[Okc-wp4] EO seminars this fall and a few updates

[Haakon Andresen]

Dear everyone,

The first seminar of the semester will be held on the 5th of September and will take place in the VLR room in the astrophysics department, which is one of the
common areas on the 6th floor. Due to a lack of rooms big enough to fit us all, we are one of the larger working groups, we had problems finding a room for the first meeting.
Let me know if you need help finding the room, it is right next to the main entrance to the astro department.

When: 13:15 on September 5th
Where: The VLR room in the astro department (let me know if you need help finding it)
Speaker: Julian Westerweck
Black hole spectroscopy and beyond no-hair
Black hole quasi-normal modes are proving a rich phenomenon in terms of their properties, data-analysis, and potential for discovery of new physics.
I present work analysing gravitational-wave data both for the signal of black holes in GR and for several types of alternative quasi-normal modes, covering scalar/vector fields, horizonless objects, and r-modes.
Black hole spectroscopy directly probes the nature of a binary merger's final object by measuring the characteristic spectrum of gravitational-wave modes emitted as it settles down from its perturbed state.
This facilitates (no-hair) tests of GR predictions, unexpectedly already using current data. I will discuss some recent advances in analysis methods helping to perform these tests and their results.
In contrast, the presence of additional post-merger signals could reveal more exotic objects or deviations from GR. Scalar- or vector-fields, if present, possess a distinct spectrum of modes, which may
couple to and drive gravitational waves with their characteristic frequencies, making them detectable. In current work we aim to constrain their presence with available data and predict future prospects using third-generation instruments.
Exotic compact objects proposed as alternatives to black holes would show characteristic signatures in their post-merger emission. Horizonless compact objects emit at late times weak but long-lived modes following the initial unmodified signal.
R-mode oscillations in compact objects consisting of fluid matter produce a similar signal. Employing methods adapted to these long-duration signals, we analyse data from the most promising detections, placing strict bounds on both the location of possible deviations from the Kerr geometry and the proposed fluid's properties.


The remaining meetings of the semester will be held in A5:1003. The tentative schedule can be found in our slack channel and will be added to the calendar shortly. The dates
are as follows:

September

  *   5th: Julian Westerweck
  *   19th: Avinash Singh

October

  *       3rd
  *       17th
  *       31st

November

  *      14th: Mariam Gogilashvile
  *      28th: Daniel Kresse

December

  *       12th

As you can wee we need speakers for October, so feel free to contact me if you want to give a talk.

Best,
Haakon (on behalf of the organisers)




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