Institute of Astronomy

ContactPiwnice k. Torunia, 87-148 Łysomice
tel.: +48 56 611 30 10
fax: +48 56 611 30 09

General Seminar

current    |    2022    |    2021    |    2020    |    2019    |    2018    |    2017

General Seminar takes place every Monday at 11.15 in Piwnice, radioastronomy seminar room.
Remote participation via the BigBlueButton (BBB).


10 October 2022

TBA

Koushik Sen


17 October 2022

TBA


24 October 2022

TBA


7 November 2022

TBA

Murat Uzundag


14 November 2022

Observing hot spots orbiting Sagittarius A* with ALMA

dr Maciej Wielgus (Max Planck Institute for Radio Astronomy, Bonn, Germany)

Abstract:
I will present a first detection of an orbiting hot spot in ALMA millimeter light curves of Sagittarius A*, the supermassive black hole in the Galactic Center. The orbital motion manifests in the loop-like patterns on the linear polarization Q-U plane, following the X-ray flare detected by Chandra. The observed hot spot period corresponds to about 70 minutes, and the implied orbital radius corresponds to about 5 Schwarzschild radii. These new observations constrain the magnetic field to be predominantly vertical and the viewing angle of the hot spot orbit to be close to face-on, which is broadly consistent with the infrared constraints provided by the VLTI observations with GRAVITY. Presented results support theoretical interpretation of the accretion system in Sagittarius A* as a magnetically arrested disk, and flaring activity as related to the magnetic reconnection.


21 November 2022

TBA


28 November 2022

TBA


5 December 2022

TBA


12 December 2022

TBA


19 December 2022

TBA


2 January 2023

TBA


9 January 2023

TBA


16 January 2023

TBA


23 January 2023

TBA


30 January 2023

TBA