| MAY 2023 - TOPICS |
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- Short News
- The 16th Conference of Hel.A.S.
- Job Opportunities in Greece
- Call for proposals 2023 - Helmos Observatory
- Call for participation in the ORP sky protection group
- Monthly Colloquium of Hel.A.S.
- Upcoming Astronomy Meetings in Greece
- About this Newsletter
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| 1. Short News |
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We would like to congratulate Dr. Vasiliki Pavlidou who was recently promoted to the position of Professor of Theoretical Astrophysics, at the Dept. of Physics of the University of Crete. The Society extends its best wishes for further success in her professional pursuits.
We would like to congratulate Dr. Konstantinos Tassis who was recently promoted to the position of Professor of Theoretical Astrophysics, at the Dept. of Physics of the University of Crete. The Society extends its best wishes for further success in his professional pursuits.
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| 2. The 16th Conference of Hel.A.S. |
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We would like to inform all members that the abstract submission deadline for the 16th Conference of HelAS is on Friday May 5, 2023. All members are encouraged to visit the web site of the conference at: https://helas.gr/conf/2023
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3. Job Opportunities in Greece
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One Post-Doctoral or alternatively PhD position on population synthesis of stellar binary systems at the Institute of Astrophysics in Herackleion (IA-FORTH) will be announced in the upcoming months. The position will be funded by the Hellenic Foundation for Research and Innovation (HFRI) scheme under the grant entitled "SFERICSS" with PI Dr. Emmanouil (Manos) Zapartas. The selected candidate will work on topics related to the energetical and mechanical feedback of binary stellar populations to their surroundings, both during the binary phase and/or during their X-ray binary phase. For that the selected candidate will use the new-generation binary population synthesis code, POSYDON, which is based on MESA stellar and binary models. The candidate will be a member of the POSYDON team, with many options for close international research collaborations. Applicants with experience in the fields of stellar and binary evolution modeling, binary and spectral population synthesis, populations of X-ray binaries and/or stellar feedback at stellar host environments and galaxies are particularly encouraged to apply. The opening will be for a postdoctoral position, but depending on the available candidates, the position can be alternatively offered to a PhD candidate. Expected starting date is in fall 2023, for a duration of up to 24 months. For the alternative case of a PhD position, a 3rd year of a paid secondment either at the University of Geneva (Switzerland) or NorthWestern University (Chicago, USA) is possible. Interested parties should contact Dr. Emmanouil (Manos) Zapartas (zapartas@noa.gr) for more details.
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4. Call for proposals 2023 - Helmos Observatory
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The call for proposals requesting observing time with the Aristarchos telescope at the Helmos Observatory is now open. For more information visit this website. The deadline for applications is May 5, 2023.
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5. Call for participation in the ORP sky protection group
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Due to light pollution and the commercial exploitation of the radio spectrum, astronomical observations and astronomical research are becoming increasingly threatened. It is therefore necessary to engage in efforts to mitigate the negative impacts of artificial electromagnetic interference (EMI) on astronomy, the environment, and society.
We would like to request your participation in the Opticon-RadioNet Pilot (ORP) sky protection group by signing up for one or more ad hoc working groups using this questionnaire. The ORP is a project supported by the European Commision and one of its activities is to create a regional initiative "Preserving the skies" with the aim to aid efforts mitigating EMI (light pollution through artificial light at night from the ground and from satellites and radio interference). The interventions foreseen are of regulatory and technical character, and can range from networking within our region to software or hardware development.
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| 6. Monthly Colloquium of Hel.A.S. |
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We are happy to announce that the May 2023 colloquium speaker is Prof. Serguei Komissarov. As usual, videos of all past colloquia are available in the Youtube channel of the Society. Details of the upcoming colloquium follow:
26th Monthly Colloquium of Hel.A.S. - 9 May 2023
"Electrically-charged black holes and the Blandford-Znajek mechanism"
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Prof. Serguei Komissarov, (University of Leeds, UK)
Tuesday, 9 May 2023 at 15:00 Athens time (UTC + 3:00)
Click for ZOOM link
(Meeting ID: 890 8016 7097 and Passcode: 931930)
Abstract: Recently, it was claimed by King & Pringle that accretion of electric charge by a black hole rotating in an aligned external magnetic field results in a “dead” vacuum magnetosphere, where the electric field is totally screened, no vacuum breakdown is possible, and the Blandford-Znajek mechanism cannot operate. Here we study in detail the properties of the Wald solution for electrically charged black holes discussed in their paper. Our results show that the claim is erroneous as in the solution with the critical charge q0 = 2aB0 there exists a drop of electrostatic potential along all magnetic field lines except the one coinciding with the symmetry axis. It is also found that while uncharged rotating black holes expel external vacuum magnetic field from their event horizon (the Meissner effect), electric charging of black holes pulls the magnetic field lines back on it, resembling what has been observed in some previous force-free, RMHD and PIC simulations of black hole magnetospheres. This suggests that accretion of electric charge may indeed be a feature of the black hole electrodynamics. However, our analysis shows that the value q0 of the BH charge given by Wald is likely to be only an upper limit, and that the actual value depends on the details of the magnetospheric physics.
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| 7. Upcoming Astronomy Meetings in Greece |
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| 8. About this Newsletter |
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This Newsletter was sent to all members of Hel.A.S. who have e-mail access. The next edition of the Newsletter will be mailed around June 1, 2023. Please send your announcements (e.g., appointments / departures, job openings, research opportunities, awards, conferences in Greece) or comments before May 25, 2023. If you do not wish to receive future issues of this Newsletter or the e-mail address to which it was sent is not your preferred one, please inform the Secretary of Hel.A.S. at secretary@helas.gr.
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