General Seminar (2025)
current | 2025 | 2024 | 2023 | 2022 | 2021 | 2020 | 2019 | 2018 | 2017
General Seminar takes place every Monday at 11.15 in Piwnice, radioastronomy seminar room.
Remote participation via the BigBlueButton (BBB).
13 January 2025
“Progenitors of LGRBs: Are single stars enough?”
mgr Rafia Sarwar
Institute of Astronomy, Nicolaus Copernicus University
Abstract:
Stars more massive than 8 M☉ are ignited by nuclear-burning processes of chemical elements in their interiors until the formation of the carbon-oxygen core that marks the end of their life cycle. The final fate of evolved massive stars is classically linked to energetic and luminous transient sources: long-duration gamma-ray bursts (LGRBs). I present the revised and expanded single-star models using MESA and new observational comparisons in this work. My study demonstrates the impact of rotation during the evolution of these stars, leading to chemically homogeneous evolution followed by various types of supernova explosions. I also compare these theoretical models with the observed number of LGRBs to date with known redshifts. The comparison reveals that the updated massive-star physics can explain the observed distribution more fairly than previous studies, primarily due to the way mass loss from stellar winds is treated during evolution.
20 January 2025
“Red novae and their remnants: how stars merge and what is the outcome”
dr hab. Tomasz Kamiński, prof. CAMK
Nicolaus Copernicus Astronomical Center PAS, Toruń
Abstract:
Red novae are transient events powered by stellar collisions of normal (non-compact) stars. I am going to summarize recent advancements in red nova observations and in modelling of stellar mergers. For instance, I am going to briefly discuss how observations of circumstellar matter help us to identify the mechanisms that lead to a collision and fast coalescence. I am going to mention future prospects of observing red novae with LSST-Rubin and what consequences they may have. Finally, I am going to present my future project to observe the radioactive nuclide of 26Al in merger remnants and in other objects.
27 January 2025
“Playing hide and seek with galaxies”
dr hab. Katarzyna Małek, prof. NCBJ
Astrophysics Division, National Centre for Nuclear Research, Warszawa
Abstract:
What is the nature of low surface brightness (LSB) galaxies? How many types of LSB galaxies exist, and how do they relate to the global mass distribution in our Universe? Furthermore, how can these galaxies be identified in existing surveys, as we now prepare for the Vera C. Rubin Legacy Survey of Space and Time, which will detect a significant number of LSB galaxies, but only in optical bands? I will present a selection of new results from our research group, including insights into their potential dust content and clustering properties, which highlight the complexity of this topic and pave the way for new discoveries.
3 February 2025
“Exploring blazar flares with threshold autoregressive models and spectral energy distribution modeling”
mgr Klaudia Kowalczyk
Institute of Astronomy, Nicolaus Copernicus University
Abstract:
Blazars are a unique class of active galactic nuclei (AGNs) hosting relativistic jets pointing almost directly at the observer. They are known to be highly variable sources in all energy bands, from radio waves to very high-energy gamma rays, where they exhibit powerful flares. Their variability is assumed to originate in the jet. By modeling blazars’ spectral energy distribution (SED), we can study the innermost non-visible parts of blazars. I will present a novel method of differentiating quiescent states from flares in blazar gamma-ray light curves using the self-exciting threshold autoregressive (SETAR) model. I will also show the preliminary results of modeling blazar SEDs and linking the obtained physical parameters to different states of blazars.
24 February 2025
“On the Polish In-kind program to the Rubin-LSST project”
dr hab. Paweł Pietrukowicz, prof. UW
Warsaw University Astronomical Observatory, Warsaw
Abstract:
The Vera C. Rubin Observatory Legacy Survey of Space and Time (Rubin-LSST) will receive the first light this year. The first data release is expected in 2026. Poland participates in the survey through the In-kind program, which includes constructing and servicing an Independent Data Access Center (IDAC) accompanied by software development and providing associated derived data products. I will describe the survey and the Polish contribution to the Rubin-LSST in details.
3 March 2025
“How can genome mining from space-dwelling bacteria help us colonize other planets?”
dr Łukasz Szydłowski
Sano Center For Computational Personalized Medicine, Kraków
Abstract:
In the vastness of space, where radiation from stars like the Sun is lethal and darkness is almost absolute, the existence of life seems impossible. Yet, there are organisms that have learned to cope with these conditions. A team of researchers from Poland and Turkey, in close collaboration with partners from NASA’s Jet Propulsion Laboratory has conducted research on how microorganisms adapt to the extreme conditions in space. As a result, a groundbreaking scientific paper titled “Adaptation to space conditions of novel bacterial species isolated from the International Space Station revealed by functional gene annotations and comparative genome analysis” has been published in the prestigious journal Microbiome. The authors of the publication examined the adaptive mechanisms of bacteria collected from the ISS. The findings indicate that microorganisms isolated from inside the ISS have adapted to life in outer space.
Promising Directions in the Development of New Antibiotics.
Discoveries in space genomics are possible thanks to tools using deep machine learning for functional annotations. The genomes of bacteria found on the ISS contain genes for antibiotic resistance and biofilm formation, as well as potential new antimicrobial compounds. This discovery could lead to the development of new drugs that will have applications in both space missions and on Earth. Thanks to this research, we can not only improve the health of astronauts in difficult space conditions but also create innovative therapies for people that will help fight treatment-resistant infections and support the development of new strategies for treating infectious diseases.
Potatoes on Mars and Medicines from Space.
AstroFarms, a company founded by Dr. Łukasz Szydłowski, is one of the most innovative projects aimed at transferring agriculture beyond Earth. AstroFarms is developing the cultivation of adapted potato varieties on lunar and Martian simulators, creating the foundations for future agriculture on other planets. The company is also working on developing microorganisms that will enable the bioproduction of many important substances: pharmaceuticals, polymers, biofuels, etc. This solution aims to ensure self-sufficiency for future space inhabitants, reduce dependence on Earth’s resources, shorten the supply chain, and expand research to other celestial bodies. The use of microorganisms as biofactories to provide optimal nutrition may concern not only future inhabitants of space stations but also people on Earth, where comprehensive nutrition and disease prevention is one of humanity’s challenges.
10 March 2025
“University of Zielona Gora (Remote) Observatory – current state and planned development”
dr Michał Żejmo
Janusz Gil Institute of Astronomy, University of Zielona Góra
Abstract:
In 2021, the Janusz Gil Institute of Astronomy, University of Zielona Gora was equipped with a system consisting of two telescopes – a main telescope of CDK design with a diameter of 20 inches and an auxiliary telescope of RASA design with a diameter of 11 inches. The two telescopes form a single system for both deep space observations and observations related to the Space Surveillance and Tracking (SST). The system was tested in Spain for a year, then transported to the hosting site in Chile.
In my presentation, I will discuss the experience of using the system, its involvement and achievements in scientific projects, its application in student education and the popularisation of astronomy, as well as future plans to expand the system with new telescopes and create a Remote Observatory of the University of Zielona Góra.
17 March 2025
“Heating of the solar atmosphere and generation of the solar wind as central problems of heliophysics”
mgr inż. Mariia Pelekhata
Institute of Physics, Maria Curie-Skłodowska University in Lublin
Abstract:
The presentation is based on a doctoral dissertation focused on key problems in heliophysics, such as the mechanisms of solar atmospheric heating and the generation of the solar wind. Special attention is given to the role of magnetohydrodynamic (MHD) waves in processes occurring in the photosphere and chromosphere.
The presentation discusses the theoretical foundations of the Sun’s structure, the properties of solar plasma, and the dynamics of MHD waves. It also introduces numerical plasma models, including two-fluid and three-fluid approaches, which allow for the analysis of energy transport in the solar atmosphere.
The presentation provides an overview of the research methods and selected results obtained from numerical simulations, offering new insights into plasma heating mechanisms and their significance for the evolution of the solar atmosphere. The findings contribute to a better understanding of the processes occurring in the Sun’s atmosphere and serve as a foundation for further studies on MHD wave dynamics and their role in energy transport in solar plasma.
24 March 2025
“Rho Cassiopeiae – a review of the new observations and analyses”
dr hab. Krzysztof M. Gęsicki, prof. UMK
Institute of Astronomy, Nicolaus Copernicus University in Toruń
Abstract:
The iconic yellow hypergiant star Rho Cas recently was a subject of interesting scientific research. I will review the new data and analyses which were published during last couple of years, focusing on the attempt to find some order within its irregular variability.
31 March 2025
“Stars as laboratories to test theories of gravity”
dr Aneta Wojnar
Institute of Theoretical Physics, University of Wrocław, Poland
Department of Theoretical Physics, Complutense University of Madrid, Spain
Abstract:
I will provide a brief overview of the latest research in the physics of (sub-)stellar objects in the context of modified gravity. Our primary focus will be on the matter’s properties of these objects, including the equation of state, specific heats, and other relevant characteristics. Additionally, we will explore the internal processes of these objects, such as light element burning, crystallization, and cooling, and discuss potential methods for testing modified gravity theories using seismic data.
8 April 2025 – TUESDAY
“Novel approaches for understanding the multi-wavelength picture of blazars”
dr Lea Heckmann
Université Paris Cité, CNRS, Astroparticule et Cosmologie, Paris, France
Max-Planck-Institut für Physik, Garching, Germany
Abstract:
Blazars are prime objects to investigate in the current multi-messenger era. However, even though they have been studied for decades, we are still deciphering their underlying emission and acceleration mechanisms. In this talk, I will present my research focusing on understanding our brightest TeV blazars in a multi-wavelength (MWL) context. I will focus on two main approaches:
The first approach explores the possibilities opened by the newly available X-ray polarization measurements of blazars by IXPE and combines them with the MWL picture. While the first studies involving data up to the very-high-energy (VHE) gamma-rays cover moderate emission states, a flaring event of Mrk 421 occurred simultaneous to IXPE observations in December 2023. In our study, we manage to explain the observed VHE flare simultaneous to stochastic fluctuations observed in the X-ray polarization and a counter-clockwise hysteresis in the X-rays with highly turbulent electron-ion plasma crossing a shock front inside the blazar jet.
The second approach is exploiting novel analysis methods to investigate blazar data. One the one hand, we use an unsupervised learning technique to identify emission states of blazars in a more unbiased way as done to date. Applied to a long-term MWL data set of the blazar Mrk 501, it allows to identify various high- to low activity-emissions states and finds a distinctive pattern between radio and X-ray fluxes indicating multiple emission zones. On the other hand, we are developing a framework to enable the theoretical interpretation of multi-messenger datasets using the open-source Python package Gammapy. It allows to perform minimization directly on instrumental counts instead of flux points reducing biases coming from the flux point generation, and allowing a simpler treatment of systematics between different instruments and datasets. The goal is to provide an open framework to the community, which can be used to fit any iterable leptonic and hadronic model to MWL datasets.
14 April 2025
“Radio-emitting active galactic nuclei at milliarcsecond-scale resolution”
dr Krisztina Gabányi
Department of Astronomy, ELTE, Eotvos University, Budapest, Hungary
HUN-REN-ELTE Extragalactic Research Group, ELTE, Eotvos University, Budapest, Hungary
Konkoly Observatory, HUN-REN Research Centre for Astronomy and Earth Sciences, Budapest, Hungary
Institute of Astronomy, Nicolaus Copernicus University, Toruń, Poland
Abstract:
Today the Very Long Baseline Interferometry (VLBI) technique provides the highest achievable resolution in astronomy. In studying the radio emission of active galactic nuclei (AGN), VLBI can deliver accurate positions, reveal the origin of the radio emission, help to discriminate between star formation and AGN-related emission, expose the details of jet structure at levels at least tens of parsecs and, as recently demonstrated, can image the black hole shadow.
In my talk, I will focus on two topics. First, how various radio interferometric observations can help to find dual AGN or refute such claims in individual objects. According to the current structure formation model, galaxies are formed via the merger of smaller ones, thus it is expected that the dual (or multiple) systems of their central supermassive black holes (SMBH) can form. During the interaction process, numerical simulations show that at least one of the SMBHs becomes active at less than 10 kpc separation. I will present a few cases to illustrate the power and shortcomings of radio observations in this field.
Second, I will show how radio interferometric observations can help to study AGN at high redshifts, z>4. These studies provide essential constraints for the formation and evolution of SMBHs and can reveal the interaction between the jets and the dense material surrounding powerful jetted AGN.
Special Seminar
29 April 2025 – TUESDAY
” The German Centre for Astrophysics: Building Infrastructure and Partnerships for Future Scientific Collaboration”
dr Pavlo Plotko
Deutsches Zentrum für Astrophysik / German Center for Astrophysics (DZA) in formation
c/o Deutsches Elektronen-Synchrotron (DESY)
Abstract:
The German Centre for Astrophysics (DZA) is a major scientific initiative in Germany, set to be officially founded in 2025. Currently in its establishment phase, DZA is focused on creating the necessary infrastructure—both technical and collaborative—that will support groundbreaking research and drive fundamental transformation in eastern Germany. Located at the intersection of the German-Polish-Czech border, DZA aims to build strong partnerships with institutions in Poland, the Czech Republic, and across Eastern Europe.
One of DZA’s key scientific goals is to ensure that, once operational, it will serve as an open and efficient hub for gravitational wave astronomy, radio astronomy, optical astronomy, multi-messenger astrophysics, and advanced data science.
This talk will present the idea and mission behind DZA, explain why this new center is being created, and outline how it will operate once established. It will also highlight DZA’s planned scientific focus areas and describe how today’s efforts, particularly in building connections with neighboring countries, are laying the foundation for seamless and productive collaboration in the future.