J. Sollerman
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View article: A Luminous and Hot Infrared through X-Ray Transient at a 5 kpc Offset from a Dwarf Galaxy
A Luminous and Hot Infrared through X-Ray Transient at a 5 kpc Offset from a Dwarf Galaxy Open
We are searching for hot, constant-color, offset optical flares in the Zwicky Transient Facility data stream that are >10″ from any galaxy in public imaging data from the PanSTARRS survey. Here, we present the first discovery from this sea…
View article: Discovery of SN 2025wny: A Strongly Gravitationally Lensed Superluminous Supernova at <i>z</i> = 2.01
Discovery of SN 2025wny: A Strongly Gravitationally Lensed Superluminous Supernova at <i>z</i> = 2.01 Open
We present the discovery of SN 2025wny (ZTF25abnjznp/GOTO25gqt) and spectroscopic classification of this event as the first gravitationally lensed Type I superluminous supernova (SLSN-I). Deep ground-based follow-up observations resolve fo…
View article: A Late-time Radio Survey of Type Ia-CSM Supernovae with the Very Large Array
A Late-time Radio Survey of Type Ia-CSM Supernovae with the Very Large Array Open
Type Ia-CSM supernovae (SNe) are a rare and peculiar subclass of thermonuclear SNe characterized by emission lines of hydrogen or helium, indicative of high-density circumstellar medium (CSM). Their implied mass-loss rates of ∼10 −4 –10 −1…
View article: SN 2021lwz: Another Exotic Luminous and Fast Evolving Optical Type Ic Broad-Lined Supernova ?
SN 2021lwz: Another Exotic Luminous and Fast Evolving Optical Type Ic Broad-Lined Supernova ? Open
Context. Current large-scale, high-cadence surveys, such as the Zwicky Transient Facility (ZTF), provide detections of new and rare types of transients and supernovae whose physical origins are not well understood. Aims. We investigate the…
View article: AppleCiDEr II: SpectraNet -- A Deep Learning Network for Spectroscopic Data
AppleCiDEr II: SpectraNet -- A Deep Learning Network for Spectroscopic Data Open
Time-domain surveys such as the Zwicky Transient Facility (ZTF) have opened a new frontier in the discovery and characterization of transients. While photometric light curves provide broad temporal coverage, spectroscopic observations rema…
View article: SN 2023xgo: Helium-rich Type Icn or Carbon-Flash Type Ibn supernova?
SN 2023xgo: Helium-rich Type Icn or Carbon-Flash Type Ibn supernova? Open
We present observations of SN 2023xgo, a transitional Type Ibn/Icn SN, from −5.6 to 63 days relative to r-band peak. Early spectra show C iii λ5696 emission like Type Icn SNe, shifting to Type Ibn features. The He i velocities (1800-10000 …
View article: The La Silla Schmidt Southern Survey
The La Silla Schmidt Southern Survey Open
We present the La Silla Schmidt Southern Survey (LS4), a new wide-field, time-domain survey to be conducted with the 1 m ESO Schmidt telescope. The 268 megapixel LS4 camera mosaics 32 2k × 4k fully depleted CCDs, providing a ∼20 deg 2 fiel…
View article: The ambiguous AT2022rze: changing-look AGN mimicking a supernova in a merging galaxy system
The ambiguous AT2022rze: changing-look AGN mimicking a supernova in a merging galaxy system Open
AT2022rze is a luminous, ambiguous transient located south-east of the geometric centre of its host galaxy at redshift $z = 0.08$. The host appears to be formed by a merging galaxy system. The observed characteristics of AT2022rze are remi…
View article: MUSE observations reveal optical coronal iron lines from shock emission in supernova remnant 0540−69.3
MUSE observations reveal optical coronal iron lines from shock emission in supernova remnant 0540−69.3 Open
We investigate the optical shock emission from the Large Magellanic Cloud supernova remnant 0540−69.3 (SNR 0540) using Multi Unit Spectroscopic Explorer integral-field-unit data from the Very Large Telescope. The observations cover the spe…
View article: SN 2023uqf: An Interacting Supernova Coincident with a High-Energy Neutrino
SN 2023uqf: An Interacting Supernova Coincident with a High-Energy Neutrino Open
Astrophysical high-energy (TeV-PeV) neutrinos were first discovered in 2013, but their origin remains largely unknown. Here we present SN 2023uqf, a supernova found in coincidence with high-energy neutrino IC231004A, as part of a systemati…
View article: A Luminous Red Optical Flare and Hard X-Ray Emission in the Tidal Disruption Event AT 2024kmq
A Luminous Red Optical Flare and Hard X-Ray Emission in the Tidal Disruption Event AT 2024kmq Open
We present the optical discovery and multiwavelength follow-up observations of AT 2024kmq, a likely tidal disruption event (TDE) associated with a supermassive ( M BH ∼ 10 8 M ⊙ ) black hole in a massive galaxy at z = 0.192. The optical li…
View article: IIb or not IIb: A Catalog of ZTF Kilonova Imposters
IIb or not IIb: A Catalog of ZTF Kilonova Imposters Open
Among the various classes of fast optical transients (FOTs), kilonovae (KNe), which can emerge as a result of neutron star mergers, are extremely challenging to observe because of not only the rapid timescale on which they fade (on the ord…
View article: EP250108a/SN 2025kg: A Jet-driven Stellar Explosion Interacting with Circumstellar Material
EP250108a/SN 2025kg: A Jet-driven Stellar Explosion Interacting with Circumstellar Material Open
We present optical, radio, and X-ray observations of EP250108a/SN 2025kg, a broad-line Type Ic supernova (SN Ic-BL) accompanying an Einstein Probe (EP) fast X-ray transient at z = 0.176. EP250108a/SN 2025kg possesses a double-peaked optica…
View article: Applying multimodal learning to Classify transient Detections Early (AppleCiDEr) I: Data set, methods, and infrastructure
Applying multimodal learning to Classify transient Detections Early (AppleCiDEr) I: Data set, methods, and infrastructure Open
Modern time-domain surveys like the Zwicky Transient Facility (ZTF) and the Legacy Survey of Space and Time (LSST) generate hundreds of thousands to millions of alerts, demanding automatic, unified classification of transients and variable…
View article: AT2019cmw: A highly luminous, cooling featureless TDE candidate from the disruption of a high mass star in an early-type galaxy
AT2019cmw: A highly luminous, cooling featureless TDE candidate from the disruption of a high mass star in an early-type galaxy Open
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 ~$\mathrm{10^{45.6}\,erg\,s^{-1}}$, it is one of the most lu…
View article: The Type I superluminous supernova catalogue – II. Spectroscopic evolution in the photospheric phase, velocity measurements, and constraints on diversity
The Type I superluminous supernova catalogue – II. Spectroscopic evolution in the photospheric phase, velocity measurements, and constraints on diversity Open
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…
View article: Luminous, rapidly declining supernovae as stripped transitional objects in low-metallicity environments: The case of SN 2022lxg
Luminous, rapidly declining supernovae as stripped transitional objects in low-metallicity environments: The case of SN 2022lxg Open
We present an analysis of the optical and near-infrared properties of SN 2022lxg, a bright ( M g peak = −19.41 mag) and rapidly evolving supernova (SN). It was discovered within a day of explosion, and rose to peak brightness in ∼10 d. Two…
View article: Twin peaks: SN 2021uvy and SN 2022hgk in the landscape of double-peaked stripped envelope supernovae
Twin peaks: SN 2021uvy and SN 2022hgk in the landscape of double-peaked stripped envelope supernovae Open
In recent years, a class of stripped-envelope supernovae (SESNe) showing two distinct light-curve peaks has emerged, where the first peak cannot be attributed to shock cooling emission. Such peculiar SNe are often studied individually, exp…
View article: LIGO/Virgo/KAGRA neutron star merger candidate S250206dm: Zwicky Transient Facility observations
LIGO/Virgo/KAGRA neutron star merger candidate S250206dm: Zwicky Transient Facility observations Open
We present the searches conducted with the Zwicky Transient Facility (ZTF) in response to S250206dm, a bona fide event with a false alarm rate of one in 25 years, detected by the International Gravitational Wave Network (IGWN). Although th…
View article: Low-Luminosity Type IIP Supernovae from the Zwicky Transient Facility Census of the Local Universe. II: Lightcurve Analysis
Low-Luminosity Type IIP Supernovae from the Zwicky Transient Facility Census of the Local Universe. II: Lightcurve Analysis Open
The Zwicky Transient Facility Census of the Local Universe survey yielded a sample of 330 Type IIP supernovae (SNe) with well-constrained peak luminosities. In paper I (arXiv:2502.19493), we measured their luminosity function and volumetri…
View article: A Late-time Radio Survey of Type Ia-CSM Supernovae with the Very Large Array
A Late-time Radio Survey of Type Ia-CSM Supernovae with the Very Large Array Open
Type Ia-CSM supernovae (SNe) are a rare and peculiar subclass of thermonuclear SNe characterized by emission lines of hydrogen or helium, indicative of a high-density circumstellar medium (CSM). Their implied mass-loss rates of $\sim 10^{-…
View article: Observational diversity of bright long-lived Type II supernovae
Observational diversity of bright long-lived Type II supernovae Open
Context. In various types of supernovae (SNe), strong interaction between the SN ejecta and circumstellar material (CSM) has been reported. This raises questions about their progenitors and mass-loss processes shortly before the explosion.…
View article: SN 2023xgo: Helium-rich Type Icn or Carbon-Flash Type Ibn supernova?
SN 2023xgo: Helium-rich Type Icn or Carbon-Flash Type Ibn supernova? Open
We present observations of SN~2023xgo, a transitional Type Ibn/Icn supernova, from $-5.6$ to $+63$~days relative to the $r$-band peak. Early spectra show C~III $λ5696$ emission reminiscent of Type~Icn SNe, which later gives way to Type~Ibn…
View article: The Jetted Tidal Disruption Event AT2022cmc: Investigating Connections to the Optical Tidal Disruption Event Population and Spectral Subclasses Through Late-Time Follow-up
The Jetted Tidal Disruption Event AT2022cmc: Investigating Connections to the Optical Tidal Disruption Event Population and Spectral Subclasses Through Late-Time Follow-up Open
AT2022cmc is the first on-axis jetted tidal disruption event (TDE) to be discovered at optical wavelengths. The optically bright nature of AT2022cmc presents an unprecedented opportunity to place this jetted TDE in the context of the large…
View article: Inferring CSM properties of Type II SNe using a magnitude-limited ZTF sample
Inferring CSM properties of Type II SNe using a magnitude-limited ZTF sample Open
Although all Type II supernovae (SNe) originate from massive stars possessing a hydrogen-rich envelope, their light-curve morphology is diverse, reflecting poorly characterized heterogeneity in the physical properties of their progenitor s…
View article: Hydrodynamical modelling of Type IIb SNe
Hydrodynamical modelling of Type IIb SNe Open
We present HYDE, a new one-dimensional hydrodynamical code, and use it to construct a grid of supernova (SN) models based on solar-metallicity bare helium-core models evolved to the verge of core-collapse with MESA STAR. This grid is suite…
View article: A Massive Black Hole 0.8 kpc from the Host Nucleus Revealed by the Offset Tidal Disruption Event AT2024tvd
A Massive Black Hole 0.8 kpc from the Host Nucleus Revealed by the Offset Tidal Disruption Event AT2024tvd Open
Tidal disruption events (TDEs) that are spatially offset from the nuclei of their host galaxies offer a new probe of massive black hole (MBH) wanderers, binaries, triples, and recoiling MBHs. Here we present AT2024tvd, the first off-nuclea…
View article: The <tt>BTSbot-nearby</tt> Discovery of SN 2024jlf: Rapid, Autonomous Follow-up Probes Interaction in an 18.5 Mpc Type IIP Supernova
The BTSbot-nearby Discovery of SN 2024jlf: Rapid, Autonomous Follow-up Probes Interaction in an 18.5 Mpc Type IIP Supernova Open
We present observations of the Type IIP supernova (SN) SN 2024jlf, including spectroscopy beginning just 0.7 days (∼17 hr) after first light. Rapid follow-up was enabled by the new BTSbot-nearby program, which involves autonomously trigger…
View article: The Nature of Optical Afterglows without Gamma-Ray Bursts: Identification of AT2023lcr and Multiwavelength Modeling
The Nature of Optical Afterglows without Gamma-Ray Bursts: Identification of AT2023lcr and Multiwavelength Modeling Open
In the past few years, the improved sensitivity and cadence of wide-field optical surveys have enabled the discovery of several afterglows without associated detected gamma-ray bursts (GRBs). We present the identification, observations, an…
View article: A luminous and hot infrared through X-ray transient at a 5 kpc offset from a dwarf galaxy
A luminous and hot infrared through X-ray transient at a 5 kpc offset from a dwarf galaxy Open
We are searching for hot, constant-color, offset optical flares in the Zwicky Transient Facility (ZTF) data stream that are ${>}10''$ from any galaxy in public imaging data from the PanSTARRS survey. Here, we present the first discovery fr…