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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

Abstract:
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).

The third activity of the first period on Work Package 2 was the Digital Signal Processing course part I,  presented between 04.10-08.10.2021 by eng. Ronald de Wild, on-site on the campus of the Technical University of Sofia. 10 participants from the Technical University, the Institute of Astronomy, and Sofia University, attended the course and learned the basics of the theory of Signals, Transforms, and Systems. 

The DSP course is divided into two modules. In the first part (“Basic DSP”), basic topics on digital signal processing have been treated. The knowledge of DSP at MSc-level treated in the first module will be needed for the second part (“Advanced DSP”). 

A list of the topics treated during the course program “Basic DSP”:

Signals (part 1 of 2) classifications; representations; operations 

Transforms (part 1 of 3) [Continuous-Time] Fourier Transform 

Signals (part 2 of 2) sampling; quantization 

Transforms (part 2 of 3) Discrete-Time Fourier Transform (DTFT) & Z-Transform 

Systems (part 1 of 3) general: characterization; properties; behavior Systems (part 2 of 3) specific: LTI digital filters: classification; analysis; synthesis

The students have now acquired all the knowledge necessary for the next module of the course!

The second training module for RF techniques and Development [WP2-Task 2] was presented on-site at ASTRON between 27-09-2021 and 01-10-2021 by a team consisting of Michel Arts, Mark Bentum, Juergen Morawietz, Ronald de Wild and Pietro Zucca, on-site at ASTRON. The course was structured in a full week of training including the theory module, practical exercises, and a tour of the facilities at ASTRON, including the LOFAR core and the Westerbork telescope. Seven participants from the Technical University of Sofia attended the course. 

The course program “RF Training II” included: 

• 4 hours of RF Theory, 
• two modules of Hands-On Training of 6 hours, 
• visit of the Antenna lab facilities, 
• a RF application lecture of 3 hours
• antenna hands on workshop 4 hours
• visit of Telescopes and astronomical applications class 8 hours