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We present a new approach to the pointing determination of Imaging Atmospheric Cherenkov Telescopes (IACTs). This method is universal and can be applied to any IACT with minor modifications. It uses the trajectories of the stars in the…

Instrumentation and Methods for Astrophysics · Physics 2023-10-09 Mykhailo Dalchenko , Matthieu Heller

Applying the standard weighted mean formula, [sum_i {n_i sigma^{-2}_i}] / [sum_i {sigma^{-2}_i}], to determine the weighted mean of data, n_i, drawn from a Poisson distribution, will, on average, underestimate the true mean by ~1 for all…

Astrophysics · Physics 2009-10-31 Kenneth J. Mighell

The key features of the MATPHOT algorithm for precise and accurate stellar photometry and astrometry using discrete Point Spread Functions are described. A discrete Point Spread Function (PSF) is a sampled version of a continuous PSF which…

Astrophysics · Physics 2009-11-11 Kenneth J. Mighell

The luminosity functions of galaxies and quasars provide invaluable information about galaxy and quasar formation. Estimating the luminosity function from magnitude limited samples is relatively straightforward, provided that the distances…

Astrophysics · Physics 2008-11-26 Ravi K. Sheth

We describe a straightforward modification of frequently invoked methods for the determination of the statistical significance of a gamma-ray signal observed in a counting process. A simple criterion is proposed to decide whether a set of…

Instrumentation and Methods for Astrophysics · Physics 2015-09-02 Dalibor Nosek , Stanislav Stefanik , Jana Nosková

The High Altitude Water Cherenkov (HAWC) Observatory continuously observes gamma-rays between 100 GeV to 100 TeV in an instantaneous field of view of about 2 steradians above the array. The large amount of raw data, the importance of small…

Instrumentation and Methods for Astrophysics · Physics 2019-08-14 Patrick W. Younk , Robert J. Lauer , Giacomo Vianello , J. Patrick Harding , Hugo Alberto Ayala Solares , Hao Zhou , Michelle Hui

In astronomy multiple images are frequently obtained at the same position of the sky for follow-up co-addition as it helps one go deeper and look for fainter objects. With large scale panchromatic synoptic surveys becoming more common,…

Astrophysics · Physics 2007-05-23 G. Jogesh Babu , Ashish Mahabal , S. G. Djorgovski , R. Williams

The main goal of the LISA Pathfinder (LPF) mission is to fully characterize the acceleration noise models and to test key technologies for future space-based gravitational-wave observatories similar to the eLISA concept. The data analysis…

Precise knowledge of the point spread function (PSF) underpins many data analysis steps in astronomy, from photometry and astrometry to source de-blending and deconvolution. In adaptive optics (AO) observations, however, the PSF is highly…

Instrumentation and Methods for Astrophysics · Physics 2026-04-02 Arseniy Kuznetsov , Benoit Neichel , Sylvain Oberti , Thierry Fusco

We describe a Bayesian approach to estimating luminosity functions. We derive the likelihood function and posterior probability distribution for the luminosity function, given the observed data, and we compare the Bayesian approach with…

Astrophysics · Physics 2009-11-13 Brandon C. Kelly , Xiaohui Fan , Marianne Vestergaard

Monte Carlo is a versatile and frequently used tool in statistical physics and beyond. Correspondingly, the number of algorithms and variants reported in the literature is vast, and an overview is not easy to achieve. In this pedagogical…

Statistical Mechanics · Physics 2010-01-04 Michael Kastner

Imaging atmospheric Cherenkov telescopes are continuously exposed to varying weather conditions that have short and long-term effects on their response to Cherenkov light from extensive air showers. This work presents the implementation of…

Instrumentation and Methods for Astrophysics · Physics 2022-09-21 M. Nievas Rosillo

The Atmospheric Cherenkov Imaging Technique has opened up the gamma-ray spectrum from 100 GeV to 50 TeV to astrophysical exploration. The development of the technique (with emphasis on the early days) is described as are the basic…

Astrophysics · Physics 2016-11-09 Trevor C. Weekes

Field-level inference is emerging as a promising technique for optimally extracting information from cosmological datasets. Indeed, previous analyses have shown field-based inference produces tighter parameter constraints than power…

Cosmology and Nongalactic Astrophysics · Physics 2023-07-04 Supranta S. Boruah , Eduardo Rozo

Imaging air Cherenkov telescopes (IACTs) detect the Cherenkov light from extensive air showers (EAS) initiated by very high energy (VHE) gamma-rays impinging on the Earth's atmosphere. Due to the overwhelming background from hadron induced…

Imaging Air Cherenkov Telescopes (IACTs) detect very high energetic (VHE) gamma rays. They observe the Cherenkov light emitted in electromagnetic shower cascades that gamma rays induce in the atmosphere. A precise reconstruction of the…

Instrumentation and Methods for Astrophysics · Physics 2023-05-01 Fabian Leuschner , Johannes Schäfer , Simon Steinmassl , Tim Lukas Holch , Konrad Bernlöhr , Stefan Funk , Jim Hinton , Stefan Ohm , Gerd Pühlhofer

A stochastic algorithm is proposed, finding the set of generalized means associated to a probability measure on a compact Riemannian manifold M and a continuous cost function on the product of M by itself. Generalized means include p-means…

Probability · Mathematics 2013-05-28 Marc Arnaudon , Laurent Miclo

The Cherenkov Telescope Array (CTA) will be the next generation ground-based very-high-energy gamma-ray observatory, constituted by tens of Imaging Atmospheric Cherenkov Telescopes at two sites once its construction and commissioning are…

Instrumentation and Methods for Astrophysics · Physics 2023-09-29 Rune Michael Dominik , Maximilian Linhoff , Julian Sitarek

We present a stacking method that makes use of co-added maps of gamma-ray counts produced from data taken with the Fermi Large Area Telescope. Sources with low integrated gamma-ray fluxes that are not detected individually may become…

Instrumentation and Methods for Astrophysics · Physics 2015-06-11 B. Huber , C. Farnier , A. Manalaysay , U. Straumann , R. Walter

Next-generation cosmological surveys will observe larger cosmic volumes than ever before, enabling us to access information on the primordial Universe, as well as on relativistic effects. In a companion paper, we applied a Fisher analysis…

Cosmology and Nongalactic Astrophysics · Physics 2021-12-03 Jan-Albert Viljoen , José Fonseca , Roy Maartens