Wednesday Colloquium


"ROSETTA cometary mission; 18 months of the 67P/C-G comet observations"

Włodzimierz Kofman (Space Research Center, Warsaw)

ROSETTA space mission studies the comet Churyumov-Gerasimenko (67P / C-G). The mission is composed of an Orbiter and Philae lander. The payload contains multiple instruments performing the teledetection and in situe measurements. The probe is accompanying the comet on its journey around the sun on the orbits close to a nucleus on the distance from tens to hundreds kilometers. The scientific objective of the mission is the study the cometary material, the surface and the internal structure of the comet and their evolution on the their journay around the sun. The main scientific questions are: How formed and evolved comets? What are the physical propreties, structure of surface and interior of comets? What is the composition of the ice grains, molecules, organic? Have they played a role in the evolution of the planets? The instruments on board the probe continued observations for over a 18 months. On 12 November 2014 Philae lander, landed on the surface of the comet. This is a spectacular success and the first cometary landing in the history of the exploration of the solar system. The observations lasted for 63 hours. In our presentation we will describe the payload of the probe and Philae. We will present and discuss certain observations by orbiter and also by Philae and some scientific results. We will describe more specifically CONSERT experience. CONSERT is a bistatic radar on the ROSETTA, which the primary scientific goal is to investigate the deep interior of the nucleus of comet 67/P Churyumov-Gerasimenko. The radar had operated between the Rosetta spacecraft and Philae lander and through radio tomographic mapping between the lander and the main spacecraft, obtained important scientific results. The measurement made on 12-13 November 2014, during the first science sequence begun to reveal the internal structure of Comet 67P/Churyumov-Gerasimenko.


"The first direct detection of gravitational waves"

Piotr Jaranowski (University of Bialystok)

On September 14, 2015 the two LIGO detectors simultaneously observed a gravitational-wave signal coming from the merger of two stellar-mass black holes. After very quick look at the history of gravitational-wave research, the observation as well as detectors, search algorithms, and source properties will be described in more detail, some astrophysical implications of the observation will also be sketched. The contribution of the Polish POLGRAW group to the discovery will be presented.


"The nature and origin of ultra-high energy cosmic ray particles"

Peter Biermann (Max Planck Institut für Radioastronomie, Bonn)

The origin of ultra high energy cosmic ray particles is still not settled, but there is growing recognition, that at the highest energies the abundances are mostly nuclei such as Carbon or heavier. At lower energies we now detect the expected proton component, possibly coming from high redshifts. This implies due to propagation constraints, that the maximal energy particles come from just a few Mpc, and the arrival directions suggest the radio galaxy Centaurus A, as was predicted 1963 by Ginzburg. Radio galaxies as sources of ultra high energy cosmic rays are also required to explain in situ observations of spectra. This allows then to connect to one plausible origin of very high energy neutrinos, recent mergers of super-massive black holes, in turn a source of a predicted low frequency gravitational wave background.


"How to determine the mass of the black hole"

Janusz Ziółkowski (NCAC, Warsaw)


"Levitating Atmospheres and Radius Expansion Bursts"

Włodzimierz Klużniak (NCAC, Warsaw)