 Mpc) system, Mrk 71, using a combination of optical and far-IR emission lines to measure and correct for temperature fluctuation effects. Our far-IR result is inconsistent ($> 2 \sigma$ significance) with the metallicity from recombination lines and instead indicates little to no bias in the standard $T_e$ method, ruling out the long-standing hypothesis that the ADF is explained by temperature fluctuations for this object. Our results provide a framework to accurately measure metallicity across cosmic history, including with recent data reaching within the first billion years with JWST and the Atacama Large Millimeter Array (ALMA)., Comment: 26 pages, 7 figures. Accepted for publication

We present JWST/NIRSpec prism spectroscopy of seven galaxies selected from the Cosmic Evolution Early Release Science Survey (CEERS) NIRCam imaging with photometric redshifts z_phot>8. We measure emission line redshifts of z=7.65 and 8.64 for two galaxies, and z=9.77(+0.37,-0.29) and 10.01(+0.14,-0.19) for two others via the detection of continuum breaks consistent with Lyman-alpha opacity from a mostly neutral intergalactic medium. The presence (absense) of strong breaks (strong emission lines) give high confidence that these two galaxies are at z>9.6, but the break-derived redshifts have large uncertainties given the low spectral resolution and relatively low signal-to-noise of the CEERS NIRSpec prism data. The two z~10 sources are relatively luminous (M_UV<-20), with blue continua (-2.38 candidates with CEERS NIRSpec spectroscopy do not have secure redshifts, but the absence of emission lines in their spectra is consistent with redshifts z>9.6. We find that z>8 photometric redshifts are generally in agreement (within uncertainties) with the spectroscopic values. However, the photometric redshifts tend to be slightly overestimated (average Delta(z)=0.50+/-0.12), suggesting that current templates do not fully describe the spectra of very high-z sources. Overall, our results solidifies photometric evidence for a high space density of bright galaxies at z>8 compared to theoretical model predictions, and further disfavors an accelerated decline in the integrated UV luminosity density at z>8., Comment: Published in ApJL. 19 pages, 9 figures, 7 tables. File with Table 6 included in source .tar file

During the first 500 million years of cosmic history, the first stars and galaxies formed, seeding the Universe with heavy elements and eventually reionizing the intergalactic medium. Observations with JWST have uncovered a surprisingly high abundance of candidates for early star-forming galaxies, with distances (redshifts, $z$), estimated from multi-band photometry, as large as $z\approx 16$, far beyond pre-JWST limits. While generally robust, such photometric redshifts can suffer from degeneracies and occasionally catastrophic errors. Spectroscopic measurement is required to validate these sources and to reliably quantify physical properties that can constrain galaxy formation models and cosmology. Here we present JWST spectroscopy that confirms redshifts for two very luminous galaxies with $z > 11$, but also demonstrates that another candidate with suggested $z\approx 16$ instead has $z = 4.9$, with an unusual combination of nebular line emission and dust reddening that mimics the colors expected for much more distant objects. These results reinforce evidence for the early, rapid formation of remarkably luminous galaxies, while also highlighting the necessity of spectroscopic verification. The large abundance of bright, early galaxies may indicate shortcomings in current galaxy formation models, or deviation from physical properties (such as the stellar initial mass function) that are generally believed to hold at later times., Comment: Accelerated Article Preview (AAP) version published in Nature

We present an overview of the CANDELS Lyman-a Emission At Reionization (CLEAR) survey. CLEAR is a 130 orbit program of the Hubble Space Telescope using the Wide Field Camera 3 (WFC3) IR G102 grism. CLEAR targets 12 pointings divided between the GOODS-N and GOODS-S fields of the Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey (CANDELS). Combined with existing spectroscopic data from other programs, the full CLEAR dataset includes spectroscopic imaging of these fields over 0.8-1.7 um. In this Paper, we describe the CLEAR survey, the survey strategy, the data acquisition, reduction, processing, and science products and catalogs released alongside this paper. The catalogs include emission line fluxes and redshifts derived from the combination of the photometry and grism spectroscopy for 6048 galaxies, primarily ranging from 0.2 < z < 3. We also provide an overview of CLEAR science goals and results. In conjunction with this Paper we provide links to electronic versions of the data products, including 1D + 2D extracted spectra and emission line maps., Comment: Accepted in ApJS. 29 pages, 14 figures. The data products (1D + 2D spectra, emission line maps) and catalogs (photometric and spectroscopic catalogs of GOODS-N and GOODS-S) are available at https://archive.stsci.edu/hlsp/clear

We report the discovery of an accreting supermassive black hole at z=8.679, in CEERS_1019, a galaxy previously discovered via a Ly$\alpha$-break by Hubble and with a Ly$\alpha$ redshift from Keck. As part of the Cosmic Evolution Early Release Science (CEERS) survey, we observed this source with JWST/NIRSpec spectroscopy, MIRI and NIRCam imaging, and NIRCam/WFSS slitless spectroscopy. The NIRSpec spectra uncover many emission lines, and the strong [O III] emission line confirms the ground-based Ly$\alpha$ redshift. We detect a significant broad (FWHM~1200 km/s) component in the H$\beta$ emission line, which we conclude originates in the broad-line region of an active galactic nucleus (AGN), as the lack of a broad component in the forbidden lines rejects an outflow origin. This hypothesis is supported by the presence of high-ionization lines, as well as a spatial point-source component embedded within a smoother surface brightness profile. The mass of the black hole is log($M_{BH}/M_{\odot})=6.95{\pm}0.37$, and we estimate that it is accreting at 1.2 ($\pm$0.5) x the Eddington limit. The 1-8 $\mu$m photometric spectral energy distribution (SED) from NIRCam and MIRI shows a continuum dominated by starlight and constrains the host galaxy to be massive (log M/M$_{\odot}$~9.5) and highly star-forming (SFR~30 M$_{\odot}$ yr$^{-1}$). Ratios of the strong emission lines show that the gas in this galaxy is metal-poor (Z/Z$_{\odot}$~0.1), dense (n$_{e}$~10$^{3}$ cm$^{-3}$), and highly ionized (log U~-2.1), consistent with the general galaxy population observed with JWST at high redshifts. We use this presently highest-redshift AGN discovery to place constraints on black hole seeding models and find that a combination of either super-Eddington accretion from stellar seeds or Eddington accretion from massive black hole seeds is required to form this object by the observed epoch., Comment: 26 pages, 14 figures, 6 tables, published in ApJL

We present the mid-IR (MIR) morphologies for 64 star-forming galaxies at $0.210^{9}~M_\odot}$ using JWST MIRI observations from the Cosmic Evolution Early Release Science survey (CEERS). The MIRI bands span the MIR (7.7--21~$\mu$m), enabling us to measure the effective radii ($R_{\rm{eff}}$) and S\'{e}rsic indexes of these SFGs at rest-frame 6.2 and 7.7 $\mu$m, which contains strong emission from Polycyclic aromatic hydrocarbon (PAH) features, a well-established tracer of star formation in galaxies. We define a ``PAH-band'' as the MIRI bandpass that contains these features at the redshift of the galaxy. We then compare the galaxy morphologies in the PAH-bands to those in rest-frame Near-UV (NUV) using HST ACS/F435W or ACS/F606W and optical/near-IR using HST WFC3/F160W imaging from UVCANDELS and CANDELS, where the NUV-band and F160W trace the profile of (unobscured) massive stars and the stellar continuum, respectively. The $R_{\rm{eff}}$ of galaxies in the PAH-band are slightly smaller ($\sim$10\%) than those in F160W for galaxies with $\rm{M_*\gtrsim10^{9.5}~M_\odot}$ at $z\leq1.2$, but the PAH-band and F160W have a similar fractions of light within 1 kpc. In contrast, the $R_{\rm{eff}}$ of galaxies in the NUV-band are larger, with lower fractions of light within 1 kpc compared to F160W for galaxies at $z\leq1.2$. Using the MIRI data to estimate the $\rm{SFR_{\rm{IR}}}$ surface density, we find the correlation between the $\rm{SFR_{\rm{IR}}}$ surface density and stellar mass has a steeper slope than that of the $\rm{SFR_{\rm{UV}}}$ surface density and stellar mass, suggesting more massive galaxies having increasing amounts of obscured fraction of star formation in their inner regions. This paper demonstrates how the high-angular resolution data from JWST/MIRI can reveal new information about the morphology of obscured-star formation., Comment: 28 pages, 11 figures, Accepted by ApJ

We present results from the Cosmic Evolution Early Release Survey (CEERS) on the stellar-population parameters for 28 galaxies with redshifts $4

We perform a ground-based near-infrared spectroscopic survey using the Keck/MOSFIRE spectrograph to target Ly$\alpha$ emission at $7.0$4$\sigma$ level in eight $z>7$ galaxies, which include additional members of the known $z\sim7.7$ Ly$\alpha$-emitter (LAE) cluster (Tilvi et al. 2020). With the addition of these newly-discovered $z\sim7.7$ LAEs, this is currently the largest measured LAE cluster at $z>7$. The unusually-high Ly$\alpha$ detection rate at $z\sim7.7$ in this field suggests significantly stronger Ly$\alpha$ emission from the clustered LAEs than from the rest of our targets. We estimate the ionized bubble sizes around these LAEs and conclude that the LAEs are clustered within an extended ionized structure created by overlapping ionized bubbles which allow the easier escape of Ly$\alpha$ from galaxies. It is remarkable that the brightest object in the cluster has the lowest measured redshift of the Ly$\alpha$ line, being placed in front of the other LAEs in the line-of-sight direction. This suggests that we are witnessing the enhanced IGM transmission of Ly$\alpha$ from galaxies on the rear side of an ionized area. This could be a consequence of Ly$\alpha$ radiative transfer: Ly$\alpha$ close to the central velocity is substantially scattered by the IGM while Ly$\alpha$ from the rear-side galaxies is significantly redshifted to where it has a clear path., Comment: Submitted to ApJ (17 pages, 8 figures, 4 tables)

We introduce the DESI LOW-Z Secondary Target Survey, which combines the wide-area capabilities of the Dark Energy Spectroscopic Instrument (DESI) with an efficient, low-redshift target selection method. Our selection consists of a set of color and surface brightness cuts, combined with modern machine learning methods, to target low-redshift dwarf galaxies ($z$ < 0.03) between $19 < r < 21$ with high completeness. We employ a convolutional neural network (CNN) to select high-priority targets. The LOW-Z survey has already obtained over 22,000 redshifts of dwarf galaxies (M$_* < 10^9$ M$_\odot$), comparable to the number of dwarf galaxies discovered in SDSS-DR8 and GAMA. As a spare fiber survey, LOW-Z currently receives fiber allocation for just ~50% of its targets. However, we estimate that our selection is highly complete: for galaxies at $z < 0.03$ within our magnitude limits, we achieve better than 95% completeness with ~1% efficiency using catalog-level photometric cuts. We also demonstrate that our CNN selections $z<0.03$ galaxies from the photometric cuts subsample at least ten times more efficiently while maintaining high completeness. The full five-year DESI program will expand the LOW-Z sample, densely mapping the low-redshift Universe, providing an unprecedented sample of dwarf galaxies, and providing critical information about how to pursue effective and efficient low-redshift surveys., Comment: 24 pages, 14 figures, data to reproduce figures: https://zenodo.org/record/7422591

We present an investigation into the first 500 Myr of galaxy evolution from the Cosmic Evolution Early Release Science (CEERS) survey. CEERS, one of 13 JWST ERS programs, targets galaxy formation from z~0.5 to z>10 using several imaging and spectroscopic modes. We make use of the first epoch of CEERS NIRCam imaging, spanning 35.5 sq. arcmin, to search for candidate galaxies at z>9. Following a detailed data reduction process implementing several custom steps to produce high-quality reduced images, we perform multi-band photometry across seven NIRCam broad and medium-band (and six Hubble broadband) filters focusing on robust colors and accurate total fluxes. We measure photometric redshifts and devise a robust set of selection criteria to identify a sample of 26 galaxy candidates at z~9-16. These objects are compact with a median half-light radius of ~0.5 kpc. We present an early estimate of the z~11 rest-frame ultraviolet (UV) luminosity function, finding that the number density of galaxies at M_UV ~ -20 appears to evolve very little from z~9 to z~11. We also find that the abundance (surface density [arcmin^-2]) of our candidates exceeds nearly all theoretical predictions. We explore potential implications, including that at z>10 star formation may be dominated by top-heavy initial mass functions, which would result in an increased ratio of UV light per unit halo mass, though a complete lack of dust attenuation and/or changing star-formation physics may also play a role. While spectroscopic confirmation of these sources is urgently required, our results suggest that the deeper views to come with JWST should yield prolific samples of ultra-high-redshift galaxies with which to further explore these conclusions., Comment: Replaced with published version

We present ALMA Band~7 observations of a remarkably bright galaxy candidate at $z_{\rm phot}$=$16.7^{+1.9}_{-0.3}$ ($M_{\rm UV}$=$-21.6$), S5-z17-1, identified in JWST Early Release Observation data of Stephen's Quintet. We do not detect the dust continuum at 866~$\mu$m, ruling out the possibility that \targb\ is a low-$z$ dusty starburst with a star-formation rate of $\gtrsim 30$~$M_{\odot}$~yr$^{-1}$. We detect a 5.1$\sigma$ line feature at $338.726\pm0.007$~GHz exactly coinciding with the JWST source position, with a 2\% likelihood of the signal being spurious. The most likely line identification would be [OIII]52$\mu$m at $z=16.01$ or [CII]158$\mu$m at $z=4.61$, whose line luminosities do not violate the non-detection of the dust continuum in both cases. Together with three other $z\gtrsim$ 11--13 candidate galaxies recently observed with ALMA, we conduct a joint ALMA and JWST spectral energy distribution (SED) analysis and find that the high-$z$ solution at $z\sim$11--17 is favored in every candidate as a very blue (UV continuum slope of $\simeq-2.3$) and luminous ($M_{\rm UV}\simeq[-$24:$-21]$) system. Still, we find in several candidates that reasonable SED fits ($\Delta$ $\chi^{2}\lesssim4$) are reproduced by type-II quasar and/or quiescent galaxy templates with strong emission lines at $z\sim3$--5, where such populations predicted from their luminosity functions and EW([OIII]+H$\beta$) distributions are abundant in survey volumes used for the identification of the $z\sim$11--17 candidates. While these recent ALMA observation results have strengthened the likelihood of the high-$z$ solutions, lower-$z$ possibilities are not completely ruled out in several of the $z\sim$11--17 candidates, indicating the need to consider the relative surface densities of the lower-$z$ contaminants in the ultra high-$z$ galaxy search., Comment: 25 pages, 8 figures, 7 tables. ApJ in press

We analyze a sample of 25 [Ne V] $\lambda$3426 emission-line galaxies at $1.4

Lyman Break Galaxy (LBG) candidates at z>10 are rapidly being identified in JWST/NIRCam observations. Due to the (redshifted) break produced by neutral hydrogen absorption of rest-frame UV photons, these sources are expected to drop out in the bluer filters while being well detected in redder filters. However, here we show that dust-enshrouded star-forming galaxies at lower redshifts (z<7) may also mimic the near-infrared (near-IR) colors of z>10 LBGs, representing potential contaminants in LBG candidate samples. First, we analyze CEERS-DSFG-1, a NIRCam dropout undetected in the F115W and F150W filters but detected at longer wavelengths. Combining the JWST data with (sub)millimeter constraints, including deep NOEMA interferometric observations, we show that this source is a dusty star-forming galaxy (DSFG) at z~5.1. We also present a tentative 2.6sigma SCUBA-2 detection at 850um around a recently identified z~16 LBG candidate in the same field and show that, if the emission is real and associated with this candidate, the available photometry is consistent with a z~5 dusty galaxy with strong nebular emission lines despite its blue near-IR colors. Further observations on this candidate are imperative to mitigate the low confidence of this tentative submillimeter emission and its positional uncertainty. Our analysis shows that robust (sub)millimeter detections of NIRCam dropout galaxies likely imply z=4-6 redshift solutions, where the observed near-IR break would be the result of a strong rest-frame optical Balmer break combined with high dust attenuation and strong nebular line emission, rather than the rest-frame UV Lyman break. This provides evidence that DSFGs may contaminate searches for ultra high-redshift LBG candidates from JWST observations., Comment: Published in The Astrophysical Journal Letters (updated to match the published version)

We report the discovery of a candidate galaxy with a photo-z of z~12 in the first epoch of the JWST Cosmic Evolution Early Release Science (CEERS) Survey. Following conservative selection criteria we identify a source with a robust z_phot = 11.8^+0.3_-0.2 (1-sigma uncertainty) with m_F200W=27.3, and >7-sigma detections in five filters. The source is not detected at lambda < 1.4um in deep imaging from both HST and JWST, and has faint ~3-sigma detections in JWST F150W and HST F160W, which signal a Ly-alpha break near the red edge of both filters, implying z~12. This object (Maisie's Galaxy) exhibits F115W-F200W > 1.9 mag (2-sigma lower limit) with a blue continuum slope, resulting in 99.6% of the photo-z PDF favoring z > 11. All data quality images show no artifacts at the candidate's position, and independent analyses consistently find a strong preference for z > 11. Its colors are inconsistent with Galactic stars, and it is resolved (r_h = 340 +/- 14 pc). Maisie's Galaxy has log M*/Msol ~ 8.5 and is highly star-forming (log sSFR ~ -8.2 yr^-1), with a blue rest-UV color (beta ~ -2.5) indicating little dust though not extremely low metallicity. While the presence of this source is in tension with most predictions, it agrees with empirical extrapolations assuming UV luminosity functions which smoothly decline with increasing redshift. Should followup spectroscopy validate this redshift, our Universe was already aglow with galaxies less than 400 Myr after the Big Bang., Comment: 17 pages, 6 figures, 3 tables, ApJL in press. Summary of changes from original submission: Improvements in astrometry generated a weak detection in F150W that reduces the photo-z to 11.8 but does not increase the likelihood of lower-z solutions. A full discussion of changes from the original version is available at: https://web.corral.tacc.utexas.edu/ceersdata/papers/Maisie_update.pdf

We present rest-frame optical emission-line flux ratio measurements for five $z>5$ galaxies observed by the JWST Near-Infared Spectrograph (NIRSpec) in the SMACS 0723 Early Release Observations. We add several quality-control and post-processing steps to the NIRSpec pipeline reduction products in order to ensure reliable relative flux calibration of emission lines that are closely separated in wavelength, despite the uncertain \textit{absolute} spectrophotometry of the current version of the reductions. Compared to $z\sim3$ galaxies in the literature, the $z>5$ galaxies have similar [OIII]$\lambda$5008/H$\beta$ ratios, similar [OIII]$\lambda$4364/H$\gamma$ ratios, and higher ($\sim$0.5 dex) [NeIII]$\lambda$3870/[OII]$\lambda$3728 ratios. We compare the observations to MAPPINGS V photoionization models and find that the measured [NeIII]$\lambda$3870/[OII]$\lambda$3728, [OIII]$\lambda$4364/H$\gamma$, and [OIII]$\lambda$5008/H$\beta$ emission-line ratios are consistent with an interstellar medium that has very high ionization ($\log(Q) \simeq 8-9$, units of cm~s$^{-1}$), low metallicity ($Z/Z_\odot \lesssim 0.2$), and very high pressure ($\log(P/k) \simeq 8-9$, units of cm$^{-3}$). The combination of [OIII]$\lambda$4364/H$\gamma$ and [OIII]$\lambda$(4960+5008)/H$\beta$ line ratios indicate very high electron temperatures of $4.1<\log(T_e/{\rm K})<4.4$, further implying metallicities of $Z/Z_\odot \lesssim 0.2$ with the application of low-redshift calibrations for ``$T_e$-based'' metallicities. These observations represent a tantalizing new view of the physical conditions of the interstellar medium in galaxies at cosmic dawn., Comment: Accepted for publication in AAS Journals. 14 pages, 6 figures, 3 tables

Using spatially resolved H-alpha emission line maps of star-forming galaxies, we study the evolution of gradients in galaxy assembly over a wide range in redshift ($0.5

We use deep spectroscopy from the Hubble Space Telescope (HST) Wide-Field-Camera 3 (WFC3) IR grisms combined with broad-band photometry to study the stellar populations, gas ionization and chemical abundances in star-forming galaxies at $z\sim 1.1-2.3$. The data stem from the CANDELS Lyman-$\alpha$ Emission At Reionization (CLEAR) survey. At these redshifts the grism spectroscopy measure the [OII] 3727, 3729, [OIII] 4959, 5008, H-$\beta$ strong emission features, which constrain the ionization parameter and oxygen abundance of the nebular gas. We compare the line flux measurements to predictions from updated photoionization models (MAPPINGS (Kewley et al. 2019), which include an updated treatment of nebular gas pressure, log P/k = $n_e T_e$. Compared to low-redshift samples ($z\sim 0.2$) at fixed stellar mass, llog M / M$_\odot$ = 9.4-9.8, the CLEAR galaxies at z=1.35 (z=1.90) have lower gas-phase metallicity, $\Delta$(log Z) = 0.25 (0.35) dex, and higher ionization parameters, $\Delta$(log q) = 0.25 (0.35) dex, where U = q/c. We provide updated analytic calibrations between the [OIII], [OII], and H-$\beta$ emission line ratios, metallicity, and ionization parameter. The CLEAR galaxies show that at fixed stellar mass, the gas ionization parameter is correlated with the galaxy specific star-formation rates (sSFRs), where $\Delta$ log q = 0.4 $\Delta$(log sSFR), derived from changes in the strength of galaxy H-$\beta$ equivalent width. We interpret this as a consequence of higher gas densities, lower gas covering fractions, combined with higher escape fraction of H-ionizing photons. We discuss both tests to confirm these assertions and implications this has for future observations of galaxies at higher redshifts., Comment: 37 pages, plethora of figures, accepted for publication in ApJ. Updated with accepted version

The PRObabilistic Value-Added Bright Galaxy Survey (PROVABGS) catalog will provide measurements of galaxy properties, such as stellar mass ($M_*$), star formation rate (${\rm SFR}$), stellar metallicity ($Z_{\rm MW}$), and stellar age ($t_{\rm age, MW}$), for >10 million galaxies of the DESI Bright Galaxy Survey. Full posterior distributions of the galaxy properties will be inferred using state-of-the-art Bayesian spectral energy distribution (SED) modeling of DESI spectroscopy and Legacy Surveys photometry. In this work, we present the SED model, Bayesian inference framework, and methodology of PROVABGS. Furthermore, we apply the PROVABGS SED modeling on realistic synthetic DESI spectra and photometry, constructed using the L-GALAXIES semi-analytic model. We compare the inferred galaxy properties to the true galaxy properties of the simulation using a hierarchical Bayesian framework to quantify accuracy and precision. Overall, we accurately infer the true $M_*$, ${\rm SFR}$, $Z_{\rm MW}$, and $t_{\rm age, MW}$ of the simulated galaxies. However, the priors on galaxy properties induced by the SED model have a significant impact on the posteriors. They impose a ${\rm SFR}{>}10^{-1} M_\odot/{\rm yr}$ lower bound on ${\rm SFR}$, a ${\sim}0.3$ dex bias on $\log Z_{\rm MW}$ for galaxies with low spectral signal-to-noise, and $t_{\rm age, MW} < 8\,{\rm Gyr}$ upper bound on stellar age. This work also demonstrates that a joint analysis of spectra and photometry significantly improves the constraints on galaxy properties over photometry alone and is necessary to mitigate the impact of the priors. With the methodology presented and validated in this work, PROVABGS will maximize information extracted from DESI observations and provide a probabilistic value-added galaxy catalog that will extend current galaxy studies to new regimes and unlock cutting-edge probabilistic analyses., Comment: 40 pages, 17 figures, submitted to ApJ, the PROVABGS SED modeling pipeline is publicly available at https://github.com/changhoonhahn/provabgs

We present "Extending the Satellites Around Galactic Analogs Survey" (xSAGA), a method for identifying low-$z$ galaxies on the basis of optical imaging, and results on the spatial distributions of xSAGA satellites around host galaxies. Using spectroscopic redshift catalogs from the SAGA Survey as a training data set, we have optimized a convolutional neural network (CNN) to identify $z < 0.03$ galaxies from more distant objects using image cutouts from the DESI Legacy Imaging Surveys. From the sample of $> 100,000$ CNN-selected low-$z$ galaxies, we identify $>20,000$ probable satellites located between 36-300 projected kpc from NASA-Sloan Atlas central galaxies in the stellar mass range $9.5 < \log(M_\star/M_\odot) < 11$. We characterize the incompleteness and contamination for CNN-selected samples, and apply corrections in order to estimate the true number of satellites as a function of projected radial distance from their hosts. Satellite richness depends strongly on host stellar mass, such that more massive host galaxies have more satellites, and on host morphology, such that elliptical hosts have more satellites than disky hosts with comparable stellar masses. We also find a strong inverse correlation between satellite richness and the magnitude gap between a host and its brightest satellite. The normalized satellite radial distribution between 36-300 kpc does not depend strongly on host stellar mass, morphology, or magnitude gap. The satellite abundances and radial distributions we measure are in reasonable agreement with predictions from hydrodynamic simulations. Our results deliver unprecedented statistical power for studying satellite galaxy populations, and highlight the promise of using machine learning for extending galaxy samples of wide-area surveys., Comment: 27 pages, 18 figures, 1 table. Accepted to ApJ. Code available at https://github.com/jwuphysics/xsaga

We investigate the role of environment on star-formation rates of galaxies at various cosmic densities in well-studied clusters. We present the star-forming main sequence for 163 galaxies in four EDisCS clusters in the range 0.4 $<$ z $<$ 0.7. We use {\em Hubble Space Telescope}/Wide Field Camera 3 observations of the H$\alpha$ emission line to span three distinct local environments: the cluster core, infall region, and external field galaxies. The main sequence defined from our observations is consistent with other published H$\alpha$ distributions at similar redshifts, but differs from those derived from star-formation tracers such as 24$\mu$m. We find that the H$\alpha$-derived star-formation rates for the 67 galaxies with stellar masses greater than the mass-completeness limit of M$_*>$ 10$^{9.75}$M\textsubscript{\(\odot\)} show little dependence on environment. At face value, the similarities in the star-formation rate distributions in the three environments may indicate that the process of finally shutting down star formation is rapid, however, the depth of our data and size of our sample make it difficult to conclusively test this scenario. Despite having significant H$\alpha$ emission, 21 galaxies are classified as {\em UVJ}-quiescent and may represent a demonstration of the quenching of star formation caught in the act., Comment: 25 pages, 15 figures, 5 tables. Accepted for publication in Monthly Notices of the Royal Astronomical Society

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., Comment: Accepted to ApJ

We use Hubble Space Telescope WFC3 G102 and G141 grism spectroscopy to measure rest-optical emission-line ratios of 533 galaxies at $z\sim1.5$ in the CANDELS Ly$\alpha$ Emission at Reionization (CLEAR) survey. We compare $\frac{[OIII]}{H\beta}$ vs. $\frac{[SII]}{(H\alpha +[NII])}$ as an "unVO87" diagram for 461 galaxies and $\frac{[OIII]}{Hb}$ vs. $\frac{[NeIII]}{[OII]}$ as an "OHNO" diagram for 91 galaxies. The unVO87 diagram does not effectively separate active galactic nuclei (AGN) and $[NeV]$ sources from star-forming galaxies, indicating that the unVO87 properties of star-forming galaxies evolve with redshift and overlap with AGN emission-line signatures at $z>1$. The OHNO diagram effectively separates X-ray AGN and $[NeV]$-emitting galaxies from the rest of the population. We find that the $\frac{[OIII]}{H\beta}$ line ratios are significantly anti-correlated with stellar mass and significantly correlated with $\log(L_{H\beta})$, while $\frac{[SII]}{(H\alpha +[NII])}$ is significantly anti-correlated with $\log(L_{H\beta})$. Comparison with MAPPINGS~V photoionization models indicates that these trends are consistent with lower metallicity and higher ionization in low-mass and high-SFR galaxies. We do not find evidence for redshift evolution of the emission-line ratios outside of the correlations with mass and SFR.Our results suggest that the OHNO diagram of $\frac{[OIII]}{Hb}$ vs. $\frac{[NeIII]}{[OII]}$ will be a useful indicator of AGN content and gas conditions in very high-redshift galaxies to be observed by the James Webb Space Telescope., Comment: 20 pages, 22 figures

We present ALMA CO(2-1) spectroscopy of 6 massive (log$_{10}$M$_{\rm{*}}/\rm{M}_\odot>$11.3) quiescent galaxies at $z\sim1.5$. These data represent the largest sample using CO emission to trace molecular gas in quiescent galaxies above $z>1$, achieving an average 3$\sigma$ sensitivity of M$_{\rm{H_{2}}}\sim10^{10}\rm{M}_\odot$. We detect one galaxy at 4$\sigma$ significance and place upper limits on the molecular gas reservoirs of the other 5, finding molecular gas mass fractions M$_{\rm{H_{2}}}$/M$_{\rm{*}}$=f$_{\rm{H_{2}}}<2-6$% (3$\sigma$ upper limits). This is 1-2 orders of magnitude lower than coeval star-forming galaxies at similar stellar mass, and comparable to galaxies at $z=0$ with similarly low sSFR. This indicates that their molecular gas reservoirs were rapidly and efficiently used up or destroyed, and that gas fractions are uniformly low ($<$6%) despite the structural diversity of our sample. The implied rapid depletion time of molecular gas (t$_{\rm{dep}}<0.6$ Gyr) disagrees with extrapolations of empirical scaling relations to low sSFR. We find that our low gas fractions are instead in agreement with predictions from both the recent SIMBA cosmological simulation, and from analytical "bathtub" models for gas accretion onto galaxies in massive dark matter halos (log$_{10}M_{\rm{halo}}/\rm{M}_\odot\sim14$ at $z=0$). Such high mass halos reach a critical mass of log$_{10}M_{\rm{halo}}/\rm{M}_\odot>12$ by $z\sim4$ that halt the accretion of baryons early in the Universe. Our data is consistent with a simple picture where galaxies truncate accretion and then consume the existing gas at or faster than typical main sequence rates. Alternatively, we cannot rule out that these galaxies reside in lower mass halos, and low gas fractions may instead reflect either stronger feedback, or more efficient gas consumption., Comment: accepted for publication in ApJ

We report on the gas-phase metallicity gradients of a sample of 264 star-forming galaxies at 0.6 < z < 2.6, measured through deep near-infrared Hubble Space Telescope slitless spectroscopy. The observations include 12-orbit depth Hubble/WFC3 G102 grism spectra taken as a part of the CANDELS Lya Emission at Reionization (CLEAR) survey, and archival WFC3 G102+G141 grism spectra overlapping the CLEAR footprint. The majority of galaxies (84%) in this sample are consistent with a zero or slightly positive metallicity gradient across the full mass range probed (8.5 < log M_*/M_sun < 10.5). We measure the intrinsic population scatter of the metallicity gradients, and show that it increases with decreasing stellar mass---consistent with previous reports in the literature, but confirmed here with a much larger sample. To understand the physical mechanisms governing this scatter, we search for correlations between the observed gradient and various stellar population properties at fixed mass. However, we find no evidence for a correlation with the galaxy properties we consider---including star-formation rates, sizes, star-formation rate surface densities, and star-formation rates per gravitational potential energy. We use the observed weakness of these correlations to provide material constraints for predicted intrinsic correlations from theoretical models., Comment: 19 pages, 10 figures (v2: typo fixed in Figure 10 label); submitted to ApJ

We use \Pab\ (1282~nm) observations from the Hubble Space Telescope ($\HST$) G141 grism to study the star-formation and dust attenuation properties of a sample of 29 low-redshift ($z < 0.287$) galaxies in the CANDELS Ly$\alpha$ Emission at Reionization (CLEAR) survey. We first compare the nebular attenuation from $\Pab/\Ha$ with the stellar attenuation inferred from the spectral energy distribution, finding that the galaxies in our sample are consistent with an average ratio of the continuum attenuation to the nebular gas of 0.44, but with a large amount of excess scatter beyond the observational uncertainties. Much of this scatter is linked to a large variation between the nebular dust attenuation as measured by (space-based) $\Pab$ to (ground-based) $\Ha$ to that from (ground-based) $\Ha/\Hb$. This implies there are important differences between attenuation measured from grism-based / wide-aperture $\Pab$ fluxes and the ground-based / slit-measured Balmer decrement. We next compare star-formation rates (SFRs) from $\Pab$ to those from dust-corrected UV. We perform a survival analysis to infer a census of \Pab\ emission implied by both detections and non-detections. We find evidence that galaxies with lower stellar mass have more scatter in their ratio of \Pab\ to attenuation-corrected UV SFRs. When considering our \Pab\ detection limits, this observation supports the idea that lower mass galaxies experience "burstier" star-formation histories. Together, these results show that \Pab\ is a valuable tracer of a galaxy's SFR, probing different timescales of star-formation and potentially revealing star-formation that is otherwise missed by UV and optical tracers., Comment: 20 pages, 15 figures, 2 tables, submitted to ApJ

We present the Stage II results from the ongoing Satellites Around Galactic Analogs (SAGA) Survey. Upon completion, the SAGA Survey will spectroscopically identify satellite galaxies brighter than $ M_{r,o} = -12.3 $ around 100 Milky Way (MW) analogs at $ z \sim 0.01 $. In Stage II, we have more than quadrupled the sample size of Stage I, delivering results from 127 satellites around 36 MW analogs with an improved target selection strategy and deep photometric imaging catalogs from the Dark Energy Survey and the Legacy Surveys. We have obtained 25,372 galaxy redshifts, peaking around $ z = 0.2 $. These data significantly increase spectroscopic coverage for very low redshift objects in $ 17 < r_o < 20.75 $ around SAGA hosts, creating a unique data set that places the Local Group in a wider context. The number of confirmed satellites per system ranges from zero to nine, and correlates with host galaxy and brightest satellite luminosities. We find that the number and the luminosities of MW satellites are consistent with being drawn from the same underlying distribution as SAGA systems. The majority of confirmed SAGA satellites are star forming, and the quenched fraction increases as satellite stellar mass and projected radius from the host galaxy decrease. Overall, the satellite quenched fraction among SAGA systems is lower than that in the Local Group. We compare the luminosity functions and radial distributions of SAGA satellites with theoretical predictions based on cold dark matter simulations and an empirical galaxy-halo connection model and find that the results are broadly in agreement., Comment: 42 pages, 22 figures, 3 tables. See Sec. 9 (p.28) for summary and figure index. Main results are shown in Sec. 6-8 (Fig. 8-18). Accepted by ApJ. Data available on survey website: https://sagasurvey.org

Massive galaxy clusters undergo strong evolution from z~1.6 to z~0.5, with overdense environments at high-z characterized by abundant dust-obscured star formation and stellar mass growth which rapidly give way to widespread quenching. Data spanning the near- to far-infrared (IR) spectrum can directly trace this transformation; however, such studies have largely been limited to the massive galaxy end of cluster populations. In this work, we present ``total light" stacking techniques spanning 3.4-500{\mu}m aimed at revealing the total cluster IR emission, including low mass members and potential intracluster dust. We detail our procedures for WISE, Spitzer, and Herschel imaging, including corrections to recover the total stacked emission in the case of high fractions of detected galaxies. We apply our stacking techniques to 232 well-studied massive (log M200/Msun~13.8) clusters across multiple z bins, recovering extended cluster emission at all wavelengths, typically at >5sigma. We measure the averaged near- to far-IR radial profiles and SEDs, quantifying the total stellar and dust content. The near-IR radial profiles are well described by an NFW model with a high (c~7) concentration parameter. Dust emission is similarly concentrated, albeit suppressed at small radii (r<0.2Mpc). The measured SEDs lack warm dust, consistent with the colder SEDs expected for low mass galaxies. We derive total stellar masses consistent with the theoretical Mhalo-M_star relation and specific-star formation rates that evolve strongly with redshift, echoing that of massive (log Mstar/Msun>10) cluster galaxies. Separating out the massive galaxy population reveals that the majority of cluster far-IR emission (~70-80%) is provided by the low mass constituents, which differs from field galaxies. This effect may be a combination of mass-dependent quenching and excess dust in low mass cluster galaxies., Comment: 32 pages, 16 figures, 7 tables. Submitted to MNRAS, comments welcome!

The origin of the correlations between mass, morphology, quenched fraction, and formation history in galaxies is difficult to define, primarily due to the uncertainties in galaxy star-formation histories. Star-formation histories are better constrained for higher redshift galaxies, observed closer to their formation and quenching epochs. Here we use "non-parametric" star-formation histories and a nested sampling method to derive constraints on the formation and quenching timescales of quiescent galaxies at $0.7$10.25, where $\Sigma_1$ is the stellar mass within 1~pkpc (proper kpc). Quiescent galaxies with the highest stellar-mass surface density, $\log\Sigma_1 / (M_\odot\ \mathrm{kpc}^{-2}) > 10.25$, } show a \textit{minimum} formation redshift: all such objects in our sample have $z_{50} > 2.9$. Quiescent galaxies with lower surface density, $\log \Sigma_1 / (M_\odot\ \mathrm{kpc}^{-2}) = 9.5 - 10.25$, show a range of formation epochs ($z_{50} \simeq 1.5 - 8$), implying these galaxies experienced a range of formation and assembly histories. We argue that the surface density threshold $\log\Sigma_1/(M_\odot\ \mathrm{kpc}^{-2})>10.25$ uniquely identifies galaxies that formed in the first few Gyr after the Big Bang, and we discuss the implications this has for galaxy formation models., Comment: 13 pages, 7 figures, accepted for publication in ApJ. Includes an interactive online appendix (https://vince-ec.github.io/appendix/appendix)

We present initial results from the Cosmic Ultraviolet Baryon Survey (CUBS). CUBS is designed to map diffuse baryonic structures at redshift z<~1 using absorption-line spectroscopy of 15 UV-bright QSOs with matching deep galaxy survey data. CUBS QSOs are selected based on their NUV brightness to avoid biases against the presence of intervening Lyman Limit Systems (LLSs) at zabs<1. We report five new LLSs of log N(HI)/cm^-2 >~ 17.2 over a total redshift survey pathlength of dz=9.3, and a number density of n(z)=0.43 (-0.18, +0.26). Considering all absorbers with log N(HI)/cm^-2 > 16.5 leads to n(z)=1.08 (-0.25, +0.31) at z<1. All LLSs exhibit a multi-component structure and associated metal transitions from multiple ionization states such as CII, CIII, MgII, SiII, SiIII, and OVI absorption. Differential chemical enrichment levels as well as ionization states are directly observed across individual components in three LLSs. We present deep galaxy survey data obtained using the VLT-MUSE integral field spectrograph and the Magellan Telescopes, reaching sensitivities necessary for detecting galaxies fainter than 0.1L* at d<~300 physical kpc (pkpc) in all five fields. A diverse range of galaxy properties is seen around these LLSs, from a low-mass dwarf galaxy pair, a co-rotating gaseous halo/disk, a star-forming galaxy, a massive quiescent galaxy, to a galaxy group. The closest galaxies have projected distances ranging from d=15 to 72 pkpc and intrinsic luminosities from ~0.01L* to ~3L*. Our study shows that LLSs originate in a variety of galaxy environments and trace gaseous structures with a broad range of metallicities., Comment: 26 pages, 14 figures, MNRAS in press

Fundamental coding and software development skills are increasingly necessary for success in nearly every aspect of astronomical and astrophysical research as large surveys and high resolution simulations become the norm. However, professional training in these skills is inaccessible or impractical for many members of our community. Students and professionals alike have been expected to acquire these skills on their own, apart from formal classroom curriculum or on-the-job training. Despite the recognized importance of these skills, there is little opportunity to develop them - even for interested researchers. To ensure a workforce capable of taking advantage of the computational resources and the large volumes of data coming in the next decade, we must identify and support ways to make software development training widely accessible to community members, regardless of affiliation or career level. To develop and sustain a technology capable astronomical and astrophysical workforce, we recommend that agencies make funding and other resources available in order to encourage, support and, in some cases, require progress on necessary training, infrastructure and policies. In this white paper, we focus on recommendations for how funding agencies can lead in the promotion of activities to support the astronomy and astrophysical workforce in the 2020s., Comment: Submitted as a ASTRO2020 Decadal Survey APC position paper. arXiv admin note: substantial text overlap with arXiv:1905.05116

We present high spatial resolution imaging of the CO(1-0) line from the Karl G. Jansky Very Large Array (VLA) of COSMOS27289, a massive, compact star forming galaxy at z=2.234. This galaxy was selected to be structurally similar to z~2 passive galaxies. Our previous observations showed that it is very gas-poor with respect to typical star-forming galaxies at these redshifts, consistent with a rapid transition to quiescence as the molecular gas is depleted. The new data show that both the molecular gas fraction f_H2 = M_H2/M_star and the molecular gas depletion time t_dep = M_H2/SFR are lower in the central 1-2kpc of the galaxy and rise at larger radii ~2-4kpc. These observations are consistent with a scenario in which COSMOS27289 will imminently cease star formation in the inner regions before the outskirts, i.e. inside-out quenching, the first time this phenomenon has been seen via observations of molecular gas in the high-redshift universe. We find good qualitative and quantitative agreement with a hydrodynamical simulation of galaxy quenching, in which the central suppression of molecular gas arises due to rapid gas consumption and outflows that evacuate the central regions of gas. Our results provide independent evidence for inside-out quenching of star formation as a plausible formation mechanism for z~2 quiescent galaxies., Comment: 12 pages, 6 figures. Accepted for publication in ApJ

Software is a critical part of modern research, and yet there are insufficient mechanisms in the scholarly ecosystem to acknowledge, cite, and measure the impact of research software. The majority of academic fields rely on a one-dimensional credit model whereby academic articles (and their associated citations) are the dominant factor in the success of a researcher's career. In the petabyte era of astronomical science, citing software and measuring its impact enables academia to retain and reward researchers that make significant software contributions. These highly skilled researchers must be retained to maximize the scientific return from petabyte-scale datasets. Evolving beyond the one-dimensional credit model requires overcoming several key challenges, including the current scholarly ecosystem and scientific culture issues. This white paper will present these challenges and suggest practical solutions for elevating the role of software as a product of the research enterprise., Comment: arXiv admin note: substantial text overlap with arXiv:1905.05116

We report the serendipitous detection of two 3 mm continuum sources found in deep ALMA Band 3 observations to study intermediate redshift galaxies in the COSMOS field. One is near a foreground galaxy at 1.3", but is a previously unknown dust-obscured star-forming galaxy (DSFG) at probable $z_{CO}=3.329$, illustrating the risk of misidentifying shorter wavelength counterparts. The optical-to-mm spectral energy distribution (SED) favors a grey $\lambda^{-0.4}$ attenuation curve and results in significantly larger stellar mass and SFR compared to a Calzetti starburst law, suggesting caution when relating progenitors and descendants based on these quantities. The other source is missing from all previous optical/near-infrared/sub-mm/radio catalogs ("ALMA-only"), and remains undetected even in stacked ultradeep optical ($>29.6$ AB) and near-infrared ($>27.9$ AB) images. Using the ALMA position as a prior reveals faint $SNR\sim3$ measurements in stacked IRAC 3.6+4.5, ultradeep SCUBA2 850$\mu$m, and VLA 3GHz, indicating the source is real. The SED is robustly reproduced by a massive $M^*=10^{10.8}$M$_\odot$ and $M_{gas}=10^{11}$M$_\odot$, highly obscured $A_V\sim4$, star forming $SFR\sim300$ M$_{\odot}$yr$^{-1}$ galaxy at redshift $z=5.5\pm$1.1. The ultrasmall 8 arcmin$^{2}$ survey area implies a large yet uncertain contribution to the cosmic star formation rate density CSFRD(z=5) $\sim0.9\times10^{-2}$ M$_{\odot}$ yr$^{-1}$ Mpc$^{-3}$, comparable to all ultraviolet-selected galaxies combined. These results indicate the existence of a prominent population of DSFGs at $z>4$, below the typical detection limit of bright galaxies found in single-dish sub-mm surveys, but with larger space densities $\sim3 \times 10^{-5}$ Mpc$^{-3}$, higher duty cycles $50-100\%$, contributing more to the CSFRD, and potentially dominating the high-mass galaxy stellar mass function., Comment: Accepted for publication in ApJ. 2 galaxies, too many pages, 8 figures, 2 tables

Using the Spitzer Space Telescope and Herschel Space Observatory, we have conducted a survey of infrared galaxies in the field of the galaxy cluster Abell S1063 (AS1063) at $z=0.347$, which is one of the most massive clusters known and a target of the HST CLASH and Frontier-Field surveys. The Spitzer/MIPS 24 $\mu$m and Herschel/PACS & SPIRE images revealed that the core of AS1063 is surprisingly devoid of infrared sources, showing only a few detectable sources within the central r$\sim1^{\prime}$. There is, however, one particularly bright source (2.3 mJy at 24 $\mu$m; 106 mJy at 160 $\mu$m), which corresponds to a background galaxy at $z=0.61$. The modest magnification factor (4.0$\times$) implies that this galaxy is intrinsically IR-luminous (L$_{\rm IR}=3.1\times10^{11}\ \rm L_{\odot}$). What is particularly interesting about this galaxy is that HST optical/near-infrared images show a remarkably bright and large (1 kpc) clump at one edge of the disk. Our follow-up optical/near-infrared spectroscopy shows Balmer (H$\alpha$-H8) and forbidden emission from this clump ([OII] $\lambda$3727, [OIII] $\lambda\lambda$4959,5007, [NII] $\lambda\lambda$6548,6583), indicating that it is a HII region. The HII region appears to have formed in-situ, as kinematically it is part of a rotating disk, and there is no evidence of nearby interacting galaxies. With an extinction correction of A$_{\rm V}=1.5$ mag, the star formation rate of this giant HII region is $\sim$10 M$_{\odot}$ yr$^{-1}$, which is exceptionally large, even for high redshift HII regions. Such a large and luminous HII region is often seen at $z\sim2$ but quite rare in the nearby Universe., Comment: Accepted for publication in the Astrophysical Journal. 29 pages, 15 figures