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STELLAR Seminar on November 2, 2021

The third STELLAR seminar lecture will be by Dr. Harish Vedantham of ASTRON. His online seminar will be held on Tuesday, November 2 2021, at 15:00h CET, over Zoom (connection details below).

“Radio flashes from plasma storms around exoplanets”
Dr. Harish Vedantham
ASTRON, The Netherlands Institute of Radio Astronomy
Watch the video of the Seminar

Low frequency (< few hundred MHz) radio observations uniquely trace several processes that determine the habitability of exoplanets. Coronal plasma ejections that erode planetary atmospheres can be detected using the characteristic radio bursts they emit. Planetary magnetic fields that largely determine the planetary defence against the stellar onslaught can also be detected using radio observations. Radio observations of such phenomena in the solar system are commonplace. I will argue that the extrasolar frontier is now also within reach thanks to powerful new low-frequency telescopes such as LOFAR. I will describe an observational program using LOFAR to systematically survey the low-frequency radio sky for stellar, brown dwarf and exoplanetary emission with unprecedented sensitivities reaching a fraction of a milliJansky at 150 MHz and below. I will present some early successes of this campaign including (a) the discovery of evidence for magnetic interaction between a star and its planet and (b) the discovery of a cold brown dwarf directly in the radio band using its magnetospheric emissions. I will end with an outlook for harnessing radio astronomy’s unique diagnostic capabilities to advance exoplanet science.

About Dr. Vedantham: Staff astronomer, ASTRON & Visiting Assistant Prof. at Univ of Groningen (2018-current); Recipient of Dutch Vidi grant for 2021.
Past affiliations: Millikan fellow at Caltech (2015-2018), PhD University of Groningen (2011-2015).

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STELLAR Seminar on August 17

A STELLAR Seminar will be delivered online by Dr. Peijin Zhang from the University of Science and Technology of China and the Institute of Astronomy, Bulgarian Academy of Sciences, on Tuesday, August 17, at 15:00h CET.

“Observation, Modeling, and Wave-Propagation Simulations on the Source of Solar Radio Burst”
Dr. Peijin Zhang
University of Science and Technology of China / Institute of Astronomy, Bulgarian Academy of Sciences

The Seminar is free to attend and held online. Find the abstract and connection info at the STELLAR Seminars page.

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LOFAR Science Workshop at Astron!

The most recent activity of the STELLAR project was the LOFAR Science Workshop, which was held July 26-30, 2021, at ASTRON’s beautiful building near Dwingeloo, The Netherlands. The Bulgarian team, made up of six scientists, PhD and undergraduate students from the Institute of Astronomy (BAS) and two scientists from the Techical University of Sofia, learned about the research done with LOFAR, with an accent on space weather and the Earth’s ionosphere. Tutorials and exercises in processing and analyzing LOFAR data were led by Dr. Pietro Zucca and Dr. Maaijke Mevius. The Bulgarian team had the opportunity to visit the LOFAR core and the Westerbork Synthesis Radio Telescope (WSRT), and enjoyed the cool Dutch summer!

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STELLAR Space Weather Workshop Lectures Online

All video recordings of the Space Weather Workshop, organized by DIAS and held online July 12-15, 2021, are now available for free viewing! They can be found at the Workshop website:

They are also available on our STELLAR Lecture Series page.

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STELLAR Space Weather Workshop Begins!

The STELLAR Space Weather Workshop with a radio twist starts online today, July 12. It is part of the STELLAR H2020 project led by the Institute of Astronomy. The workshop is organised and led by our colleagues from the Dublin Institute of Advanced Studies. For four days, Bulgarian and international students and scientists will learn important details about solar activity, its interactions with planets and interplanetary space, and how we can observe them in radio frequencies. Daily exercises in data analysis with Python are also included.

Learn more at

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Registration for the DIAS Space Weather Workshop, 12-15 July, is now open!

As part of the STELLAR project, DIAS will be hosting a workshop on space weather with a radio twist. This workshop will trace space weather phenomenon from their solar origins, propagation through the low corona, out into the heliosphere and finally possible interactions with planetary bodies. The workshop is aimed at early career stage researchers or those unfamiliar with space weather. The workshop will be held online between 12-15 July.

Registration is open until June 25 here:

To find out more about the workshop, topics, and lectures, head to

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The “Intro to Antennas” class was a success!

The first activity of the STELLAR project took place in mid-February! The Introduction to Antennas course, originally planned to be held at ASTRON (in Dwingeloo, The Netherlands) for up to six people (faculty, researchers, and students) from the Institute of Astronomy (BAS) and the Technical University of Sofia, was transformed into an online course due to the COVID-19 pandemic. The course was attended by 57 participants from 13 research institutions!

The short course was held over Zoom, as three separate three-hour-long lectures. It was led by Dr. David Prinsloo of ASTRON – an expert in the design of antennas and antenna arrays for radio astronomy. Dr. Prinsloo is a researcher with the Smart Front-ends Group at the Innovations and Systems department of The Netherlands Institute for Radio Astronomy. His primary research interest is on antenna designs for both phased array and reflector-based radio telescopes.

The course participants learned the ins and outs of fundamental antenna parameters, basic antenna types, as well as antenna arrays. As the final module of the course, the students participated in the design of a realistic antenna array.

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The Antennas for Testing LOFAR-BG station sites have arrived!

Christmas is coming, and with it – gifts! The Institute of Astronomy recently got a long-awaited shipment from The Netherlands – a huge crate with the test antennas for our future LOFAR-BG station 🙂

After carefully unwrapping and checking the contents for damage, we delivered them to Assoc. Prof. Peter Petkov from the Radiocommunications Dept. of the Technical University-Sofia, for testing and preparing the measurement system. Our main goal is to measure the levels of radio noise (background) in the spectral bands of the low-frequency (10-90 MHz) and high-frequency (110-250 MHz) antennas of LOFAR at the pre-selected possible sites for the LOFAR-BG station.

After making sure the components were in order and assembling the test system, it was time for some real measurements! A great first place to start is always the parking lot in front of the University 🙂

The initial tests were successful, and very soon we will begin measurements on site. More news to come!

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LOFAR-BG Accepted in the Updated National Roadmap for Scientific Infrastructure!

The LOFAR-BG infrastructure project, coordinated by the Institute of astronomy and National Astronomical Observatory (IANAO), was recently approved for inclusion into the updated National Roadmap for Scientific Infrastructure 2021-2027! We are very pleased with this successful outcome.

In the next 13 years, the project execution foresees the building and development of a Bulgarian observational station of the pan-European distributed LOFAR radio telescope, and the creation of human potential for carrying out specific astrophysical and geophysical research with the Bulgarian station and the entire LOFAR telescope.

In addition, the successful execution of this project will guarantee the development of scientific and engineering potential, of the capability for hardware and software maintenance of the LOFAR-BG station, of capability for processing and archiving of petabyte-scale volumes of observational data, and of new automated analysis methodologies via Artificial Intellect. The project foresees active partnerships and exchange of know-how with industry, as well as dissemination and outreach activities.

The LOFAR-BG station will position Bulgaria at the top of radioastronomical observing capabilities in Southeastern Europe. Maintaining and enriching further this unique research infrastructure will enable the development of innovative scientific and engineering topics in ICT (real-time signal processing, time series and image analysis with AI, data clustering and archiving), as well as transfer of scientific and technological know-how from international collaborations. An additional goal of the project is creation of spin-off companies in radio communications and ICT.

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The STELLAR Project Approved!

We would like to share the wonderful news that our project proposal “Scientific and Technological Excellence by Leveraging LOFAR Advancements in Radio Astronomy” (STELLAR) to the H2020-WIDESPREAD-05-2020-Twinning program has been approved by the European Commission with funding of nearly 900 000 Euro!

The STELLAR project duration will be three years. Its main goal is to increase the capability of Bulgarian astronomers and radio engineers to work with the LOFAR telescope. The Institute of Astronomy and National Astronomical Observatory (IANAO) will serve as coordinator of the project. The Technical University of Sofia (TUS) will also participate from the Bulgarian side. The international partners on the project will be the Dublin Institute for Advanced Studies (DIAS) and the Netherlands Institute for Radio Astronomy (ASTRON). They will prepare and carry out a number of training events in the Netherlands, Ireland, and Bulgaria, for Bulgarian astronomers and engineers.

The STELLAR project is part of a long-term strategy of IANAO to develop modern radio astronomy in Bulgaria, by providing access to the newest pan-European and worldwide observational infrastructures. It will help the small but dynamic radio astronomical community in Bulgaria to obtain and develop the necessary skills and expertise for successfully building, maintaining, and exploiting a Bulgarian LOFAR station. Apart from the training events, the project will include the realization of three open summer schools in Bulgaria – in radio astronomy, space weather, and radio technologies. It is expected that the STELLAR project will begin in September 2020.