|
| |
|
| |
|
| |
|
| |
|
|
Vliv silného gravitačního pole kompaktních objektů na jejich záření
Sochora, Vjačeslav ; Karas, Vladimír (advisor) ; Schee, Jan (referee)
In the present work we describe different cosmic systems that contain the compact objects (neutron stars or black holes). The accretion of the matter on the compact object is a main source of the radiation and that is why we consider several models of accretion. The energy of emitted radiation is different from the observed energy due to the gravitational redshift and the Doppler shift. We are interested in the minimum and maximum values of this change of emitted radiation. We show how to calculate these extremes in Kerr metric by the help of the elliptic integrals assuming that the emission radius, the angular momentum of black hole, and the inclination angle of the observer are given.
|
|
| |
|
| |
|
| |
|
|
The study of gamma-ray bursts detected by satellite RHESSI
Řípa, Jakub ; Mészáros, Attila (advisor) ; Karas, Vladimír (referee)
The beginning of the theoretical section of this diploma thesis is pointed to a discovery of the gamma-ray bursts. Then it is pointed to a brief historical summary of the different instruments dedicated to the GRB's field. Because the main aim of this work is the basic analysis and the classifying of the observed gamma-ray bursts by RHESSI solar satellite (which has observed more than 220 GRBs yet), a technical description of this instrument is introduced. It is followed by a part about gamma-ray production mechanisms. In this work there are also mentioned some related gamma-ray sources e.g. SGRs. The theoretical résumé is concluded by the description of the GRB's afterglows and some preferred models of their origins. In the proper study there was done the morphological classifying of the GRB's temporal profiles. Next there was studied the duration distribution with orientation to determine number of the subclasses using lognormal fits and the 2 test. Distribution of the radial distances of the gamma-ray sources can be examined by the log N vs. log P. dependence. The results are properly discussed and compared with the results of the BATSE instrument (including the V/Vmax test). In the final stage of this work, there is argued the dependence between the hardness ratios and the durations.
|
|
| |
guest ::
RSS feed.