6 papers
An Halpha survey of infrared bow-shocks around OB-type stars
Kuljeet Singh Saddal, Michaela Kraus, Dieter H. Nickeler +3
Bow shocks (BSs) around massive stars are commonly identified in mid-infrared (MIR) surveys. In contrast, systematic optical investigations of these structures remain scarce with o…
Multi-epoch afterglow rebrightenings in GRB 250129A: Evidence for successive shock interactions
D. Akl, S. Antier, H. Koehn +105
Most long gamma-ray bursts (GRBs) exhibit afterglows broadly consistent with external forward-shock emission, typically described by smooth broken power-law decays in the multiband…
ZTF25abjmnps (AT2025ulz) and S250818k: A Candidate Superkilonova from a Sub-threshold Sub-Solar Gravitational Wave Trigger
Mansi M. Kasliwal, Tomas Ahumada, Robert Stein +61
On August 18, 2025, the LIGO-Virgo-KAGRA collaboration reported gravitational waves from a sub-threshold binary neutron star merger. If astrophysical, this event would have a surpr…
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…
Interstellar comet 3I/ATLAS: discovery and physical description
Bryce T. Bolin, Matthew Belyakov, Christoffer Fremling +18
We describe the physical characteristics of interstellar comet 3I/ATLAS, discovered on 2025 July 1 by the Asteroid Terrestrial-impact Last Alert System. The comet has eccentricity,…
FRAM Next Generation at the Pierre Auger Observatory: cloud monitoring in the age of CMOS cameras
Jan Ebr, Sergey Karpov
The visibility of stars is often used for cloud detection using all-sky cameras, which have however only a limited reach and resolution near the horizon due to the lack of detectab…