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Contributions to the XXXth General Assembly of IAU

During the XXXth General Assembly of the International Astronomical Union (in Vienna, Austria) I participated in a number of different meetings. In particular:

1. A poster at the IAU Focus Meeting FM14 on IAU’s role on global astronomy outreach, the latest challenges and bridging different communities (August 23, 2018):

“A paradigm to develop new contributors to Astronomy”

G. Maravelias, E. Vourliotis, K. Marouda, I. Belias, E. Kardasis, P. Papadeas, J. D. Strikis, E. Vakalopoulos, O. Voutyras

One of the most regular activities of amateur clubs is scientific outreach, a paramount chan-
nel to disseminate scientific results. It is typically performed through talks given by both ex-
perts (professional astronomers) and non-experts to a diverse audience, including amateur as-
tronomers. However, this is a rather passive, one-way, approach. The advance of technology
has provided all the tools that can help the audience/amateurs to become more active in the
scientific output. What is often missing is the proper guidance. To address that within the
Greek amateur community the Hellenic Amateur Astronomy Association materialized a train-
ing program (free-of-charge and open-accessed) to develop scientific thought and the practical
capabilities for amateurs to produce valuable results. The program ran from November 2014 to
May 2015 focusing each session (month) to: the Sun, variable stars, comets, planets, artificial
satellites, meteors. A professional and/or an experienced amateur astronomer was leading each
session consisting of a theoretical part (highlights of the field, necessary observational tech-
niques) and a hands-on part (observations and data analysis). At least 50 unique participants
gained significant experience by following parts or the complete program.

arXiv: 1810.04562

2. A talk at the meeting of Division G: Stars and Stellar Physics (August 24 and 27, 2018)

“Rings around B[e] Supergiants”

G. Maravelias, M. Kraus, L. Cidale, M. Borges Fernandes, M. L. Arias, A. F. Torres

Massive stars affect strongly the insterstellar medium through their intense stellar winds and their rich chemically processed material as they evolve. In specific short-lived transition phases (e.g. B[e] Supergiants, Luminous Blue Variables, Yellow Hypergiants) the mass-loss becomes more enhanced and usually eruptive. This leads to the formation of a complex circumstellar environment, which is not always well understood. To improve our knowledge on these phases we examined the structures found around the B[e] supergiants for a sample of Galactic and Magellanic Cloud sources. Using high-resolution optical and near-infrared spectra, we examine a set of key emission features ([OI], [CaII], CO bandheads) to trace their physical conditions and kinematics in their formation regions. Assuming Keplerian rotation of the circumstellar material we find that each B[e] Supergiant is surrounded by a unique distribution of single and/or multiple equatorial rings. Moroever, we find that these structures seem to be more stable and long-lived around single stars rather than binaries that show significant spectroscopic and photometric variability.

3. A poster at the IAU Symposium 346 on High-mass X-ray binaries: illuminating the passage from massive binaries to merging compact objects (August 27 – 31, 2018)

Clarifying the population of HMXBs in the Small Magellanic Cloud

G. Maravelias, A. Zezas, V. Antoniou, D. Hatzidimitriou, F. Haberl

Almost all confirmed optical counterparts of HMXBs in the SMC are OB stars with equatorial decretion disks (OBe). These sources emit strongly in Balmer lines and standout when imaged through narrow-band Hα imaging. The lack of secure counterparts for a significant fraction of the HMXBs motivated us to search for more. Using the catalogs for OB/OBe stars (Maravelias et al. 2017) and for HMXBs (Haberl & Sturm 2016) we detect 70 optical counterparts (out of 104 covered by our survey). We provide the first identification of the optical counterpart to the source XTEJ0050-731. We verify that 17 previously uncertain optical counterparts are indeed the proper matches. Regarding 52 confirmed HMXBs (known optical counterparts with Hα emission), we detect 39 as OBe and another 13 as OB stars. This allows a direct estimation of the fraction of active OBe stars in HMXBs that show Hα emission at a given epoch to be at least ∼ 75% of their total HMXB population.

arXiv: 1811.10933

And a short note:
I had opted to present the poster works as e-posters, i.e. displayed as an electronic pdf/presentation on interactive monitors which would be placed at each poster halls. The motivation behind this was the fact that the posters could be uploaded before the official start of each session and be available over the whole (two-week) period. But there were some issues:
1. There were only two monitors at each hall, so if somebody else was talking over their poster you had to wait… and wait… and wait… It happened to me that I wanted to show my poster to a colleague but some other people were in front of the monitor for such a long time that it became obvious that it would be easier finally to show it through my laptop.
2. It was not finally that appealing to use as somebody would have to go and see the list of all posters and select each poster to see in detail. In other words you couldn’t browser the posters like what you do when you walk around in the poster session. It would have been much nicer to have the posters rolling somehow randomly in the monitors and continuously to widen their visibility.
3. Interactive it might have been but it was not easy to navigate (e.g. change the session and see another than the active one at that time), while in many cases there were a few bugs (zooming in that resulted in hiding some presentations, or crashing during the slide change).

XXXth General Assembly of IAU – week 2

The second week of the XXXth GA started very early actually as they were actually 3 plenary talks of the IAU 346 Symposium on “High-mass X-ray binaries: illuminating the passage from massive binaries to merging compact objects” (which actually deserves a post of its own, if I ever manage to make…). After that, we had the second day of the Division Days where I had a talk (in Division G) on the B[e] Supergiants (see for more the post on my contributions to this GA).

Apart from the scientific part there were again a lot of people (with an important percentage being different from the first week) going around the exhibition and the various happenings. One of them was of course the General Assembly itself.

The booth of Officina Stellare.

Display of a telescope system from PlaneWave Instruments.

The booths of ESA, ESO, and of the IAU’s Office of Astronomy for Development (2nd week).

Exhibition “boxes” for the 100 years of the IAU.

Before any official discussion engagement at the General Assembly, there was a musical performance:

One of the key issues to discuss in this assembly was the suggestion to rename the Hubble law to Hubble-Lemaitre law. There was actually a lively discussion with arguments from both sides. An indicative voting was made but the final decision will be based on a more detailed poll sent to all members of the IAU.

Although not formally decided, the revised Hubble-Lemaitre law was presented.

Presenting the resolution for renaming the Hubble law to Hubble-Lemaitre law (during the IAU GA 2018, in Viena)

The, indicative, voting process for the Hubble-Lemaitre law.

Then, the assembly proceed with more bureaucratic issues (among which was also the approval of new members, such myself!). Last but not least, there was the announcement for the organizer of the IAU GA of 2024 (as for 2021 is Korea) which is South Africa (after a strong competition with Mexico). The GA resolved with some folklore dance and music.

Another voting process during the IAU General Assembly of 2018.

At the very end of the GA, kids and adults (mainly from the IAU’s Office of Astronomy for Development) were playing with this giant Earth-like balloon.

The final day ended a bit earlier than others allowing us a bit more more time to relax. After all it was almost two weeks of many conferences and meetings in parallel that had developed considerable tiredness. I was more than happy to return home the next day and rest a bit more over the weekend, and enjoy some of the promotional stuff (see below!).

A small collection of various promotional stuff (pins, stickers, etc) and my badge from the IAU GA 2018 (and I have actually forgotten to put some more…!).

Various stuff from the IAU GA. I actually won this t-shirt at the lottery of the Korean booth (!).

Dinner time during IAU2018

Conferences feed the brain … but the body needs fuel too! Enjoying some local Viennese cuisine and wine.

XXXth General Assembly of IAU – week 1

The XXXth General Assembly of the IAU is held in Vienna, Austria, from Aug 20 to 31, 2018. The first week is finished now and tomorrow the second starts.

It is the biggest convention I have been so far with almost 3000 attendees, from all around the world literally. If I was to use only one world to describe it, ti would be “HUGE”! The Vienna International Center is great as it is neally easy to navigate and it can accommodate such an event. It is also very interesting and definitely uncommon to see exhibitors in astronomical conferences. You can find a large variety of booths from publishers, telescope/instrument companies, universities/telescopes/institutions advertising their projects, societies promoting their work, ESO and ESA, and an exhibition dedicated to the 100th anniversary of IAU. To all of these add the promotional stuff and gifts (from stickers to t-shirts and bags) and you get a rather different atmosphere sometimes.

A perspective of the exhibition.

A perspective of the exhibition.

The supernova - part of the 100th anniversary of the IAU.

The supernova – part of the 100th anniversary of the IAU.


LEGO models of some telescope facilities - part of the 100th anniversary of the IAU.

LEGO models of some telescope facilities – part of the 100th anniversary of the IAU.

Of course the main core is the various symposia and meetings. I came in Vienna on Tuesday (Aug 22) so as to take a look at the session on circumstellar environment around AGB stars (IAU Symposium 343: Why Galaxies Care About AGB Stars: A Continuing Challenge through Cosmic Time). Then, in the afternoon I went to the reception of the Focus Meeting 14: IAU’s role on global astronomy outreach, the latest challenges and bridging different communities, which was held at the Natural History Museum of Vienna. That was finally an amazing experience. Apart from getting to know fellow participants we got a free tour around the museum by its director. The museum exhibits an overwhelming collection, which represents only a small fraction of its collection (which is stored under the floors that are open to the public, and is accessible only to its scientists). On the next day (Thursday) the meeting took place, where I had an eposter representing the collective work we have done with the Hellenic Amateur Astronomy Association.

Then on Friday the Division G (Stars and Stellar Physics) Days, started, which I followed as much as possible, although I did tried to listen to other talks (the University of Vienna provided a very useful app to check the program and create your own agenda to easily follow whatever interests you most).

Another interesting week in starting tomorrow. I have a talk at the Division G Days and a poster contribution at the IAU Symposium 346: High-mass X-ray binaries: illuminating the passage from massive binaries to merging compact objects.

A fascinating comparison of what we knew in 1919 and in 2019 - Part of the 100th anniversary of the IAU.

A fascinating comparison of what we knew in 1919 and in 2019. It is amazing how our knowledge has advances. (Part of the 100th anniversary of the IAU.)