Publications (10)
SN 2025adpq: A Type Ia supernova in a collisional ring formed during a major galaxy merger
Brendan O'Connor, Xander J. Hall, Tomas Cabrera +16
Galaxy mergers can both trigger star formation and rearrange where stars live, producing long-lived tidal structures and collisionally driven density waves (known as collisional ri…
AT2025ulz and S250818k: Leveraging DESI spectroscopy in the hunt for a kilonova associated with a sub-solar mass gravitational wave candidate
Xander J. Hall, Antonella Palmese, Brendan O'Connor +47
On August 18th, 2025, the LIGO--Virgo--KAGRA collaboration reported a sub-threshold gravitational wave candidate detection consistent with a sub-solar-mass neutron star merger, den…
EP260321a/SN 2026gzf: The Faintest Shock Breakout Associated with a Broad-Lined Supernova
Brendan O'Connor, Xander J. Hall, Malte Busmann +33
The explosion of a star is first marked by the shock wave breaking out of the stellar surface, producing a burst of ultraviolet and X-ray radiation. These events are observationall…
Discovery of a Supernova Following the Einstein Probe Transient EP250302a at z = 1.131
Brendan O'Connor, Malte Busmann, James Freeburn +7
We present a multi-wavelength analysis of the Einstein Probe (EP) fast X-ray transient (FXT) EP250302a located at redshift . Despite its luminous prompt X-ray emission, th…
LIGO/Virgo/KAGRA neutron star merger candidate S250206dm: Zwicky Transient Facility observations
Tomás Ahumada, Shreya Anand, Mattia Bulla +49
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 I…
GRB 260310A/SN 2026fgk: Photometric and Spectroscopic Evolution of a Nearby GRB-Supernova and an Exceptionally Bright Afterglow at z=0.153
Brendan O'Connor, Malte Busmann, Xander J. Hall +24
The association of broad-lined Type Ic supernovae with long-duration gamma-ray bursts (GRBs) has been known for 28 years. However, only about seventy gamma-ray burst supernovae (GR…
Electromagnetic Follow-up of the Sub-Solar Mass Gravitational Wave Candidate S251112cm: Kilonova Constraints and a Coincident IIb Supernova
Xander J. Hall, Tomas Ahumada, Julius Gassert +25
On November 12th, 2025 the LIGO--Virgo--KAGRA (LVK) collaboration reported gravitational waves (GWs) from a compact object merger candidate (S251112cm) with at least one sub-solar…
EP250827b/SN 2025wkm: An X-ray Flash-Supernova Powered by a Central Engine and Circumstellar Interaction
Gokul P. Srinivasaragavan, Dongyue Li, Xander J. Hall +100
We present the discovery of EP250827b/SN 2025wkm, an X-ray Flash (XRF) discovered by the Einstein Probe (EP), accompanied by a broad-line Type Ic supernova (SN Ic-BL) at $z = 0.119…
Kilonova constraints for the LIGO/Virgo/KAGRA neutron star merger candidate S250206dm: GW-MMADS observations
Lei Hu, Tomás Cabrera, Antonella Palmese +35
Gravitational wave (GW) neutron star mergers with an associated electromagnetic counterpart constitute powerful probes of binary evolution, the production sites of heavy elements,…
AT2025ulz and S250818k: Investigating early time observations of a subsolar mass gravitational-wave binary neutron star merger candidate
Xander J. Hall, Malte Busmann, Hauke Koehn +32
Over the past LIGO--Virgo--KAGRA (LVK) observing runs, it has become increasingly clear that identifying the next electromagnetic counterparts to gravitational-wave (GW) neutron st…