Wednesday Colloquium


"Jet launching and hadronic processes in blazars"

Andrzej Zdziarski (NCAC, Warsaw)

The first part will be devoted to testing the model of jet launching utilizing the energy of black-hole rotation from magnetically arrested discs. This can be done by measuring magnetic fields in jets, in particular using the radio core shift, which is a dependence of the position of a radio core on frequency. A new variant of this method is presented. Application of it to luminous blazars implies that the jet opening angles are much smaller than the canonical value of 1/Gamma_jet. This then implies that the magnetization parameter is <<1, requiring the existence of an efficient mechanism of the magnetic-to-kinetic energy conversion. The second part will be devoted to a study of consequences of the blazar model with emission dominated by hadronic processes, recently quite popular, to models of accretion. It is shown that the power of jets in this model is both highly super-Eddington and exceeding the accretion luminosity by a factor of thousands. This is shown to be inconsistent with standard accretion models, which presents a strong argument against the hadronic model.


"Spatially resolved observations of planetary nebulae by Herschel Space Observatory"

Ryszard Szczerba (NCAC, Toruń)

Herschel PLanetary Nebulae Survey (HerPLaNS) was a photometric and spectroscopic survey of Planetary Nebulae (PNe) in the far-IR using the Herschel Space Observatory. It was one of the largest open time programes with about 200 hours of observations allocated. The project is part of a bigger project, which aims at collecting multi-wavelength observations from the X-ray to the millimetre wavelengths to fully charecterse the energetic system of PNe. In my talk I will present results we have obtained up to now using the collected data.


"Nonthermal emission from supernova remnants"

Oleh Petruk (Institute for Applied Problems in Mechanics and Mathematics, Lviv National University, Ukraine)

Supernova remnants (SNRs) are the main objects to study acceleration of galactic cosmic rays. Magnetic field in the Galaxy deflects relativistic particles on their way toward the observer. Therefore, information about high-energy processes in SNRs may be inferred only from their nonthermal emission. We review the present status of observations and modeling of the cosmic-ray radiation in SNRs, in radio, X-ray and gamma-ray bands.