[
{
"id": "authors:72dbx-r9123",
"collection": "authors",
"collection_id": "72dbx-r9123",
"cite_using_url": "https://authors.library.caltech.edu/records/72dbx-r9123",
"type": "article",
"title": "Ghosts of Eruptions Past: Searching for Historical Galactic Supernovae using Variable Thermal Dust Echoes and Machine Learning",
"author": [
{
"family_name": "Vega",
"given_name": "Justin",
"orcid": "0000-0003-1481-8076"
},
{
"family_name": "De",
"given_name": "Kishalay",
"orcid": "0000-0002-8989-0542"
},
{
"family_name": "Mahabal",
"given_name": "Ashish",
"orcid": "0000-0003-2242-0244",
"clpid": "Mahabal-A-A"
},
{
"family_name": "Jencson",
"given_name": "Jacob E.",
"orcid": "0000-0001-5754-4007",
"clpid": "Jencson-Jacob"
},
{
"family_name": "Karambelkar",
"given_name": "Viraj R.",
"orcid": "0000-0003-2758-159X"
},
{
"family_name": "Rest",
"given_name": "Armin",
"orcid": "0000-0002-4410-5387"
},
{
"family_name": "Masterson",
"given_name": "Megan",
"orcid": "0000-0003-4127-0739"
}
],
"abstract": "\n
The Galactic core-collapse supernova (SN) rate is estimated at ≈1–3 per century; however, no optically visible SN has been discovered in the past 400 yr. Although records of the last optically detected SN (Cassiopeia A) are debated, it is revealed today via its bright, variable mid-infrared (MIR) dust echoes—offering the possibility of identifying dust-obscured, missed events via their dust echoes. We present the first all-sky, untargeted search for thermal dust echoes of luminous Galactic transients using difference imaging on 12 yr of time-resolved NEOWISE coadds (spanning 2009–2022) followed by statistical detection of variable extended sources. We use echo features around Cas A, together with archival catalogs, to train a convolutional neural network to classify transient candidates as dust echoes, point sources, artifacts, and high proper motion stars. Our model achieves ≈94% accuracy in distinguishing echoes from other variable sources. Applying the classifier to ≈11 million transient candidates, we search for spatial overdensities of echoes across the Galactic plane. We find that Cas A is the only region exhibiting echoes at the Wide-field Infrared Survey Explorer (WISE) sensitivity threshold of W2 surface brightness of ≈20 Vega mag arcsec−2—reflecting its unique combination of young age and luminous shock breakout. We present the largest catalog of time-resolved echo positions of Cas A (20,477 within 10\u2218) that are being used for studies of the surrounding interstellar medium with the James Webb Space Telescope. Our results lay the groundwork for the imminent Roman space telescope surveys—which will achieve ≈100 × higher sensitivity and ≈30 × better spatial resolution at wavelengths of \u22722.5 μm.
\n
The OpenUniverse2024 simulation suite is a cross-collaboration effort to produce matched simulated imaging for multiple surveys as they would observe a common simulated sky. Both the simulated data and associated tools used to produce it are intended to uniquely enable a wide range of studies to maximize the science potential of the next generation of cosmological surveys. We have produced simulated imaging for approximately 70 deg² of the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST) Wide-Fast-Deep survey and the Nancy Grace Roman Space Telescope High-Latitude Wide-Area Survey, as well as overlapping versions of the ELAIS-S1 Deep-Drilling Field for LSST and the High-Latitude Time-Domain Survey for Roman. OpenUniverse2024 includes (i) an early version of the updated extragalactic model called Diffsky, which substantially improves the realism of optical and infrared photometry of objects, compared to previous versions of these models; (ii) updated transient models that extend through the wavelength range probed by Roman and Rubin; and (iii) improved survey, telescope, and instrument realism based on up-to-date survey plans and known properties of the instruments. It is built on a new and updated suite of simulation tools that improves the ease of consistently simulating multiple observatories viewing the same sky. The approximately 400 TB of synthetic survey imaging and simulated universe catalogs are publicly available, and we preview some scientific uses of the simulations.
",
"doi": "10.1093/mnras/staf1833",
"issn": "0035-8711",
"publisher": "Royal Astronomical Society",
"publication": "Monthly Notices of the Royal Astronomical Society",
"publication_date": "2025-12",
"series_number": "4",
"volume": "544",
"issue": "4",
"pages": "3799-3823"
},
{
"id": "authors:jhr58-tyf21",
"collection": "authors",
"collection_id": "jhr58-tyf21",
"cite_using_url": "https://authors.library.caltech.edu/records/jhr58-tyf21",
"type": "article",
"title": "JWST/MIRI Observations of Newly Formed Dust in the Cold, Dense Shell of the Type IIn SN 2005ip",
"author": [
{
"family_name": "Shahbandeh",
"given_name": "Melissa",
"orcid": "0000-0002-9301-5302"
},
{
"family_name": "Fox",
"given_name": "Ori D.",
"orcid": "0000-0003-2238-1572"
},
{
"family_name": "Temim",
"given_name": "Tea",
"orcid": "0000-0001-7380-3144"
},
{
"family_name": "Dwek",
"given_name": "Eli"
},
{
"family_name": "Sarangi",
"given_name": "Arkaprabha",
"orcid": "0000-0002-9820-679X"
},
{
"family_name": "Smith",
"given_name": "Nathan",
"orcid": "0000-0001-5510-2424"
},
{
"family_name": "Dessart",
"given_name": "Luc",
"orcid": "0000-0003-0599-8407"
},
{
"family_name": "Nickson",
"given_name": "Bryony"
},
{
"family_name": "Engesser",
"given_name": "Michael",
"orcid": "0000-0003-0209-674X"
},
{
"family_name": "Filippenko",
"given_name": "Alexei V.",
"orcid": "0000-0003-3460-0103"
},
{
"family_name": "Brink",
"given_name": "Thomas G.",
"orcid": "0000-0001-5955-2502"
},
{
"family_name": "Zheng",
"given_name": "WeiKang",
"orcid": "0000-0002-2636-6508"
},
{
"family_name": "Szalai",
"given_name": "Tam\u00e1s",
"orcid": "0000-0003-4610-1117"
},
{
"family_name": "Johansson",
"given_name": "Joel"
},
{
"family_name": "Rest",
"given_name": "Armin",
"orcid": "0000-0002-4410-5387"
},
{
"family_name": "Van Dyk",
"given_name": "Schuyler D.",
"orcid": "0000-0001-9038-9950",
"clpid": "Van-Dyk-Schuyler-D"
},
{
"family_name": "Andrews",
"given_name": "Jennifer",
"orcid": "0000-0003-0123-0062"
},
{
"family_name": "Ashall",
"given_name": "Chris",
"orcid": "0000-0002-5221-7557"
},
{
"family_name": "Clayton",
"given_name": "Geoffrey C.",
"orcid": "0000-0002-0141-7436"
},
{
"family_name": "De Looze",
"given_name": "Ilse",
"orcid": "0000-0001-9419-6355"
},
{
"family_name": "DerKacy",
"given_name": "James M.",
"orcid": "0000-0002-7566-6080"
},
{
"family_name": "Dulude",
"given_name": "Michael"
},
{
"family_name": "Foley",
"given_name": "Ryan J.",
"orcid": "0000-0002-2445-5275"
},
{
"family_name": "Gezari",
"given_name": "Suvi",
"orcid": "0000-0003-3703-5154"
},
{
"family_name": "Gomez",
"given_name": "Sebastian",
"orcid": "0000-0001-6395-6702"
},
{
"family_name": "Gonzaga",
"given_name": "Shireen"
},
{
"family_name": "Indukuri",
"given_name": "Siva"
},
{
"family_name": "Jencson",
"given_name": "Jacob",
"orcid": "0000-0001-5754-4007",
"clpid": "Jencson-Jacob"
},
{
"family_name": "Kasliwal",
"given_name": "Mansi",
"orcid": "0000-0002-5619-4938",
"clpid": "Kasliwal-M-M"
},
{
"family_name": "Lane",
"given_name": "Zachary G.",
"orcid": "0009-0003-8380-4003"
},
{
"family_name": "Lau",
"given_name": "Ryan"
},
{
"family_name": "Law",
"given_name": "David",
"orcid": "0000-0002-9402-186X"
},
{
"family_name": "Marston",
"given_name": "Anthony",
"orcid": "0000-0001-5788-5258"
},
{
"family_name": "Milisavljevic",
"given_name": "Dan",
"orcid": "0000-0002-0763-3885"
},
{
"family_name": "O'Steen",
"given_name": "Richard",
"orcid": "0000-0002-2432-8946"
},
{
"family_name": "Pierel",
"given_name": "Justin",
"orcid": "0000-0002-2361-7201"
},
{
"family_name": "Siebert",
"given_name": "Matthew",
"orcid": "0000-0003-2445-3891"
},
{
"family_name": "Skrutskie",
"given_name": "Michael"
},
{
"family_name": "Strolger",
"given_name": "Lou",
"orcid": "0000-0002-7756-4440"
},
{
"family_name": "Tinyanont",
"given_name": "Samaporn",
"orcid": "0000-0002-1481-4676"
},
{
"family_name": "Wang",
"given_name": "Qinan",
"orcid": "0000-0001-5233-6989"
},
{
"family_name": "Williams",
"given_name": "Brian",
"orcid": "0000-0003-2063-381X"
},
{
"family_name": "Xiao",
"given_name": "Lin",
"orcid": "0000-0002-6986-5593"
},
{
"family_name": "Yang",
"given_name": "Yi",
"orcid": "0000-0002-6535-8500"
},
{
"family_name": "Zs\u00edros",
"given_name": "Szanna",
"orcid": "0000-0001-7473-4208"
}
],
"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 (\u22730.08 M\u2299) 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 (\u22730.005 M\u2299) 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.
",
"doi": "10.3847/1538-4357/adce77",
"issn": "0004-637X",
"publisher": "American Astronomical Society",
"publication": "Astrophysical Journal",
"publication_date": "2025-06-01",
"series_number": "2",
"volume": "985",
"issue": "2",
"pages": "262"
},
{
"id": "authors:hhv62-btr26",
"collection": "authors",
"collection_id": "hhv62-btr26",
"cite_using_url": "https://authors.library.caltech.edu/records/hhv62-btr26",
"type": "article",
"title": "Cryoscope: A Cryogenic Infrared Survey Telescope in Antarctica",
"author": [
{
"family_name": "Kasliwal",
"given_name": "Mansi M.",
"orcid": "0000-0002-5619-4938",
"clpid": "Kasliwal-M-M"
},
{
"family_name": "Earley",
"given_name": "Nicholas",
"orcid": "0000-0001-6627-9903",
"clpid": "Earley-Nicholas"
},
{
"family_name": "Smith",
"given_name": "Roger",
"orcid": "0000-0001-7062-9726",
"clpid": "Smith-R-M"
},
{
"family_name": "Guillot",
"given_name": "Tristan",
"orcid": "0000-0002-7188-8428"
},
{
"family_name": "Travouillon",
"given_name": "Tony",
"orcid": "0000-0001-9304-6718"
},
{
"family_name": "Fucik",
"given_name": "Jason",
"clpid": "Fucik-Jason"
},
{
"family_name": "Abe",
"given_name": "Lyu",
"orcid": "0000-0002-0856-4527"
},
{
"family_name": "Greffe",
"given_name": "Timothee",
"orcid": "0000-0003-4594-1827",
"clpid": "Greffe-Timothee"
},
{
"family_name": "Agabi",
"given_name": "Abdelkrim",
"orcid": "0000-0001-7948-6493"
},
{
"family_name": "Ashley",
"given_name": "Michael C. B.",
"orcid": "0000-0003-1412-2028"
},
{
"family_name": "Triaud",
"given_name": "Amaury H. M. J.",
"orcid": "0000-0002-5510-8751"
},
{
"family_name": "Tinyanont",
"given_name": "Samaporn",
"orcid": "0000-0002-1481-4676"
},
{
"family_name": "Antier",
"given_name": "Sarah",
"orcid": "0000-0002-7686-3334"
},
{
"family_name": "Bendjoya",
"given_name": "Philippe",
"orcid": "0000-0002-4278-1437"
},
{
"family_name": "Bhattarai",
"given_name": "Rohan",
"orcid": "0009-0007-0323-4733",
"clpid": "Bhattarai-Rohan"
},
{
"family_name": "Bertz",
"given_name": "Rob",
"clpid": "Bertz-Rob"
},
{
"family_name": "Brugger",
"given_name": "James",
"clpid": "Brugger-James"
},
{
"family_name": "Burdanov",
"given_name": "Artem",
"orcid": "0000-0001-9892-2406"
},
{
"family_name": "Caiazzo",
"given_name": "Ilaria",
"orcid": "0000-0002-4770-5388",
"clpid": "Caiazzo-Ilaria"
},
{
"family_name": "Carry",
"given_name": "Benoit",
"orcid": "0000-0001-5242-3089"
},
{
"family_name": "Casagrande",
"given_name": "Luca",
"orcid": "0000-0003-2688-7511"
},
{
"family_name": "Cenko",
"given_name": "Brad",
"orcid": "0000-0003-1673-970X"
},
{
"family_name": "Cooke",
"given_name": "Jeff",
"orcid": "0000-0001-5703-2108"
},
{
"family_name": "De",
"given_name": "Kishalay",
"orcid": "0000-0002-8989-0542"
},
{
"family_name": "Dekany",
"given_name": "Richard",
"clpid": "Dekany-Richard"
},
{
"family_name": "Deloupy",
"given_name": "Vincent",
"orcid": "0009-0007-5876-546X"
},
{
"family_name": "Dornic",
"given_name": "Damien",
"orcid": "0000-0001-5729-1468"
},
{
"family_name": "Fahey",
"given_name": "Lauren",
"clpid": "Fahey-Lauren"
},
{
"family_name": "Figer",
"given_name": "Don"
},
{
"family_name": "Freeman",
"given_name": "Kenneth",
"orcid": "0000-0001-6280-1207"
},
{
"family_name": "Frostig",
"given_name": "Danielle",
"orcid": "0000-0002-7197-9004"
},
{
"family_name": "Graham",
"given_name": "Matthew J.",
"orcid": "0000-0002-3168-0139",
"clpid": "Graham-M-J"
},
{
"family_name": "G\u00fcnther",
"given_name": "Maximilian",
"orcid": "0000-0002-3164-9086"
},
{
"family_name": "Hale",
"given_name": "David",
"clpid": "Hale-David"
},
{
"family_name": "Bland-Hawthorn",
"given_name": "Joss",
"orcid": "0000-0001-7516-4016"
},
{
"family_name": "Illuminati",
"given_name": "Giulia"
},
{
"family_name": "Jencson",
"given_name": "Jacob",
"orcid": "0000-0001-5754-4007",
"clpid": "Jencson-Jacob"
},
{
"family_name": "Karambelkar",
"given_name": "Viraj",
"orcid": "0000-0003-2758-159X",
"clpid": "Karambelkar-Viraj"
},
{
"family_name": "Key",
"given_name": "Renee"
},
{
"family_name": "Lau",
"given_name": "Ryan M.",
"orcid": "0000-0003-0778-0321"
},
{
"family_name": "Li",
"given_name": "Maggie",
"orcid": "0009-0001-6911-9144",
"clpid": "Li-Maggie"
},
{
"family_name": "Lubin",
"given_name": "Philip"
},
{
"family_name": "Neill",
"given_name": "Don",
"clpid": "Neill-Don"
},
{
"family_name": "Pahuja",
"given_name": "Rishi",
"orcid": "0000-0002-9542-6068",
"clpid": "Pahuja-Rishi"
},
{
"family_name": "Pian",
"given_name": "Elena",
"orcid": "0000-0001-8646-4858"
},
{
"family_name": "de Ugarte Postigo",
"given_name": "Antonio",
"orcid": "0000-0001-7717-5085"
},
{
"family_name": "Roberts",
"given_name": "Mitsuko",
"clpid": "Roberts-Mitsuko"
},
{
"family_name": "Rodriguez",
"given_name": "Hector",
"clpid": "Rodriguez-Hector"
},
{
"family_name": "Rose",
"given_name": "Sam",
"orcid": "0000-0003-4725-4481",
"clpid": "Rose-Sam"
},
{
"family_name": "Ruiter",
"given_name": "Ashley J.",
"orcid": "0000-0002-4794-6835"
},
{
"family_name": "Schmider",
"given_name": "Fran\u00e7ois-Xavier",
"orcid": "0000-0003-3914-3546"
},
{
"family_name": "Simcoe",
"given_name": "Robert A.",
"orcid": "0000-0003-3769-9559"
},
{
"family_name": "Stein",
"given_name": "Robert",
"orcid": "0000-0003-2434-0387"
},
{
"family_name": "Suarez",
"given_name": "Olga",
"orcid": "0000-0002-3503-3617"
},
{
"family_name": "Taylor",
"given_name": "Edward N.",
"orcid": "0000-0002-3958-0343"
},
{
"family_name": "Weber",
"given_name": "Bob",
"clpid": "Weber-Bob"
},
{
"family_name": "Wen",
"given_name": "Linqing",
"orcid": "0000-0001-7987-295X"
},
{
"family_name": "de Wit",
"given_name": "Julien",
"orcid": "0000-0003-2415-2191"
},
{
"family_name": "Zarzaca",
"given_name": "Ray",
"clpid": "Zarzaca-Ray"
},
{
"family_name": "Zimmer",
"given_name": "Jake",
"orcid": "0009-0007-9419-5118",
"clpid": "Zimmer-Jake"
}
],
"abstract": "\n
We present Cryoscope, a new 50 deg2 field-of-view, 1.2 m aperture, Kdark survey 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 2 μm, 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 the Kdark passband, 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.
\n
Aims. We investigate the photometric characteristics of a sample of intermediate-luminosity red transients (ILRTs), a class of elusive objects with peak luminosity between that of classical novae and standard supernovae. Our goal is to provide a stepping stone in the path to reveal the physical origin of such events, thanks to the analysis of the datasets collected.
\nMethods. We present the multi-wavelength photometric follow-up of four ILRTs, namely NGC 300 2008OT-1, AT 2019abn, AT 2019ahd, and AT 2019udc. Through the analysis and modelling of their spectral energy distribution and bolometric light curves, we inferred the physical parameters associated with these transients.
\nResults. All four objects display a single-peaked light curve which ends in a linear decline in magnitudes at late phases. A flux excess with respect to a single blackbody emission is detected in the infrared domain for three objects in our sample, a few months after maximum. This feature, commonly found in ILRTs, is interpreted as a sign of dust formation. Mid-infrared monitoring of NGC 300 2008OT-1 761 days after maximum allowed us to infer the presence of ∼10−3–10−5 M\u2299 of dust, depending on the chemical composition and the grain size adopted. The late-time decline of the bolometric light curves of the considered ILRTs is shallower than expected for 56Ni decay, hence requiring an additional powering mechanism. James Webb Space Telescope observations of AT 2019abn prove that the object has faded below its progenitor luminosity in the mid-infrared domain, five years after its peak. Together with the disappearance of NGC 300 2008OT-1 in Spitzer images seven years after its discovery, this supports the terminal explosion scenario for ILRTs. With a simple semi-analytical model we tried to reproduce the observed bolometric light curves in the context of a few solar masses ejected at few 103 km s−1 and enshrouded in an optically thick circumstellar medium.
",
"doi": "10.1051/0004-6361/202451733",
"issn": "0004-6361",
"publisher": "EDP Sciences",
"publication": "Astronomy & Astrophysics",
"publication_date": "2025-03",
"volume": "695",
"pages": "A42"
},
{
"id": "authors:ebr8w-24m21",
"collection": "authors",
"collection_id": "ebr8w-24m21",
"cite_using_url": "https://authors.library.caltech.edu/records/ebr8w-24m21",
"type": "article",
"title": "A Diverse, Overlooked Population of Type Ia Supernovae Exhibiting Mid-infrared Signatures of Delayed Circumstellar Interaction",
"author": [
{
"family_name": "Mo",
"given_name": "Geoffrey",
"orcid": "0000-0001-6331-112X"
},
{
"family_name": "De",
"given_name": "Kishalay",
"orcid": "0000-0002-8989-0542"
},
{
"family_name": "Wiston",
"given_name": "Eli",
"orcid": "0009-0002-4843-2913"
},
{
"family_name": "A. J.",
"given_name": "Nayana",
"orcid": "0000-0002-8070-5400"
},
{
"family_name": "Margutti",
"given_name": "Raffaella",
"orcid": "0000-0003-4768-7586"
},
{
"family_name": "Frostig",
"given_name": "Danielle",
"orcid": "0000-0002-7197-9004"
},
{
"family_name": "Sollerman",
"given_name": "Jesper",
"orcid": "0000-0003-1546-6615"
},
{
"family_name": "Sharma",
"given_name": "Yashvi",
"orcid": "0000-0003-4531-1745",
"clpid": "Sharma-Yashvi"
},
{
"family_name": "Moriya",
"given_name": "Takashi J.",
"orcid": "0000-0003-1169-1954"
},
{
"family_name": "Burdge",
"given_name": "Kevin B.",
"orcid": "0000-0002-7226-836X"
},
{
"family_name": "Jencson",
"given_name": "Jacob",
"orcid": "0000-0001-5754-4007",
"clpid": "Jencson-Jacob"
},
{
"family_name": "Karambelkar",
"given_name": "Viraj R.",
"orcid": "0000-0003-2758-159X",
"clpid": "Karambelkar-Viraj-R"
},
{
"family_name": "Lourie",
"given_name": "Nathan P.",
"orcid": "0000-0002-4585-9981"
}
],
"abstract": "\n
Type Ia supernovae (SNe Ia) arise from the thermonuclear explosions of white dwarfs in multiple-star systems. A rare subclass of SNe Ia exhibit signatures of interaction with circumstellar material (CSM), allowing for direct constraints on companion material. While most known events show evidence for dense nearby CSM identified via peak-light spectroscopy (as SNe Ia-CSM), targeted late-time searches have revealed a handful of cases exhibiting delayed CSM interaction with detached shells. Here we present the first all-sky search for late CSM interaction in SNe Ia using a new image subtraction pipeline for mid-infrared data from the NEOWISE space telescope. Analyzing a sample of ≈8500 SNe Ia, we report evidence for late-time mid-infrared brightening in five previously overlooked events spanning subtypes SNe Iax, SNe Ia-91T, and super-Chandra SNe Ia. Our systematic search doubles the known sample and suggests that \u22730.05% of SNe Ia exhibit mid-infrared signatures of delayed CSM interaction. The mid-infrared light curves ubiquitously indicate the presence of multiple (or extended) detached CSM shells located at \u22731016–1017 cm, containing 10−6 to 10−4 M\u2299 of dust, with some sources showing evidence for new dust formation, possibly within the cold, dense shell of the ejecta. We do not detect interaction signatures in spectroscopic and radio follow-up; however, the limits are largely consistent with previously confirmed events given the sensitivity and observation phase. Our results highlight that CSM interaction is more prevalent than previously estimated from optical and ultraviolet searches and that mid-infrared synoptic surveys provide a unique window into this phenomenon.
\n
\n
Narrow transient emission lines (flash-ionization features) in early supernova (SN) spectra trace the presence of circumstellar material (CSM) around the massive progenitor stars of core-collapse SNe. The lines disappear within days after the SN explosion, suggesting that this material is spatially confined, and originates from enhanced mass loss shortly (months to a few years) prior to the explosion. We performed a systematic survey of H-rich (Type II) SNe discovered within less than 2 days from the explosion during the first phase of the Zwicky Transient Facility survey (2018–2020), finding 30 events for which a first spectrum was obtained within <2 days from the explosion. The measured fraction of events showing flash-ionization features (>36% at the 95% confidence level) confirms that elevated mass loss in massive stars prior to SN explosion is common. We find that SNe II showing flash-ionization features are not significantly brighter, nor bluer, nor more slowly rising than those without. This implies that CSM interaction does not contribute significantly to their early continuum emission, and that the CSM is likely optically thin. We measured the persistence duration of flash-ionization emission and find that most SNe show flash features for ≈5 days. Rarer events, with persistence timescales >10 days, are brighter and rise longer, suggesting these may be intermediate between regular SNe II and strongly interacting SNe IIn.
\n