scholarly journals The Large Magellanic Cloud with the Cherenkov Telescope Array

2019 ◽  
Vol 209 ◽  
pp. 01021
Author(s):  
María Isabel Bernardos ◽  
María Benito ◽  
Fabio Iocco ◽  
Salvatore Mangano ◽  
Olga Sergijenko ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Region Of Interest ◽  
Cosmic Ray ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Point Sources ◽  
Detection Sensitivity ◽  
Telescope Array ◽  
Star Forming ◽  
Cherenkov Telescope

The Large Magellanic Cloud (LMC) is a spiral galaxy, satellite of the Milky way with a high star formation activity. It represents a unique laboratory for studying an extended and spatially resolved star-forming galaxy through gamma-ray observatories. Therefore, the LMC survey is one of the key science projects for the Cherenkov Telescope Array (CTA), the next-generation ground-based gamma-ray observatory. In this document we present the work performed over the last year by the CTA working group dedicated to the LMC, in order to offer a first characterization of the LMC at TeV energies. We have performed detectability forecasts based on the expected CTA performance for all sources in the region of interest of the LMC with known emission at GeV energies and above. Based on previous observations made by Fermi-LAT and H.E.S.S. we have characterized all point sources, extended sources and diffuse emission produced by cosmic-ray propagation, extrapolating their spectra to CTA energies. Finally, we have characterized the signal expected by different annihilation mechanisms of dark matter (DM) particles within the LMC, computing the detection sensitivity curve for this target in the cross-section-to-mass plane.

scholarly journals Cosmic Rays and the Dynamic Balance in the Large Magellanic Cloud

1990 ◽  
Vol 123 ◽  
pp. 537-541
Author(s):  
Carl E. Fichtel ◽  
Mehmet E. Ozel ◽  
Robert G. Stone
Keyword(s):  
Cosmic Rays ◽  
Gamma Ray ◽  
Dynamic Balance ◽  
Cosmic Ray ◽  
Large Magellanic Cloud ◽  
High Energy ◽  
Magellanic Cloud ◽  
Density Level ◽  
Energy Gamma ◽  
Galactic Dynamic

AbstractPresent and future measurement of the Large Magellanic Cloud (LMC) particularly in the radio and high energy gamma ray range offer the possibility of understanding the density and distribution of the cosmic rays in a galaxy other than our own and the role that they play in galactic dynamic balance. After a study of the consistency of the measurements and interpretation of the synchrotron radiation from our own galaxy, the cosmic ray distribution for the LMC is calculated under the assumption that the cosmic ray nucleon to electron ratio is the same and the relation to the magnetic fields are the same, although the implications of alternatives are discussed. It is seen that the cosmic ray density level appears to be similar to that in our own galaxy, but varying in position in a manner generally consistent with the concept of correlation with the matter on a broad scale.

scholarly journals Performance optimization of the air shower simulation program for the Cherenkov Telescope Array

2019 ◽  
Vol 214 ◽  
pp. 05041 ◽  
Author(s):  
Luisa Arrabito ◽  
Konrad Bernlöhr ◽  
Johan Bregeon ◽  
Gernot Maier ◽  
Philippe Langlois ◽  
...  
Keyword(s):  
Performance Optimization ◽  
Gamma Ray ◽  
Cosmic Ray ◽  
High Energy ◽  
Telescope Array ◽  
Cherenkov Telescope ◽  
Cpu Time ◽  
Very High Energy ◽  
Under Construction ◽  
Very High

The Cherenkov Telescope Array (CTA), currently under construction, is the next-generation instrument in the field of very high energy gamma-ray astronomy. The first data are expected by the end of 2018, while the scientific operations will start in 2022 for a duration of about 30 years. In order to characterize the instrument response to the Cherenkov light emitted when cosmic ray showers develop in the atmosphere, detailed Monte Carlo simulations will be regularly performed in parallel to CTA operation. The estimated CPU time associated to these simulations is very high, of the order of 200 millions HS06 hours per year. Reducing the CPU time devoted to simulations would allow either to reduce infrastructure cost or to better cover the large phase space. In this paper, we focus on the main computing step (70% of the whole CPU time) implemented in the CORSIKA program, and specifically on the mod-ule responsible for the propagation of Cherenkov photons in the atmosphere. We present our preliminary studies about different options of code optimization, with a particular focus on vectorization facilities (SIMD instructions). Our proposals take care, as automatically as possible, of the hardware portability constraints introduced by the grid computing environment that hosts these simulations. Performance evaluation in terms of running-time and accuracy is provided.

scholarly journals Atmospheric monitoring using the Cherenkov Transparency Coefficient for the Cherenkov Telescope Array

2019 ◽  
Vol 197 ◽  
pp. 02010
Author(s):  
Stanislav Stefanik ◽  
Dalibor Nosek
Keyword(s):  
Monte Carlo ◽  
Gamma Ray ◽  
Cosmic Ray ◽  
Atmospheric Conditions ◽  
Air Showers ◽  
Atmospheric Transmission ◽  
Telescope Array ◽  
Cherenkov Telescope ◽  
Reliable Monitoring ◽  
Inherent Part

The future ground-based gamma-ray observatory, the Cherenkov Telescope Array (CTA) will require reliable monitoring of the atmosphere which is an inherent part of the detector. We discuss here the implementation of the extended method of the Cherenkov Transparency Coeffcient for the atmospheric calibration for the CTA. The method estimates the atmospheric transmission of Cherenkov light, relying on the measurement of the rates of cosmic ray-induced air showers that trigger different pairs of telescopes. We examine the performance of our approach utilizing Monte Carlo simulations assuming various atmospheric conditions and CTA observation configurations.

scholarly journals The Crab nebula variability at short time-scales with the Cherenkov telescope array

2020 ◽  
Vol 501 (1) ◽  
pp. 337-346
Author(s):  
E Mestre ◽  
E de Oña Wilhelmi ◽  
D Khangulyan ◽  
R Zanin ◽  
F Acero ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Crab Nebula ◽  
Spectral Energy Distribution ◽  
Spectral Energy ◽  
Telescope Array ◽  
Cherenkov Telescopes ◽  
Cherenkov Telescope ◽  
Emission Models ◽  
Short Time ◽  
The Crab Nebula

ABSTRACT Since 2009, several rapid and bright flares have been observed at high energies (>100 MeV) from the direction of the Crab nebula. Several hypotheses have been put forward to explain this phenomenon, but the origin is still unclear. The detection of counterparts at higher energies with the next generation of Cherenkov telescopes will be determinant to constrain the underlying emission mechanisms. We aim at studying the capability of the Cherenkov Telescope Array (CTA) to explore the physics behind the flares, by performing simulations of the Crab nebula spectral energy distribution, both in flaring and steady state, for different parameters related to the physical conditions in the nebula. In particular, we explore the data recorded by Fermi during two particular flares that occurred in 2011 and 2013. The expected GeV and TeV gamma-ray emission is derived using different radiation models. The resulting emission is convoluted with the CTA response and tested for detection, obtaining an exclusion region for the space of parameters that rule the different flare emission models. Our simulations show different scenarios that may be favourable for achieving the detection of the flares in Crab with CTA, in different regimes of energy. In particular, we find that observations with low sub-100 GeV energy threshold telescopes could provide the most model-constraining results.

The Gamma-ray Cherenkov Telescope, an end-to end Schwarzschild-Couder telescope prototype proposed for the Cherenkov Telescope Array

2016 ◽  
Author(s):  
J. L. Dournaux ◽  
A. Abchiche ◽  
D. Allan ◽  
J. P. Amans ◽  
T. P. Armstrong ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Telescope Array ◽  
Cherenkov Telescope ◽  
End To End

scholarly journals Search for point sources of ultra-high-energy photons with the Telescope Array surface detector

2020 ◽  
Vol 492 (3) ◽  
pp. 3984-3993 ◽  
Author(s):  
R U Abbasi ◽  
M Abe ◽  
T Abu-Zayyad ◽  
M Allen ◽  
R Azuma ◽  
...  
Keyword(s):  
Point Source ◽  
Cosmic Ray ◽  
High Energy ◽  
Point Sources ◽  
Ultra High Energy ◽  
Telescope Array ◽  
Air Shower ◽  
Upper Limits ◽  
Surface Detector ◽  
Blind Search

ABSTRACT The surface detector (SD) of the Telescope Array (TA) experiment allows us to detect indirectly photons with energies of the order of 1018 eV and higher, and to separate photons from the cosmic ray background. In this paper, we present the results of a blind search for point sources of ultra-high-energy (UHE) photons in the Northern sky using the TA SD data. The photon-induced extensive air showers are separated from the hadron-induced extensive air shower background by means of a multivariate classifier based upon 16 parameters that characterize the air shower events. No significant evidence for the photon point sources is found. The upper limits are set on the flux of photons from each particular direction in the sky within the TA field of view, according to the experiment’s angular resolution for photons. The average 95 per cent confidence level upper-limits for the point-source flux of photons with energies greater than 1018, 1018.5, 1019, 1019.5 and 1020 eV are 0.094, 0.029, 0.010, 0.0073 and 0.0058 km−2yr−1, respectively. For energies higher than 1018.5 eV, the photon point-source limits are set for the first time. Numerical results for each given direction in each energy range are provided as a supplement to this paper.

Formation History of Binary Clusters in the Large Magellanic Cloud

2018 ◽  
Vol 14 (S344) ◽  
pp. 118-121
Author(s):  
Rhorom Priyatikanto ◽  
Mochamad Ikbal Arifyanto ◽  
Rendy Darma ◽  
Aprilia ◽  
Muhamad Irfan Hakim
Keyword(s):  
Binary Star ◽  
Cluster Formation ◽  
Formation Rate ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Small Magellanic Cloud ◽  
Star Forming ◽  
Binary Clusters ◽  
Formation History ◽  
History Of

AbstractGlobal history of star or cluster formation in the Large Magellanic Cloud (LMC) has been the center of interest in several studies as it is thought to be influenced by tidal interaction with the Small Magellanic Cloud and even the Milky Way. This study focus on the formation history of the LMC in relation with the context of binary star clusters population, the apparent binary fraction (e.g., percentage of cluster pairs) in different epoch were calculated and analyzed. From the established distributions, it can be deduced that the binary clusters tend to be young (∽ 100 Myr) while their locations coincide with the locations of star forming complexes. There is an indication that the binary fraction increases as the rise of star formation rate in the last millions years. In the LMC, the increase of binary fraction at age ∽ 100 Myr can be associated to the last episode of close encounter with the Small Magellanic Cloud at ∽ 150 Myr ago. This observational evidence supports the theory of binary cluster formation through the fission of molecular cloud where the encounter between galaxies enhanced the clouds velocity dispersion which in turn increased the probability of cloud-cloud collisions that produce binary clusters.

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