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Nordic-Baltic Astronomy Days 2026

26–29 May 2026
Radisson Blu Marina Palace Hotel
Europe/Helsinki timezone

Session

27-B2: AGN

We-08B
27 May 2026, 15:00
Room B

Room B

Description

Chair: Marianne Vestergaard

Presentation materials

There are no materials yet.

  1. 284. Radiation Transport Simulations of Quasi-Periodic Eruptions from Star-Disk Collisions
    Indrek Vurm (University of Tartu)
    27/05/2026, 15:00
    Oral

    Periodic collisions between a star on an inclined orbit around a supermassive black hole and its accretion disk offers a promising explanation for the recently discovered X-ray quasi-periodic eruptions (QPEs) from galactic nuclei. Each passage through the disk midplane shocks and compresses gas ahead of the star, which subsequently re-expands above the disk as a quasi-spherical cloud. We...

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  2. 285. Sundman and the final parsec problem
    Mauri Valtonen (University of Turku)
    27/05/2026, 15:15
    Oral

    Supermassive binary black holes in galactic nuclei evolve in three stages: (1) The binary contracts by ejecting stars from its neighbourhood by the slingshot process, (2) The binary loses angular momentum via slingshot ejections and becomes very eccentric, and (3) The binary enters the strong gravitational wave regime and quickly contracts and becomes circularized again. Aarseth (2006)...

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  3. 286. Understanding Jet Formation through Changing-look Phenomena with VLBI
    Gregory Walsh (Niels Bohr Institute)
    27/05/2026, 15:30
    Oral

    Changing-look Active Galactic Nuclei (CLAGN) have dramatically altered our understanding of the astrophysical processes governing supermassive black hole accretion. Determining the phenomena that drive accretion state transitions in CLAGN, e.g., Seyfert Type I to Type II or vice versa, remains an open question in contemporary studies. An important factor to consider in theoretical models...

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  4. 287. Quasar Tomography: Mapping the physical structure of AGN
    Vito Tuhtan (Copenhagen University, DARK research center)
    27/05/2026, 15:45
    Oral

    Although active galactic nuclei (AGN) have been studied extensively for more than six decades, the physical origin of their powerful luminosities and the structure and geometry of their central regions remain a mystery. The aim of this study is to interpret UV and optical spectroscopic observations by combining reverberation mapping with photoionization modeling. Reverberation mapping has been...

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  5. 288. Echo Mapping of Accretion Flows around Supermassive Black Holes
    Ms Roberta Vieliute (University of St Andrews)
    27/05/2026, 16:00
    Oral

    The intricate structure of the most luminous objects in the universe - Active Galactic Nuclei (AGN) - cannot be spatially resolved with current telescopes. Instead, we can probe the inner regions of AGN indirectly by exploiting their highly variable, multi-wavelength nature through the powerful technique of Reverberation Mapping (RM). Ionizing photons in the vicinity of the central black hole...

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