The Messenger

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Issue 186
Messenger Issue 186

The Messenger Issue 186

Highlights include:

  • Bodensteiner, J., Heida, M. et al.: Detecting Stripped Stars While Searching for Quiescent Black Holes
  • Hatziminaoglou, E., Privon, G. et al.: Redesigning the ALMA User Experience from End to End
  • Gentile Fusillo, N., Ginolfi, M.: The ESO Summer Research Programme 2020 and 2021

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Table of Content No. 186 | 2022
Astronomical Science
Bodensteiner, J., Heida, M. et al.
Detecting Stripped Stars While Searching for Quiescent Black Holes
ADS BibCode: 2022Msngr.186....3B
Bodensteiner, J., Heida, M., Abdul-Masih, M., Baade, D., Banyard, G., Bowman, D., Fabry, M., Frost, A., Mahy, L., Marchant, P., Mérand, A., Reggiani, M., Rivinius, T., Sana, H., Selman, F., Shenar, T.
While the number of stellar-mass black holes detected in X-rays or as gravitational wave sources is steadily increasing, the known population remains orders of magnitude smaller than predicted by stellar evolution theory. A significant fraction of stellar-mass black holes is expected to hide in X-ray-quiet binaries where they are paired with a “normal” star. Although a handful of such quiescent black hole candidates have been proposed, the majority have been challenged by follow-up investigations. A confusion that emerged recently concerns binary systems that appear to contain a normal B-type star with an unseen companion, believed to be a black hole. On closer inspection, some of these seemingly normal B-type stars instead turn out to be stars stripped of most of their mass through an interaction with their binary companion, which in at least two cases is a rapidly rotating star rather than a compact object. These contaminants in the search for quiescent black holes are themselves extremely interesting objects as they represent a rare phase of binary evolution, and should be given special attention when searching for binaries hosting black holes in large spectroscopic studies.

Zwaan, M., Ivison, R. et al.
ALMACAL: Surveying the Universe with ALMA Calibrator Observations
ADS BibCode: 2022Msngr.186...10Z
Zwaan, M., Ivison, R., Peroux, C., Chen, J., Klitsch, A., Hamanowicz, A., Szakacs, R., Weng, S., Biggs, A., Smail, I.
The Atacama Large Millimeter/submillimeter Array (ALMA) has accumulated thousands of hours of observing time on calibrator sources, which are typically bright quasars. These calibration scans are usually observed with the same instrumental setup as the science targets and have enormous potential for conducting science. ALMACAL is a survey that is exploiting these data which are accumulating “for free” with every scheduled ALMA observing project. Here, we present a brief survey status update and summarise the science that can be achieved. For instance, if data acquired during multiple visits to many ALMA calibrators are combined, low continuum noise levels can be reached, allowing the detection of faint dusty star-forming galaxies in a number of bands. Also, redshifted CO and other emission and absorption lines are detected in the ALMACAL data. The total on-source integration time for all ALMACAL scans to date amounts to approximately 2500 hours, more than all ALMA Large Programmes to date combined.

Bagnulo, S., Landstreet, J.
The Isolated Magnetic White Dwarfs
ADS BibCode: 2022Msngr.186...14B
Bagnulo, S., Landstreet, J.
About one star in four will end its life as a magnetic white dwarf. Although magnetism is a very common feature in degenerate stars, we still do not know much about its origin and evolution. Our volume-limited spectropolarimetric survey of white dwarfs reveals statistical characteristics that may help to understand it.

Hatziminaoglou, E., Privon, G. et al.
Redesigning the ALMA User Experience from End to End
ADS BibCode: 2022Msngr.186...20H
Hatziminaoglou, E., Privon, G., Shimajiri, Y., Toribio, C., Popping, G., Guzman-Ramirez, L., König, S., Plunkett, A., Rygl, K., Avison, A., Biggs, A., Díaz Trigo, M., Guglielmetti, F., Macias Quevedo, E., Maud, L., Miotello, A., Petry, D., Randall, S., Stoehr, F., van Kampen, E., Zwaan, M.
In the middle of the COVID-19 pandemic and while the ALMA antennas were still powered down, ALMA launched a global initiative to Redesign the User eXperience (RedUX). The RedUX Working Group (WG) interviewed ALMA users worldwide, equally spread amongst the three regions (North America, East Asia and Europe) between November 2020 and May 2021. The discussions that took place at the RedUX interviews were distilled and concrete suggestions for improvements were passed by the RedUX WG to individual teams responsible for ALMA software components, WGs or regions, as well as to the ALMA Integrated Science Operations Team.

Astronomical News
Gentile Fusillo, N., Ginolfi, M.
The ESO Summer Research Programme 2020 and 2021
ADS BibCode: 2022Msngr.186...26F
Gentile Fusillo, N., Ginolfi, M.
The ESO summer research programme, a great success when it was first held in 2019, is now a regular event in the ESO calendar. Because of the restrictions resulting from the global pandemic, the second and third programmes were held in a virtual format without hosting the participating students in Garching. Nonetheless, both programmes attracted over 400 applicants from over 50 countries. In 2020 and 2021, 11 successful students (at BSc and MSc level) were invited to carry out scientific projects under the supervision of ESO Fellows and staff members for six weeks between July and August. The students carried out research in different fields of astronomy, from galactic structures to stellar evolution and planetary formation.

Herenz, E., Marchetti, T. et al.
ESO Fellow Days 2021 in Cyberspace
ADS BibCode: 2022Msngr.186...30H
Herenz, E., Marchetti, T., Ginolfi, M., Hsieh, P.
We used the unique circumstances of the global pandemic to reboot the ESO Fellow Days as a virtual online meeting. More than twenty Fellows connected to a two-day meeting on 20 and 21 October 2021 via the collaboration platform Microsoft Teams and the virtual reality space Gather. The activities of the event were chosen in advance by public vote. Feedback from the participants testified to their overall satisfaction and exposed the need to have meetings between Chilean and Garching Fellows on a regular basis.

Boffin, H., Alei, E. et al.
Report on the ESO Workshop "Atmospheres, Atmospheres! Do I look like I care about atmospheres?"
ADS BibCode: 2022Msngr.186...32B
Boffin, H., Alei, E., Casasayas Barris, N., Chasiotis-Klingner, S., Danielski, C., Fisher, C., Gandhi, S., MacDonald, R., Rickman, E., Sedaghati, E., Zak, J.
The discovery rate of exoplanets has been such that we have now moved from a simple detection regime to one in which planets can be characterised. Alongside precise determinations of planetary radii and bulk compositions, the properties of their atmospheres are now being revealed. This provides a powerful window onto the formation history of planetary systems, the composition of the initial protoplanetary disc in which planets form, and the locations of planet formation. Moreover, this allows us to study various chemical and thermodynamical processes in the upper atmosphere, as well as to probe planetary interiors. ESO recently organised an online workshop on these topics, with some quite unique aspects: it addressed results from transmission and emission spectroscopy from the ground in the study of exo-atmospheres; it looked at synergies with studies of giant planets in the Solar System; it provided two days of hands-on activities to prepare the future generation; and it included invited talks by the most promising young scientists working in this field.

Fragkoudi, F., Santamaría Miranda, A.
Fellows at ESO
ADS BibCode: 2022Msngr.186...37E
Fragkoudi, F., Santamaría Miranda, A.

ESO Launches Visitor Programme for Scientists Working in Ukraine
ADS BibCode: 2022Msngr.186...39E

Annual Index 2021 (Nos. 182–185)
ADS BibCode: 2022Msngr.186Q..39E