I will show uniqueness of the Kerr near-horizon geometries within the collection of nearby geometries. The result will be presented in the wider context of the black hole uniqueness theorems.

I would like to present the total-intensity 610 MHz GMRT dedicated observations together with multifrequency analysis of the peculiar radio source SBS B1646+499. It is a hybrid blazar which merges the properties of a BL Lacertae object and a flat-spectrum radio-loud quasar. In addition, it possesses a 14 kpc-long radio jet and a newly disclosed 562 kpc, extended, steep spectrum radio halo. The estimated value of the spectral index of the extended structure is -1.43 ± 0.28 and indicates aging of the electron population with an increasing distance from the central source. The detailed map of the center of this source reveals the jet's spectrum curvature with the mean value of -0.88 ± 0.09. The unique structure of this object could be caused by multiple jet activity of the central AGN.

I will report on the discovery of GW170817 - the first binary neutron star coalescence to be seen in gravitational waves. This event has triggered an unprecedented electromagnetic observation campaign and has brought numerous insights and solutions to long standing astrophysical puzzles. I will describe the astronomical and physical implications of this recent result.

I will present on the importance of tracing infrared features in interstellar medium. Specifically, I will show the breakdown of polycyclic aromatic hydrocarbon (PAH) infrared emission features, the analysis and fitting of such features, the importance of certain features as tracers for star activity, as well as key correlations in the analysis of ISM.

The long-time behavior of nonlinear dispersive waves subject to spatial confinement can be very rich and complex because, in contrast to unbounded domains, waves cannot disperse to infinity and keep self-interacting for all times. If, in addition, the linear spectrum around the ground state is fully resonant, then the nonlinearity can produce significant effects for arbitrarily small perturbations. The weak field dynamics of such systems can be approximated by solutions of the corresponding infinite-dimensional time-averaged Hamiltonian systems, which govern resonant interactions between the modes. A major mathematical challenge in this context is to describe the energy transfer between the modes. I will discuss the problem for different models with particular focus on Einstein equations with negative cosmological constant describing weakly turbulent behavior of small perturbations of the anti-de Sitter (AdS) spacetime.

The KDA EXT model (extension of the KDA model of FR II-type double radio source evolution) have been applied and confronted with the observational data for selected FR II-type sources with significantly aged radio spectra. The observational data of the sample of FR II-type radio galaxies with radio spectra strongly bent at their highest frequencies, chosen due to their available radio and optical data required as the model input, is used for testing the usefulness of the KDA EXT model. The dynamical evolution of FR II-type sources predicted with the KDA EXT model is briefly presented and discussed. The results are then compared to the ones obtained with the classical KDA approach, assuming the source's continuous injection and self-similarity.

Ordered magnetic fields are generally believed not to exist in the intergalactic space of galaxy groups; on the one hand, it is known that groups undergo violent interactions that could easily disrupt the delicate fabric of a non-turbulent field, on the other hand - it was never said that survival of such a field is an impossible occurrence. The most well-known galaxy groups, the Stephan's Quintet, once again turns to be an amazing object, this time in regards to the matter of the existence of a regular magnetic field. Our new study, done with the high-fidelity WSRT data, reveals strong hints that a non-negligible field is present in the volume inhabited by the Quintet, and it is a large-scale, strong, and regular one. As for the moment, no other group was found to host similar magnetic fields, as the Quintet does.

We report the selection of blazar candidates behind the Large and Small Magellanic Clouds. Both, flat spectrum radio quasar and BL Lacertae objects were selected based on the long-term, multi-colour Optical Gravitational Lensing Experiment photometric data. We cross-correlated the Magellanic Quasar Survey catalogue of spectroscopically confirmed quasars and quasar candidates located behind the Magellanic Clouds with the radio data at 6 frequencies from 0.8 to 20 GHz. Among the 1,654 objects visible in optical range, we identified a sample of 44 newly selected blazar candidates, including 27 flat spectrum radio quasars and 17 BL Lacs. We examined selected objects with respect to their radio, optical, and mid-infrared properties.

I present the most recent results of the VIMOS Public Extragalactic Redshift Survey (VIPERS). VIPERS - with its ∼ 90,000 spectroscopically measured galaxies in an unprecedentedly large volume (5 x 10⁷ h^-3 Mpc³), and an effective spectroscopic sampling > 40% - can be considered the state-of-the-art counterpart of "local" (z<0.2) cosmological surveys but targeting the epoch at z ∼ 1. How different were galaxies 8 bln years ago in comparison to their descendants we find in our local Universe? What are the properties of the 3D cosmic structure emerging from VIPERS measurements? What they tell us about the properties and history of the cosmic structure woven from dark matter and even more elusive dark energy? What do they add to our understanding of the evolution of the Universe and galaxies themselves? I try to address at least some of these questions - and show new challenges emerging from these new results.

Core-Collapse Supernovae (CCSNe) are the spectacular and violent deaths of massive stars. The study of Gravitational Waves (GW) from CCSNe can help elucidate the explosion mechanism and give us information about the physical properties of the collapsed core like Equation of State, neutrino mass hierarchy, core mass, proto-neutron star evolving size as well as unknown physics (silent supernovae or quark stars). In this talk I will review the state-of-art techniques used to search for GW from CCSNe and current work on detection perspectives with future GW Observatories. Given the large variety of possible GW morphologies (usually long and broadband), the reconstruction of the waveform and extraction of physical information is a difficult task. It requires a deep understanding of multi-dimensional CCSN simulations, data analysis caveats, detector response, as well as understanding how insights provided by neutrino and electromagnetic messengers help us extract GW signals from the detector noise. In the LIGO/Virgo Supernova Working Group we work on all aspects leading to direct detection of GW from CCSN and extracting physical information. I will talk about properties of the CCSN waveforms, their deterministic and non-deterministic components, algorithm development that uses the deterministic features (like g-modes) used to increase the visible distance for CCSN detection. I will also review the detection range, future algorithm developments and detection capabilities with the designs of future detector configurations.

Inaugurated in March 2015, the High-Altitude Water Cherenkov Observatory (HAWC) is a TeV gamma-ray detector built on the slope of the Sierra Negra volcano (4100 m a.s.l.) in Puebla, Mexico. The detector consists of 300 water Cherenkov detectors (WCDs) spread on a 22000 square meter area. HAWC explores the gamma-ray sky at TeV energies with a large field of view (two thirds of the sky every day) and high duty cycle (more than 90% uptime). HAWC main scientific goals are the study of Galactic sources at high energies, diffuse and extended gamma-ray emission, transient emission from Active Galactic Nucleus (AGNs) and Gamma-Ray Bursts (GRBs). In this talk I will explain the details of the observatory, will summarize the recent results from the experiment, and discuss the future plans of the collaboration.

Core-Collapse Supernovae (CCSNe) are the spectacular and violent deaths of massive stars. The study of Gravitational Waves (GW) from CCSNe can help elucidate the explosion mechanism and give us information about the physical properties of the collapsed core like Equation of State, neutrino mass hierarchy, core mass, proto-neutron star evolving size as well as unknown physics (silent supernovae or quark stars). In this talk I will review the state-of-art techniques used to search for GW from CCSNe and current work on detection perspectives with future GW Observatories. Given the large variety of possible GW morphologies (usually long and broadband), the reconstruction of the waveform and extraction of physical information is a difficult task. It requires a deep understanding of multi-dimensional CCSN simulations, data analysis caveats, detector response, as well as understanding how insights provided by neutrino and electromagnetic messengers help us extract GW signals from the detector noise. In the LIGO/Virgo Supernova Working Group we work on all aspects leading to direct detection of GW from CCSN and extracting physical information. I will talk about properties of the CCSN waveforms, their deterministic and non-deterministic components, algorithm development that uses the deterministic features (like g-modes) used to increase the visible distance for CCSN detection. I will also review the detection range, future algorithm developments and detection capabilities with the designs of future detector configurations.

We present a detailed analysis of the best-quality multiwavelength data gathered for the large-scale jet in the core-dominated quasar 3C 273. We analyze all the archival observations of the target with the Chandra X-ray Observatory, the far-ultraviolet observations with the Hubble Space Telescope, and the 8.4 GHz map obtained with the Very Large Array. In our study, we focus on investigating the morphology of the outflow at different frequencies, and therefore we apply various techniques for the image deconvolution, paying particular attention to a precise modeling of the Chandra and Hubble point-spread functions. We find that the prominent brightness enhancements in the X-ray and far-ultraviolet jet of 3C 273 (the "knots") are not point-like, and can be resolved transversely as extended features with sizes of about 0.5 kpc. Also, the radio outflow is wider than the deconvolved X-ray/ultraviolet jet. We have also found circumstantial evidence that the intensity peaks of the X-ray knots are located systematically upstream of the corresponding radio intensity peaks, with the projected spatial offsets along the jet ranging from < 0.2 kpc up to 1 kpc.

Recent direct detections of gravitational waves provide historically-first observations of space-time strong-field dynamics. I will present the current status of the tests concerning general relativity, dense-matter physics and the propagation of gravity using the the inspiral-merger-ringdown observations of binary black holes and neutron star coalescences, and talk of the outlook for the future.

The discovery of stars pulsating in both pressure (p) and gravity (g) modes has opened up the possibility of getting more stringent constraints on parameters of a model and theory. The simultaneous excitation of p and g modes offers "touching" stellar regions sensitive to various physical processes. The presence of high-order g modes in early B-type main sequence stars is the most challenging fact calling for explanation because these modes are stable in all standard-opacity models. Ipso facto, seismic modelling of p/g-mode pulsators is more demanding and more complex and sophisticated approach is needed. Our goal is to draw conclusions about missing components and needed modifications in modelling of interiors of hot main sequence stars. In particular, we have shown that in each case, significant modifications of the opacity profile are indispensable to explain all pulsational properties. This is also an important test of these microphysics data. I will present the results of the complex seismic analysis of a few pulsating stars of the β Cep/SPB type.

The FSRQ CTA 102 underwent an incredible outburst lasting 4 months in late 2016 and early 2017. Fluxes rose and fell symmetrically with peak fluxes a factor 50 higher than in quiescence in the gamma-ray domain, and even a factor 100 higher in the optical domain. One possibility to explain the symmetry of the long-term evolution of the event is the ablation of a gas cloud by the relativistic jet. This gradually injects matter into the jet depending on how deep the cloud has penetrated the jet. The resulting lightcurve fits the data extremely well. Potential origins of the cloud will be discussed.

A new window into the magnetic universe has been opened by radio-telescope facilities that allow broadband, continuum-polarisation observations at high spectral resolution. The bright radio sky accessible by current facilities is dominated by active galactic nuclei (AGN) that produce powerful jets of relativistic plasma emitting non-thermal synchrotron radiation. Accurately characterising the Faraday rotation properties of these radio AGN is important for studying the magnetised structures intrinsic to the AGN and also for using them as reliable statistical probes of foreground magnetic fields (e.g. the intergalactic medium, intervening galaxies and the Galactic ISM). Here I will present recent results from millimetre, centimetre and metre wavelength spectro-polarimetric observations that highlight the different magnetoionic regions that are probed, and the challenges related to the interpretations of these results.

Wide-angle photometric surveys of previously uncharted sky areas or wavelength regimes will always bring in unexpected sources whose existence and properties cannot be easily predicted from earlier observations. Such objects can be efficiently sought for with novelty detection algorithms. I will present an application of such a method, called one-class support vector machines (OCSVM), to search for anomalous patterns among sources preselected from the mid-infrared AllWISE catalogue covering the whole sky. OCSVM successfully finds artefacts, such as objects with spurious photometry due to blending, but most importantly also real sources of genuine astrophysical interest. Among the latter, OCSVM has identified a sample of heavily reddened AGN/quasar candidates distributed uniformly over the sky and in a large part absent from other WISE-based AGN catalogues. It also allowes to find a specific group of sources of mixed types, mostly stars and compact galaxies. By combining the semi-supervised OCSVM algorithm with standard classification methods it will be possible to improve the latter by accounting for sources which are not present in the training sample but are otherwise well-represented in the target set.

1I/2017 U1 ('Oumuamua) is a recently discovered minor body, identified by the Pan-STARRS survey on 19 October 2017. Unlike any previously seen, it follows a sensational hyperbolic trajectory, implying arrival from far in the interstellar space and origin in another planetary system. 'Oumuamua is thus the long-sought link between our own Solar System and systems around other stars, heralding an onset of a new field in astronomy. Our group has played an important role in the effort of characterizing this unique body. We were awarded 12 hr of DDT on the Gemini North 8.1-m telescope - the largest time allocation dedicated to 'Oumuamua on a telescope of this class. As a result, we obtained the highest quality photometric and spectroscopic data, which have revealed some remarkable and unexpected properties. We will review the current state of knowledge on 'Oumuamua, discuss the impact of this body on science and society, and speculate on possible future avenues.

BRITE mission occured to be a success in doing photometry from space with nanosatellites. I will present some highlights of the scientific results from this ongoing space mission. In addition, I'll show a concept of UVSat, a new Polish space mission aimed at doing simultaneous ultraviolet and visual photometry in wide field of view. I will focus on the potential science that can be done using data from such a satellite.

One of the main objectives of cosmic ray studies are precise measurements of particles with extreme energies. Large and sophisticated detectors are used to find events seen as showers starting in the Earth atmosphere with record energies larger than 100 EeV. However, super-preshowers developing before reaching the Earth as a bunch of correlated particles may spread over larger areas and need an extended set of detectors to be discovered. The Cosmic Ray Extremely Distributed Observatory (CREDO) is a solution to find such phenomena. Even simple detectors measuring the particle arrival time only are useful in this approach, as they are sufficient both to provide candidate events for a super-preshower and to determine the direction from which it is arriving.
The general idea of the Cosmic Ray Extremely Distributed Observatory will be presented and the condition necessary to detect super-preshowers and accuracy of the measurment of their direction will be discussed.

Recent theoretical results indicate that relativistic shocks in extragalactic sources are unable to accelerate ultra high energy cosmic rays. We study relativistic jets in Active Galactic Nuclei, where the maximum energy of electrons accelerated in the termination shocks is about 1 TeV. We show that this maximum energy cannot be constrained by synchrotron losses as usually assumed, and we propose that it is determined by the geometry of the (unperturbed) magnetic field. Giving that relativistic shocks are characteristically quasi-perpendicular, the mean-free path of particles being accelerated cannot exceed the Larmor radius in the unperturbed field. This condition applies to electrons and protons and therefore the maximum energy of ions is also about 1 TeV. As a consequence, relativistic jet termination shocks are poor cosmic ray accelerators. We present Cygnus A as a case study.

Stars beyond the MS are frequently avoided in planet searches because they are known to exhibit various types of variability: RV variations of unknown origin were pointed out to be common in red giants (RGs) by Walker et al. (1989), and multiple pulsation modes are often present. In addition, the rotation of starspots across the stellar disk can affect the spectral line profiles of these stars (Vogt et al. 1987; Walker et al. 1992; Saar & Donahue 1997). However, soon after the first discovery (Frink et al. 2002), searches for planets around stars beyond the MS have become recognized as important in building a complete picture of planet formation and evolution for several reasons. First, they allow extending the reach of the most versatile RV technique, which is not applicable on the MS because of the high effective temperature of the stars and their fast rotation rates, to objects with masses significantly higher than solar (e.g., ο UMa, a 3 M_⊙ giant with a planet -- Sato et al. 2012). Second, the planetary systems around evolved stars are much older than those around MS stars, and therefore they are suitable for long-term dynamical stability considerations. Planetary systems around giants are also subject to changes induced by stellar evolution, and therefore are suitable for studies of star -- planet interactions, and last but not least, evolved planetary systems carry information on the initial population of planetary systems to be found around white dwarfs. It is no surprise then that several projects devoted to searches for RV planets that orbit RGs were launched. One of the largest of them is the PennState Torun Centre for Astronomy Planet Search (PTPS, Niedzielski et al. 2007; Niedzielski & Wolszczan 2008a,b). In my talk I will present the sample of PTPS, current status of our planet search and the most recent discoveries. I will also discuss some properties of the exoplanets around evolved stars from the PTPS perspective. Last few minutes of my talk I will dedicate to a brief description of ESO ELT HIRES spectrograph and polish contribution to the instrument.

I present an analysis of multi-timescale variability in line of sight X-ray absorbing gas in Seyfert active galactic nuclei. The goal is to derive the statistical constraints for recent clumpy absorbing torus models, which represent the paradigm shift away from the classical "solid donut" morphology. I used the vast archive of Rossi X-ray Timing Explorer multi-timescale monitoring of dozens of type I and Compton-thin type II Seyfert AGN to search for discrete absorption events due to clouds transiting the line of sight. Most of the detected clouds are Compton-thin and located in the outer BLR or inner dusty torus. I discuss the resulting implications for cloud distributions in the context of the clumpy-torus models. I also present preliminary results from XMM, Chandra, and Suzaku archival studies of Compton-thin type IIs. We present the density profiles of the highest-quality eclipse events, possible connections to the mechanisms that form and launch clouds.

Studies at low and intermediate redshift ranges show that the relation between the luminous structure and underlying dark matter distribution is not straightforward and depend on the various properties of galaxy population. Naturally one would like to extend these studies of the luminous-dark matter relations to the high redshift ranges (z>2) in order to improve our understanding of the evolution of the universe structure. During my seminar I will present the recent attempts to describe the large scale structure of the universe in early epochs of its evolution (z>2). In this context I will demonstrate my study of the dependence of galaxy clustering on luminosity and stellar mass in the redshift range 2 < z < 3.5 using spectroscopic data from the VIMOS Ultra Deep Survey (VUDS). I will show the series of my recent results quantified using a power-law approximation of the correlation function and in the framework of the five parameter HOD (Halo Occupation Distribution) model, which indicate that at z ∼ 3 the correlation length, and all HOD characteristic masses depends on the luminosity and stellar mass - the bright and most massive galaxies are the ones that are the most strongly clustered and are likely to occupy the most massive dark matter haloes. I will conclude with the presentation of my measurements of the large scale galaxy bias and stellar-to-halo mass relation at high redshift.

The Optical Gravitational Lensing Experiment (OGLE) is one of the world's largest optical surveys devoted to searching for variability in the sky. In the last year, the project celebrated its 25th anniversary. During its long history, the OGLE survey collected about one trillion individual photometric measurements for more than one billion stars in the Milky Way and in nearby galaxies. These data has led to many discoveries in various fields of astronomy: gravitational lensing and microlensing, extrasolar planets, cosmic distance scale, structure of galaxies, Kuiper belt objects, etc. Variable stars occupy a special position among the most important achievements of the survey. The OGLE Collection of Variable Stars currently contains nearly one million objects of various types and this is the largest set of variable stars ever obtained by any astronomical project. I will present the most spectacular OGLE discoveries in the field of variable stars.

I shall present the modern status of research on supernova remnants in gamma-rays, paying particular attention to prospects of their observations by the future CTA observatory. Then some cutting edge X-ray studies will be outlined as well as efforts in the three-dimensional magneto-hydrodynamic modeling of these objects which are interesting and important for high-energy astrophysics.

There is a natural request of calculate something faster and faster. Usually people want to use modern supercomputers because they think, supercomputers have incredibly fast CPU. The most powerful machine in OAUJ is our cluster. Surprisingly it has only 2.2GHz CPU clock. The power in our cluster and modern supercomputers lies in a number of CPUs working together. To use that power some knowledge how to use several CPUs for the same task is necessary. I'll present a short introduction to our cluster, and I'll give some basic introduction to parallel computations - in general, and on our cluster.

In this talk I will introduce our study on Gamma ray bursts (GRBs). From the review of several GRB correlations a relevant scatter in the physical quantities is observed, thus no definitive claims can be stated. In the study of selection effects in the Luminosity-Time correlation (Dainotti et al. 2008), assuming different efficiency functions for the detector, we confirm the previous results presented in the literature (Dainotti et al. 2013). Additionally, a weak redshift evolution for the ratio between the star formation rate and the GRB formation rate is found. Finally, I will describe the analysis of the temporal power-law decay indices in the GRB afterglow phase, α, for a sample of 176 GRBs (139 long GRBs, 12 short GRBs with extended emission and 25 X-Ray Flashes (XRFs)) with known redshifts. We discover a convincing regular trend between α and the afterglow luminosity at the end time of the plateau phase, L_a, and a systematic variation is also visible between α and the ratio between the GRB afterglow luminosity and the luminosity value of the Luminosity-Time correlation best fit line at the same time. A proposed toy model accounting for this systematic effect applied to the luminosity of the analysed GRB distribution results in a slightly tighter Luminosity-Time correlation.

Gamma-ray Bursts (GRBs) are the brightest explosions in nature. They can be detected from the local to the distant Universe. This exceptional luminosity is produced by material expelled from a newly formed black hole at almost the speed of light, making GRBs powerful both as beacons to the early Universe, and as laboratories to test physics at its most extreme. Our understanding of these enigmatic events was revolutionised with the launch of Swift and almost 15 years later we have large enough samples, with measured redshift, from which we can perform robust statistical analysis of the GRB. During this talk I will present a correlation observed in the afterglows of long duration Swift Gamma-ray Bursts (GRBs) discovered between the initial luminosity (measured at restframe 200s) and average afterglow decay rate. This correlation does not depend on the presence of specific light curve features, and is potentially applicable to all long GRB afterglows. We will also investigate the implications of this correlation, including its usefulness for cosmology, and test whether the standard afterglow model is consistent with the observations.

Polish Astronomical Society is an organization of professional astronomers with about 250 members. It's activities can be divided into two categories: science related activities and science communication activities. During the presentation there will be an opportunity to get information about all major projects run by the organization, some of it's future plans and also how to become a member of the organization and some useful information for members. Moreover, you may learn what are the International Astronomical Union (IAU) plans for 2019, as IAU is preparing for it's 100 years global celebrations.

The main part of VIRGO.UA scientific work is concerned with analysis of XMM-Newton archival observations of extragalactic objects. A sample of 5021 extragalactic X-ray sources was compiled and used for studying Seyfert galaxies and galaxy clusters. VIRGO.UA computer facilities are also used for LSS description in optical band with SDSS and HyperLeda data. New methods for extragalactic filament detection were developed and tested at the distances up to 500 Mpc. The next aim is theoretical statistical model of spatial distribution of X-ray galaxies in different components of LSS.