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The High Energy Stereoscopic System (H.E.S.S.) is an array of five imaging atmospheric Cherenkov telescopes in Namibia observing gamma-rays in the energy range from a few tens of GeV to a few tens of TeV. The Cherenkov signal detected by…

Instrumentation and Methods for Astrophysics · Physics 2019-08-15 Justus Zorn , H. E. S. S. Collaboration

A new approach to Gamma/Hadron separation algorithms is proposed. The differences between Gamma and Hadron showers are notorious in two main aspects. The first is the wideness of the shower, and the second is the distribution of the angles…

Astrophysics · Physics 2007-07-31 S. Andringa , P. Assis , M. Pimenta , A. Pina , B. Tome

Cherenkov Telescope Array (CTA) is an upcoming instrument that will start a new generation of atmospheric Cherenkov telescopes. CTA is expected not only to provide an unprecedented sensitivity in the tens of GeV to hundreds of TeV range,…

Instrumentation and Methods for Astrophysics · Physics 2019-07-11 Julian Sitarek , Dorota Sobczyńska , Katarzyna Adamczyk , Michał Szanecki

The energy-dependent abundance of elements in cosmic rays plays an important role in understanding their acceleration and propagation. Most current results are obtained either from direct measurements by balloon- or satellite-borne…

Instrumentation and Methods for Astrophysics · Physics 2019-08-13 Henrike Fleischhack

The time profiles of Cherenkov images of cosmic-ray showers and of gamma-ray showers are investigated, using data gathered with the HEGRA system of imaging atmospheric Cherenkov telescopes during the 1997 outbursts of Mrk 501. Photon…

Astrophysics · Physics 2009-10-31 HEGRA Collaboration , M. Hess et al

Atmospheric fluorescence is usually neglected in the reconstruction of the signals registered by Cherenkov telescopes, both IACTs and wide-angle detector arrays. In this paper we quantify the fluorescence contribution to the total light…

Instrumentation and Methods for Astrophysics · Physics 2018-12-10 Daniel Morcuende , Jaime Rosado , José Luis Contreras , Fernando Arqueros

A detailed case study of $\gamma$-hadron segregation for a ground based atmospheric Cherenkov telescope is presented. We have evaluated and compared various supervised machine learning methods such as the Random Forest method, Artificial…

Instrumentation and Methods for Astrophysics · Physics 2015-06-23 Mradul Sharma , J. Nayak , M. K. Koul , S. Bose , Abhas Mitra

We propose a new approach, based on the Hanbury Brown and Twiss intensity interferometry, to transform a Cherenkov telescope to its equivalent optical telescope. We show that, based on the use of photonics components borrowed from…

Instrumentation and Methods for Astrophysics · Physics 2021-05-26 Pierre-Marie Gori , Farrokh Vakili , Jean-Pierre Rivet , William Guerin , Mathilde Hugbart , Andrea Chiavassa , Adrien Vakili , Robin Kaiser , Guillaume Labeyrie

A wide field-of-view Cherenkov telescope has been working in the surroundings of the Yakutsk array experiment since 2012. Its main function is to measure the waveform of the Cherenkov radiation signal induced by extensive air showers of…

Instrumentation and Methods for Astrophysics · Physics 2022-03-01 A. A. Ivanov , S. V. Matarkin , L. V. Timofeev

Water Cherenkov detectors like Super-Kamiokande, and the next generation Hyper-Kamiokande are adding gadolinium to their water to improve the detection of neutrons. By detecting neutrons in addition to the leptons in neutrino interactions,…

Instrumentation and Detectors · Physics 2023-01-16 Blair Jamieson , Matt Stubbs , Sheela Ramanna , John Walker , Nick Prouse , Ryosuke Akutsu , Patrick de Perio , Wojciech Fedorko

We have developed a method for the linear reconstruction of an image from undersampled, dithered data, which has been used to create the distributed, combined Hubble Deep Field images -- the deepest optical images yet taken of the universe.…

Astrophysics · Physics 2015-06-24 Andrew Fruchter , Richard Hook

We present a framework for the optimal filtering of spherical signals contaminated by realizations of an additive, zero-mean, uncorrelated and anisotropic noise process on the sphere. Filtering is performed in the wavelet domain given by…

Signal Processing · Electrical Eng. & Systems 2021-02-09 Adeem Aslam , Zubair Khalid , Jason D. McEwen

This work is a methodical study on hybrid reconstruction techniques for hybrid imaging/timing Cherenkov observations. This type of hybrid array is to be realized at the gamma-observatory TAIGA intended for very high energy gamma-ray…

Instrumentation and Methods for Astrophysics · Physics 2018-08-29 E. B. Postnikov , A. A. Grinyuk , L. A. Kuzmichev , L. G. Sveshnikova

Hyperspectral images often have hundreds of spectral bands of different wavelengths captured by aircraft or satellites that record land coverage. Identifying detailed classes of pixels becomes feasible due to the enhancement in spectral and…

Computer Vision and Pattern Recognition · Computer Science 2022-04-21 Raymond H. Chan , Ruoning Li

Image Fusion, a technique which combines complimentary information from different images of the same scene so that the fused image is more suitable for segmentation, feature extraction, object recognition and Human Visual System. In this…

Information Theory · Computer Science 2008-12-04 R. Balasubramanian , Gaurav Bhatnagar

Wavelet functions allow the sparse and efficient representation of a signal at different scales. Recently the application of wavelets to the denoising of maps of cosmic microwave background (CMB) fluctuations has been proposed. The…

Astrophysics · Physics 2009-11-07 Klaus Maisinger , M. P. Hobson , A. N. Lasenby

Indirect detection of gamma rays with ground-based observatories is currently the most sensitive experimental approach to characterize the gamma-ray sky at energies $>0.1$\,TeV. Ground-based detection of gamma-rays relies on the…

High Energy Astrophysical Phenomena · Physics 2024-01-10 Manel Errando , Takayuki Saito

We compared convolutional neural networks to the classical boosted decision trees for the separation of atmospheric particle showers generated by gamma rays from the particle-induced background. We conduct the comparison of the two…

Instrumentation and Methods for Astrophysics · Physics 2020-08-26 Etienne Lyard , Roland Walter , Vitalii Sliusar , Nicolas Produit

We present a new method for the analysis of images, a fundamental task in observational astronomy. It is based on the linear decomposition of each object in the image into a series of localised basis functions of different shapes, which we…

Astrophysics · Physics 2008-11-26 Alexandre Refregier

We consider wavelets as a tool to perform a variety of tasks in the context of analyzing cosmic microwave background (CMB) maps. Using Spherical Haar Wavelets we define a position and angular-scale-dependent measure of power that can be…

Astrophysics · Physics 2009-10-31 L. Tenorio , A. H. Jaffe , S. Hanany , C. H. Lineweaver
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