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październik/october 2023 |
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2023-10-06 |
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dr GRZEGORZ STACHOWSKI |
Obserwatorium Astronomiczne UJ |
ZN OA 1588 |
16th International Olimpiad on Astronomy and Astrophysics
The 16th International Olimpiad on Astronomy and Astrophysics (IOAA)
was held in Poland from 10-20th August 2023 with representatives
of over 50 countries. I will give an overview of the event and exmaples
of problem tasks, the scale of the organisation and the impact the IOAA
has on the astronomical community.
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2023-10-13 |
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2023-10-20 |
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dr hab. SEBASTIAN SZYBKA, prof. UJ |
Obserwatorium Astronomiczne UJ |
ZN OA 1589 |
Chaos and Einstein-Rosen gravitational waves
We demonstrate the existence of chaotic geodesics for the Einstein--Rosen standing gravitational waves.
The complex dynamics of massive test particles are governed by a chaotic heteroclinic network.
We present the fractal associated with the system under investigation.
Gravitational standing waves produce intricate patterns through test particles
in a vague analogy to mechanical vibrations generating Chladni figures and complicated shapes of Faraday waves.
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2023-10-27 |
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prof. NORBERT WERNER |
Department of Theoretical Physics and Astrophysics Masaryk University, Brno (Czech Republic) |
ZN OA 1590 |
Accreting massive black holes and QUVIK a Czech UV space telescope
Most galaxies comparable to or larger than the mass of the Milky Way host
hot, X-ray emitting atmospheres and accreting supermassive black holes. I
will present results based on radio and X-ray observations, which indicate
that in massive early-type galaxies the central radio sources are mostly
switched on, and the mechanical jet power correlates with the mass of the
central black hole.
I will introduce the QUVIK (Quick Ultra-VIolet Kilonova surveyor) mission,
which has recently been approved for funding. QUVIK, a Czech national
science and technology mission, is a UV space telescope designed to study
the energetic transient sky. The mission will also provide unique
opportunities for studying accreting black holes, including reverberation
mapping, tidal disruption events, and peculiar sources in galactic
nuclei.
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listopad/november 2023 |
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2023-11-03 |
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2023-11-10 |
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dzień wolny na UJ / Holiday break
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godzina 12:30 / at 12:30 p.m. |
2023-11-17 |
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mgr PIOTR GUZIK |
Obserwatorium Astronomiczne UJ |
ZN OA 1591 |
Publiczna obrona pracy doktorskiej / Public PhD defense Interstellar minor bodies in the Solar System
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2023-11-24 |
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mgr ARPITA MISRA |
Obserwatorium Astronomiczne UJ |
ZN OA 1592 |
Multifrequency studies of radio galaxies with distorted jets
Radio galaxy jets strikingly remain straight and collimated for distances ranging from a few kiloparsecs to megaparsecs for millions of years. However, since the advent of deep sky surveys, the discovery of radio galaxies with bent radio jets has been ever-increasing. These
sources, classified as X-shaped or S-shaped, signify a dynamic interplay between the radio jets, the central active region, and the intergalactic medium. The evolution of such radio sources is explained using several theoretical models, including galaxy mergers, but direct
evidence has remained observationally sparse. In this talk, I will present multifrequency observations and radio analysis of a few such sources and discuss the possible mechanisms behind their formation.
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grudzień/december 2023 |
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Odwołane / Cancelled |
2023-12-01 |
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mgr DOMINIKA KRÓL |
Obserwatorium Astronomiczne UJ |
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Origins of X-ray Emission in Heavily Obscured Young Radio Sources
The X-ray continuum emission of active galactic nuclei (AGN) may
be reflected by circumnuclear dusty tori, producing prominent fluorescence
iron lines at X-ray frequencies. I will present the results of broad-band
emission modeling for three radio-loud AGNs belonging to the class of
Compact Symmetric Objects (CSOs). These AGNs, identified as J1511+0518,
OQ+208, and 2021+614, exhibit narrow Fe Kα lines and high intrinsic X-ray
absorbing column densities. We argue that the intrinsic X-ray continuum in
all these sources can be attributed to the inverse-Compton emission of
compact radio lobes. Furthermore, we propose that the observed iron lines
may be generated by the reflection of the lobes' continuum off the
surrounding cold dust.
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2023-12-08 |
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mgr SAGAR SETHI |
Obserwatorium Astronomiczne UJ |
ZN OA 1593 |
Discovery of 100 kpc twin jet in a peculiar S-shaped radio galaxy
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2023-12-15 |
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2023-12-22 |
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przerwa świąteczna / Holiday break
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2023-12-29 |
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przerwa świąteczna / Holiday break
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styczeń/january 2024 |
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2024-01-05 |
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przerwa świąteczna / Holiday break
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2024-01-12 |
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mgr DOMINIKA KRÓL |
Obserwatorium Astronomiczne UJ |
ZN OA 1594 |
Origins of X-ray Emission in Heavily Obscured Young Radio Sources
The X-ray continuum emission of active galactic nuclei (AGN) may
be reflected by circumnuclear dusty tori, producing prominent fluorescence
iron lines at X-ray frequencies. I will present the results of broad-band
emission modeling for three radio-loud AGNs belonging to the class of
Compact Symmetric Objects (CSOs). These AGNs, identified as J1511+0518,
OQ+208, and 2021+614, exhibit narrow Fe Kα lines and high intrinsic X-ray
absorbing column densities. We argue that the intrinsic X-ray continuum in
all these sources can be attributed to the inverse-Compton emission of
compact radio lobes. Furthermore, we propose that the observed iron lines
may be generated by the reflection of the lobes' continuum off the
surrounding cold dust.
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2024-01-19 |
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dr hab. WOJCIECH LEWANDOWSKI, prof. UZ dr hab. JAROSŁAW KIJAK, prof. UZ |
Instytut Astronomii im. Janusza Gila, Uniwersytet Zielonogórski |
ZN OA 1595 |
Pulsar observations using the PL611 LOFAR station in Łazy
Pulsar observations using the PL611 Polish LOFAR station in Łazy started in 2017,
and regular observing projects a year later. Since then we observe pulsars
almost every week for c.a. 30 hours fully utilizing the station's stand-alone time.
The main research project was focused on the monitoring of the influence
of the Ionized Interstellar Medium (IISM) on the pulsar signals via the means
of observations of interstellar scattering and dispersion measure variations.
Such observations were only rarely conducted for individual pulsars before,
and almost never for a period exceeding a year or two. This means that the data
we gathered provides an excellent opportunity to not only study the scattering
and dispersion effects for the observed objects, but also - through the estimations
of the variability of related parameters - it will allow us to make one of the first
insights into the anisotropy and inhomogeneity of the IISM. Recently we also started
another observing program: the study of individual pulses, which yields interesting
results that are important for the understanding of the pulsar emission mechanisms.
These observations clearly show, that interesting and innovative research can be performed
with relatively small radio telescopes, such as a single LOFAR station.
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2024-01-26 |
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dr OLEH KOBZAR |
Obserwatorium Astronomiczne UJ |
ZN OA 1596 |
Electron acceleration at rippled low-Mach-number shocks in high-beta cosmic plasma
Shock waves in cosmic plasma are usually assumed to be a places of particle acceleration.
They can be observed in different astrophysical objects at widely varying scales,
up to large-scale shocks in the clusters of galaxies. In this case, the galaxy merger shocks
are found to generate X-ray and radio emission, that indicate the efficient electron acceleration at these objects.
Typically, merger shocks propagate in relatively hot plasma with plasma beta β >> 1 at low Mach numbers, M << 10.
The detailed mechanisms of the particle acceleration at such conditions are not fully understood yet.
Recent studies indicate that Shock Drift Acceleration (SDA) accompanied by the particle-wave interaction
can be responsible for the initial electron energization here.
Our last investigations with use of the large-scale 2D Particle-In-Cell (PIC) simulations demonstrate
the important role of the multi-scale wave structures, especially the ion-scale shock rippling modes,
in the electron acceleration at low-Mach-number hi-beta shocks. We showed that the main mechanism
of the electron acceleration at such conditions is stochastic SDA (or SSDA).
Its dependence on the pre-shock plasma conditions is also studied.
Although we do not observe direct transition to the Diffusive Shock Acceleration (DSA),
which could produce particles with highest observed energies, the SSDA nevertheless
looks like a plausible mechanism for the electron injection to DSA.
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luty/february 2024 |
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2024-02-02 |
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przerwa egzaminacyjna / Exam break
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2024-02-09 |
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przerwa egzaminacyjna / Exam break
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2024-02-16 |
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ferie zimowe / Holiday break
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2024-02-23 |
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przerwa egzaminacyjna / Exam break
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marzec/march 2024 |
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2024-03-01 |
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mgr DAWID CHUDY |
Obserwatorium Astronomiczne UJ |
ZN OA 1597 |
Galaxy merger classification using Convulutional Neural Networks trained on preprocessed IllustrisTNG data
In the Lambda-CDM cosmology galaxies are thought to form through
the hierarchical merging of smaller structures, hence galaxy mergers
provide crucial insights into how galaxies evolve over time.
The merging process can trigger star formation, feed supermassive
black holes which may affect galaxy morphology. This work aims to find
if it is possible to create a technique to conduct a classification
of merging and nonmerging galaxies with machine learning approach
using Convolutional Neural Network. One can use visual inspection
to define the stage of a merger, but this method is not easily
reproducible and is mostly subjective. Recent studies have shown
that it is possible to use machine learning methods to address this problem.
Around 500000 i-band (standard SDSS filter, 7480Å) images
of size 128 x 128 pixels used for this study come
from Next Generation Illustris Simulations (IllustrisTNG),
a cosmological gravo-magnetohydrodynamical simulations.
Our previous research shows that information is not easily
extracted from the raw images by CNN, which is why this time
our neural network has been fed with processed images.
We created models of each galaxy on the images. Sersic profile
of each galaxy has been subtracted from the original images
to leave behind everything that does not match the profile.
During the talk, we will discuss how the models were made
and how their subtraction from the original photo affected the results.
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seminarium nadzwyczajne: godzina 10:00 / special seminar at 10:00 a.m. |
2024-03-08 |
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Zakład Astrofizyki Relatywistycznej i Kosmologii (ZARiK) Zakład Astronomii Gwiazdowej i Pozagalaktycznej (ZAGiP) |
Obserwatorium Astronomiczne UJ |
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Department presentations for students (in Polish)
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seminarium nadzwyczajne: godzina 10:00 / special seminar at 10:00 a.m. |
2024-03-15 |
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Zakład Astrofizyki Wysokich Energii (ZAWE) Zakład Radioastronomii i Fizyki Kosmicznej (ZRiFK) |
Obserwatorium Astronomiczne UJ |
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Department presentations for students (in Polish)
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2024-03-15 |
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mgr FREDERIK ANDERSEN |
Friedrich-Alexander-Universität Erlangen-Nürnberg, Germany |
ZN OA 1598 |
Neutrino Astronomy
This presentation provides an overview of neutrino astronomy, focusing on key aspects such as neutrino physics fundamentals,
historical milestones in neutrino research, detector mechanisms, and recent results from KM3NeT and IceCube experiments. Through precise analysis of
neutrino signals, these experiments shed light on astrophysical phenomena, offering crucial insights into the universe's most elusive and energetic events.
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2024-03-22 |
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mgr GOUTHAM ANITHA KUMARI |
Obserwatorium Astronomiczne UJ |
ZN OA 1599 |
The Photometric study of sdB stars in short period binary systems
Hot subdwarf B stars (sdB) are stellar objects at the late stage of their stellar evolution.
These helium burning objects are the product of excessive loss of hydrogen envelope before the helium flash.
The origins of these objects are believed to arise from binary interactions, with three primary formation
channels proposed: common-envelope ejection (CEE), stable Roche-lobe overflow (RLOF) mechanism,
and the merger of two low-mass white dwarfs (Han et al., 2002, 2003). These objects are crucial
for studying the late stages of stellar evolution, binary interactions, and stellar interiors,
particularly through the analysis of their pulsations. Current research indicates that approximately
60% of identified sdB stars are located within binary systems. Depending on the interactions between
the sdB and its companion, these binaries are divided into two main groups, the systems with long orbital
periods (longer than one year) produced in a stable RLOF, and the short period systems (order of hours)
which evolved via the CEE. In this presentation I will provide an overview of my work with analysis
of these sdB stars in binary systems. That is, from observations to the modeling of their light curves.
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2024-03-29 |
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Wielki Piątek / Holiday break
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kwiecień/april 2024 |
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2024-04-05 |
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mgr SYED NAQVI |
Obserwatorium Astronomiczne UJ |
ZN OA 1600 |
Eccentric Gravitational Waves: From Theory to Data
Gravitational waves (GW) from compact objects offer crucial insights into their astrophysical origins.
However, most GW waveforms rely on quasi-circular templates, presenting challenges for future
detections and interpretations. Effects like eccentricity, impacting GW waveforms, are garnering interest
in terms of their detectability by GW detectors. This talk will first present an overview of GW theory
and data analysis, then delve into the role of eccentricity in the formation channels of compact binaries.
Finally, it will briefly introduce optimization techniques used in eccentric gravitational wave searches.
A portion of this talk is tailored for a younger audience as an introduction to GW research.
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2024-04-12 |
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dr KOUSHIK SEN |
Uniwersytet Mikołaja Kopernika w Toruniu |
ZN OA 1601 |
Massive Algol binaries as whetstones for understanding the progenitors of gravitational wave mergers
All except one mass transfer episode in the isolated binary evolution channel occur at short timescales
and, hence, are difficult to observe. This leads to many unconstrained assumptions in modelling
mass transfer phases. The uncertainties percolate through our understanding of progenitors
of stripped-envelope supernovae and gravitational wave mergers. As the only exception,
the nuclear-timescale so-called 'slow Case A' mass transfer phase in short-period binaries
have many Algol binaries as observational counterparts. Since a thermal timescale mass transfer
precedes the slow Case A phase, in-situ constraints on stellar and binary physics assumptions,
such as mass transfer efficiency, tidal strength and internal mixing, can be obtained through
population synthesis studies of massive Algols. I will discuss the current state-of-the-art modelling
and observations of these binaries and our identification of a novel outcome from this binary
evolution channel, namely the 'reverse Algols'. We identified semi-detached binaries where
the more massive star transfers mass to a less massive companion on a nuclear timescale.
We also found that binary stripping can form Wolf-Rayet binaries on the main sequence with identified
observational counterparts. Our population synthesis results predict ~5% of massive binaries
(30-90 Msun) in the main sequence in the above configuration.
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2024-04-19 |
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prof. dr hab. ZBIGNIEW POSTAWA |
WFAiS UJ |
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Spotkanie z kandydatem na stanowisko Dziekana WFAiS
Prof. Zbigniew Postawa is the cadidate for the position of Dean of WFAiIS, who expressed his wish
to meet with our Observatory community, the Observatory Council members in particular,
and discussions on expectations towards future dean authorities.
The meeting will be held mostly in Polish, but there should be a possibility
to discuss some issues in English.
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2024-04-26 |
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maj/may 2024 |
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2024-05-03 |
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Święto 3 Maja / Holiday break
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2024-05-10 |
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REZERWACJA |
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2024-05-17 |
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2024-05-24 |
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2024-05-31 |
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piątek po Święcie Bożego Ciała / Holiday break
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czerwiec/june 2024 |
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2024-06-07 |
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REZERWACJA |
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2024-06-14 |
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2024-06-21 |
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przerwa egzaminacyjna / Exam break
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2024-06-28 |
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przerwa egzaminacyjna / Exam break
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lipiec/july 2024 |
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sierpień/august 2024 |
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wrzesień/september 2024 |
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