Nordic-Baltic Astronomy Days 2026

Session

28-B3: Miscellaneous

Th-10B

28 May 2026, 16:45

Room B

Description

Chair: Alexander Mustill

348. Quasi-Normal Modes of Black Holes in EsGB Gravity

Håvard Skåli (Institute of Theoretical Astrophysics, University of Oslo)

28/05/2026, 16:45

Oral

Black holes provide unique laboratories for testing gravity in the strong-field regime. The ringdown phase of a merger is particularly valuable, as it encodes the quasi-normal modes (QNMs) of the remnant black hole. In general relativity, these modes depend only on the mass and spin, making them powerful probes of the no-hair theorem. Modified gravity can alter this spectrum, offering...

349. The Escape Problem of Fast Radio Bursts: Strong Electromagnetic Waves and Fractals

Mr Ethan van Woerkom (University of Helsinki)

28/05/2026, 17:00

Oral

Fast Radio Bursts (FRBs) are short, intense bursts of radio waves (100 MHz-10 GHz) lasting between 4 μs - 10 ms. These bursts, with typical luminosities of order 10^41 erg/s, have been detected at cosmological distances up to redshift z=2.1. Their extreme energetics and great brevity lead to unphysically high brightness temperatures (around 10^37 K), which implies a coherent emission...

350. Optical polarization of the neutron X-ray binary Sco X-1

Alejandra Diaz Teodori

28/05/2026, 17:15

Oral

Neutron star X-ray binaries exhibit complex phenomena that require multiwavelength polarimetric data to understand. Among them, Scorpius X-1 displays particularly remarkable behaviour across wavelengths. X-ray polarimetry has revealed an intricate geometry of the inner accretion region, while optical photometry has shown a bimodal flux distribution with a 12.5 h lag behind the X-ray state...

351. Detection of Ellerman Bombs in SST observations

Rebecca Nguyen (University of Oslo)

28/05/2026, 17:30

Oral

Magnetic reconnections play a crucial role in shaping the dynamics of active regions in the solar atmosphere. It is a fundamental physical process where the reconfiguration of the magnetic field converts magnetic energy into kinetic and thermal energy. Magnetic reconnection events occur on different spatial scales, often associated with solar flares
and coronal mass ejections. At the smallest...

352. Dynamical Sculpting of Planet Populations in Crowded Environments

Mika Kontiainen (Institute of Astronomy, University of Cambridge)

28/05/2026, 17:45

Oral

Few planetary systems form in isolation. With both internal and external processes sculpting their orbital architectures over time, quantifying the extent of dynamical processing planets undergo in their birth environments is essential for mapping their present-day demographics to their primordial populations. Hot Jupiters – giant planets with orbital periods under ten days – provide a...

353. Photometric modeling of the regolith in the Reiner Gamma and Mare Ingenii lunar swirls

Vesa Björn (University of Helsinki)

28/05/2026, 18:00

Oral

Lunar swirls are bright-albedo areas on the surface of the Moon that appear to twist and turn across the surface. Multiple swirl formation processes have been hypothesized, including shielding from space weathering, i.e., small meteoroid impacts and charged particles from the Sun (e.g., Hood & Schubert, Sci 208, 49, 1980), dust accumulation and lofting (e.g., Garrick-Bethell et al., Icar 212,...