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Abstract Palomar Gattini-IR (PGIR) is a wide-field, synoptic infrared time domain survey covering ≈15,000 sq. deg. of the accessible sky at ≈1–3 night cadence to a depth ofJ≈ 13.0 and ≈14.9 Vega mag in and outside the Galactic plane, respectively. Here, we present the first data release ofJ-band light curves of Two Micron All Sky Survey (2MASS) sources within the survey footprint covering approximately the first four years of operations. We describe the construction of the source catalog based on 2MASS point sources, followed by exposure filtering criteria and forced PSF photometry. The catalog contains light curves of ≈286 million unique sources with 2MASS magnitudes ofJ< 15.5 mag, with a total of ≈50 billion photometric measurements and ≈20 billion individual source detections at signal-to-noise-ratio > 3. We demonstrate the photometric fidelity of the catalog by (i) quantifying the magnitude-dependent accuracy and uncertainty of the photometry with respect to 2MASS and (ii) comparing against forced PGIR aperture photometry for known variable sources. We present simple filtering criteria for selecting reliable photometric measurements as well as examplePythonnotebooks for users. This catalog is one of the largest compilation of nightly cadence, synoptic infrared light curves to date, comparable to those in the largest optical surveys, providing a stepping stone to upcoming infrared surveys in the coming decade. 

Abstract Supernova (SN) 2014C is a rare transitional event that exploded as a hydrogen-poor, helium-rich Type Ib SN and subsequently interacted with a hydrogen-rich circumstellar medium (CSM) a few months postexplosion. This unique interacting object provides an opportunity to probe the mass-loss history of a stripped-envelope SN progenitor. Using the James Webb Space Telescope (JWST), we observed SN 2014C with the Mid-Infrared Instrument Medium Resolution Spectrometer at 3477 days postexplosion (rest frame), and the Near-Infrared Spectrograph Integral Field Unit at 3568 days postexplosion, covering 1.7–25μm. The bolometric luminosity indicates that the SN is still interacting with the same CSM that was observed with the Spitzer Space Telescope 40–1920 days postexplosion. JWST spectra and near-contemporaneous optical and near-infrared spectra show strong [Neii] 12.831μm, He 1.083μm, Hα, and forbidden oxygen ([Oi]λλ6300, 6364, [Oii]λλ7319, 7330, and [Oiii]λλ4959, 5007) emission lines with asymmetric profiles, suggesting a highly asymmetric CSM. The mid-IR continuum can be explained by ∼0.036M_⊙of carbonaceous dust at ∼300 K and ∼0.043M_⊙of silicate dust at ∼200 K. The observed dust mass has increased tenfold since the last Spitzer observation 4 yr ago, with evidence suggesting that new grains have condensed in the cold dense shell between the forward and reverse shocks. This dust mass places SN 2014C among the dustiest SNe in the mid-IR and supports the emerging observational trend that SN explosions produce enough dust to explain the observed dust mass at high redshifts. 

The central regions of the Milky Way constitute a unique laboratory for a wide swath of astrophysical studies; consequently, the inner ∼400 pc have been the target of numerous large surveys at all accessible wavelengths. In this paper, we present a catalog of sources at 25 and 37μm located within all of the regions observed with the SOFIA/FORCAST instrument in the inner ∼200 pc of the Galaxy. The majority of the observations were obtained as part of the SOFIA Cycle 7 Galactic Center Legacy program survey, which was designed to complement the Spitzer/MIPS 24μm catalog in regions saturated in the MIPS observations. Due to the wide variety of source types captured by our observations at 25 and 37μm, we do not limit the FORCAST source catalog to unresolved point sources, or treat all sources as if they are pointlike sources. The catalog includes all detectable sources in the regions, resulting in a catalog of 950 sources, including point sources, compact sources, and extended sources. We also provide the user with metrics to discriminate between the source types. 

Abstract Classical Wolf–Rayet (W-R) stars are the descendants of massive OB stars that have lost their hydrogen envelopes and are burning helium in their cores prior to exploding as Type Ib/c supernovae. The mechanisms for losing their hydrogen envelopes are either through binary interactions or through strong stellar winds potentially coupled with episodic mass loss. Among the bright classical W-R stars, the binary system WR 137 (HD 192641; WC7d + O9e) is the subject of this paper. This binary is known to have a 13 yr period and produces dust near periastron. Here we report on interferometry with the Center for High Angular Resolution Astronomy Array collected over a decade of time and providing the first visual orbit for the system. We combine these astrometric measurements with archival radial velocities to measure masses of the stars ofM_WR= 9.5 ± 3.4M_⊙andM_O= 17.3 ± 1.9M_⊙when we use the most recent Gaia distance. These results are then compared to predicted dust distribution using these orbital elements, which match the observed imaging from JWST as discussed recently by Lau et al. Furthermore, we compare the system to the Binary Population And Spectral Synthesis models, finding that the W-R star likely formed through stellar winds and not through binary interactions. However, the companion O star did likely accrete some material from the W-R star’s mass loss to provide the rotation seen today that drives its status as an Oe star. 

Abstract Dust from core-collapse supernovae (CCSNe), specifically Type IIP supernovae (SNe IIP), has been suggested to be a significant source of the dust observed in high-redshift galaxies. CCSNe eject large amounts of newly formed heavy elements, which can condense into dust grains in the cooling ejecta. However, infrared (IR) observations of typical CCSNe generally measure dust masses that are too small to account for the dust production needed at high redshifts. Type IIn SNe (SNe IIn), classified by their dense circumstellar medium, are also known to exhibit strong IR emission from warm dust, but the dust origin and heating mechanism have generally remained unconstrained because of limited observational capabilities in the mid-IR (MIR). Here, we present a JWST/MIRI Medium Resolution Spectrograph spectrum of the SN IIn SN 2005ip nearly 17 yr post-explosion. The SN IIn SN 2005ip is one of the longest-lasting and most well-studied SNe observed to date. Combined with a Spitzer MIR spectrum of SN 2005ip obtained in 2008, this data set provides a rare 15 yr baseline, allowing for a unique investigation of the evolution of dust. The JWST spectrum shows the emergence of an optically thin silicate dust component (≳0.08M_⊙) that is either not present or more compact/optically thick in the earlier Spitzer spectrum. Our analysis shows that this dust is likely newly formed in the cold, dense shell (CDS), between the forward and reverse shocks, and was not preexisting at the time of the explosion. There is also a smaller mass of carbonaceous dust (≳0.005M_⊙) in the ejecta. These observations provide new insights into the role of SN dust production, particularly within the CDS, and its potential contribution to the rapid dust enrichment of the early Universe. 

Abstract We present new JWST/MIRI Medium Resolution Spectroscopy and Keck spectra of SN 1995N obtained in 2022–2023, more than 10,000 days after the supernova (SN) explosion. These spectra are among the latest direct detections of a core-collapse SN, both through emission lines in the optical and thermal continuum from infrared (IR) dust emission. The new IR data show that dust heating from radiation produced by the ejecta interacting with circumstellar matter is still present but greatly reduced from when SN 1995N was observed by the Spitzer Space Telescope and WISE in 2009/2010 and 2018, when the dust mass was estimated to be 0.4M_⊙. New radiative-transfer modeling suggests that the dust mass and grain size may have increased between 2010 and 2023. The new data can alternatively be well fit with a dust mass of 0.4M_⊙and a much reduced heating source luminosity. The new late-time spectra show unusually strong oxygen forbidden lines, stronger than the Hαemission. This indicates that SN 1995N may have exploded as a stripped-envelope SN, which then interacted with a massive H-rich circumstellar shell, changing it from intrinsically Type Ib/c to Type IIn. The late-time spectrum results when the reverse shock begins to excite the inner H-poor, O-rich ejecta. This change in the spectrum is rarely seen but marks the start of the transition from SN to SN remnant. 

Abstract We present Cryoscope, a new 50 deg²field-of-view, 1.2 m aperture,K_darksurvey telescope to be located at Dome C, Antarctica. Cryoscope has an innovative optical–thermal design wherein the entire telescope is cryogenically cooled. Cryoscope also explores new detector technology to cost-effectively tile the full focal plane. Leveraging the dark Antarctic sky and minimizing telescope thermal emission, Cryoscope achieves unprecedented deep, wide, fast, and red observations, matching and exceeding volumetric survey speeds from the Ultraviolet Explorer, Vera Rubin Observatory, Nancy Grace Roman Space Telescope, SPHEREx, and NEO Surveyor. By providing coverage beyond wavelengths of 2μm, we aim to create the most comprehensive dynamic movie of the most obscured reaches of the Universe. Cryoscope will be a dedicated discovery engine for electromagnetic emission from coalescing compact binaries, Earth-like exoplanets orbiting cold stars, and multiple facets of time-domain, stellar, and solar system science. In this paper, we describe the scientific drivers and technical innovations for this new discovery engine operating in theK_darkpassband, why we choose to deploy it in Antarctica, and the status of a fifth-scale prototype designed as a Pathfinder to retire technological risks prior to full-scale implementation. We plan to deploy the Cryoscope Pathfinder to Dome C in 2026 December and the full-scale telescope by 2030. 

Abstract We analyze pre-explosion near- and mid-infrared (IR) imaging of the site of SN 2023ixf in the nearby spiral galaxy M101 and characterize the candidate progenitor star. The star displays compelling evidence of variability with a possible period of ≈1000 days and an amplitude of Δ m ≈ 0.6 mag in extensive monitoring with the Spitzer Space Telescope since 2004, likely indicative of radial pulsations. Variability consistent with this period is also seen in the near-IR J and K s bands between 2010 and 2023, up to just 10 days before the explosion. Beyond the periodic variability, we do not find evidence for any IR-bright pre-supernova outbursts in this time period. The IR brightness ( M K s = − 10.7 mag) and color ( J − K s = 1.6 mag) of the star suggest a luminous and dusty red supergiant. Modeling of the phase-averaged spectral energy distribution (SED) yields constraints on the stellar temperature ( T eff = 3500 − 1400 + 800 K) and luminosity ( log L / L ⊙ = 5.1 ± 0.2 ). This places the candidate among the most luminous Type II supernova progenitors with direct imaging constraints, with the caveat that many of these rely only on optical measurements. Comparison with stellar evolution models gives an initial mass of M init = 17 ± 4 M ⊙ . We estimate the pre-supernova mass-loss rate of the star between 3 and 19 yr before explosion from the SED modeling at M ̇ ≈ 3 × 10 − 5 to 3 × 10 −4 M ⊙ yr −1 for an assumed wind velocity of v w = 10 km s −1 , perhaps pointing to enhanced mass loss in a pulsation-driven wind. 

Abstract We report our Spitzer Space Telescope observations and detections of the binary neutron star merger GW170817. At 4.5 μm, GW170817 is detected at 21.9  mag AB at +43 days and 23.9 mag AB at +74 days after merger. At 3.6 μm, GW170817 is not detected to a limit of 23.2 mag AB at +43 days and 23.1 mag AB at  +74 days. Our detections constitute the latest and reddest constraints on the kilonova/macronova emission and composition of heavy elements. The 4.5 μm luminosity at this late phase cannot be explained by elements exclusively from the first abundance peak of the r-process. Moreover, the steep decline in the Spitzer band, with a power-law index of 3.4 ± 0.2, can be explained by a few of the heaviest isotopes with half-life around 14  d dominating the luminosity (e.g. 140Ba, 143Pr, 147Nd, 156Eu, 191Os, 223Ra, 225Ra, 233Pa, 234Th) or a model with lower deposition efficiency. This data offers evidence that the heaviest elements in the second and third r-process abundance peak were indeed synthesized. Our conclusion is verified by both analytics and network simulations and robust despite intricacies and uncertainties in the nuclear physics. Future observations with Spitzer and James Webb Space Telescope will further illuminate the relative abundance of the synthesized heavy elements. 

We present optical and infrared (IR) light curves of the enshrouded massive binary NaSt1 (WR 122) with observations from Palomar Gattini-IR (PGIR), the Zwicky Transient Facility (ZTF), the Katzman Automatic Imaging Telescope (KAIT), and the All-Sky Automated Survey for Supernovae (ASAS-SN). The optical and IR light curves span between 2014 July and 2020 Oct., revealing periodic, sinusoidal variability from NaSt1 with a P=305.2±1.0 d period. We also present historical IR light curves taken between 1983 July and 1989 May that also indicate NaSt1 exhibits long-term IR variability on timescales of ∼decades. Fixed-period sinusoidal fits to the recent optical and IR light curves show that amplitude of NaSt1's variability is different at different wavelengths and also reveal significant phase offsets of ∼18 d between the ZTF r and PGIR J light curves.We interpret the ∼300 d period of the observed variability as the orbital period of a binary system in NaSt1. Assuming a circular orbit and adopting a range of combined stellar mass values in the range 20-100 M⊙ in NaSt1, we estimate orbital separations of ∼2-4 au. We suggest that the sinusoidal photometric variability of NaSt1 may arise from variations in the line-of-sight optical depth toward circumstellar optical/IR emitting regions throughout its orbit due to colliding-wind dust formation. We provide an interpretation on the nature of NaSt1 and speculate that the mass-transfer process may have been triggered by Roche-lobe overflow (RLOF) during an eruptive phase of a Ofpe/WN9 star. Lastly, we claim that NaSt1 ceased RLOF mass transfer ≲3400 yr ago.