Monte Carlo design studies for the Cherenkov Telescope Array

Abstract

The Cherenkov Telescopes Array (CTA) is planned as the future instrument for very-high-energy (VHE) gamma-ray astronomy with a wide energy range of four orders of magnitude and an improvement in sensitivity compared to current instruments of about an order of magnitude. Monte Carlo simulations are a crucial tool in the design of CTA. The ultimate goal of these simulations is to find the most cost-effective solution for given physics goals and thus sensitivity goals or to find, for a given cost, the solution best suited for different types of targets with CTA. Apart from uncertain component cost estimates, the main problem in this procedure is the dependence on a huge number of configuration parameters, both in specifications of individual telescope types and in the array layout. This is addressed by simulation of a huge array intended as a superset of many different realistic array layouts, and also by simulation of array subsets for different telescope parameters. Different analysis methods - in use with current installations and extended (or developed specifically) for CTA - are applied to the simulated data sets for deriving the expected sensitivity of CTA. In this paper we describe the current status of this iterative approach to optimize the CTA design and layout. (C) 2012 Elsevier B.V. All rights reserved

1WHSP: An IR-based sample of ~1000 VHEγ-ray blazar candidates

“…Given that variability of one order of magnitude or even larger is often observed in the X-ray and TeV bands, most of the HSP blazars in our sample (with the exception of those at very high redshift) may be detectable during flaring episodes by the present generation of Cherenkov telescopes, and certainly by the future CTA, as shown in Fig. 14. There we present the SED of 1WHSP J172504.3+115215 and compare the sensitivities of Fermi-LAT (for a four year exposure) and CTA (for a 50 h exposure Bernlöhr et al 2013), which are approximately equivalent at the energy of 50 GeV.…”

Capabilities of future intensity interferometers for observing fast-rotating stars: imaging with two- and three-telescope correlations

“…Equations 7 and 8 will be used for adding noise to the simulated data presented in Section 4. If we assume individual CTA telescope areas of ∼ 43 m 2 (roughly ∼ 3.7 m dishes consistent with Bernlöhr et al (2013)), an electronic bandwidth of ∼ 2 GHz, a quantum efficiency of ∼ 60%, λ = 545 nm, and an optical bandwidth of ∼ 10 11 s −1 for 50 hrs of observing time on a 3 rd magnitude star (corresponding to n ∼ 10 −5 m −2 s −1 Hz −1 , depending on stellar temperature), we obtain SN R (2) ∼ 2000 and a SN R (3) ∼ 3. Both SN R (2) and SN R (3) can benefit from using multiple spectral channels since the SN R improves as the square root of the number of spectral channels.…”

“…Then we take the Fast Fourier Transform (FFT) of the pristine image, and sample the data in the (u, v) plane as determined by the telescope array configuration and the observing wavelength. A possible CTA array configuration (Bernlöhr et al 2013) is shown in Figure 2, consisting of 74 telescopes of 4 m and 7 m telescopes, spread out over 2 kilometers. Such an array provides 2701 baselines pairs, ranging from 14 m to 2 km, and 70300 telescope triplets.…”

Cut-off characterisation of energy spectra of bright fermi sources: Current instrument limits and future possibilities

“…In this study we focus on the impact of the performance of the CTA observatory on the determination of the spectral parameters of the sources we have studied in the previous section, comparing the SEDs that we obtained with the Fermi -LAT and the SEDs that we would expect from CTA. For this section we make use of instrument response functions for a preliminary design of the southern array 9 , based on the study of Bernlöhr et al (2013). We highlight that these IRFs are still very preliminary as the observatory is not yet in place.…”