4 research outputs found
A new unfolding method for the MAGIC telescope
Get PDFThe presented thesis describes an unfolding method whose principle is to determine the probability that a certain set of events has a certain range of energy. Unfolding methods are not related to the analyzed data and one is interested in the extent to which the unfolding solution encapsulates the
unfolding variables in the data. For this purpose, new factors have been defined. These factors enable the use of the unfolding methods for obtaining information about the unfolding variables in the data, independent of the unfolding solutions. Amongst others, this information determines
whether the unfolding variables exist in the data after applying standard (analysis) cuts or additional ones. This opens the way to study the effects of different cuts on the data and how they will change the content of the unfolding variables in the data. Additionally, the unfolding method is applied to three special AGN: Markarian 421, Markarian 501 and PKS 2155304.
The obtained spectra follow the results of already established methods, and in most of the cases (Markarian 501 and PKS 2155304)
the spectra could be extended to higher and/or lower energies
University of Dortmund by
No full textSupervised by Prof. Dr. Dr. Wolfgang RhodeAnd we complain that we exhaust ourselves too fast when, on the contrary, we should wonder how new the world appears to us, just because, for a moment, we have forgotten it
Telescope: An Automatic Feature Extraction and Transformation Approach for Time Series Forecasting on a Level-Playing Field
No full textSuzaku and Multi-wavelength Observations of OJ 287 during the Periodic Optical Outburst in 2007.
Get PDFSuzaku observations of the blazar OJ 287 were performed in 2007 April 10-13 and November 7-9. They correspond to a quiescent and a flaring state, respectively. The X-ray spectra of the source can be well-described with single power-law models in both exposures. The derived X-ray photon index and the flux density at 1 keV were found to be Γ = 1.65±0.02 and S1keV = 215±5 nJy in the quiescent state. In the flaring state, the source exhibited a harder X-ray spectrum (Γ = 1.50±0.01) with a nearly doubled X-ray flux density of S1keV = 404+6-5nJy. Moreover, significant hard X-ray signals were detected up to 27 keV. In cooperation with Suzaku, simultaneous radio, optical, and very-high-energy γ-ray observations of OJ 287 were performed with the Nobeyama Millimeter Array, the KANATA telescope, and the MAGIC telescope, respectively. The radio and optical fluxes in the flaring state (3.04±0.46 Jy and 8.93±0.05 mJy at 86.75 Hz and in the V-band, respectively) were found to be higher by a factor of 2-3 than those in the quiescent state (1.73±0.26 Jy and 3.03±0.01 mJy at 86.75 Hz and in the V-band, respectively). No notable γ-ray events were detected in either observation. The spectral energy distribution of OJ 287 indicated that the X-ray spectrum was dominated by inverse Compton radiation in both observations, while synchrotron radiation exhibited a spectral cutoff at around the optical frequency. Furthermore, no significant difference in the synchrotron cutoff frequency was found between the quiescent and flaring states. According to a simple synchrotron self-Compton model, the change of the spectral energy distribution is due to an increase in the energy density of electrons with small changes of both the magnetic field strength and the maximum Lorentz factor of electrons
