We present the design and observations of low resolution JWSTNIRSpec PRISM spectroscopy from the Ultradeep NIRSpec and NIRCam ObserVations before the Epoch of Reionization UNCOVER Cycle 1 JWST Treasury program. Targets are selected using JWSTNIRCam photometry from UNCOVER and other programs and cover a wide range of categories and redshifts to ensure the legacy value of the survey. These categories include the first galaxies at zgtrsim10 faint galaxies during the Epoch of Reionization zsim68 high redshift AGN zgtrsim6 Population III star candidates distant quiescent and dusty galaxies 1lesssim z lesssim 6 and filler galaxies sampling redshiftcolormagnitude space from zsim 0.113. Seven NIRSpec MSA masks across the extended Abell 2744 cluster were observed along with NIRCam parallel imaging in 8 filters F090W F115W F150W F200W F277W F356W F410M F444W F480M over a total area of 26 arcmin2 overlapping existing HST coverage from programs including the Hubble Frontier Fields and BUFFALO. We successfully observed 553 objects down to mmathrmF444Wsim30mathrmAB and by leveraging mask overlaps we reach total ontarget exposure times ranging from 2.416.7h. We demonstrate the success rate and distribution of confirmed redshifts and also highlight the rich information revealed by these ultradeep spectra for a subset of our targets. An updated lens model of Abell 2744 is also presented including 14 additional spectroscopic redshifts and finding a total cluster mass of MmathrmSL2.1pm0.3times1015mathrmModot. We publicly release reduced 1D and 2D spectra for all objects observed in Summer 2023 along with a spectroscopic redshift catalog and the updated lens model of the cluster httpsjwstuncover.github.ioDR4.html.
['Astrophysics - Astrophysics of Galaxies']
The UNCOVER Survey First Release of Ultradeep JWSTNIRSpec PRISM spectra for 700 galaxies from z0.313 in Abell 2744
{'The UNCOVER Survey: First Release of Ultradeep JWST/NIRSpec PRISM spectra for ∼ 700 galaxies from z ∼ 0 . 3 -13 in Abell 2744': "Sedona H. Price, 1 Rachel Bezanson, 1 Ivo Labbe, 2 Lukas J. Furtak, 3 Anna de Graaff, 4 Jenny E. Greene, 5 Vasily Kokorev, 6 David J. Setton, 5, ∗ Katherine A. Suess, 7, † Gabriel Brammer, 8 Sam E. Cutler, 9 Joel Leja, 10, 11, 12 Richard Pan, 13 Bingjie Wang ( 王 冰 洁 ), 10, 11, 12 John R. Weaver, 9 Katherine E. Whitaker, 9, 14 Hakim Atek, 15 Adam J. Burgasser, 16 Iryna Chemerynska, 15 Pratika Dayal, 17 Robert Feldmann, 18 Natascha M. Forster Schreiber, 19 Yoshinobu Fudamoto, 20 Seiji Fujimoto, 6, † Karl Glazebrook, 21 Andy D. Goulding, 5 Gourav Khullar, 1 Mariska Kriek, 22 Danilo Marchesini, 13 Michael V. Maseda, 23 Tim B. Miller, 24 Adam Muzzin, 25 Themiya Nanayakkara, 21 Erica Nelson, 26 Pascal A. Oesch, 27, 8 Heath Shipley, 28 Renske Smit, 29 Edward N. Taylor, 2 Pieter van Dokkum, 30 Christina C. Williams, 31 and Adi Zitrin 3  \n1 Department of Physics and Astronomy and PITT PACC, University of Pittsburgh, Pittsburgh, PA 15260, USA 2 Centre for Astrophysics and Supercomputing, Swinburne University of Technology, Melbourne, VIC 3122, Australia 3 Physics Department, Ben-Gurion University of the Negev, P.O. Box 653, Be'er-Sheva 84105, Israel 4 Max-Planck-Institut fur Astronomie, Konigstuhl 17, D-69117, Heidelberg, Germany 5 Department of Astrophysical Sciences, Princeton University, 4 Ivy Lane, Princeton, NJ 08544, USA 6 Department of Astronomy, The University of Texas at Austin, Austin, TX 78712, USA 7 Kavli Institute for Particle Astrophysics and Cosmology and Department of Physics, Stanford University, Stanford, CA 94305, USA 8 Cosmic Dawn Center (DAWN), Niels Bohr Institute, University of Copenhagen, Jagtvej 128, København N, DK-2200, Denmark 9 Department of Astronomy, University of Massachusetts, Amherst, MA 01003, USA 10 Department of Astronomy & Astrophysics, The Pennsylvania State University, University Park, PA 16802, USA 11 Institute for Computational & Data Sciences, The Pennsylvania State University, University Park, PA 16802, USA 12 Institute for Gravitation and the Cosmos, The Pennsylvania State University, University Park, PA 16802, USA 13 Department of Physics and Astronomy, Tufts University, 574 Boston Ave., Medford, MA 02155, USA 14 Cosmic Dawn Center (DAWN), Denmark 15 Institut d'Astrophysique de Paris, CNRS, Sorbonne Universit'e, 98bis Boulevard Arago, 75014, Paris, France 16 Department of Astronomy & Astrophysics, UC San Diego, La Jolla, CA, USA 17 Kapteyn Astronomical Institute, University of Groningen, 9700 AV Groningen, The Netherlands 18 Department of Astrophysics, University of Zurich, CH-8057, Switzerland 19 Max-Planck-Institut fur extraterrestrische Physik, Giessenbachstrasse 1, 85748 Garching, Germany 20 Center for Frontier Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan 21 Centre for Astrophysics and Supercomputing, Swinburne University of Technology, PO Box 218, Hawthorn, VIC 3122, Australia 22 Leiden Observatory, Leiden University, P.O.Box 9513, NL-2300 AA Leiden, The Netherlands 23 Department of Astronomy, University of Wisconsin-Madison, 475 N. Charter St., Madison, WI 53706, USA 24 Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA), Northwestern University,1800 Sherman Ave, Evanston, IL 60201, USA 25 Department of Physics and Astronomy, York University, 4700 Keele Street, Toronto, Ontario, ON MJ3 1P3, Canada 26 Department for Astrophysical and Planetary Science, University of Colorado, Boulder, CO 80309, USA 27 Department of Astronomy, University of Geneva, Chemin Pegasi 51, 1290 Versoix, Switzerland 28 Department of Physics, Texas State University, San Marcos, TX 78666, USA 29 Astrophysics Research Institute, Liverpool John Moores University, 146 Brownlow Hill, Liverpool L3 5RF, UK 30 Astronomy Department, Yale University, 219 Prospect St, New Haven, CT 06511, USA 31 NSF's National Optical-Infrared Astronomy Research Laboratory, 950 North Cherry Avenue, Tucson, AZ 85719, USA", 'ABSTRACT': 'We present the design and observations of low resolution JWST/NIRSpec PRISM spectroscopy from the Ultradeep NIRSpec and NIRCam ObserVations before the Epoch of Reionization (UNCOVER) Cycle 1 JWST Treasury program. Targets are selected using JWST/NIRCam photometry from UNCOVER and other programs, and cover a wide range of categories and redshifts to ensure the legacy value of the survey. These categories include the first galaxies at z ≳ 10, faint galaxies during the Epoch of Reionization ( z ∼ 6 -8), high redshift AGN ( z ≳ 6), Population III star candidates, distant quiescent and dusty galaxies (1 ≲ z ≲ 6), and filler galaxies sampling redshift-color-magnitude space  \nfrom z ∼ 0 . 1 -13. Seven NIRSpec MSA masks across the extended Abell 2744 cluster were observed, along with NIRCam parallel imaging in 8 filters (F090W, F115W, F150W, F200W, F277W, F356W, F410M, F444W, F480M) over a total area of ∼ 26 arcmin 2 , overlapping existing HST coverage from programs including the Hubble Frontier Fields and BUFFALO. We successfully observed 553 objects down to m F444W ∼ 30AB, and by leveraging mask overlaps, we reach total on-target exposure times ranging from 2 . 4 -16 . 7h. We demonstrate the success rate and distribution of confirmed redshifts, and also highlight the rich information revealed by these ultradeep spectra for a subset of our targets. An updated lens model of Abell 2744 is also presented, including 14 additional spectroscopic redshifts and finding a total cluster mass of M SL = (2 . 1 ± 0 . 3) × 10 15 M ⊙ . We publicly release reduced 1D and 2D spectra for all objects observed in Summer 2023 along with a spectroscopic redshift catalog and the updated lens model of the cluster (https://jwst-uncover.github.io/DR4.html).  \nKeywords: Galaxy evolution (594) - Galaxy formation (595) - High-redshift galaxies (734)', '1. INTRODUCTION': "Deep JWST imaging from early programs has already begun to revolutionize our understanding of the faint, distant universe. The observatory has met or exceeded nearly every pre-flight expectation (Rieke et al. 2023), and early data has enabled us to find and begin characterizing many galaxy populations that were previously inaccessible: from the first generation of galaxies at Cosmic Dawn (e.g., Naidu et al. 2022, Atek et al. 2023, Finkelstein et al. 2023, Robertson et al. 2023, 2024, Casey et al. 2024), to the faint galaxies driving the reionization of the universe at z ∼ 6 -9 (e.g., P'erez-Gonz'alez et al. 2023), to early quiescent galaxies at z ∼ 3 -5 (e.g., Carnall et al. 2023a, Valentino et al. 2023). JWST imaging also provides new insights into galaxies' detailed structures (at z ≲ 6; e.g., Ferreira et al. 2022, 2023, Kartaltepe et al. 2023, Martorano et al. 2023, Nelson et al. 2023, van der Wel et al. 2024, among many others), including reaching low stellar masses approaching those of the dwarf galaxy population ( M ∗ ∼ 10 6 M ⊙ , e.g., Suess et al. 2023) and revealing the structures of heavily dustobscured galaxies which were previously observable only in the sub-millimeter (e.g., Kokorev et al. 2023, Price et al. 2023, Wu et al. 2023). Ultradeep JWST imaging has additionally enabled detections of possible globular clusters as early as z ∼ 1 . 4 (e.g., Mowla et al. 2022, Claeyssens et al. 2023, Forbes & Romanowsky 2023), as well as more detailed studies of globular clusters within galaxies out to at least z ∼ 0 . 3 (e.g., Harris & ReinaCampos 2023, 2024). Early JWST imaging has also yielded surprises, including larger than anticipated numbers of very luminous early galaxies (e.g., Naidu et al. 2022, Atek et al. 2023, Austin et al. 2023, Bradley et al.  \n2023, Finkelstein et al. 2023, Adams et al. 2024, Casey et al. 2024, Chemerynska et al. 2024a, Robertson et al. 2024) and an unexpected, relatively numerous population of obscured active galactic nuclei (AGN) candidates at high redshift (e.g., Labbe et al. 2023, Furtak et al. 2023a, Barro et al. 2024, Kokorev et al. 2024, Williams et al. 2024).  \nTaking the next step in exploring these newly uncovered parameter spaces requires leveraging JWST's spectroscopic capabilities to both confirm galaxies' redshifts and to probe their internal physical properties in detail. Even with the high sensitivity of JWST/NIRSpec (Boker et al. 2023), pushing to the most distant and faint regimes is best accomplished with very deep observations in cluster fields, where the strong gravitational lensing boost reaches intrinsically fainter populations by 1 -2 magnitudes relative to blank fields. Complementing the aforementioned imaging results, spectra from early JWST programs have already revealed new discoveries and unprecedented measurements. Results from this early spectroscopy include confirming the redshifts and properties of galaxies at z ≳ 9 (e.g., Arrabal Haro et al. 2023a,b, Curtis-Lake et al. 2023, Roberts-Borsani et al. 2023), and confirming and characterizing high-redshift obscured AGN (e.g., Harikane et al. 2023, Maiolino et al. 2023, Matthee et al. 2024) as well as quiescent galaxies at z ≳ 3 (e.g., Carnall et al. 2023b, de Graaff et al. 2024a, Glazebrook et al. 2024, Carnall et al. 2024).  \nThe Ultradeep NIRSpec and NIRCam ObserVations before the Epoch of Reionization (UNCOVER) Cycle 1 Treasury survey (Bezanson et al. 2022) was designed to collect these deep spectra early in the JWST mission. UNCOVER was designed to obtain ultradeep, multiband NIRCam imaging, photometrically detect and characterize galaxies down to mag F444W ∼ 30 AB (Weaver et al. 2024), and then select targets from these newly-observable populations for follow up ultra-  \nep NIRSpec/PRISM multi-object spectroscopy (Ferruit et al. 2022). The low resolution PRISM mode provides both high sensitivity and wide spectral coverage (i.e., Boker et al. 2023), enabling us to constrain continuum breaks down to ∼ 29AB and measure rest-frame ultraviolet (UV) to near infrared (NIR) emission and absorption features raging from galaxies within the cluster itself at z ∼ 0 . 3 out to the earliest epochs at z ≳ 10. Early UNCOVER spectroscopic results already address many of these aims, including finding objects among the first generation of galaxies (e.g., Wang et al. 2023a), characterizing distant obscured AGN (e.g., Greene et al. 2024), and uncovering early quiescent galaxy formation (e.g., Setton et al. 2024).  \nIn this paper we present an overview of the UNCOVER NIRSpec/PRISM spectroscopic observations of 668 targets in the Abell 2744 strong lensing cluster field, as well as our coordinated parallel NIRCam imaging which overlaps with existing HST observations from the Hubble Frontier Fields (HFF; Lotz et al. 2017) and BUFFALO (Steinhardt et al. 2020) programs. We detail the target selection and mask design and the observations (Sec. 2), and the spectroscopic reduction and redshift measurements (Sec. 3). We also present the redshift success rate and distribution of measured redshifts, and discuss example cases of spectra addressing the scientific objectives of the UNCOVER survey (Sec. 4). This paper accompanies the public release of early reduced NIRSpec/PRISM spectra, spectroscopic redshifts, and the NIRCam parallel imaging. All magnitudes given are in the AB system (Oke 1974).", '2.1. Target Selection': "Targets are primarily selected from photometric catalogs constructed from all publicly available HST and JWST imaging over Abell 2744 as of June 2023. The JWST/NIRCam observations are: UNCOVER (PIs Labbe & Bezanson, JWST-GO-2561; Bezanson et al. 2022), the Early Release Science program GLASS (PI: Treu, JWST-ERS-1324; Treu et al. 2022), and a Director's Discretionary program (PI: Chen, JWST-DD2756), providing a total of 8 filters: F090W, F115W, F150W, F200W, F277W, F356W, F410M, and F444W. The archival HST data consists of HST-GO-11689 (PI: Dupke), HST-GO-13386 (PI: Rodney), HST-DD-13495 (PI: Lotz; Lotz et al. 2017), and HST-GO-15117 (PI: Steinhardt; Steinhardt et al. 2020), providing coverage in 7 filters: F435W, F606W, F814W, F105W, F125W, F140W, and F160W. The majority of the targets are selected from the UNCOVER NIRCam-selected catalog (as presented in Weaver et al. 2024), using inter-  \nnal version v2.2.0. This version, containing ∼ 50 , 000 objects down to a combined long-wavelength (LW; F277W+F356W+F444W) depth of ∼ 30 . 5AB in the deepest regions, included improved treatment of PSFhomogenization and estimates of total magnitudes compared to the initial public DR1 (January 2023). 1 While selecting targets, UNCOVER stellar population modeling including Prospectorβ and eazy were considered (as in Weaver et al. 2024, Wang et al. 2024). However, the default UNCOVER catalogs excluded a small number of interesting sources, e.g., highly lensed, multiply imaged and/or shredded objects. In these cases, targets were added by hand (with target IDs > 60000). Furthermore, a subset of the targets were selected based on information from other wavelengths, including ALMA sub-mm/mm (DUALZ, PI: Fujimoto, Fujimoto et al. 2023a; ALCS, PI: Kohno, Fujimoto et al. 2023b; ALMA Frontier Fields, PI: Bauer; Mu˜noz Arancibia et al. 2023) and Chandra X-ray (e.g., Bogd'an et al. 2024) observations.  \nFor target selection, the updated version of the Furtak et al. (2023b) analytic lens model of Abell 2744 was used ( v1.1 ). 2 This version includes one additional multiple image system in the northern sub-structure (system 82), and more importantly, an additional spectroscopic redshift in the north-western sub-structure from new VLT/MUSE observations of the cluster (system 68 at z = 2 . 584, Bergamini et al. 2023a; see also Appendix B.2). The v1.1 lens model achieved a lens plane average image reproduction root-mean-square (RMS) of ∆ RMS = 0 . 51 '' .  \nAs the UNCOVER science goals cover a wide range of topics, including potentially risky unknown-unknowns, the final spectroscopic targeting is complex. The prioritization scheme for assigning targets to masks is as follows. Categories corresponding to the originally proposed science cases (see Bezanson et al. 2022) are roughly prioritized corresponding to rarity and scientific value: 1) any z> 12 candidates, 2) z> 9 galaxies prioritized by brightness, 3) Pop III candidate sources,  \nFigure 1. UNCOVER NIRSpec MSA mask footprints within the Abell 2744 cluster field. Shaded regions denote the regions of magnification µ > 2 , 10 , 100 (grayscale, light to dark) from the updated UNCOVER lensing maps ( v2.0 ) for a source at redshift z s = 8, and existing NIRCam coverage (from Cycle 1 imaging) is shown with the black outline. The masks, shown with colored outlines, span most of the imaging footprint over a range of low- and high-magnification regions. The electrical short-impacted Mask 1 is marked with a dotted outline. (Note Masks 5-7 have near-complete overlap.)  \n<!-- image -->  \nRA  \n4) faint highly magnified 6 <z< 7 galaxies, 3 5) z> 4 quiescent galaxies, 6) z> 6 AGN, 7) z> 4 dusty galaxies, and other galaxies with ALMA detections (e.g., Fujimoto et al. 2023a), 8) low mass quiescent galaxies at 1 <z< 6, 9) any unusual or unexpected sources, 10) extreme emission line galaxies, and finally 11) mass-selected 'filler' galaxies sampled in bins of redshift, mass, and F150W -LW color (using the LW noise equalized-F277W+F356W+F444W image, and eazy -derived mass and redshifts). For these filler targets, the numerical priority class n was set to be proportional to the log 2 inverse of the cumulative surface density in each property. As the mask design software eMPT (Bonaventura et al. 2023) maps priority class n to weight according to a 1 / 2 n weighting scheme, this approximately equates to an importance sampling scheme that is flat in color, magnitude, and redshift (i.e., sparsely sam-  \nTable 1. NIRSpec MSA Masks  \nNote -The sample includes 668 unique targets, with some targets on multiple masks.  \npling regions of parameter space with many objects, and densely sampling where objects are less common).", '2.2. Mask Designs & Observations': 'The NIRSpec/PRISM observations are split into 7 microshutter array (MSA) mask configurations, with permask exposure times of 2.6-4.4h (see Table 1). As shown in Figure 1, these masks cover the UNCOVER NIRCam primary footprint, with overlaps allowing for repeated observations of faint, high-priority targets. The masks were designed iteratively using eMPT (Bonaventura et al. 2023), designing each mask in sequence according to target priority, then modifying the priorities to ensure targets requiring deeper integrations are placed on additional masks until the required exposure time is met. This procedure was repeated using hand-specified mask positions until an optimal design (in terms of both number of highest priority targets and total number of targets) was reached. In total, 668 unique targets are assigned to masks, with total planned exposure times ranging from 2.6 to 17.4 hours.  \nThe NIRSpec observations were taken on 31 July - 2 August 2023, with a 2-POINT-WITH-NIRCam-SIZE2 dither pattern and a 3 shutter slitlet nod pattern. The NIRSpec NRSIRS2RAPID and NRSIRS2 readout patterns were adopted for Masks 1-3 and 4-7, respectively. Coordinated parallel NIRCam imaging was also taken (as described in Appendix A). The observations were taken with a V3PA angle ∼ 266 or NIRSpec MSA aperture PA ∼ 44 . 56 (see exact values in Table 1), to ensure  \nefficient MSA coverage over the UNCOVER NIRCam footprint and to overlap the parallel NIRCam imaging with existing HST/ACS and WFC3 observations from the HFF (Lotz et al. 2017) and BUFFALO (Steinhardt et al. 2020) programs.  \nAn electrical short early in Visit 1 severely impacted both detectors, with complete loss for most sources and severely reduced data quality in a minority of objects; repeat observations of a slightly modified Mask 1 (due to small differences in PA) were approved, and were observed on 30-31 July 2024. Additionally, a solid state recorder (SSR) drive exception (relating to drive space) impacted the Visit 3 observations, leading to a loss of 7% of the NIRSpec integration time in Mask 3 (1 frame each for both detectors; yielding a total exposure of 2.4h) as well as 66% of the NIRCam parallel imaging (all of F150W, F200W, F356W, F444W). Repeat observations of the NIRCam parallel for Visit 3 (in all 6 filters, given a probable observing PA change) were also approved, and observed on 31 July 2024. All repeat observations will be included in a future release. Given these setbacks, and a small percentage of failed reduction/extractions or other data quality issues, here we present robust spectra for 553 objects, with exposure times of 2.4-16.7 hours.', '3.1. Spectroscopic reduction & 1D extraction': "The PRISM spectra are reduced using msaexp (v0.8.5; Brammer 2023a), grizli (v1.11.9; Brammer 2023b), and the JWST jwst pipeline (v1.14.0; Bushouse et al. 2024) using the jwst 1241.pmap reference files. Level 1 products are downloaded from MAST 4 , and then msaexp (using grizli ) runs the jwst stage 1 pipeline, inserting the snowblind 5 (Davies 2024) improved 'snowball' identification and correction procedure after the Jump step. msaexp next applies a 1 /f correction, and, finally, a median pedestal bias offset of the science data ( sci extension) and multiplicative scaling factor to the read noise array ( rnoise extension) are calculated from empty parts of each exposure that should not have any contribution from sky or source photons. Further steps of the jwst stage 2 pipeline are then run to assign the world coordinate system (WCS), flag open microshutters, identify and extract 2D slits, apply slit-level flat-fielding, correct for vignetting of the MSA bars, and apply the photometric calibration.  \nFor this first spectroscopic data release, local background subtraction is performed by taking differences of the 2D spectrum arrays at the different telescope nod positions. 6 This local background subtraction is performed on the original 2D slitlet cutouts before performing drizzle resampling. msaexp then rectifies the 2D spectra from each exposure and resamples them into a final stack with an algorithm analogous to drizzle (Fruchter & Hook 2002), adopting a pixel fraction and wavelength sampling of 1.0. In contrast to the STScI jwst drizzle resampling algorithm, the spectra here are only rectified along the columns of the cross-dispersion axis and all wavelength bins are kept fully independent, which eliminates the correlated noise in the dispersion direction that results from a full 2D drizzle resampling.  \nThe final 1D spectra are then extracted from the local background-subtracted 2D spectra using an optimal extraction (Horne 1986) scheme, modified to account for the variable spatial resolution across the full PRISM wavelength range. A 2D Gaussian profile for this optimal extraction is fit to the curved traces of the original spectral cutouts with parameters for both the profile width and a spatial offset relative to the position expected from the mask and input catalog metadata. The 2D profile is rebinned and rectified in the same way as the science data, and the optimally-weighted extraction is performed in the rectified frame. Path-loss corrections computed by msaexp are included in the final spectra using the predicted intra-shutter position and assuming an axisymmetric Gaussian shape with the width determined from the fit to the cross-dispersion profile described above.  \nWe note that some objects are observed on multiple masks. In the current reduction, all frames of a target are directly combined during the reduction, implicitly assuming that the slitlets of different masks cover the same spatial region of that source. We also note that we have not attempted to apply any aperture corrections (beyond the path-loss correction described above); in some cases, it may be beneficial for users to derive a wavelength-dependent aperture correction when jointly modeling photometry and spectroscopy. Finally, we note that for this first release, spectra from the shortimpacted Mask 1 are not reduced. The spectra from the repeat observation of Mask 1, and the spectra taken along with the repeat of the Visit 3 NIRCam parallel imaging, will be included in future spectroscopic releases.  \nFigure 2. Total magnification map of our new v2.0 SL model of Abell 2744 for a source at redshift z s = 10. The black contours represent magnification thresholds of µ = 2 and µ = 4.  \n<!-- image -->  \n|  \n|", '3.2. Spectroscopic redshifts and line fluxes': 'The spectroscopic redshifts for this data release are determined from the reduced, full-depth 1D spectra using msaexp . First, redshift fits are performed using the eazy (Brammer et al. 2008) corr sfhz 13 galaxy template set with a wide allowed redshift range ( z = [0 . 05 , 14]). A second redshift fit is then performed with a library of spectral lines and cubic splines for a flexible continuum model, restricted within ± 0 . 03(1 + z ) of the template best-fit redshift (or within the range z = [0 . 05 , 14] if the template fit failed). Models for the emission lines are generated in msaexp as pixel-integrated Gaussians with widths taken from the wavelength-dependent spectral resolution curve provided by STScI and used by the JWST exposure time calculator ( R ∼ 50 at 1.5 µ m, R ∼ 300 at 5 µ m; 7 jwst nirspec prism disp.fits). The prism disperser does not spectrally resolve typical galaxy emission lines, though extremely broad emission (e.g., due to broad-line AGN or outflows) can be resolved.  \nThe spectroscopic redshift for each object is determined as follows: (1) from the template fit, for objects with only continuum features based on visual inspection (i.e., only breaks or stellar bumps and no emission lines); or else (2) from the lines+splines fit, if at least one emission line is detected with signal-to-noise S / N ≥ 3 in that fit (and the target was not flagged as only having  \ncontinuum features in visual inspection); or finally (3) from the template fit, from the template fit, if no line is detected. The redshift uncertainties for all targets are taken from the 16, 84 th percentiles of the full redshift range template fit (or from the lines+splines fit, if the template fit failed).  \nThe redshift fits are examined by multiple (minimum 3) team members, and flagged based on the number and robustness of the detected spectral features, as described in Table 2. The redshift quality flag, flag zspec qual , denotes secure redshifts (= 3; from two or more secure spectral features, e.g., two robustly-detected emission lines, one clear break and one robust emission line, two robustly-detected absorption features), solid redshifts (= 2; from one broad continuum feature, either a break or stellar bump, or from two less robust features, e.g., two marginally-detected emission lines or one marginally detected emission line and a break), tentative but unreliable redshifts (= 1), and no redshift solution (= 0). A flag flag successful spectrum is also included, indicating whether the target spectrum was successfully observed and reduced (= 1) or not (= 0; due to data quality issues or missing spectra).  \nIn select cases identified during the visual fit inspection (14 objects; 2.5%), the redshifts are manually refit with alternative settings (i.e., multiple robust emission lines where the initial template fits yielded inaccurate redshift estimates; noise misidentified as lines when the redshifts are more robustly measured from template fits to continuum breaks) or are fixed (the 3 brown dwarfs at z spec = 0; see Sec. 4.2). The redshift quality flag is updated based on these modified redshift solutions.  \nIn addition to spectroscopic redshifts, we also determine line fluxes from the msaexp fits for each object. We adopt the values from the same fit as the best-fit redshift (described above). The reported line fluxes are not corrected for lensing magnification.  \nAccompanying this paper, we publicly release reduced spectra and spectroscopic redshifts from the UNCOVER NIRSpec/MSA observations taken in Summer 2023. 8 This data release (UNCOVER DR4) includes the 1D optimally extracted spectra and the 2D spectra with local background subtraction, for all successfully reduced spectra. The redshift catalog for this release (described in Table 2 and the downloadable machine readable format version) includes the measured redshifts (if any), redshift and spectra quality flags, the total exposure time, and the assigned masks for the full set of targeted  \nFigure 3. Redshift distribution of spectroscopically confirmed galaxies with robust redshifts ( flag zspec qual ≥ 2). Panel a: Redshift histogram, split by redshift quality flag. Panel b: Spectroscopic versus photometric redshifts, using Prospectorβ -derived z phot from the internal v2.2.0 catalog (used during MSA target selection, including only HST and JWST/NIRCam broad-band filters), with the uncertainties showing the 16, 84 th percentiles. Catastrophic outliers (with | ∆ z | = ( z phot -z spec ) / (1+ z spec ) > 0 . 15; boundary denoted with dotted lines) are colored red.  \n<!-- image -->  \nobjects. Subsequent spectroscopic releases will include the observations from the repeated Visits 1 & 3 and both global- and local-background subtracted spectra (optimized for extended and point sources, respectively) and an updated redshift catalog.  \nReduced mosaics of the NIRCam parallel observations are also available, constructed following the same procedures as the cluster NIRCam observations (except that modeling and subtraction of bright cluster galaxy and intracluster light is not performed). Full details about the parallel mosaics are presented in the UNCOVER survey paper (Bezanson et al. 2022).', '3.3. Updating the UNCOVER lens model': "We also use the UNCOVER spectroscopy to update the lens model of Abell 2744 presented in Furtak et al. (2023b) and include the new v2.0 model in the data release. As described in detail in Appendix B, this model incorporates the UNCOVER DR4 spectroscopic redshifts of multiple images, and all currently available JWST imaging for cluster member selection. In total, we added 14 spectroscopic redshifts compared to our initial v1.0 model. The model is constructed with an updated version of the analytic lens modeling method by Zitrin et al. (2015). We refer the reader to Appendix B and Furtak et al. (2023b) for details of the parameterization for our lensing model of Abell 2744.  \nWith these constraints, the model achieves an average image reproduction error of ∆ RMS = 0 . 60 '' , which  \nis slightly better than our v1.0 model (∆ RMS = 0 . 66 '' Furtak et al. 2023b). The critical lines and multiple image positions are shown in Figure 9 in Appendix B and we show an updated magnification map at source redshift z s = 10 in Figure 2. We find the cluster to have a total critical area of A crit = 0 . 63 arcmin 2 for a source at z s = 2. This translates to an effective Einstein radius of θ E = 26 . 9 '' ± 2 . 7 '' enclosing a mass of M ( < θ E ) = (1 . 0 ± 0 . 2) × 10 14 M ⊙ . These also agree well with our measurements from our v1.0 model (Furtak et al. 2023b). Summing the surface mass density over the entire field (see Figure 9), we obtain a total cluster mass of M SL = (2 . 1 ± 0 . 3) × 10 15 M ⊙ . This is comparable to an M 200 mass and thus places Abell 2744 well within the mass range of typical clusters with the same Einstein radius (e.g. Fox et al. 2022).  \nThe v2.0 lens model is included in the UNCOVER DR4. The public lensing products include deflection α , convergence κ , shear γ , magnification µ and potential ψ maps, normalized to D ds /D s = 1, as well as catalogs of the cluster member galaxies and multiple images used. The JWST cluster member selection and spectroscopic redshifts of multiple images are further detailed in Appendices B.1 and B.2 respectively. We also updated the UNCOVER photometric and spectroscopic catalogs with magnification and shear parameters from the v2.0 model. Individual models of each of the three sub-structures separately are also available on re-  \nFigure 4a shows that successfully-observed spectroscopic targets with and without robust redshifts ( flag zspec qual ≥ and < 2, purple filled and gray open circles, respectively) have similar F277W-F444W colors. On average, targets without robust redshifts are fainter in F444W than spectroscopically-confirmed objects, though both have overlapping distributions down  \n<!-- image -->  \n<!-- image -->  \na  \nm  \ng  \na  \nm  \nFigure 4. Distribution of the spectroscopic sample relative to the full UNCOVER photometric catalog ( left ) and the redshift measurement success rate ( right ) over total F444W magnitude versus F277W-F444W color. All values are taken from the internal v2.2.0 catalog (used for designing masks). Panel a: Points indicate the spectroscopically-confirmed objects ( flag zspec qual ≥ 2; filled purple circles), targets without robust redshifts ( flag zspec qual < 2; dark gray open circles), and targets with data quality issues (e.g., those on MSA1; gray crosses). Contours denote the parent photometric sample distribution (with use phot = 1; see Weaver et al. 2024; 1,2,3 σ levels). Side panels show histograms over mag F444W and F277W-F444W (line colors the same as points in the main panel). Though the sample selection incorporates multiple disparate categories, overall the targets follow the distribution of the parent sample down to mag F444W ∼ 29 AB. Successfully-observed targets without measured z spec do not have systematically redder/bluer colors compared to the spectroscopically-confirmed ones. The unconfirmed targets are fainter on average than the confirmed objects, though their distribution does overlap down to the very faintest magnitudes (mag F444W ≳ 30 AB) Panel b: 2D and 1D histograms of the redshift measurement success fraction over mag F444W and F277WF444W, defined as the fraction of objects with robust redshifts over the total number of successfully-observed targets. The success fraction is very high over most of this space, though drops to ∼ 30 -50% at mag F444W ∼ 29 AB.  \nquest, each achieving local image reproduction errors of ∆ RMS ≃ 0 . 2 '' .", '4.1. Success rate and redshift distribution for spectroscopically-confirmed objects': 'The UNCOVER spectroscopic redshift catalog includes a 74% success rate, with robust redshifts (i.e., defined as flag zspec qual ≥ 2; see Table 2 and Sec. 3.2) for 409 of the 553 targets with successfully observed and reduced spectra. A histogram of the redshift distribution of spectroscopically confirmed targets, split by flag zspec qual , is shown in Figure 3a. We measure secure redshifts (based on two or more secure spectral features; flag zspec qual = 3) for 327 objects, spanning from z ∼ 0 . 3 to z ∼ 10. The 82 galaxies with solid redshifts (based on one broad continuum feature or 2 less robust features; flag zspec qual = 2) also span a wide redshift range ( z ∼ 0 . 2 -13). This latter category includes most of the targeted galaxies in the Abell  \n2744 cluster itself, as most have very red spectra with no emission lines and only a broad stellar bump (resulting in lower redshift precision).  \nWe compare the spectroscopic and photometric redshifts for our sample of spectroscopically-confirmed galaxies in Figure 3b. We find the majority of the Prospectorβ -derived z phot (from the internal v2.2.0 catalog, the most up-to-date catalog used during MSA design in early Summer 2023) are in good agreement with the measured z spec , with a low normalized median absolute deviation σ NMAD = 0 . 060. However, there is a relatively high fraction of catastrophic photometric redshift outliers (with | ∆ z | = ( z phot -z spec ) / (1 + z spec ) > 0 . 15; 17.6%, red circles).  \nto the very faintest magnitudes (mag F444W ≳ 30 AB). This is quantified in Figure 4b, as the spectroscopic success fraction is very high for bright targets, but drops only to ∼ 30 -50% at mag F444W ∼ 29 AB (excepting a few extremely faint targets at mag F444W ≳ 30 AB). The distributions of the targets with and without robustlymeasured redshifts suggest that while low S/N does contribute to failed spectroscopic confirmations, low S/N is not entirely responsible for the failed spectroscopic confirmations. Color likewise appears to not drive failed z spec measurements.  \nWe similarly find catastrophic photometric redshift failures within of the spectroscopically-confirmed sample ( | ∆ z | > 0 . 15; shown with red points in Figure 3) are not primarily driven by low S/N or color, as these objects exhibit a wide range of magnitudes and F277WF444W colors similar to the complete spectroscopically confirmed sample. Preliminary visual inspection suggests some of these outliers are due to confusion of the Lyman and Balmer breaks in the Prospectorβ redshift fits, while others may be explained by emission line boosting of the broad-band photometry. We note that for the few very red targets (F277W -F444W ≳ 1), nearly all have catastrophic photometric redshift failures, suggesting additional spectral templates for photometric redshift fitting may be needed to capture the extreme colors of these objects. A more detailed discussion of photometric redshift outliers relative to the measured z spec will be presented in a forthcoming paper (see also Suess et al. 2024).', '4.2. Scientific objectives addressed by the UNCOVER spectroscopic sample': "With a high redshift success rate (74% of targets with robust redshifts) and very deep spectra (up to 16.7h for five individual targets, and up to 38h with multiply lensed images of one object), these NIRSpec observations provide a treasure trove for studies ranging from galaxies within the Abell 2744 cluster itself out to the first galaxies at Cosmic Dawn. We demonstrate the wide range of spectral features seen in the full UNCOVER sample of 409 galaxies with robust z spec ( flag zspec qual ≥ 2) ranging from z ∼ 0 . 3 to z ∼ 13 in Figure 5. An incredible diversity of features can be seen in these ultradeep spectra: Paschen lines, HeI -10833 ˚ A, and the polycyclic aromatic hydrocarbon (PAH) 3.3 µ m feature are seen in galaxies at the lowest redshifts, and [SIII] -9068 , 9531 ˚ A ˚ A are seen out to z ∼ 5. H α is detected out to z ∼ 7, and H β and [OIII] -4959 , 5007 ˚ A ˚ A are seen in all galaxies except those at the very highest redshifts. The Balmer break is  \nseen in galaxies at z ≳ 1, while the Lyman break (and Ly α ) are seen at z ≳ 4 . 5.  \nAn overview of the science cases addressed by the UNCOVER spectra are highlighted in Figure 6, showing a subset of objects from our sample. We have spectroscopically confirmed and begun characterizing the rest-frame UV spectra of 10 early galaxies at z ≥ 8 . 5 (see e.g., Fujimoto et al. 2023c), including two among the first generation of galaxies at z spec = 13 . 03 and z spec = 12 . 39 (as presented in Wang et al. 2023a). Our sample also features a number of early AGN at z > 6, including an X-ray luminous AGN at z spec = 10 . 1 (Bogd'an et al. 2024, Goulding et al. 2023) and a broad-line AGN at z spec = 8 . 5 (Kokorev et al. 2023). Other targets include a number of dust-reddened, high-redshift objects described as 'little red dots' (e.g., Labbe et al. 2023, Furtak et al. 2024a, Greene et al. 2024). The PRISM spectra also yield the first spectroscopic constraints on low-mass, low-luminosity galaxies during the Epoch of Reionization ( z ∼ 6 -8), including direct constraints on the ionizing photon production efficiency that yield evidence that these faint galaxies are the primary drivers of the reionization of the Universe (Atek et al. 2024, Dayal et al. 2024), and extending the mass-metallicity relation to the low-mass end (Chemerynska et al. 2024b).  \nOur spectroscopic sample additionally includes a range of dusty galaxies out to z ∼ 4, both with (e.g., some of the objects presented in Kokorev et al. 2023 and Price et al. 2023) and without ALMA continuum detections (from e.g., DUALZ, Fujimoto et al. 2023a). Two targeted galaxies at low redshift ( z ≲ 0 . 5) reveal detections of the 3.3 µ m PAH emission feature and ice absorption features. Also targeted are a number of quiescent galaxies extending from low redshift to z ≳ 3. This includes a massive, dusty quiescent galaxy confirmed at z spec = 3 . 97 (Setton et al. 2024), with the deep PRISM spectra revealing its detailed star formation history that indicates the early formation of its dense stellar core. Finally, we obtained spectra for three brown dwarfs located within our own Milky Way (Langeroodi & Hjorth 2023, Burgasser et al. 2024): one explicitly targeted, and two that were selected based on the photometric criteria for dust-reddened 'little red dots' and AGN at high redshift. These deep spectra reveal the spectral classifications, temperatures, and metallicities, as well as characterizing molecular features within the brown dwarf atmospheres.  \nz  \nFigure 5. NIRSpec/PRISM spectra for all UNCOVER targets with secure ( flag zspec qual = 3, N = 327; top ) and solid ( flag zspec qual = 2, N = 82; bottom ) redshifts, shifted to the restframe and ordered by increasing redshift. The wavelength axis is split, with linear and log scaling below and above 1 . 2 µ m, respectively. The locations of notable emission and absorption/break features are annotated above and below the spectra.  \n<!-- image -->  \nf  \nRest-frame Wavelength [ Å ]  \n<!-- image -->  \nFigure 6. Overview of 1D spectra for a subset of our sample, highlighting key science themes addressed by the UNCOVER survey and mask design strategy. All spectra are shown in the restframe in f λ units (with arbitrary normalization and shifting), with the shaded contour denoting the uncertainty. The redshift and MSA ID of each object are annotated next to the spectra. Vertical lines mark the wavelengths of selected emission features.  \nTable 2. Redshift catalog from UNCOVER NIRSpec/PRISM spectra  \nNote -The full table is available in machine readable format from https://jwst-uncover.github.io/DR4.html.  \nColumns:  \n- (1) MSA ID (corresponding to internal v2.2.0).\n- (2) Targeted Right Ascension and Declination (internal v2.2.0 catalog; J2000, decimal degrees).\n- (3) Spectroscopic redshift.\n- (4)-(6) 16/50/84th percentile from redshift fit p ( z ) distribution.\n- (7) Redshift quality flag: 3 = secure, based on two or more secure spectral features (e.g., two robustly-detected emission lines, one clear break and one robust emission line, two robustly-detected absorption features); 2 = solid, based on one broad continuum feature or two less robust features (e.g., a break or stellar bump, or two marginally-detected emission lines, or one marginally-detected emission lines and a break); 1 = tentative but unreliable redshift; 0 = no redshift. For analysis, using redshifts with quality flag = 3 or = 2 is recommended.\n- (8) Spectrum flag: 1 = successfully observed and reduced spectrum; 0 = no spectrum/data quality issue.\n- (9) Feature flag, for spectra containing two or more emission lines (1=yes, 0=no).\n- (10) Feature flag, for spectra containing a break + an emission line (1=yes, 0=no).\n- (11) Feature flag, for spectra containing only a break and strong absorption features (1=yes, 0=no).\n- (12) Feature flag, for spectra containing only a break (1=yes, 0=no).\n- (13) Feature flag, for spectra containing only a stellar bump (1=yes, 0=no).\n- (14) Fit method for best-fit redshift.\n- (15) Fit method for redshift uncertainties/percentiles.\n- (16) Total exposure time (hours).\n- (17) List of masks on which each object was included (comma separated string).\n- (18) Closest match DR3 ID (Weaver et al. 2024, Wang et al. 2024).\n- (19) Separation of DR3 & MSA RA/Dec, in arcsec.", '5. FINAL REMARKS': 'The ultradeep PRISM spectra from the UNCOVER program add immense value to the already rich - and still growing - treasure trove of public observations in the Abell 2744 lensing cluster field. This first data release of the 1D and 2D spectra (with local background subtraction), along with derived catalogs with quality flags, is publicly available on the survey website (https://jwst-uncover.github.io/DR4.html). Future spectroscopic releases will include the repeat observations of MSA1 and spectra accompanying the Visit 3 repeat of the NIRCam parallel imaging (observed 30-31 July 2024). Additional improvements in the reduction and released products will include global background subtraction and more sophisticated modeling of emission lines.  \nThis work is based in part on observations made with the NASA/ESA/CSA James Webb Space Telescope . The data were obtained from the Mikulski Archive for Space Telescopes at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-03127 for JWST. These observations are associated with JWST-GO-2561. Support for program JWST-GO-  \n2561 was provided by NASA through a grant from the Space Telescope Science Institute, which is operated by the Associations of Universities for Research in Astronomy, Incorporated, under NASA contract NAS5-26555. The specific observations analyzed can be accessed via 10.17909/8k5c-xr27. Cloud-based data processing and file storage for this work is provided by the AWS Cloud Credits for Research program. The Cosmic Dawn Center is funded by the Danish National Research Foundation (DNRF) under grant #140. The BGU lensing group acknowledges support by grant No. 2020750 from the United States-Israel Binational Science Foundation (BSF) and grant No. 2109066 from the United States National Science Foundation (NSF), by the Israel Science Foundation Grant No. 864/23, and by the Ministry of Science & Technology, Israel.  \nFacilities: JWST(NIRSpec, NIRCam)  \nSoftware: astropy (Astropy Collaboration et al. 2013, 2018, 2022), eMPT (Bonaventura et al. 2023), jwst pipeline (v1.14.0; Bushouse et al. 2024), msaexp (v0.8.5; Brammer 2023a), grizli (v1.11.9; Brammer 2023b), eazy (Brammer et al. 2008), matplotlib (Hunter 2007), numpy (Harris et al. 2020), scipy (Virtanen et al. 2020), seaborn (Waskom et al. 2017), snowblind (Davies 2024)', 'A. PARALLEL NIRCAM IMAGING': 'Coordinated parallel NIRCam imaging was taken simultaneously with the primary NIRSpec/PRISM multiobject spectroscopy. Altogether imaging was taken in 7 broadband and 2 medium band filters (see Table 3), using the MEDIUM8 readout pattern for all exposures. This parallel imaging overlaps existing HST/ACS and WFC3 observations (HFF, Lotz et al. 2017; BUFFALO, Steinhardt et al. 2020; see Figure 7). The cumulative exposure time per filter over the parallel footprint ranges from 0.9 to 5.9 hours, with total areas ranging from 9.2 to 26.9 sq. arcmin. This includes imaging in six of the broadband filters that covers the full parallel area (excepting observation issues), and imaging in F090W and the two medium bands F410M and F480M that were only taken in parallel with Mask 5 (see Table 3).', 'B. UPDATES TO THE UNCOVER STRONG LENSING MODEL OF ABELL 2744': "We use the UNCOVER spectroscopy, described in this work, as well new JWST/NIRCam imaging (Suess et al.  \n2024) and grism spectroscopy (R. Naidu & J. Matthee, et al., in prep.) of the Abell 2744 field to update the UNCOVER strong lensing (SL) model of the cluster, as presented in Section 3.3.  \nThe parametric lens model of Abell 2744 is constructed with an updated version of the Zitrin et al. (2015) analytical method. It comprises five smooth cluster-scale dark matter halos centered on each of the sub-clusters' BCG, modeled as pseudo-isothermal elliptical mass distributions (PIEMDs; Kassiola & Kovner 1993), and 552 cluster member galaxies (see Appendix B.1), modeled as dual pseudo-isothermal ellipsoids (dPIEs; El'ıasd'ottir et al. 2007). We refer the reader to Furtak et al. (2023b) for more details on the implementation and setup of our Abell 2744 model.  \nWhile the currently available v1.1 SL model presented in Furtak et al. (2023b) is based on HST-selected cluster members and mostly photometric multiple image systems in the northern and north-western extended cluster sub-structures, the v2.0 model presented here adds additional cluster member galaxies selected with JWST (Appendix B.1) and new spectroscopic redshifts  \nFigure 7. The NIRCam parallel footprints, plotted over the existing NIRCam and HST/ACS+WFC3 coverage footprints and the lensing contours as shown in Figure 1. Coverage of F090W, F410M, and F480M is restricted to Visit 5 (taken in parallel to Mask 5) and is shown in purple, and all other filters with full parallel pointing coverage (F115W, F150W, F200W, F277W, F356W, F444W) are shown in blue.  \n<!-- image -->  \nFigure 8. JWST/NIRCam color-magnitude diagram of objects detected in Abell 2744, showing the cluster's red sequence. Known spectroscopic and photometric cluster members from Bergamini et al. (2023b) are shown as red and orange dots and our red sequence selection is shown as the blue shaded area.  \n<!-- image -->  \nof multiple image systems as constraints (section B.2). The new SL model (Appendix 3.3) maps are also made public on the UNCOVER website in the framework of DR4 (https://jwst-uncover.github.io/DR4.html; see Appendix 3.3).  \nTable 3. NIRCam Parallel Imaging  \nNote -Depths are calculated within 0. '' 16 and 0. '' 32 diameter apertures in the short and long wavelength bands, respectively, using noise properties derived from the weight maps and corrected to total assuming a point source geometry. As the footprint is inhomogenous, these estimates correspond to a 0.7 arcmin 2 box centered at (3 . 6012969 , -30 . 4908199). Columns: (1) NIRCam filter. (2) Filter exposure time across footprint (hours). (3) Total filter footprint area (sq. arcmin). (4) Imaging 5 σ depth. (5) Mask(s) with which the filter was observed in parallel.", 'B.1. JWST cluster member selection': "Thanks to the JWST Medium Bands, Mega Science program ( MegaScience ; Suess et al. 2024), we now have NIRCam F070W and F090W imaging data covering the entire UNCOVER field at our disposal. These two filters straddle the 4000 ˚ A break at the cluster's redshift z d = 0 . 308 and are therefore ideally suited for photometric selection of cluster members from the red sequence (e.g. Repp & Ebeling 2018). We use SExtractor (Bertin &Arnouts 1996) in dual-imaging mode to detect sources in the F090W mosaic and measure their photometry in F070W and F090W. Following our approach in Furtak et al. (2023b) and Furtak et al. (2024b), we then use the colors of the known spectroscopic cluster members from Bergamini et al. (2023b) to calibrate the cluster's red sequence in the color-magnitude diagram (see Figure 8). Cluster members are then selected in a color-window of width 0.1 around the red sequence and brighter than 23 magnitudes in the F090W band. The resulting sample is cross-matched with the known spectroscopic and HST-selected cluster members (Furtak et al. 2023b) to make sure no galaxy is counted doubly.  \nAs a result, we complement our previous cluster member sample from Furtak et al. (2023b) with 132 new NIRCam selected cluster members. This bring the total  \nTable 4. New spectroscopic redshifts of multiply-imaged sources included in our v2.0 SL model of Abell 2744.  \nNote -A full table of multiple images used in the v2.0 model is included in the public SL model release at https://jwst-uncover.github. io/DR4.html.  \nColumns: (1) ID number of the multiple image system. (2) ID number of the MSA-slit on one of the images. (3) Spectroscopic redshift. (4) Reference to the spectroscopic redshift measurement.  \nnumber of cluster members included in the SL model to 552, now spanning the entire 45 arcmin 2 of the UNCOVER field. The new, NIRCam-selected sample in particular adds cluster members in the north-east to north-west of the cluster, areas which were not covered with HST.", 'B.2. New spectroscopic redshifts of multiple images': "The unprecedented depth and areal coverage of the UNCOVER survey's imaging (Bezanson et al. 2022) enabled us to detect new multiple image systems in northwestern and northern extensions of Abell 2744 which were previously not know to be dense enough to produce strong lensing (Furtak et al. 2023b). These new systems  \nwere however not constrained with spectroscopic redshifts in the first UNCOVER model ( v1.0 ) due to lack of spectroscopic coverage in those areas. Multiple images without precise redshift information are known to significantly bias SL models of galaxy clusters (e.g. Johnson & Sharon 2016) which is why spectroscopic redshifts are paramount for accurate SL modeling and magnification estimates.  \nAfter the publication of our v1.0 model (Furtak et al. 2023b), new VLT/MUSE observations found system 68 to lie at z spec = 2 . 584 (Bergamini et al. 2023a). We included that new redshift in our v1.1 model release in June 2023, but the model remained mostly constrained with photometric systems in the north-west and the north. With the UNCOVER JWST/NIRSpec observations presented in this work, we are now able to spectroscopically confirm numerous multiple image systems in the whole UNCOVER field. In total, we obtained 10 new spectroscopic redshifts. These in particular include the triply-imaged high-redshift AGN A2744-QSO1 at z spec = 7 . 045 (system 53; Furtak et al. 2024a), a low-mass heavily star-forming object at z spec = 6 . 875 (system 86; Atek et al. 2024), and a massive quiescent galaxy at z spec = 2 . 322 stretched into an arc (system 67; Siegel et al. in prep.). In addition, the JWST Cycle 2 program All the Little Things (ALT; Program-IS: 3516 PIs J. Matthee & R. Naidu) observed the Abell 2744 field with JWST/NIRCam grism spectroscopy in the F356W filter, which enabled the discovery of two new multiple image systems at z spec = 6 . 873 (system 84) and z spec = 4 . 753 (system 85) respectively (R. Naidu & J. Matthee, et al., in prep.), which we also included in the model. Note that system 84 also has an UNCOVER NIRSpec redshift which agrees with the ALT redshifts.  \nWe list all new multiple image redshifts in Table 4 and show them in Figure 9. In total, our new v2.0 SL model is constrained by 187 multiple images belonging to 66 individual sources. Of these, 60 sources now have spectroscopic redshifts, leaving only 6 multiply-imaged sources with free redshifts in the model. For additional constraining power, we now also use parity information of 4 very close knot systems, systems 65.3, 67.3, 78.3, and 80.2, as constraints in the model (see equations 8 and 9 in Furtak et al. 2023b). A full list of multiple images, including coordinates and redshifts, is included in the public v2.0 SL model release.", 'REFERENCES': "Adams, N. J., Conselice, C. J., Austin, D., et al. 2024, ApJ,  \n965, 169, doi: 10.3847/1538-4357/ad2a7b  \nArrabal Haro, P., Dickinson, M., Finkelstein, S. L., et al.  \n2023a, ApJL, 951, L22, doi: 10.3847/2041-8213/acdd54  \nFigure 9. A 4 . 3 ' × 4 . 8 ' cutout of an UNCOVER and MegaScience NIRCam composite-color image of Abell 2744 including all broad and medium bands. Overlaid we show the critical curves of our SL model for source redshifts z s = 1 . 6881 (corresponding to system 1) and z s = 10 in blue and purple respectively. Multiple images from Bergamini et al. (2023b), used with spectroscopic redshifts in our v1.0 model, are shown in yellow and multiple images with new spectroscopic redshifts in our v2.0 model are shown in green. Photometric multiple images are shown in red. The area between the main cluster and the north-western sub-structure in particular has high magnifications of order µ ≳ 4 for sources at z s = 10 (see Fig. 2). 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