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Journal Club


"The Moral Machine experiment"

Magdalena Sieniawska (CAMK, Warsaw)

With the rapid development of artificial intelligence have come concerns about how machines will make moral decisions, and the major challenge of quantifying societal expectations about the ethical principles that should guide machine behavior. The presentation is based on the work of E. Awad and collaborators:


"Changing-Look Quasar Candidates: First Results from Follow-up Spectroscopy"

Marzena Śniegowska (CAMK, Warsaw)

The talk is based on the recent work presented in


"Dynamical mass of a type-II Cepheid in an eclipsing system with a disk"

Bogumił Pilecki (CAMK, Warsaw)

The talk is based on the original research paper, about the first measurement of the dynamical mass for a type II Cepheid in an eclipsing system with a disk.


"A study of Pulsation & Rotation in a sample of A-K type stars in the Kepler field"

Sowgata Chowdhury (CAMK, Warsaw)

The talk is based on


"X-rays from neutron star atmospheres at low accretion rates"

Ekaterina Sokolova-Lapa (Astronomisches Institut der Universität Erlangen-Nürnberg)

The accretion powered X-ray pulsars are one of the brightest X-ray sources of our galaxy. Despite the long period of research, we still do not have a self consistent model for the emerging radiation that would describe the spectral energy distribution of these sources. Often, only phenomenological models are used for investigation. The reason for this is partly due to the computational difficulties involved in analytical and numerical modeling, partly still due to some lack of understanding of the physical processes in such extreme conditions. The X-ray radiation during accretion onto the magnetized neutron star originates from regions with very high temperature and strong magnetic fields which makes the propagation of the radiation highly anisotropic. The radiation is strongly polarized due to magnetized plasma effects and vacuum birefringence. In this talk, I will introduce accreting neutron stars and outline the main difficulties encountered in modeling the spectral formation process, with the focus on low accretion rate case when the accreting matter stops to the rest in the neutron star atmosphere.


"Confronting gravitational-wave observations with modern nuclear physics constraints"

Paweł Haensel (CAMK, Warsaw)

The talk is based on the recent work of I. Tews, J. Margueron and S. Reddy:


"The FeII/MgII flux ratio of low-luminosity quasars at z~3"

Marzena Śniegowska (CAMK, Warsaw)

The talk is based on the recent work of Jaejin Shin, Tohru Nagao, Jong-Hak Woo, Huynh Anh N. Le,


"Aboriginal Australians can did discover the variability of Betelgeuse"

Brynmor Haskell (CAMK, Warsaw)

The presentation is based on


"Red Nova 2022: update"

Janusz Ziolkowski (CAMK, Warsaw)

Prof. Janusz Ziolkowski (CAMK, Warszawa) will tell us some updated on the foreseen collision of KIC 9832227.


"News from Cyg X-1"

Janusz Ziolkowski (CAMK, Warsaw)


"Observations of the black hole silhouette in M87 by the Event Horizon Telescope"

Krzysztof Nalewajko (CAMK, Warsaw)

The talk is based on the report of the first image of a black hole, by the EHT Collaboration:


"Latest Results from the SALT X-ray Binary Transients Program"

Phil Charles (Southampton University)

The Southern African Large Telescope is the largest single optical telescope in the southern hemisphere, situated at the South African Astronomical Observatory field station. SALT is funded by a consortium of international partners from South Africa, the United States, Germany, Poland, India, the United Kingdom and New Zealand. The telescope has been in full science operation since 2011 and is realising its huge potential ( see the official website ). Professor P. Charles will tell us the latest news about SALT.


"How would a nearby kilonova look on camera?"

Swayamtrupta Panda (CAMK, Warsaw)

Swayamtrupta Panda will present us the latest results from Gupte and Bartos (2019),


"Deep-Learning Continuous Gravitational Waves"

Filip Morawski (CAMK, Warsaw)

Based on arxiv: 1904.13291v2


"The disc vanishes"

Jean-Pierre Lasota (CAMK, Warsaw)

New observations are consistent with theoretical predictions that during the low states FO Aquarii, the accretion disk dissipates into a ring of diamagnetic blobs. The talk is based on


"Radio/X-ray correlation in black hole accretion systems"

Fu-Guo Xie (Shanghai Astronomical Observatory)

Jet is an unique feature of black hole BH) accretion systems. The linear relationship (in Log space) between radio and X-ray luminosities and BH mass provides a direct hint on the connection between accretion and ejection (jet). In this talk, I will address two projects. 1) The fundamental plane of BH activity for quiescent AGNs, where we gather from literature a sample of 73 sources, and confirm the radio/X-ray correlation slope steepens to 1.2 (compared to the normal 0.6). Such steepening is consistent with a jet origin in X-ray emission in quiescent AGNs. 2) The observations and theoretical interpretation of the so-called outlier sources with a hybrid radio/X-ray correlation.


"High-energy properties of young radio sources"

Dr. Malgosia Sobolewska (Smithsonian Astrophysical Observatory)

Formation of relativistic jets is one manifestation of black hole (BH) activity. Jets impact BH surrounding and in consequence affect BH feeding and growth. This coupling is believed to be essential to the AGN-galaxy feedback, which likely is present already at the stage of the initial jet launching. Contrary to theoretical predictions, young radio jets proved to be relatively faint and observing them has been challenging before the Chandra and XMM-Newton era. I will discuss the most recent X-ray results for a sample of Compact Symmetric Objects (CSO; radio structure sizes < 1kpc, ages < 3000 years) based on the high quality broadband spectra obtained with Chandra, XMM-Newton, and NuSTAR. We find evidence for a dichotomy of the CSO environment: X-ray obscured CSOs appear to have smaller radio sizes than X-ray unobscured CSOs with the same radio power. Thus, the environment may play a crucial role in regulating the early growth of the radio jets. Importantly, X-ray studies of the CSOs, in conjunction with the recent developments in lower energy bands, offer new insights for understanding the structure and size of the AGN obscuring torus.


"Unprecedented Near-Infrared Brightness and Variability of Sgr A*"

Alex Markowitz (CAMK, Warsaw)

The electromagnetic counterpart to the Galactic center supermassive black hole, Sgr A*, has been observed in the near-infrared for over 20 years and is known to be highly variable. We report new Keck Telescope observations showing that Sgr A* reached much brighter flux levels in 2019 than ever measured at near-infrared wavelengths. In the K0 band, Sgr A* reached flux levels of ∼ 6 mJy, twice the level of the previously observed peak flux from > 13, 000 measurements over 130 nights with the VLT and Keck Telescopes. We also observe a factor of 75 change in flux over a 2-hour time span with no obvious color changes between 1.6 µm and 2.1 µm. The distribution of flux variations observed this year is also significantly different than the historical distribution. Using the most comprehensive statistical model published, the probability of a single night exhibiting peak flux levels observed this year, given historical Keck observations, is less than 0.3%. The probability to observe the flux levels similar to all 4 nights of data in 2019 is less than 0.05%. This increase in brightness and variability may indicate a period of heightened activity from Sgr A* or a change in its accretion state. It may also indicate that the current model is not sufficient to model Sgr A* at high flux levels and should be updated. Potential physical origins of Sgr A*’s unprecedented brightness may be from changes in the accretion-flow as a result of the star S0-2’s closest passage to the black hole in 2018 or from a delayed reaction to the approach of the dusty object G2 in 2014. Additional multi-wavelength observations will be necessary to both monitor Sgr A* for potential state changes and to constrain the physical processes responsible for its current variability.


"Maybe we will touch Black Holes soon!"

Lorenzo Gavassino (Camk, Warsaw)

The talk is based on the recent work of Jakub Scholtz and James Unwin,


"Building ATHENA in Poland"

Agata Rozanska (CAMK, Warsaw)

The stalk will be about current progress in building subsystems for ATHENA mission in Poland.


"The B or not the B and how to get it"

Radek Stompor (CNRS, Laboratoire AstroParticule et Cosmologie)

The Cosmic Microwave Background is one of the most important observables in the present-day cosmology and one of our best windows onto the early Universe and the physics at the extremely high energies. The speaker will review the physics of the CMB B-mode polarization and current efforts to detect it.


"A giant exoplanet orbiting a very-low-mass star challenges planet formation models"

Katarzyna Rusinek (CAMK, Warsaw)

The talk is based on the work of . M dwarfs, the most common type of star, are low-mass objects that emit most of their faint light in the near-infrared, making it difficult to detect any orbiting exoplanets. The nearby M dwarf GJ 3512 has been observed in the optical and near-infrared. Periodic variations in the star's radial velocity show that it hosts a gas giant exoplanet on an eccentric orbit. The authors use simulations to show that such a large exoplanet around such a small star has implications for models of planet formation.


"An eclipsing binary with Balmer emission lines"

Mradumay Sadh (CAMK, Warsaw)

Mradumay Sadh will summarize his ongoing personal research project.


"Relativistic reflection and reverberation"

Barbara De Marco (CAMK, Warsaw)

The talk is mostly based on the work of Wang et al. 2019, "Relativistic reflection and reverberation in GX 339-4 with NICER and NuSTAR"