Observing the Galactic Plane with the Cherenkov Telescope Array

The Cherenkov Telescope Array is a next generation ground-based gamma-ray observatory de- signed to detect photons in the 20 GeV to 300 TeV energy range. With a sensitivity improvement of up to one order of magnitude on the entire energy range with respect to currently operating facilities, coupled with significantly better angular resolution, the array will be used to address many open questions in high-energy astrophysics. In addition, CTA will explore the ultra-high energy (E >50 TeV) window with great sensitivity for the first time. CTA is expected to reveal a detailed picture of the Galactic plane at the highest energies, and to discover around one hundred new supernova remnants and many hundreds of pulsar wind nebulae, according to current population estimates. The ability of the observatory to resolve such a large number of Galactic sources is one of the challenges to be faced. In this paper, we will present the first simulated scan of the Galactic plane with a realistic observation strategy, with particular attention to the potential source confusion. We will also present prospects for morphological studies of extended sources, such as the young SNR RX J1713.7-39.Comment: All CTA contributions at arXiv:1709.03483; PoS 35th International Cosmic Ray Conference ICRC2017 Busan, Kore

Gamma ray Cerenkov telescope image analysis

The subject of this thesis is ground based gamma ray astronomy using the imaging atmospheric Cerenkov technique. The first two chapters are introductory, and describe the field of gamma ray astronomy, the generation of extensive air showers in the atmosphere and the Cerenkov radiation they induce. Chapter three describes the atmospheric Cerenkov telescope, including the development of the imaging technique for background discrimination. The characteristics of the three University of Durham atmospheric Cerenkov telescopes and the processing and calibration of their data products are outlined. Chapter four is concerned with periodic sources of gamma ray emission and includes a review of candidate sources and time series analysis techniques. An analysis of the Mark 3 telescope SMC X-1 database is presented. An upper limit of 1.2 x 10(^-11) cm(^-2) s(^-1) above a cosmic ray threshold of 1 TeV is determined for the guard ring analysis of Mark 3 data. For an analysis of medium resolution Mark 3 imaging data, the upper limit is 2 x 10(^-10) cm(^-2) s(^-1) above a cosmic ray threshold of 500 GeV. Chapter five introduces a new method for the parameterisation of Cerenkov images of extensive air showers recorded by atmospheric Cerenkov telescopes. This method, involving the optimization of a bivariate Gaussian fit to the image, is shown to be significantly better than the standard moment based parameterisation using simulated images. In Chapter six, both of these methods are employed in an attempt to enhance the signal to noise ratio for observations of the pulsar PSR 1706-44 made with the Mark 6 telescope and some evidence for steady emission is seen. The implied fluxes are (2.6 ± 0.3 ± 0.1)x 10(^-11) cm(^-2) s(^-1) above 420 GeV for the bivariate Gaussian analysis and (1.7 ± 0.4 ± 0.2)x10(^-11) cm(^-2) s(^-1) above 500 GeV for the moment analysis

Experimental approaches for 100 TeV gamma-ray astronomy

The high energy end of gamma-ray source spectra might provide important clues regarding the nature of the processes involved in gamma-ray emission. Several galactic sources with hard emission spectra extending up to more than 30TeV have already been reported. Measurements around 100TeV and above should be an important goal for the next generation of high energy gamma-ray astronomy experiments. Here we present several techniques providing the required exposure (100 km^2.h). We focus our study on three Imaging Atmospheric Cherenkov Technique (IACT) based approaches: low elevation observations, large field of view telescopes, and large telescope arrays. We comment on the advantages and disadvantages of each approach and report simulation based estimates of their energy ranges and sensitivities.Comment: 3 pages 1 figure. Proceedings of TeV particle astrophysics 2, Madison, August 2006. http://www.icecube.wisc.edu/TeV/presentations/colin_poster.pd