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Journal Club


"The origin of the first neutron star-neutron star merger"

Krzysztof Belczyński (NCAC, Warsaw)

The talk is based on arXiv:1712.00632.


"R-modes and neutron star recycling scenario"

Magdalena Sieniawska (NCAC, Warsaw)

Talk based on [astro-ph.HE].


"General-relativistic Simulations of Four States of Accretion onto Millisecond Pulsars"

David Abarca (NCAC, Warsaw)

Talk based on arXiv:1708.06362.


"Bars and spirals in tidal interactions with an ensemble of galaxy mass models"

Marcin Semczuk (NCAC, Warsaw)

The talk is based on Pettitt et al. (2018) arxiv:1712.00882.


"The close environments of accreting massive black holes are shaped by radiative feedback"

Maitrayee Gupta (NCAC, Warsaw)

Talk is based on


"Ethics Statement and Guidelines for Good Practice of the European Astronomical Society"

Rodolfo Smiljanic (NCAC, Warsaw)

Drafted by the EAS Ethics Working Group. Approved by the EAS Council on Jan 23rd, 2018.


"Gravitational Waves and Intermediate Massive Black Hole Retention in Globular Clusters"

Giacomo Fragione (Racah Institute for Physics)

The recent discovery of gravitational waves has opened new horizons for physics. Current and upcoming missions, such as LIGO, VIRGO, KAGRA, and LISA, promise to shed light on black holes of every size from stellar mass (SBH) sizes up to supermassive black holes which reside in galactic nuclei. The intermediate mass black hole (IMBH) family has not been detected beyond any reasonable doubt neither directly nor indirectly. Recent analyses suggest observational evidence for the presence of IMBHs in the centers of two Galactic globular clusters. In this paper, we investigate the possibility that globular clusters were born with a central IMBH, which undergo repeated merger events with SBHs in the cluster core. By means of a semi-analytical method, we follow the evolution of the primordial cluster population in the galactic potential and the Gravitational Wave (GW) mergers of the binary IMBH-SBH systems. Our models predict ~IMBHs within 1 kpc from the Galactic Center. Our results show that the IMBH-SBH merger rate density changes from R~1000 Gpc^-3 yr^-1 beyond z~2 to R~1-10 Gpc^-3 yr^-1 at z~0. The rates at low redshifts may be significantly higher if young massive star clusters host IMBHs. The merger rates are dominated by IMBHs with masses between 10^3 and 10^4 solar masses. Currently, there are no LIGO/VIRGO upper limits for GW sources in this mass range, but at design sensitivity, these instruments may detect these IMBH-SBH mergers in the coming years. LISA and the Einstein Telescope will be best suited to detect these GW events. The inspirals of IMBH-SBH systems may also generate an unresolved GW background.


"Supernova-like event form (very) far away"

Katarzyna Drozd (NCAC, Warsaw)

Based on: "Studying the Ultraviolet Spectrum of the First Spectroscopically Confirmed Supernova at Redshift Two", Smith, M., 2018, ApJ, 854, 37S


"Magnetic field strength of a neutron-star-powered ultraluminous X-ray source"

Prof. Jean-Pierre Lasota (NCAC, Warsaw)

Based on



POLNS (NCAC, Warsaw)


"Alternative explanations for extreme supersolar iron abundances inferred from the energy spectrum of Cygnus X-1"

Marta A. Dziełak (NCAC, Warsaw)

The talk is based on


" Exploring accretion and jet in nearby NLS1s "

Swayamtrupta Panda (NCAC, Warsaw)

The talk is based on, Yao et al. 2018.


"Image-based deep learning for classification of noise transients in gravitational wave detectors."

Filip Morawski (NCAC, Warsaw)

The talk is based on Cuoco et al. (2018) arxiv: 1803.09933


"A lower limit to the accretion disc radius in the low-luminosity AGN NGC 1052 derived from high-angular resolution data"

Katarzyna Rusinek (NCAC, Warsaw)

The talk is based Reb et al., arXiv: 1805.02657.


"The role of electron heating physics in images and variability of the Galactic Center black hole Sagittarius A*"

Jose Ortuno (NCAC, Warsaw)

The talk is based on arxiv:1804.06416


"Role of the Plasmoid Instability in Magnetohydrodynamic Turbulence"

Qiang Chen (NCAC, Warsaw)

The talk is based on


"The largest glitch observed in the Crab pulsar"

Vadym Khomenko (NCAC, Warsaw)

The talk is based on


"On the approximations and assumptions when describing Comptonization in accreting sources. - a spectroscopical/timing view with MoCA -"

Francesco Tamborra (Astronomical Institute of the Czech academy of Sciences)

Comptonization (i.e. up-scattering of low energy photons from hot electrons) is believed to be an important mechanism in accreting sources such as X-Ray binaries and Active Galactic Nuclei and responsible to explain the hard X-ray emission we observe up to hundreds of keV in these sources. In the talk, I will show the results we have obtained with MoCA, our Monte Carlo code which includes all relativistic effects and accurate treatment of Comptonization and talk about the impact which different approximations can have on the spectrum. As a bonus, I will show the preliminary results obtained within the framework of the active scientific collaboration with CAMK on the topic of the variability induced by Comptonization.


"The CHEOPS mission"

Alexis Smith (Institute of Planetary Research, DLR)

CHEOPS - CHaracterising ExOPlanet Satellite - is ESA's first small mission, and is due to launch in the first half of 2019. CHEOPS will perform ultra-high precision photometry on bright stars already known to host planets. The mission has numerous science goals, but a major aim is to measure the bulk density of super-Earths and Neptunes orbiting bright stars and provide suitable targets for future in-depth characterisation studies of exoplanets in these mass and size ranges. A significant fraction (20 %) of observing time is open for guest observers, with the first announcement of opportunity expected soon.


"Modelling of the potential Dark matter decay signal from the Local Group sources"

Wojciech A. Hellwing (Centrum Fizyki Teoretycznej (PAN))

Dark matter particles may decay emitting photons. If the dark matter particle mass is in the keV range, a decay line in the X-ray part of the spectrum could be produced. Drawing on the family of hydrodynamic simulations of galaxy formation of the EAGLE project, we provide predictions for the expected line fluxes from galaxies of different masses, from dwarfs to bright galaxies, including Local Group analogues, and from galaxy clusters at various redshifts including Perseus analogues. We provide specific predictions for observations with XMM-Newton and with the planned X-ray telescopes XRISM and ATHENA, both for cold and warm dark matter models. We consider trends with stellar and halo mass and evaluate the scatter in the expected fluxes arising from the anisotropic halo mass distribution and from object-to-object variations. We show that the median X-ray decay flux of a galaxy measured with XMM-Newton and ATHENA is ∝ d −1.35 (M/M S ) 0.3 (1+M/M S ) 0.7 for d = [10, 40] Mpc and M S = 2×10 10 M . We also predict the expected width of the line which, for the Perseus cluster, for example, is expected to lie in the range 1300-1500 km/s


"Dynamics and formation of obscuring tori in AGNs"

Swayamtrupta Panda (CAMK, Warsaw)

Based on Bannikova et al. 2018:


"Evidence for a large exomoon orbiting Kepler-1625b"

Saikruba Krishnan (CAMK, Warsaw)

Exomoons are the natural satellites of planets orbiting stars outside our solar system, of which there are currently no confirmed examples. In a recent work, Alex Teachey and David M. Kipping, present new observations of a candidate exomoon associated with Kepler-1625b using the Hubble Space Telescope to validate or refute the moon’s presence.


"Why (Astro- and Geo-)Physicists should not use FORTRAN!"

Prof. Alex Schwarzenberg-Czerny (CAMK, Warsaw)


"Breaking the spectral degeneracies in black hole binaries with fast timing data"

Eleonora Veronica Lai (CAMK, Warsaw)

Review talk based on the recent work of M. Axelsson and C. Done:


"Three-Dimensional Simulations of Neutrino-Driven Core-Collapse Supernovae"

David Abarca (CAMK, Warsaw)

The talk will review some recent findings about 3D simulations of supernova explosions. Based on:


"Milky Way dark matter density profile and its reconstruction"

Ekaterina Karukes (ICTP South American Institute for Fundamental Research & The Institute for Theoretical Physics/Sao Paulo State University)

In this talk I am going to present the results of the dark matter density reconstruction of the Milky Way galaxy. In our analysis we assume a gNFW profile and we use the global rotation curve mass modeling. We further apply a Markov Chain Monte Carlo approach in order to perform the five parameter model fitting. We then validate the accuracy of the results on a suite of mock rotation curves where we a priori know the parameters of the underlying gNFW dark matter profile. We show that the local dark matter density values are recovered with a very good accuracy (within uncertainties < 10 per cent). We also find degeneracy between the scale radius and the inner dark matter density slope.


"Chankillo, America's first Solar Observatory"

Iván Ghezzi (Instituto de Investigaciones Arqueológicas, IFEA - Lima)

Chankillo, a prehistoric monument date 210 BC in coastal Peru, is the oldest and most complete solar observatory known throughout the world. From the Observatory, the first American astronomers observed the cyclical passage of the sun in relation to a large man-made measuring device: an "artificial horizon" formed by thirteen stone towers built on a hill to span exactly the range of positions of the sun through the year. For example, it marked the December Solstice, a key date for the start of the rainy season on the coast, by the perfect alignment observed between sunrise and Tower 13. Thanks to astronomical observations, it was possible to identify any date of the year, with an accuracy of 1 to 2 days; a real achievement for a society without writing. Chankillo is a "masterpiece of the human creative genius", and under that criterion is nominated as a World Heritage Site.