|655. ROK AKADEMICKI 2018/2019
|2018-10-05||prof. LESZEK SOKOŁOWSKI||OA UJ|
|ZN OA 1493||Inflacja wieczna i ostatnia praca Hawkinga|
|2018-10-12||prof. LESZEK SOKOŁOWSKI||OA UJ|
|ZN OA 1494||Inflacja wieczna i ostatnia praca Hawkinga cz. II|
|Publiczna obrona rozprawy doktorskiej / Public defence of doctoral thesis|
|2018-10-19||mgr MAGDALENA KULCZAK-JASTRZĘBSKA||OA UJ|
|2018-10-26||dr KATARZYNA MAŁEK||Narodowe Centrum Badań Jądrowych, Warszawa|
|ZN OA 1495||
HELP project -- modeling spectral energy distributions of thousands IR galaxies -- dust attenuation influence for main physical parameters
The primary objective of the European Union founded HELP project is to provide homogeneously calibrated multiwavelength catalogues covering roughly 1300 deg2 of the extragalactic Herschel Space Observatory surveys at wide redshift range. Millions of galaxies with UV--FIR photometry makes HELP a perfect sample for testing spectral energy distribution fitting (SED) codes, and to prepare tools for next-generation data. I am going to present the project itself, and results of SED fitting pipeline based on the pilot field for the HELP - ELAIS N1 (∼ 50,000 galaxies). I developed additional quality criteria of the fits which allow to identify the best fits and to select peculiar galaxies (like for example possible high-redshift galaxy candidates). I delivered the main physical parameters of ELAIS N1 galaxies assuming three different dust attenuation laws. We checked their influence on dust luminosity, star formation rate, stellar mass etc. We will present our results by focusing on the relation between stellar masses obtained with Calzetti 2000, Charlot and Fall 2000 and Lo Faro et al., 2017 attenuation laws.
|seminarium nadzwyczajne: godzina 14:00 / at 2:00 p.m.|
|2018-10-26||prof. ALOK CHANDRA GUPTA||Aryabhatta Research Institute of Observational Sciences - ARIES, Nainital, India|
Variability and QPOs in Blazars with Space Based Telescopes
|Dzień Zaduszny / Holiday break|
|2018-11-09||dr WOJCIECH HELLWING||Centrum Fizyki Teoretycznej PAN, Warszawa|
|ZN OA 1496||
Why and how we should test gravity on cosmological scales?
The GR is over 100 years old. The beautiful Einstein's relativity theory of space-time and gravity is one of the founding block of modern physics and cosmology in particular. In my talk, I shall discuss why one would like (and actually really need) to design and convey tests of the theory on cosmological scales. Then, I will also present a handful of theories (called Modified Gravity) that aim to rival the ruling of GR at the cosmological distances. Finally, I will present and discuss some reasonable ways for conveying cosmological test of gravity, discuss why most of them might fail and present some potentially promising avenues for new class of such tests. Concluding with why you might want to stay tuned for future in that field!
|2018-11-16||dr hab. AGATA RÓŻAŃSKA||Centrum Astronomiczne im. M.Kopernika, Warszawa|
|ZN OA 1497||
Ultraluminous X-ray sources -- new distance indicators?
We show, that broad-band NuSTAR and XMM-Newton data of three ULX sources can be successfully fitted by single model component. Our single model contains emission from non-spherical system: neutron star plus accretion disk directed towards observer. We obtained the very good fit with the reduced χ2 per degree of freedom equal 1.08 for P13, 1.01 for ULX1, and 1.14 for ULX5. The normalization of our model constrains the distance to the source. The resulting distances to P13 and ULX5 are in perfect agreement with previous distance measurements to their host galaxies. Our results confirm that P13, ULX1 and ULX5 may contain central hot neutron star. When the outgoing emission is computed by integration over the emitting surface and successfully fitted to the data, then the resulting model normalization is the direct distance indicator.
|seminarium nadzwyczajne: godzina 14:00 / at 2:00 p.m.|
|2018-11-16||prof. GOPAL-KRISHNA||Centre for Excellence in Basic Sciences -- CEBS, University of Mumbai, Mumbai, India|
|AGN variability: Some highlights and challenges|
|2018-11-23||dr hab. JERZY KRZESIŃSKI||OA UJ|
|ZN OA 1498||
Questionable "exoplanetary" signals in sdBV and sdO subdwarf light curves
According to our investigations, some of the exoplanetary signatures found in
light curves of a couple of sdBVs (KIC 5807616 and KIC 10001893) might be of a
different origin than the exoplanet light reflection or radiation. Using light
curve simulations and Fourier transform techniques, we were able to show, that
a couple (or more) of recently reported candidates for exoplanets around these
evolved objects do not exist. At least one of the "exoplanetary candidate
systems" fails our frequency stability tests, others might be just artifacts.
|2018-11-30||mgr ANNA WÓJTOWICZ||OA UJ|
|ZN OA 1499||
Jet production efficiency in the sample of the youngest radio galaxies
Compact radio galaxies, classified as Gigahertz-Peaked Spectrum (GPS) sources based on their radio spectra, are believed to represent the earliest phase in the evolution of radio-loud active galactic nuclei (AGN). We investigate the sample of 16 the youngest radio galaxies with measured kinematic ages and available X-ray data from high-resolution Chandra or XMM-Newton observations. We characterize the accretion properties and derive the jet kinetic luminosities for our sources. We found out that these youngest radio galaxies all accrete at high Eddington rates (>1%), as such, they resemble more radio quasars and broad-line radio galaxies, rather than other types of radio-loud AGN. This, along with the fact that the objects from our sample seem over-luminous in radio on the fundamental plane for the black hole activity, implies also that the radiative efficiency of the compact lobes is much higher than in the case of the evolved radio galaxies.
|2018-12-07||dr OLEH KOBZAR||Instytut Fizyki Jądrowej PAN, Kraków|
|ZN OA 1500||
Search for ultra high energy cosmic rays from radiogalaxy Virgo A
Active galactic nuclei (AGNs) are considered to be one of the most appropriate sources of ultra high energy cosmic rays (UHECRs, E > EeV). Radiogalaxy Virgo A (M87) in the centre of a cluster of galaxies Virgo Cluster (VC) can be a prominent source of UHECRs. We investigate the possible contribution of Virgo A and the VC to the flux of events with trans-GZK energies - extremely high energy cosmic rays EHECRs - from the recent Auger and Telescope Array (TA) data sets (E > 52 EeV and E > 57 EeV, respectively). We simulate EHECR propagation from Virgo A and the VC taking into account their deflections in galactic (GMF) and extragalactic (EGMF) magnetic fields and show that there is no excess of EHECR arrival directions from images of Virgo A/VC at different EHECR rigidities. By means of event-by-event analysis we recover the extragalactic arrival directions of EHECR events detected by Auger and TA for representative set of nuclei H(p), He, N, Si, Fe, and find evidences of enhanced fluxes of N-Si-Fe EHECRs from the Local Filament and Hot/Cold Spot regions. The Local Filament with its enhanced magnetic field is an expected contributor to the UHECR flux as the closest to the Earth last scattering centre, whereas Hot/Cold Spot region is a part of a larger arc-like spot, possibly created by diffusively spreading jet of UHECRs, accelerated in the relativistic jet of Virgo A during a prominent nuclear outburst about 10 - 12 Myr ago.
|2018-12-14||prof. KRZYSZTOF BELCZYŃSKI||CAMK, Warszawa|
|ZN OA 1501||
Gravitational-wave Astrophysics: BH-BH/NS-NS mergers with LIGO/Virgo
I will discuss the astrophysical importance of the recent LIGO/Virgo direct detections of gravitational-waves. Despite the fact that massive BH-BH dominance in gravitational-wave signal was predicted prior the detections, it is not at all clear which one of the several formation scenarios produces these massive mergers. This inhibits astrophysical information inference from LIGO/Virgo observations, as conclusions are different within each formation scenario. There is quite an opposite problem with the recent detection of NS-NS merger in an old elliptical host galaxy. None of the formation channels that can reproduce basic properties of the detected BH-BH mergers, can recover the NS-NS merger rate estimated by LIGO/Virgo. Despite the fact that the exact origin of LIGO/Virgo sources is not yet known, several astrophysical implications are beginning to emerge.
|2018-12-21||dr BARTOSZ GAUZA||Department of Astronomy, University of Chile, Santiago, Chile|
|ZN OA 1502||
Searching for super-Jupiters around the nearest stars using ground based mid-infrared imaging
High contrast direct imaging surveys carried out in the optical and near-infrared range have proven to be effective in finding brown dwarfs and massive planets around stars at young ages (<500 Myr). Stars in the solar vicinity though, are typically old, at ages over 1 Gyr, so that any of their substellar companions had cooled down to temperatures below 1000 K. At such temperatures the maximum flux emission shifts from near- to mid-infrared, favoring their detection in this wavelength regime. I will talk about the search for ultracool substellar companions to the nearest northern stars (within 5 pc) using the mid-IR instrument CanariCam of the 10.4-m GTC telescope.
|przerwa świąteczna / Holiday break|
|przerwa świąteczna / Holiday break|
|2019-01-11||dr ARTEM BOHDAN||Deutsches Elektronen-Synchrotron, Zeuthen, Germany|
|ZN OA 1503||
Production of non-thermal electrons at nonrelativistic perpendicular shocks of young supernova remnants
The injection problem is a key and still unresolved issue of diffusive shock acceleration theory. Electron injection mechanisms at high Mach-number nonrelativistic perpendicular shocks are under consideration here for parameters that are applicable to young SNR shocks. Using high-resolution large-scale two-dimensional fully kinetic particle-in-cell (PIC) simulations we explore the production of high-energy electrons in the shock transition. Tracing individual particles we in detail analyze the physics of the formation of non-thermal electron population. Ion reflection off the shock leads to the formation of magnetic filaments in the shock ramp, resulting from Weibel-type instabilities, and electrostatic Buneman modes in the shock foot. Electrons are accelerated via shock surfing acceleration (SSA) in the Buneman-instability region and undergo further scattering in the Weibel-instability region via a second-order Fermi-like process. The combination of these two processes leads to the formation of a non-thermal electron population, but their individual impact strongly depends on the Alfvenic Mach number and reduced ion-to-electron mass ratio. We discuss the resulting electron spectra and the relevance of our results to the physics of systems with real ion-to-electron mass ratio and fully three-dimensional systems.
|2019-01-18||dr hab. ŁUKASZ STAWARZ||OA UJ|
|ZN OA 1504||
How to measure the masses (and spins) of astrophysical black holes
Astrophysical black holes span the range of mass from several up to tens of billions solar masses. Stellar-mass black holes, believed to emerge predominantly as the end-product of the evolution of massive stars, when in a binary system with a main-sequence star, manifest most spectacularly in the X-ray domain through the emission of their accretion disks; such systems are called `X-ray Binaries'. Supermassive black holes (masses exceeding million solar masses), on the other hand, believed to form via accretion and black hole mergers in the centers of every massive galaxy, can be accessed observationally in a broad range of frequencies, from radio to γ-rays, due to the emission of their accretion disks and relativistic outflows (jets) launched from the closest vicinities of the black hole event horizons. Such accreting supermassive black holes are the central engines of various types of active galaxies, including quasars, blazars, Seyferts, and radio galaxies. They insert a direct gravitational influence on the surrounding nearby stars and gas, and also shape the evolution of the entire galaxies via interactions between the evolving interstellar medium and nuclear outflows in a complex feedback loop. In this talk I will review the methods used to measure the masses and spins of astrophysical black holes, and comment on the prospects for imaging of the nearest supermasive black holes at radio frequencies.
|2019-01-25||prof. dr hab. EWA RONDIO||Narodowe Centrum Badań Jądrowych, Świerk|
|ZN OA 1505||
Hyper-Kamiokande - the third generation detector to reveal the secrets of neutrino
Construction of the third generation gigantic water Cherenkov detector is starting in Japan. Plans for measurements of oscillation parameters, including CP violation phase, neutrinos from the Sun and Supernove, search for Dark Matter as well as proton decay searches will be presented.
|Sesja / Exam break|
|Sesja / Exam break|
|Przerwa semestralna / Semester break|
|2019-03-01||dr MIGUEL FIGUEIRA||Narodowe Centrum Badan Jadrowych, Warszawa|
|ZN OA 1506||
Star Formation: From Herschel HOBYS to ALMA
Feedback from high-mass stars such as stellar winds, radiation pressure, photoionization pressure and supernovae explosions can strongly modify the parental cloud in which they are born. As a result, the next generation of stars in the same cloud is affected and can present different physical properties. Just after their formation, the ionizing photons from high-mass stars create an HII region whose expansion compresses the neutral material and form a layer of dust and gas where star formation is seen. Statistical studies showed an overdensity of massive young objects towards these regions compared to places where no feedback is at play. I will show the results of some of these regions (RCW120, RCW79, NGC6334) observed in the Herschel Observations of OB Young Stars (HOBYS) project and the follow-up studies made on the massive objects founds towards the edge of these regions using ALMA. These follow-up studies allow us to observe directly if the massive cores found towards HII regions are a good place for the formation of massive stars.
|2019-03-08||prof. dr hab. MAREK BIESIADA||Uniwersytet Śląski w Katowicach, Katowice|
|ZN OA 1507||
Gravitational lenses as a tool in cosmology
Gravitational lensing has evolved into a mature research field with its own formalism and increasing stream of data. I will briefly introduce the subject of strong lensing focusing on its applications in cosmology. Then I will review the idea, which I've been developing with my colleagues over last decade, that strong lensing systems can be used as probes of dark energy models and non-standard physics.
|2019-03-15||dr hab. MAŁGORZATA BOGDAN||Uniwersytet Wrocławski, Wrocław|
|ZN OA 1508||
Statistical learning under sparsity
We will discuss statistical issues behind analyses of large data sets. We will explain an issue of overfitting and present several modern statistical methods for dimensionality reduction in supervised and unsupervised learning. Some of these methods were developed by our team in collaboration with statisticians from Stanford University and Ecole Polytechnique.
|2019-03-22||dr hab. KRZYSZTOF CHYŻY
dr hab. MAREK JAMROZY
dr BŁAŻEJ NIKIEL-WROCZYŃSKI
|Obserwatorium Astronomiczne UJ, Kraków|
|ZN OA 1509||
New results from LOFAR surveys
In this talk we will summarize the new results from the Low-Frequency Array (LOFAR) surveys. After a short description of the LOFAR large radio telescope network and the LOFAR surveys, we will briefly describe the methods of identification of 231,716 radio sources located in the 424 square degrees HETDEX Spring Field. Then we will focus on a specific type of radio galaxies, namely double-double radio galaxies, which have been found in this area as many as 33 objects. Next we will discuss the study of a sample of galaxy groups done with the LoTSS DR1 data. The new results suggest that a significant number of galaxy groups might host radio emission - including genuine, intergalactic structures. A fidelity comparison between the existing, supra-GHz survey data and new low frequency results from LoTSS will also be presented.
|2019-03-29||dr PAWEŁ BIELEWICZ||Narodowe Centrum Badań Jądrowych, Warszawa|
|ZN OA 1510||
Studies of statistical isotropy of the cosmic microwave background
Studies of the cosmic microwave background (CMB) are today one of the most important pillars of observational cosmology. They provide information not only on the initial conditions of the Universe but also on scales comparable to the horizon of the observable Universe. This gives a unique opportunity to pose important questions about very fundamental assumptions made in the standard cosmological model such as statistical isotropy and Gaussianity of the initial fluctuations. This also allows to test deviations from the statistical isotropy predicted in models of the Universe with multi-connected topology and deviations generated by gravitational lensing of the CMB, predicted in the standard cosmological model. Considerable effort spent on analyzing the statistical properties of the CMB maps has resulted in several reports of a breaking of statistical isotropy at large angular scales and detection of the gravitational lensing effect. I will review these studies paying special attention to the results obtained recently for the state-of-the-art data from the Planck satellite.
|2019-04-05||prof. AGNIESZKA JANIUK||Centrum Fizyki Teoretycznej PAN, Warszawa|
|ZN OA 1511||
Simulations of short GRB central engines and their jets launching
Short gamma-ray bursts (GRBs) are presumably results of binary neutron star mergers, which lead to the formation of a stellar mass black hole, surrounded by remnant matter. The strong magnetic fields help collimate jets of plasma, launched along the axis of the black hole rotation. We study the structure and evolution of the accreting plasma in the short GRBs and we model the formation of the base of relativistic, Poynting-dominated jets, via the general relativistic MHD simulations.
|2019-04-12||dr ANNA BARNACKA||Department of Astronomy, Harvard University, USA|
Obserwatorium Astronomiczne UJ, Kraków
|ZN OA 1512||
Gravitational Lenses as High-Resolution Telescopes
The inner regions of active galaxies host the most extreme and energetic phenomena in the universe including, relativistic jets, supermassive black hole binaries, and recoiling supermassive black holes. However, many of these sources can not be resolved with direct observations. I will present how strong gravitational lensing can be used to elucidate the structures of these sources from radio frequencies up to very high energy gamma rays. Future surveys, including LSST, SKA, and Euclid, will provide observations for hundreds of thousands of gravitationally lensed objects, which will allow us to apply strong gravitational lensing to study the multi-wavelength structure for large ensembles of sources. This large ensemble of gravitationally lensed active galaxies will allow us to elucidate the physical origins of multi-wavelength emissions, their connections to supermassive black holes, and their cosmic evolution.
|Wielki Piątek / Holiday break|
|2019-04-26||prof. SALVATORE CAPOZZIELLO||University of Naples, Italy|
Cosmographic reconstruction to discriminate between modified gravity and dark energy
Cosmography is a model independent approach, useful to discriminate among concurring cosmological scenarios. After reviewing the main features and shortcomings of LCDM model, we propose a cosmographic approach, based on some polynomial series like Pade', Chebyschev, etc. to investigate dark energy and modified gravity. The main result is that series convergence seems a powerful tool to extend the matching with the Hubble flow up to high redshift.
|Święto 3. Maja / Holiday break|
|2019-05-10||dr MACIEJ BILICKI||Centrum Fizyki Teoretycznej PAN, Warszawa|
|2019-05-17||prof. RYSZARD WIELEBINSKI||Max Planck Institute for Radio Astronomy, Bonn, Germany|
Cosmic magnetic fields and low-frequency astronomy in Tasmania
Prof. Ryszard Wielebinski (Doctor honoris causa of the Jagiellonian University) will tell us about the first attempts to detect magnetic fields in galaxies and the history of these studies up to nowadays. He will talk about the early stages of low-frequency astronomy in Tasmania. Interesting details of collaboration with Grote Reber and the construction of a 1-kilometer array at 2 MHz will be revealed.
|2019-05-24||prof. XAVIER HERNANDEZ||UNAM University, National University of Mexico, Mexico City, Mexico|
|2019-05-31||mgr ROMANA GROSSOVA||Masaryk University, Brno, Czech Republic|
|2019-06-07||dr hab. ŁUKASZ WYRZYKOWSKI||Obserwatorium Astronomiczne Uniwersytetu Warszawskiego, Warszawa|
|2019-06-14||mgr AGNIESZKA MIROCHA||Obserwatorium Astronomiczne UJ, Kraków|
|piątek po Święcie Bożego Ciała / Holiday break|
|wakacje / Holiday break|