Monte Carlo simulations of alternative sky observation modes with the Cherenkov Telescope Array

Abstract

We investigate possible sky survey modes with the Middle Sized Telescopes (MST, aimed at covering the energy range from $\sim$100 GeV to 10 TeV) subsystem of the Cherenkov Telescope Array (CTA). We use the standard CTA tools, CORSIKA and sim_telarray, to simulate the development of gamma-ray showers, proton background and the telescope response. We perform simulations for the H.E.S.S.-site in Namibia, which is one of the candidate sites for the CTA experiment. We study two previously considered modes, parallel and divergent, and we propose a new, convergent mode with telescopes tilted toward the array center. For each mode we provide performance parameters crucial for choosing the most efficient survey strategy. For the non-parallel modes we study the dependence on the telescope offset angle. We show that use of both the divergent and convergent modes results in potential advantages in comparison with use of the parallel mode. The fastest source detection can be achieved in the divergent mode with larger offset angles ($\sim 6^{\circ }$ from the Field of View centre for the outermost telescopes), for which the time needed to perform a scan at a given sensitivity level is shorter by a factor of $\sim$2.3 than for the parallel mode. We note, however, the direction and energy reconstruction accuracy for the divergent mode is even by a factor of $\sim 2$ worse than for other modes. Furthermore, we find that at high energies and for observation directions close to the center of the array field of view, the best performance parameters are achieved with the convergent mode, which favors this mode for deep observations of sources with hard energy spectra.

arXiv comment14 pages, two-column, 18 figures

References in corpus (12)

• Design Concepts for the Cherenkov Telescope Array
• The H.E.S.S. survey of the Inner Galaxy in very high-energy gamma-rays
• Teraelectronvolt Astronomy
• A new population of very high energy gamma-ray sources in the Milky Way
• Simulation of Imaging Atmospheric Cherenkov Telescopes with CORSIKA and sim_telarray
• Performance of the MAGIC stereo system obtained with Crab Nebula data
• Monte Carlo design studies for the Cherenkov Telescope Array
• Surveys with the Cherenkov Telescope Array
• A search for TeV gamma-ray emission from SNRs, pulsars and unidentified GeV sources in the Galactic plane in the longitude range between -2 deg and 85 deg
• The Status and future of ground-based TeV gamma-ray astronomy. A White Paper prepared for the Division of Astrophysics of the American Physical Society
• Influence of the Geomagnetic Field on the IACT detection technique for possible sites of CTA observatories
• Latest results on Galactic sources as seen in VHE gamma-rays

Cited by in corpus (7)

• On the potential of Cherenkov Telescope Arrays and KM3 Neutrino Telescopes for the detection of extended sources
• Searching for Gamma-Ray counterparts to Gravitational Waves from merging binary neutron stars with the Cherenkov Telescope Array
• Strategies for the Follow-up of Gravitational Wave Transients with the Cherenkov Telescope Array
• Sensitivity of the Cherenkov Telescope Array to dark subhalos
• Divergent pointing with the Cherenkov Telescope Array for surveys and beyond
• The Making of Catalogues of Very-High-Energy γ-ray Sources
• On the potential of atmospheric Cherenkov telescope arrays for resolving TeV gamma-ray sources in the Galactic Plane