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We obtained 838 Sloan r -band images (∼28 hr) of the GOODS-North field with the Large Binocular Camera (LBC) on the Large Binocular Telescope in order to study the presence of extended, low surface brightness features in galaxies and investigate the trade-off between image depth and resolution. The individual images were sorted by effective seeing, which allowed for optimal resolution and optimal depth mosaics to be created with all images with seeing FWHM < 0.″9 and FWHM < 2.″0, respectively. Examining bright galaxies and their substructure as well as accurately deblending overlapping objects requires the optimal resolution mosaic, while detecting the faintest objects possible (to a limiting magnitude of m AB ∼ 29.2 mag) requires the optimal depth mosaic. The better surface brightness sensitivity resulting from the larger LBC pixels, compared to those of extant WFC3/UVIS and ACS/WFC cameras aboard the Hubble Space Telescope allows for unambiguous detection of both diffuse flux and very faint tidal tails. Azimuthally-averaged radial surface brightness profiles were created for the 360 brightest galaxies in each of the two mosaics. On average, these profiles showed minimal difference between the optimal resolution and optimal depth surface brightness profiles. However, ≲15% of the profiles show excess flux in the galaxy outskirts down to surface brightness levels of μ r AB ≃ 31 mag arcsec −2 . This is relevant to Extragalactic Background Light (EBL) studies as diffuse light in the outer regions of galaxies are thought to be a major contribution to the EBL. While some additional diffuse light exists in the optimal depth profiles compared to the shallower, optimal resolution profiles, we find that diffuse light in galaxy outskirts is a minor contribution to the EBL overall in the r -band.

We obtained 838 Sloan r-band images (∼28 hr) of the GOODS-North field with the Large Binocular Camera (LBC) on the Large Binocular Telescope in order to study the presence of extended, low surface brightness features in galaxies and investigate the trade-off between image depth and resolution. The individual images were sorted by effective seeing, which allowed for optimal resolution and optimal depth mosaics to be created with all images with seeing FWHM < 0”.9 and FWHM < 2”.0, respectively. Examining bright galaxies and their substructure as well as accurately deblending overlapping objects requires the optimal resolution mosaic, while detecting the faintest objects possible (to a limiting magnitude of m AB ∼ 29.2 mag) requires the optimal depth mosaic. The better surface brightness sensitivity resulting from the larger LBC pixels, compared to those of extant WFC3/UVIS and ACS/WFC cameras aboard the Hubble Space Telescope allows for unambiguous detection of both diffuse flux and very faint tidal tails. Azimuthally-averaged radial surface brightness profiles were created for the 360 brightest galaxies in each of the two mosaics. On average, these profiles showed minimal difference between the optimal resolution and optimal depth surface brightness profiles. However, ≲15% of the profiles show excess flux in the galaxy outskirts down to surface brightness levels of μ r AB ≃ 31 mag arcsec−2. This is relevant to Extragalactic Background Light (EBL) studies as diffuse light in the outer regions of galaxies are thought to be a major contribution to the EBL. While some additional diffuse light exists in the optimal depth profiles compared to the shallower, optimal resolution profiles, we find that diffuse light in galaxy outskirts is a minor contribution to the EBL overall in the r-band.

We describe an observation designed to find Hα emission from galaxies at z≃7–12 made using the InfraRed spectrograph (IRS) on the Spitzer Space Telescope.

We present one of the first measurements of the mass-metallicity relation (MZR) in multiple massive protoclusters at cosmic noon, using Hubble Space Telescope (HST) G141 slitless spectroscopy from the MAMMOTH-Grism survey. We identify 63 protocluster member galaxies across three overdense structures at \\(z = 2\\text{-}3\\) with robust detections of [OIII], H\\(\\beta\\), and [OII] emission. The sample spans gas-phase metallicities of \\(12 + \\log(\\text{O/H}) = 8.2\\text{-}8.6\\), dust-corrected H\\(\\beta\\)-based star formation rates (SFRs) of \\(10\\)-\\(250\\,M_\\odot\\,\\text{yr}^{-1}\\), and stellar masses of \\(M_\\ast \\sim 10^{9.4}\\)-\\(10^{10.5}\\,M_\\odot\\), derived via spectral energy distribution fitting using deep HST and ground-based photometry. We stack spectra in five \\(M_\\ast\\) bins to obtain average metallicities and SFRs. Relative to field galaxies at similar redshifts, protocluster members show elevated SFRs at \\(M_\\ast < 10^{10.25}\\,M_\\odot\\) and a systematically shallower MZR: \\(12 + \\log(\\text{O/H}) = (6.96 \\pm 0.13) + (0.143 \\pm 0.017) \\times \\log(M_{\\ast}/M_{\\odot})\\). We detect a mass-dependent environmental offset: massive protocluster galaxies are metal-poor compared to field counterparts of similar mass, whereas lower-mass systems exhibit comparable or mildly enhanced metallicities. This trend is consistent with a scenario where cold-mode accretion dilutes the interstellar medium (ISM) across the full mass range, while efficient recycling of feedback-driven outflows preferentially enriches the ISM in low-mass galaxies. Finally, we assess the dependence of metallicity offsets on local overdensity and find no significant trend, likely reflecting the survey's bias toward protocluster cores.

We present a spectroscopic study of low-mass galaxies (LMGs;\\(10^8\\leq\\rm M_*/M_\\odot\\leq10^9\\)) at \\(z\\sim0.15\\) in COSMOS field, and compare it to a control sample of intermediate-mass galaxies (IMGs;\\(10^9\\leq\\rm M_*/M_\\odot\\leq10^{10}\\)) at \\(z\\sim0.35\\). We examine their star formation rates (SFRs), dust attenuation properties, and the relationship between nebular and stellar reddening. For both samples, SFRs derived from H\\(\\alpha\\) are strongly correlated with SFRs from fitting simple star formation histories (SFHs) to the galaxies' spectral energy distributions. In fitting a joint SFR-\\(\\rm M_*\\) relation, we obtain a slope of \\(\\rm {\\Delta log(SFR_{H\\alpha})}/{\\Delta log(M_*/M_\\odot)}=1.01\\pm0.03\\), indicating that fair ensembles of SFHs for galaxies at these stellar masses are well-described by scale-free, self-similar forms. We also examine their dust attenuation properties and the relationship between nebular and stellar reddening, exploring how these quantities vary with stellar mass and specific SFR (sSFR). Nebular attenuation increases with stellar mass for IMGs but is lower and less mass-dependent in LMGs, consistent with their reduced dust content. In all cases, stellar continuum attenuation is lower than nebular attenuation, as expected from the two-component dust model. The nebular-to-stellar color excess ratio in both samples is consistent with the canonical factor of 2.27. The ratio is mass-independent, but rises with sSFR in IMGs and remains constant in LMGs. These results suggest that in LMGs, efficient dispersal of birth clouds keeps the differential attenuation approximately constant across sSFR. Thus, although LMGs follow the same global SFR-\\(\\rm M_*\\) scaling as massive galaxies, their lower dust content and feedback-maintained ISM produce distinct attenuation behavior relative to IMGs.

We present deep UV imaging observations of the Great Observatories Origins Survey Northern (GOODS-N) field with AstroSat/UVIT (AstroSat UV Deep Field north - AUDFn), using one far-UV (F154W, 34.0 kilosec) and two near-UV filters (N242W, 19.2 kilosec; N245M, 15.5 kilosec). The nature of the UV sky background was explored across the UVIT field and a global mean and rms was estimated for each filter. We reach 3\\(\\sigma\\) detection limits of \\(m_{\\rm AB}\\) \\(\\sim\\) 27.35 mag, 27.28 mag and 27.02 mag for a point source in the F154W, N242W and N245M bands respectively. The 50\\% completeness limits of the FUV and NUV images are \\(m_{\\rm AB}=\\) 26.40 mag and 27.05 mag respectively. We constructed PSFs for each band and estimated their FWHM, which were found to be almost the same: 1.18\" in F154W, 1.11\" in N242W, and 1.24\" in N245M. We used SExtractor to separately identify sources in the FUV and NUV filters and produce the UV source catalog of the entire AUDFn field. The source count slope estimated in FUV and NUV is 0.57 dex mag\\(^{-1}\\) (between 19 - 25 mag) and 0.44 dex mag\\(^{-1}\\) (between 18 - 25 mag), respectively. The catalog contains 6839 and 16171 sources (brighter than the 50\\% completeness limit) in the FUV and NUV, respectively. Our FUV and NUV flux measurements of the identified sources complement existing multi-band data in the GOODS-N field, and enable us to probe rest-frame FUV properties of galaxies at redshift \\(z < 1\\) and search for candidate Lyman continuum leakers at redshift \\(z > 0.97\\).

We present far-ultraviolet (FUV) images and catalogs from the Hubble Space Telescope (HST) Advanced Camera for Surveys/Solar Blind Channel (ACS/SBC) F150LP (about 1600 Angstrom) of three extragalactic fields: GOODS-S, GOODS-N, and COSMOS. The data comprise 365 orbits of high-resolution imaging of 151 pointings covering an area of 44.7 square arcmin to typical depths of FUV about 28.7 AB (3-sigma, 0.5 arcsec diameter aperture). We provide a new model of the spatially varying dark \"glow\" created from all 365 orbits of data, and scale and subtract it from all pointings. We provide drizzled image mosaics, weight maps, and exposure time maps matched in coordinates and pixel scale to the Hubble Legacy Fields (HLF) frame, and the original COSMOS tiles. Galaxy photometry is measured within isophotes defined with existing deep Hubble F606W or F814W optical filters. We detect 1068 galaxies and provide catalogs of all optical detections, including matched IDs to existing 3D-HST and CANDELS catalogs. The redshift distribution of FUV-detected galaxies peaks at z about 0.6 and declines to z = 1.2, where the Lyman limit shifts redward of any filter transmission. These data fill the redshift gap of high-resolution far-UV imaging between z about 0 and z > 1, enabling studies of star-forming regions, dust properties, the FUV extragalactic background, and Lyman continuum emission from galaxies at z > 1.2.

We report the detection of a pair of massive quiescent galaxies likely in the process of merging at the center of the spectroscopically confirmed, extremely massive protocluster BOSS1244 at \\(z=2.24\\pm0.02\\). These galaxies, BOSS1244-QG1 and BOSS1244-QG2, were detected with Hubble Space Telescope (HST) grism slitless spectroscopic observations. These two quiescent galaxies are among the brightest member galaxies with \\(z=2.223-2.255\\) in BOSS1244 and reside at redshifts \\(z=2.244\\) and \\(z=2.242\\), with a half-light radius of \\(6.76\\pm0.50\\) and \\(2.72\\pm0.16\\) kpc, respectively. BOSS1244-QG1 and BOSS1244-QG2 are separated by a projected distance of about 70 physical kpc, implying that the two galaxies likely merge to form a massive brightest cluster galaxy (BCG) with size and mass similar to the most massive BCGs in the local Universe. We thus infer that BCG formation through dry major mergers may happen earlier than the full assembly of a cluster core, which broadens our previous understanding of the co-evolution of mature galaxy clusters and BCGs in the nearby Universe. Moreover, we find a strong density-star formation relation over a scale of \\(\\sim18\\) co-moving Mpc in BOSS1244, i.e. star formation activity decreases as density increases, implying that the quenching of star formation in BCGs and their progenitors is likely governed by environment-related processes before the virialization of the cluster core.

We analyze nebular dust attenuation and its correlation with stellar mass (\\(M_{*}\\)) and UV spectral slope (\\(\\beta\\)) in 33 lensed, low-mass star-forming galaxies at \\(1.4\\leq z \\leq 2.6\\), using Keck/MOSFIRE rest-frame optical spectroscopy. Located behind three massive lensing galaxy clusters Abell 1689, MACS J1149.5+2223, and MACS J0717.5+3745, galaxies in our sample have a median stellar mass of \\(\\log(M_{*}/M_{\\odot})=8.3\\) and an intrinsic UV absolute magnitude range of \\(-20.9

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