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październik/october 2019 |
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2018-10-04 |
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dr DOROTA KOZIEŁ-WIERZBOWSKA |
OA UJ |
ZN OA 1520 |
Radio sources in the SDSS spectroscopic catalogues
Based on the catalogue of Radio sources associated with Optical Galaxies and having
Unresolved or Extended morphologies I (ROGUE I), I will discuss the problem of
identification and classification of radio sources in the large radio surveys. The
catalogue was created by cross-matching galaxies from the SDSS with the FIRST and
NVSS catalogues. It contains more than 32,000 galaxies with a FIRST core within
3arcsec of the optical position, and is the largest, handmade catalogue of this
kind.
However, as most catalogues with a low flux density limit, it contains the mixture
of radio sources, and the separation of radio AGNs from the radio emission arising
in the star-forming regions is a challenging task. In recent papers (Best & Heckman
2012, Sabater et al. 2019) separation of these two populations was made based on
several different diagrams. But this procedure is complicated and requires the
knowledge of many different parameters, like optical emission line ratios or galaxy
mass. Therefore, during my talk I will also discuss a single diagram that can be
used to distinguish radio emission produced by jets from the one emitted in
star-forming regions.
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2019-10-11 |
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ZN OA 1521 |
Gathering in Honor of Prof. Katarzyna Otmianowska-Mazur
Uroczyste podziękowanie Pani Profesor Katarzynie Otmianowskiej-Mazur za
długoletnią współpracę naukową oraz zaangażowanie w budowę stacji LOFAR-a
w Polsce.
Po uroczystości dr Błażej Nikiel-Wroczyński wygłosi wykład "LoTSS -
najnowszy przegląd nieba realizowany przez LOFAR-a".
A special gathering in honor of Prof. Katarzyna Otmianowska-Mazur, to
express our gratitude for a long-term scientific collaboration, as well as
for her involvement in setting up the LOFAR station in Poland.
After the gathering, dr Błażej Nikiel-Wroczyński will give a talk "LoTSS
- LOFAR newest sky survey".
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2019-10-18 |
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2019-10-25 |
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listopad/november 2019 |
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2019-11-01 |
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Wszystkich Świętych / Holiday break |
2019-11-08 |
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prof. PAOLO VALORE |
Universita' di Milano Statale and Milano Bicocca, Italy |
ZN OA 1522 |
Kinds of things and our choices. Ontology and presuppositons
Contemporary ontology tells us what exists, specifying the categories of
objects that we should assume. I address some complications that arise
when we try to build a philosophical reconstruction of the link between
individuals and categories, with some examples mutuated from bio-medical
research. These complications arise from the fact that given a domain of
individuals, any classificatory principle determines a set of things.
Therefore, there are many alternative ways of classifying things in
classes according to their shared properties, producing different patterns
of classification in categories guided by different theoretical
assumptions. In fact, if we are not able to specify the strategy of the
intended relevant properties and our preferences in advance, the empirical
data themselves do not help us spot the perspicuous kinds. These
theoretical assumptions can be considered the metaphysical background of
any theory that assumes the notion of intrinsic property and pertinent and
meaningful category.
REFERENCES:
P. Valore (2018). “Resemblance, Exemplification, and Ontology”. In:
American Philosophical Quarterly, 55 (2): 131-140
P. Valore (2018). “The Quest for Higher Order Criteria for Meta-Ontology:
Metaphysics Vindicated”. In: Philosophy. Journal of the Higher School of
Economics, I, 4: 13–26
P. Valore (2017). “Natural Kinds, Similarity, and Individual Cases.
Ontological Presupposition and Ethical Implications”. In: Psychological,
Emotional, Social and Cognitive Aspects of Implantable Cardiac Devices.
Ed. G.M. Manzoni, R. Proietti, G. Pietrabissa, G. Castelnuovo. Dordrecht,
New York, London: Springer Nature
P. Valore (2016). Fundamentals of Ontological Commitment. Berlin-Boston:
De Gruyter
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2019-11-15 |
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mgr SEBASTIANO SAVASTANO |
Universita' di Bologna, Italy |
ZN OA 1523 |
Primordial Dark Matter Halos from fifth forces
Dark matter is an essential ingredient of modern cosmology, its
fundamental nature being one of the biggest open enigmas in physics. I
discuss the possibility to provide the entire dark matter content in form
of screened dark compact objects which could be potentially generated
during the radiation dominated era. In the standard cosmological scenario,
this would be suppressed due to the fast expansion rate of the Universe
lead by radiative pressure. Nevertheless, the introduction of an
additional long-range attractive interaction stronger than gravity
enhances the growth of fluctuations in the density field of a
non-interacting matter fluid, which eventually collapse in Primordial Dark
Matter Halos. Finally, I analyse in which conditions these structures
might evade microlensing constraints and cosmic microwave background
energy injection bounds.
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2019-11-22 |
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dr hab. JAN CZERNIAWSKI |
Instytut Filozofii UJ, Kraków |
ZN OA 1524 |
Construction of Kinematical Transformations in Special Relativity
In the didactics of Special Relativity, kinematical transformations
are usually introduced by imposing on general
linear transformations the condition that the principle of constancy of
light velocity. However, this way does not enable catching an intuitive
meaning of the transformations analogous to the one enabled for Galilean
transformations by their construction, supported by the standard figure.
Two versions of such construction for proper Lorentz transformations will
be presented, first based on familiar experimental results and the
standard signal synchronizing procedure, and second on some more general
assumptions, the synchronizing procedure by infinitely slow clock
transport, and the condition that the transformations form a group. Both
are supported by the same standard figure as for Galilean
transformations.
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2019-11-29 |
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dr MARIUSZ TARNOPOLSKI |
OA UJ |
ZN OA 1525 |
Optical variability modelling of newly identified blazar candidates behind Magellanic Clouds
We present an optical variability study of 44 newly identified blazar
candidates behind the Magellanic Clouds, including 27 flat spectrum radio
quasars (FSRQs) and 17 BL Lacertae objects (BL Lacs). The objects in the
sample possess optical OGLE light curves (LCs) spanning several (up to 17)
years. The LCs were analysed with the Lomb-Scargle periodogram, and it was
found that the power spectral densities (PSDs) exhibit breaks for several
objects, which allowed to constrain the black hole masses of 18 FSRQs.
Many sources have very steep PSDs, with high frequency spectral index in
the range 3-7. An alternative attempt to classify the LCs was made using
the Hurst exponents and the A-T plane.
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grudzień/december 2019 |
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2019-12-06 |
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dr DMITRY PROKHOROV |
University of Amsterdam, the Netherlands |
ZN OA 1526 |
Gamma-Ray Emission from Radio Galaxies
Centaurus A (Cen A), the nearest radio galaxy, was detected as a faint
emitter of very high energy (VHE) gamma rays by the H.E.S.S. telescopes in
Namibia. The flux derived from the H.E.S.S. data is notably higher than
that expected from a single zone synchrotron self-Compton model, which
adequately describes the emission from Cen A at lower energies. New
observations with H.E.S.S. were performed to clarify the spectral
characteristics of the VHE emission from Cen A. I will report on the
results of the analysis of the complete H.E.S.S. data set with twice the
exposure time of the previously published data set and also the update of
the Cen A spectrum obtained with Fermi-LAT at GeV energies. I will also
discuss prospects for H.E.S.S. observations of the radio galaxy, Fornax A.
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2019-12-13 |
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mgr GIUSEPPE SARRACINO |
Universita' Federico II di Napoli, Italy |
ZN OA 1527 |
Stellar Structure in f(R)-Gravity
The modified Lane-Emden Equation for stellar structure in f(R)-Gravity is
derived and solved numerically. This equation is derived in the Newtonian
limit by assuming a polytropic relation between the pressure and the
density. This is an integro-differential equation whose integral part can
have an oscillating behaviour with the proper choice of the Green Function
taken to derive it that can be used to describe the behaviour of variable
stars or a Yukawa-like behaviour. We solve this equation both in the
non-oscillating and oscillating case for different values of the polytropic
index and confront the different solutions with the General Relativity
case. This approach allows us to include in this theoretical scheme exotic
very massive objects and variables objects.
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2019-12-20 |
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dr ANDREY TIMOKHIN |
Uniwersytet Zielonogórski, Zielona Góra |
ZN OA 1528 |
How electron-positron pair plasma fills pulsar magnetosphere, heats NS surface, and generates radio emission.
I give an overview of recent pulsar magnetosphere models emphasizing the
importance of pair plasma generation. I discuss how much pair plasma can be
produced in pair cascades and what it means for the physics of Pulsar Wind
Nebulae. Relativistic particles accelerated in pair formation zones heat the
neutron star surface, I demonstrate that the temperatures of pulsar polar caps
predicted in the frame of modern pair cascade models agree with observations
quite well. I also present a novel robust mechanism for direct generation of
coherent radio emission in pair discharges and discuss its implications.
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2019-12-27 |
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przerwa świąteczna / Holiday break |
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styczeń/january 2020 |
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2020-01-03 |
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przerwa świąteczna / Holiday break |
2020-01-10 |
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dr H. TUGCA SENER |
Uniwersytet Pedagogiczny w Krakowie |
ZN OA 1529 |
Hot subdwarfs as common-envelope evolution outcomes
Hot subwarfs allow us to explore possible outcomes of common-envelope (CE)
ejection in a close binary. Depending on the observational results (i.e.
orbital period, mass ratio, chemical abundances, etc.) a conclusion for
these exotic systems can be reached regarding an idea of the formation and
evolution of He-rich subdwarf binaries. Besides a general perspective on
their formation, they also help us to go further on stellar evolution and
confirm our current knowledge about the outcomes of CE evolution. Some
case studies will be shown as examples.
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2020-01-17 |
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mgr ROMANA GROSSOVA |
Masaryk University, Brno, Czech Republic &
University of Torino, Torino, Italy |
ZN OA 1530 |
Powerful AGN jets and unbalanced cooling in the hot atmosphere of IC 4296
Giant elliptical galaxies are the largest galactic structures in the
Universe. They were formed within the first few Gyr after the Big Bang and
overcome only brief and explosive star formation and afterward grew only
by dry mergers and are embedded in hot X-ray emitting atmospheres. AGN
radio-mechanical feedback is considered to be balancing the heating and
cooling in these structures. A detailed study was done for giant
elliptical galaxy IC 4296 located in the group Abell 3565. The new Karl G.
Jansky Very Large Array (VLA, 1--2 GHz) radio data, supported by archival
radio, X-ray (Chandra, XMM-Newton) and optical (SOAR, HST) observations
revealed uniqueness of this source. The galaxy hosts powerful radio jets
piercing through the inner hot X-ray emitting atmosphere, depositing most
of the energy into the ambient intra-cluster medium (ICM). Whereas the
radio surface brightness of the A configuration image is consistent with a
Fanaroff-Riley Class I (FR I) system, the D configuration image reveals
two large (160 kpc), well-defined lobes (one of which is associated with
an X-ray cavity) at a projected distance 230 kpc. The total enthalpy of
the radio lobes is 7 × 1059 erg and the mechanical power output
of the jets is 1044 erg/s. The central entropy and cooling time of
the X-ray gas are unusually low and the nucleus hosts a warm
Hα+[NII] nebula and a cold molecular CO disk.
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2020-01-24 |
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dr KRZYSZTOF GŁÓD |
OA UJ |
ZN OA 1531 |
Light propagation in space-time
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2020-01-31 |
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Sesja / Exam break |
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luty/february 2020 |
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2020-02-07 |
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Sesja / Exam break |
2020-02-14 |
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Przerwa semestralna / Semester break |
2020-02-21 |
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prof. RYSZARD SZCZERBA |
Centrum Astronomiczne im. M. Kopernika - Toruń |
ZN OA 1532 |
Searching for Young Stellar Objects in the Outer Galactic Plane
I will present the results of the study aimed to uncover the population of
Young Stellar Objects (YSOs) in the relatively poorly studied star-forming
regions in the Outer Galaxy. We use the data from the "Spitzer Mapping of
the Outer Galaxy" survey (SMOG) that covered 24 deg2 region in the Outer
Galaxy (dubbed L105), l ∼ (102 -109) and b ∼ (-0.2 3.2 ), in
the IRAC 3.68.0m and MIPS 24 m bands. The SMOG data have been combined
with the data from the 2MASS (JHKs) and WISE (3.5-22 m) all-sky surveys.
We have selected YSO candidates based on the color-color selection
criteria (more than 1000), and then applied a series of filters to remove
contaminating sources (e.g., background galaxies). We have also performed
an additional search for YSO candidates among the Spitzer/SMOG sources
with the WISE counterparts by using an automated source identification
scheme based on the Machine Learning algorithms (Solarz et al. 2017). This
method identified additional YSO candidates, which were missed by
classical color-color based selection criteria.
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2020-02-28 |
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mgr RADIM PANIS |
Department of Physics, Silesian University in Opava, Czech Republic |
ZN OA 1533 |
Detection of chaotic behaviour in time series generated by charged particle motion around magnetized Schwarzschild black hole
Time series, generated by nonlinear particle motion around
magnetized/regular black hole has been studied using standard and machine
learning methods for chaos detection. Test particles constituting neutral
Kepplerian accretion disc around magnetized black hole can get easily
ionized and will start to feel external uniform magnetic field. New type
of motion for now charged particle will be possible, ionized particles can
leave the circular orbits located in accretion disc infinitesimally thin
plane and this ionization process could lead to the disk thickening or
even complete disk destruction. Detection of charged particle trajectory
chaoticity can be used in determination of accretion disk future.
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marzec/march 2020 |
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2020-03-06 |
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dr JAROSŁAW DUDA |
Instytut Informatyki i Matematyki Komputerowej,
Wydział Matematyki i Informatyki UJ |
ZN OA 1534 |
Hierarchical correlation reconstuction - between statistics and machine learning
While machine learning techniques are very powerful, they have
some weaknesses, like iterative optimization with many local minima,
large freedom of parameters, lack of their interpretability and accuracy
control. From the other side we have classical statistics based on
moments: not having these issues, but providing only a rough
description. I will talk about kind of intermediate approach combining
their advantages: with MSE-optimal moment-like coefficients, designed
such that we can directly combine them into probability density. I will
show some applications examples, like modelling conditional
distributions, or time series analysis - including multivariate and
nonstationary.
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2020-03-13 |
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ZN OA 1535 |
Spotkanie pracowników OAUJ z Dziekanem Wydziału Fizyki, Astronomii i Informatyki Stosowanej UJ, prof. dr hab. Ewą Gudowską-Nowak
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2020-03-20 |
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ODWOŁANE / CANCELLED |
2020-03-27 |
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ODWOŁANE / CANCELLED |
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kwiecień/april 2020 |
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2020-04-03 |
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ODWOŁANE / CANCELLED |
2020-04-10 |
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Wielki Piątek / Holiday break |
2020-04-17 |
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ODWOŁANE / CANCELLED |
2020-04-24 |
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ODWOŁANE / CANCELLED |
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maj/may 2020 |
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2020-05-01 |
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1 Maja / Holiday break |
2020-05-08 |
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ODWOŁANE / CANCELLED |
2020-05-15 |
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ODWOŁANE / CANCELLED |
Zoom meeting, request invitation from organizer |
2020-05-22 |
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dr hab. MARIA GIOVANNA DAINOTTI |
OA UJ |
ZN OA 1536 |
Hunting standard candles: The Gamma-Ray Burst fundamental plane relation
Gamma-ray bursts (GRBs), detected among the largest distances ever observed, can be
used in principle as cosmological tools. I will briefly introduce the challenges we
need to face to pinpoint subclasses among the GRB zoo. This is crucial for the
successful hunt of GRBs as standard candles.
Long GRBs with a plateau phase in their X-ray afterglows obeys a three-dimensional
(3D) relation (Dainotti et al. 2016), between the rest-frame time at the end of the
plateau, Ta, its corresponding X-ray luminosity, La, and the peak luminosity in the
prompt emission, Lpeak. This 3D relation identifies a GRB fundamental plane with a
scatter 54% less than the bidimensional La-Ta relation for the gold sample, composed
by GRBs with light curves with good data coverage and relatively flat plateaus. This
correlation, the tightest among the 3-parameter correlations involving plateaus,
holds for 183 Swift GRBs with known redshifts. We compare several GRB classes, such
as the short with extended emission (SEE), X-ray Flashes, GRBs associated with SNe,
only long-duration GRBs (132), selected from the total sample by excluding GRBs of the
previous classes, and the gold sample. The gold fundamental plane has an intrinsic
scatter smaller than any plane derived from the other sample classes.
The relation planes for the gold sample and the SEE are statistically different. Such
a difference points toward different magnetic fields and spin periods values within
the magnetar model.
Thus, the gold sample remains the best candidate for being a standard candle.
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2020-05-29 |
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czerwiec/june 2020 |
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2020-06-05 |
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2020-06-12 |
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piątek po Święcie Bożego Ciała / Holiday break |
2020-06-19 |
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2020-06-26 |
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Sesja / Exam break |
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lipiec/july 2020 |
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sierpień/august 2020 |
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wrzesień/september 2020 |
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