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663. ROK AKADEMICKI 2026/2027
Seminaria Piątkowe
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Czas i miejsce
Seminaria OAUJ odbywają się w piątki po angielsku.
Początek o godzinie 12:00, czas trwania: 45 minut + dyskusja.
Zainteresowani, jak również osoby
chętne do zaprezentowania referatów, powinny zgłaszać się w tej sprawie
bezpośrednio do
Marka Weżgowca.
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październik/october 2026 |
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| 2026-10-02 |
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Inauguracja Roku Akademickiego / Inauguration of the Academic Year
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| 2026-10-09 |
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| 2026-10-16 |
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dr GOURAB GIRI |
INAF-IRA, Bologna, Italy |
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Analyzing Unusual Radio Outflows in extended RAdio-galaxies [the AURORA project]
In a limited fraction of extragalactic jets, a captivating phenomenon manifests
as they deviate from their straight-line trajectories, forming mirror-symmetric (TAILED)
and inversion-symmetric (WINGED) structures. The complexity deepens with the discovery
of resembling galactic microquasars. Extended jets that follow a straight-line trajectory,
in circumstances, grow to giant scales (GRG), reaching the edge of the large-scale
structures they inhabit or stall on very compact scales. The origins of these distinct geometries
remain intensely debated, especially with present-day observations challenging prior predictions.
In this context, the project titled ‘AURORA’ focuses on numerically modeling these sources
using recently developed tools to unravel their topological origins. It examines the intricate
interconnection of jet morphology with their ambient environment alongside complex processes
within the central AGN. Emphasizing microscale processes, this investigation explores
the impact of particle cooling and reacceleration on spectral and polarization maps,
elucidating perplexing properties, e.g., anomalous spectral behavior in winged sources.
This presentation thereby outlines novel scientific inquiries,
and provides likely future directions for such jetted sources.
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| 2026-10-23 |
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dr RAMESHAN THIMMAPPA |
Department of Physics, Villanova University, USA |
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The Proper Motion Study of HST-1 in the Jet of M87 with Chandra and Hubble
The radio galaxy M87 is well known for its relativistic jet,
which contains a series of bright knots observable across
the electromagnetic spectrum. One of the most prominent features,
HST-1, is located ~70 pc from the central engine and exhibited
a dramatic X-ray flare around 2005. We investigate the morphology,
proper motion, and long-term variability of HST-1 using 112 Chandra ACIS-S
observations from 2000 to 2021, with a total exposure time of ~884 ks.
Using deconvolved X-ray images, we measure the jet brightness profile
and the separation between the core and HST-1. During the 2003–2005 flare,
we find a correlation between the X-ray flux of HST-1 and its separation from the core.
At later epochs, the separation increases steadily, corresponding to an apparent
superluminal motion of 6.6 ± 0.9c, consistent with previous measurements.
We interpret the flux–offset correlation in terms of moving shocks within the jet.
To investigate the relationship between the X-ray and UV/optical emission,
we analyze 245 Hubble Space Telescope ACS and 120 WFC3/UVIS observations from 2002 to 2022,
with a total exposure time of ~345 ks. We measure the brightness profile and proper motion
of HST-1 and compare its evolution with the X-ray emission. The optical/UV proper motion
is 1.04 ± 0.04c during 2002–2005 and 2.1 ± 0.05c during 2005–2022,
indicating apparent acceleration. The difference between the X-ray and optical/UV motions
suggests physically distinct emission regions, providing insight into shock evolution,
particle acceleration, and the internal structure of relativistic jets.
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| 2026-10-30 |
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listopad/november 2026 |
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| 2026-11-06 |
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prof. ANDRZEJ ZDZIARSKI |
CAMK PAN, Warszawa |
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The PeV photons from Cyg X-3
Cyg X-3 is a unique X-ray binary. In particular, it is a powerful
source of orbitally modulated gamma-rays at GeV energies, emitted by
its jets. Recently, the LHAASO collaboration discovered PeV photons
from Cyg X-3. Two of them have energies >3 PeV (>5000 erg), the
highest ever detected from an astrophysical source. I will discuss a
model that explains the LHAASO results. PeV-range photons are produced
when hadrons with energies up to >10 PeV interact with both the
blackbody photons and the stellar wind emitted by the donor, producing
neutral pions that subsequently decay into gamma-rays. Given the very
low cross sections for these processes and the source's low
inclination, hadrons accelerated by the counterjet toward the observer
dominate the observed emission, contrary to the usual jet dominance.
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| 2026-11-13 |
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| 2026-11-20 |
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| 2026-11-27 |
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grudzień/december 2026 |
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| 2026-12-04 |
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| 2026-12-11 |
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| 2026-12-18 |
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| 2026-12-25 |
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Święta Bożego Narodzenia / Christmas
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styczeń/january 2027 |
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| 2027-01-01 |
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Nowy Rok / New Year
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| 2027-01-08 |
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| 2027-01-15 |
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| 2027-01-22 |
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| 2027-01-29 |
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przerwa egzaminacyjna / Exam break
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luty/february 2027 |
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| 2027-02-05 |
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przerwa egzaminacyjna / Exam break
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| 2027-02-12 |
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ferie zimowe / Semester break
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| 2027-02-19 |
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przerwa egzaminacyjna / Exam break
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| 2027-02-26 |
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marzec/march 2027 |
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| 2027-03-05 |
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| 2027-03-12 |
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| 2027-03-19 |
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| 2027-03-26 |
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Wielki Piątek / Holiday break
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kwiecień/april 2027 |
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| 2027-04-02 |
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| 2027-04-09 |
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| 2027-04-16 |
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| 2027-04-23 |
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| 2027-04-30 |
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maj/may 2027 |
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| 2027-05-07 |
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| 2027-05-14 |
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| 2027-05-21 |
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| 2027-05-28 |
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piątek po Święcie Bożego Ciała / Holiday break
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czerwiec/june 2027 |
   
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| 2027-06-04 |
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| 2027-06-11 |
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| 2027-06-18 |
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przerwa egzaminacyjna / Exam break
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| 2027-06-25 |
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przerwa egzaminacyjna / Exam break
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lipiec/july 2027 |
   
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sierpień/august 2027 |
   
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wrzesień/september 2027 |
 
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