Explanipedia

Early Lightcurves of Type Ia Supernovae Are Consistent with Nondegenerate Progenitor Companions Open

Moira Andrews, R. Amaro, K. Azalee Bostroem, Yize Dong, J. Haislip , et al. · 2025

If Type Ia supernovae (SNe Ia) result from a white dwarf being ignited by Roche-lobe overflow from a nondegenerate companion, then as the SN explosion runs into the companion star its ejecta will be shocked, causing an early blue excess in…

Spectral Diversity in Type Ibn Supernovae and the Large Host Offset of SN2024acyl Open

Yize Dong, V. Ashley Villar, Anya E. Nugent, G. Hosseinzadeh, R. J. Foley , et al. · 2025

In this paper, we first present observations of SN~2024acyl, a normal Type Ibn supernova with a large projected offset ($\sim$35~kpc) from its host galaxy. The low star-formation rate measured at the explosion site raises the possibility t…

Mid-infrared Dust Evolution and Late-time Circumstellar Medium Interaction in SN 2017eaw Open

Jeniveve Pearson, Bhagya Subrayan, David J. Sand, Jennifer E. Andrews, Emma R. Beasor , et al. · 2025

We present JWST/Mid-Infrared Instrument (MIRI) and complementary ground-based near-infrared observations of the Type II SN 2017eaw taken 6 yr postexplosion. SN 2017eaw is still detected out to 25 μ m and there is minimal evolution in the m…

SN 2019hnl: A Type IIP Supernova with a Partially Stripped, Low-mass Progenitor Open

Aidan Martas, S. Valenti, Aravind P. Ravi, Yize Dong, K. Azalee Bostroem , et al. · 2025

We present optical photometry and spectroscopy of SN 2019hnl. Discovered within ∼26 hr of explosion by the ATLAS survey, SN 2019hnl is a typical Type IIP supernova (SN) with a peak absolute V -band magnitude of −16.7 ± 0.1 mag, a plateau l…

Final Moments. III. Explosion Properties and Progenitor Constraints of CSM-interacting Type II Supernovae Open

W. V. Jacobson-Galán, Luc Dessart, Kyle W. Davis, K. Azalee Bostroem, C. D. Kilpatrick , et al. · 2025

We present analysis of the plateau and late-time phase properties of a sample of 39 Type II supernovae (SNe II) that show narrow, transient, high-ionization emission lines (i.e., “IIn-like”) in their early-time spectra from interaction wit…

Early Shock Cooling Observations and Progenitor Constraints of Type IIb Supernova SN 2024uwq Open

Bhagya Subrayan, David J. Sand, K. Azalee Bostroem, Saurabh W. Jha, Aravind P. Ravi , et al. · 2025

We present early multiwavelength photometric and spectroscopic observations of the Type IIb supernova SN 2024uwq, capturing its shock-cooling emission phase and double-peaked light-curve evolution. Early spectra reveal broad H α ( v ∼ 15,5…

One Year of SN 2023ixf: Breaking through the Degenerate Parameter Space in Light-curve Models with Pulsating Progenitors Open

Brian Hsu, Nathan Smith, Jared A. Goldberg, K. Azalee Bostroem, G. Hosseinzadeh , et al. · 2025

We present and analyze the extensive optical broadband photometry of the Type II SN 2023ixf up to 1 yr after explosion. We find that, when compared to two preexisting model grids, the bolometric light curve is consistent with drastically d…

Ultraviolet Type Ia Supernova Mission: science motivation and mission concept Open

Keri Hoadley, C. McCully, Gillian Kyne, Fernando Cruz Aguirre, Moira Andrews , et al. · 2025

Late-time Hubble Space Telescope Ultraviolet Spectra of SN 2023ixf and SN 2024ggi Show Ongoing Interaction with Circumstellar Material Open

K. Azalee Bostroem, S. Valenti, David J. Sand, Jeniveve Pearson, Manisha Shrestha , et al. · 2025

We present far- and near-ultraviolet (UV) spectra of the Type II supernovae (SNe) SN~2023ixf from days 199 to 722 and SN~2024ggi at days 41 and 232. Both supernovae show broad, blueshifted, and asymmetric UV emission lines with an initial …

Limits on the ejecta mass during the search for kilonovae associated with neutron star-black hole mergers: A case study of S230518h, GW230529, S230627c and the low-significance candidate S240422ed Open

NULL AUTHOR_ID, S. Antier, K. Ackley, Tomás Ahumada, Dalya Akl , et al. · 2025

International audience

The Heavy Element Enrichment History of the Universe from Neutron Star Mergers with Habitable Worlds Observatory Open

Eric Burns, Jennifer E. Andrews, R. Szabó, Brad Cenko, Paul O'Brien , et al. · 2025

Understanding where elements were formed has been a key goal in astrophysics for nearly a century, with answers involving cosmology, stellar burning, and cosmic explosions. Since 1957, the origin of the heaviest elements (formed via the ra…

The Type I superluminous supernova catalogue – II. Spectroscopic evolution in the photospheric phase, velocity measurements, and constraints on diversity Open

A. Aamer, M. Nicholl, Sebastián Gómez, E. Berger, P. K. Blanchard , et al. · 2025

Hydrogen-poor superluminous supernovae (SLSNe) are among the most energetic explosions in the universe, reaching luminosities up to 100 times greater than those of normal supernovae. This paper presents the largest compilation of SLSN phot…

Early Shock-Cooling Observations and Progenitor Constraints of Type IIb SN 2024uwq Open

Bhagya Subrayan, David J. Sand, K. Azalee Bostroem, Saurabh W. Jha, Aravind P. Ravi , et al. · 2025

We present early multi-wavelength photometric and spectroscopic observations of the Type IIb supernova SN 2024uwq, capturing its shock-cooling emission phase and double-peaked light curve evolution. Early spectra reveal broad H-alpha (v ~ …

Shock-cooling Constraints via Early-time Observations of the Type IIb SN 2022hnt Open

Joseph Farah, D. A. Howell, G. Terreran, I. Irani, Jonathan Morag , et al. · 2025

We report the results of a rapid follow-up campaign on the Type IIb supernova (SN) 2022hnt. We present a daily, multiband, photometric follow-up using the Las Cumbres Observatory, the Zwicky Transient Facility, the orbiting Swift observato…

A Multiwavelength Autopsy of the Interacting Type IIn Supernova 2020ywx: Tracing Its Progenitor Mass-loss History for 100 Yr Before Death Open

Raphael Baer-Way, P. Chandra, M. Modjaz, Sahana Kumar, C. Pellegrino , et al. · 2025

While the subclass of interacting supernovae (SNe) with narrow hydrogen emission lines (Type IIn supernovae (SNe IIn)) consists of some of the longest-lasting and brightest supernovae (SNe) ever discovered, their progenitors are still not …

Spectroscopy of AT 2016blu’s recurring supernova impostor outbursts Open

Mojgan Aghakhanloo, Nathan Smith, Jennifer E. Andrews, A. V. Filippenko, G. Hosseinzadeh , et al. · 2025

We present spectra of the supernova (SN) impostor AT 2016blu spanning over a decade. This transient exhibits quasi-periodic outbursts with an $\sim$113 d period, likely triggered by periastron encounters in an eccentric binary system where…

Spectropolarimetry of SN 2023ixf Reveals Both Circumstellar Material and an Aspherical Helium Core Open

Manisha Shrestha, Sabrina DeSoto, David J. Sand, G. G. Williams, Jennifer L. Hoffman , et al. · 2025

We present multi-epoch optical spectropolarimetric and imaging polarimetric observations of the nearby Type II supernova (SN) 2023ixf discovered in M101 at a distance of 6.85 Mpc. The first imaging polarimetric observations were taken +2.3…

Limits on the Ejecta Mass During the Search for Kilonovae Associated with Neutron Star-Black Hole Mergers: A case study of S230518h, GW230529, S230627c and the Low-Significance Candidate S240422ed Open

M. Pillas, S. Antier, K. Ackley, Tomás Ahumada, Dalya Akl , et al. · 2025

Neutron star-black hole (NSBH) mergers, detectable via their gravitational-wave (GW) emission, are expected to produce kilonovae (KNe). Four NSBH candidates have been identified and followed-up by more than fifty instruments since the star…

Luminous Type II Short-plateau SN 2023ufx: Asymmetric Explosion of a Partially Stripped Massive Progenitor Open

Aravind P. Ravi, S. Valenti, Yize Dong, D. Hiramatsu, Stan Barmentloo , et al. · 2025

We present supernova (SN) 2023ufx, a unique Type IIP SN with the shortest known plateau duration ( t PT ∼ 47 days), a luminous V -band peak ( M V = −18.42 ± 0.08 mag), and a rapid early decline rate ( s 1 = 3.47 ± 0.09 mag (50 days) …

The Ultraviolet Type Ia Supernova CubeSat (UVIa): Science Motivation & Mission Concept Open

Keri Hoadley, C. McCully, Gillian Kyne, Fernando Cruz Aguirre, Moira Andrews , et al. · 2025

The Ultraviolet (UV) Type Ia Supernova CubeSat (UVIa) is a CubeSat/SmallSat mission concept that stands to test critical space-borne UV technology for future missions like the Habitable Worlds Observatory (HWO) while elucidating long-stand…

Asymmetries and Circumstellar Interaction in the Type II SN 2024bch Open

Jennifer E. Andrews, Manisha Shrestha, K. Azalee Bostroem, Yize Dong, Jeniveve Pearson , et al. · 2025

We present a comprehensive multi-epoch photometric and spectroscopic study of SN 2024bch, a nearby (19.9 Mpc) Type II supernova (SN) with prominent early high-ionization emission lines. Optical spectra from 2.8 days after the estimated exp…

SN 2018is: A low-luminosity Type IIP supernova with narrow hydrogen emission lines at early phases Open

R. Dastidar, Kuntal Misra, S. Valenti, D. J. Sand, A. Pastorello , et al. · 2025

We present a comprehensive photometric and spectroscopic study of the Type IIP supernova (SN) 2018is. The V band luminosity and the expansion velocity at 50 days post-explosion are −15.1 ± 0.2 mag (corrected for A V = 1.34 mag) and 1400 km…

SN 2018is: a low-luminosity Type IIP supernova with narrow hydrogen emission lines at early phases Open

R. Dastidar, Kuntal Misra, S. Valenti, D. J. Sand, A. Pastorello , et al. · 2025

We present a comprehensive photometric and spectroscopic study of the Type IIP SN 2018is. The $V$-band luminosity and the expansion velocity at 50 days post-explosion are $-$15.1$\pm$0.2 mag (corrected for A$_V$=1.34 mag) and 1400 km s$^{-…

Spectral dataset of young type Ib supernovae and their time evolution Open

N. Yesmin, C. Pellegrino, M. Modjaz, Raphael Baer-Way, D.A. Howell , et al. · 2024

Due to high-cadence automated surveys, we can now detect and classify supernovae (SNe) within a few days after explosion, if not earlier. Early-time spectra of young SNe directly probe the outermost layers of the ejecta, providing insights…

Spectroscopy of AT 2016blu's recurring supernova impostor outbursts Open

Mojgan Aghakhanloo, Nathan Smith, Jennifer E. Andrews, Alexei V. Filippenko, G. Hosseinzadeh , et al. · 2024

We present spectra of the supernova (SN) impostor AT 2016blu spanning over a decade. This transient exhibits quasiperiodic outbursts with a $\sim$113 d period, likely triggered by periastron encounters in an eccentric binary system where t…

A Multiwavelength Autopsy of the Interacting IIn Supernova 2020ywx: Tracing its Progenitor Mass-Loss History for 100 Years before Death Open

Raphael Baer-Way, P. Chandra, M. Modjaz, Sahana Kumar, C. Pellegrino , et al. · 2024

While the subclass of interacting supernovae with narrow hydrogen emission lines (SNe IIn) consists of some of the longest-lasting and brightest SNe ever discovered, their progenitors are still not well understood. Investigating SNe IIn as…

Mapping the Inner 0.1 pc of a Supermassive Black Hole Environment with the Tidal Disruption Event and Extreme Coronal-line Emitter AT 2022upj Open

Megan Newsome, I. Arcavi, D. A. Howell, C. McCully, G. Terreran , et al. · 2024

Extreme coronal-line emitters (ECLEs) are objects showing transient high-ionization lines in the centers of galaxies. They have been attributed to echoes of high-energy flares of ionizing radiation, such as those produced by tidal disrupti…

SN2023fyq: A Type Ibn Supernova with Long-standing Precursor Activity Due to Binary Interaction Open

Yize Dong, D. Tsuna, S. Valenti, David J. Sand, Jennifer E. Andrews , et al. · 2024

We present photometric and spectroscopic observations of SN 2023fyq, a Type Ibn supernova (SN) in the nearby galaxy NGC 4388 ( D ≃ 18 Mpc). In addition, we trace the 3 yr long precursor emission at the position of SN 2023fyq using data fro…

The Astropy Project: Sustaining and Growing a Community-oriented Open-source Project and the Latest Major Release (v5.0) of the Core Package* Open

The Astropy Collaboration, Adrian M. Price-Whelan, Pey Lian Lim, N. Earl, Nathaniel Starkman , et al. · 2024

\n The Astropy Project supports and fosters the development of open-source and openly developed Python packages that provide commonly needed functionality to the astronomical community. A key element of the Astropy Project is the core pack…

Rubin ToO 2024: Envisioning the Vera C. Rubin Observatory LSST Target of Opportunity program Open

Igor Andreoni, R. Margutti, John Banovetz, Sarah Greenstreet, Claire‐Alice Hébert , et al. · 2024

The Legacy Survey of Space and Time (LSST) at Vera C. Rubin Observatory is planned to begin in the Fall of 2025. The LSST survey cadence has been designed via a community-driven process regulated by the Survey Cadence Optimization Committe…

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