University of California, Santa Cruz

Radiative Transfer Modeling of Stripped-envelope Supernovae II: Neural Network Emulation of Light Curves

S. Karthik Yadavalli, V. Ashley Villar, Maria R. Drout +3

We present the first neural-network emulator of stripped-envelope supernova (SESN) lightcurves, trained on a grid of 4499 light curves simulated with the radiative transfer (RT) co…

astro-ph.HE2026★ 2 cited

Gamma-ray signature of superluminous supernovae: Fermi-LAT GeV detection of SN 2017egm and evidence of a central engine

F. Acero, A. Acharyya, A. Adelfio +116

Superluminous supernovae (SLSNe) are a rare class of transients with peak luminosities 10-100 times greater than those of standard core-collapse supernovae (SNe). The mechanisms po…

Discovery of 30 Repeating Fast Radio Burst Sources and Uniform Population Statistics of 80 Repeating Sources from CHIME/FRB

Amanda M. Cook, Kaitlyn Shin, Ziggy Pleunis +44

We present 30 newly discovered repeating fast radio burst (FRB) sources from the second catalog of bursts detected by the FRB backend on the Canadian Hydrogen Intensity Mapping Exp…

Impacts of Voids, Line of Sight Interactions, and Local Emission Environment on Detectability of Gamma-Ray AGN

Ollie Jackson, Amy Furniss, Olivier Hervet +2

Cosmic voids may have novel affects on the propagation of high-energy photons. We consider the fraction of the line of sight that intersect voids (termed \enquote{voidiness}). A pr…

astro-ph.HE2026★ 1 cited

VERITAS Observations Contemporaneous with the LHAASO Detection of NGC 4278

The VERITAS Collaboration, A. Archer, P. Bangale +66

Significant gamma-ray emission between 1 TeV and 20 TeV from a point source, 1LHAASO J1219+2915, consistent with the location of the LINER/LLAGN galaxy NGC 4278 was recently report…

The DESI Transients Survey: Legacy Classifications and Methodology

Xander J. Hall, Antonella Palmese, Segev BenZvi +56

We present the first systematic spectroscopic observations of extragalactic transients from the Dark Energy Spectroscopic Instrument (DESI), as part of the DESI Transients Survey p…

Through the Heliospheric Lens: Directional Deflection of High-Energy Cosmic-Ray Electrons and Positrons

Stefano Profumo, Aria Koul, Anika Malladi +1

We investigate how the large-scale heliosphere alters the arrival directions of high-energy cosmic-ray electrons and positrons and ask if and when this "heliospheric lens" can be i…

Multiple outflows and delayed ejections revealed by early imaging of novae

Elias Aydi, John D. Monnier, Antoine Mérand +39

Novae are thermonuclear eruptions on accreting white dwarfs in interacting binaries. Although most of the accreted envelope is expelled, the mechanism -- impulsive ejection, multip…

Constraints on Axion-Like Particles from VERITAS Observations of a Flaring Radio Galaxy in the Perseus Cluster

C. B. Adams, A. Archer, P. Bangale +62

Background: Axion-like particles (ALPs) are hypothetical particles that emerge in numerous theoretical extensions to the Standard Model. Their coupling to electromagnetic field imp…

GRB 230307A Formed No Dust or Was Not a Binary Neutron Star Merger

Prasiddha Arunachalam, Phillip Macias, Ryan. J. Foley

We present a new analysis of the JWST infrared spectra of GRB 230307A (AT 2023vfi), a long gamma-ray burst (GRB) with an infrared excess and spectral lines suggestive of significan…

A Multi-Wavelength Survey of Transient Lensing Opportunities for Primordial Black Hole Searches

Stefano Profumo

Gravitational lensing of short astrophysical transients provides a uniquely direct avenue for searching for primordial black holes (PBHs) across a vast range of masses. While past…

astro-ph.HE2025★ 5 cited

Combined dark matter search towards dwarf spheroidal galaxies with Fermi-LAT, HAWC, H.E.S.S., MAGIC, and VERITAS

LAT Collaboration, S. Abdollahi, L. Baldini +586

Dwarf spheroidal galaxies (dSphs) are excellent targets for indirect dark matter (DM) searches using gamma-ray telescopes because they are thought to have high DM content and a low…

Prospects for dark matter observations in dwarf spheroidal galaxies with the Cherenkov Telescope Array Observatory

K. Abe, S. Abe, J. Abhir +491

The dwarf spheroidal galaxies (dSphs) orbiting the Milky Way are widely regarded as systems supported by velocity dispersion against self-gravity, and as prime targets for the sear…

astro-ph.HE2025★ 1 cited

Optical spectroscopy of blazars for the Cherenkov Telescope Array Observatory- IV

B. Rajput, P. Goldoni, W. Max-Moerbeck +17

Blazars, including BL Lacs and FSRQs, are the most luminous extragalactic γ-ray sources. They account for about 56% of the sources listed in the recent Fermi-LAT catalog (4FGL-DR4)…

Radiative Transfer Modeling of Stripped-Envelope Supernovae. I: A Grid for Ejecta Parameter Inference

S. Karthik Yadavalli, V. Ashley Villar, Abigail Polin +3

We present 1,800 multiwavelength Type Ib/c supernovae light curve models obtained by running the radiation transport code Sedona and varying the mass distribution, velocity profile…

Evolution of the ZTF SLRN-2020 star-planet merger

Ricardo Yarza, Morgan MacLeod, Benjamin Idini +2

We model the optical and infrared transient ZTF SLRN-2020, previously associated with a star-planet merger. We consider the scenario in which orbital decay via tidal dissipation le…

astro-ph.HE2025★ 2 cited

AT2019cmw: A highly luminous, cooling featureless TDE candidate from the disruption of a high mass star in an early-type galaxy

Jacob L. Wise, Daniel A. Perley, Nikhil Sarin +23

We present optical/UV photometric and spectroscopic observations, as well as X-ray and radio follow-up, of the extraordinary event AT2019cmw. With a peak bolometric luminosity of ~…

astro-ph.HE2025★ 8 cited

Localisation and host galaxy identification of new Fast Radio Bursts with MeerKAT

Inés Pastor-Marazuela, Alexa C. Gordon, Ben Stappers +18

Accurately localising fast radio bursts (FRBs) is essential for understanding their birth environments and for their use as cosmological probes. Recent advances in radio interferom…

astro-ph.HE2025★ 14 cited

FRB 20250316A: A Brilliant and Nearby One-Off Fast Radio Burst Localized to 13 parsec Precision

FRB Collaboration, Thomas C. Abbott, Daniel Amouyal +83

Precise localizations of a small number of repeating fast radio bursts (FRBs) using very long baseline interferometry (VLBI) have enabled multiwavelength follow-up observations rev…

astro-ph.HE2025★ 2 cited

Multi-Model Framework for Reconstructing Gamma-Ray Burst Light Curves

A. Kaushal, A. Manchanda, M. G. Dainotti +13

Mitigating data gaps in Gamma-ray bursts (GRBs) light curves (LCs) is crucial for cosmological research, enhancing the precision of parameters, assuming perfect satellite condition…

astro-ph.HE2025★ 2 cited

Puzzling Variation of Gamma Rays from the Sun over the Solar Cycle Revealed with Fermi-LAT

A. Acharyya, A. Adelfio, M. Ajello +100

The steady-state gamma-ray emission from the Sun is thought to consist of two emission components due to interactions with Galactic cosmic rays: (1) a hadronic disk component, and…

Early and Extensive Ultraviolet Through Near Infrared Observations of the Intermediate-Luminosity Type Iax Supernovae 2024pxl

W. B. Hoogendam, C. Ashall, D. O. Jones +12

We present ultraviolet (UV) through near-infrared (NIR) photometric and spectroscopic observations of the nearby SN 2024pxl, the third Type Ia supernova (SN Ia) in NGC 6384. SN 202…

astro-ph.HE2025★ 10 cited

Large Cold Dust Reservoir Revealed in Transitional SN Ib 2014C by James Webb Space Telescope Mid-Infrared Spectroscopy

Samaporn Tinyanont, Ori D. Fox, Melissa Shahbandeh +32

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 (CS…