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Search Results: 1 - 10 of 5510 matches for " Markus Garczarczyk "
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Status of the Medium-Sized Telescope for the Cherenkov Telescope Array
Markus Garczarczyk,Stefan Schlenstedt,Louise Oakes,Ullrich Schwanke,the MST Team
Physics , 2015,
Abstract: The Cherenkov Telescope Array (CTA), is an international project for the next generation ground- based observatory for gamma-ray astronomy in the energy range from 20 GeV to 300 TeV. The sensitivity in the core energy range will be dominated by up to 40 Medium-Sized Telescopes (MSTs). The MSTs, of Davies-Cotton type with a 12 m diameter reflector are currently in the prototype phase. A full-size mechanical telescope structure has been assembled in Berlin. The telescope is partially equipped with different mirror prototypes, which are currently being tested and evaluated for performances characteristics. A report concentrating on the details of the tele- scope structure, the drive assemblies and the optics of the MST prototype will be given.
Upgrade of the MAGIC telescopes
Daniel Mazin,Diego Tescaro,Markus Garczarczyk,Gianluca Giavitto,Julian Sitarek,for the MAGIC Collaboration
Physics , 2014,
Abstract: The MAGIC telescopes are two Imaging Atmospheric Cherenkov Telescopes (IACTs) located on the Canary island of La Palma. With 17m diameter mirror dishes and ultra-fast electronics, they provide an energy threshold as low as 50 GeV for observations at low zenith angles. The first MAGIC telescope was taken in operation in 2004 whereas the second one joined in 2009. In 2011 we started a major upgrade program to improve and to unify the stereoscopic system of the two similar but at that time different telescopes. Here we report on the upgrade of the readout electronics and digital trigger of the two telescopes, the upgrade of the camera of the MAGIC I telescope as well as the commissioning of the system after this major upgrade.
MAGIC observation of GRB080430
Stefano Covino,Markus Garczarczyk,Markus Gaug,Angelo Antonelli,Denis Bastieri,Josefa Becerra-Gonzalez,Antonio La Barbera,Alessandro Carosi,Nicola Galante,Francesco Longo,Valeria Scapin,Susanna Spiro,Antonio de Ugarte-Postigo,Alessandra Galli,R. Salvaterra
Physics , 2009,
Abstract: Gamma-ray bursts are cosmological sources emitting radiation from the gamma-rays to the radio band. Substantial observational efforts have been devoted to the study of GRBs during the prompt phase, i.e. the initial burst of high-energy radiation, and during the longer-lasting afterglows. In spite of many successes in interpreting these phenomena there are still several open key questions about the fundamental emission processes, their energetics and the environment. Moreover, independently of their modeling, GRB spectra are remarkably simple, being satisfactorily fitted with power-laws, and therefore offer a very valuable tool to probe the extragalactic background light distribution affecting all high-energy observations of cosmological sources. Observations carried out with Cherenkov telescopes, as MAGIC, can be fundamental for all these scientific topics. GRB080430, being at a rather moderate redshift, z~0.76, and well-studied in the optical, although observed only a few hours after the high-energy event, is a good test case to evaluate the perspective for late-afterglow observations with ground based GeV/TeV observatories.
MAGIC observation of GRB090102
Markus Gaug,Stefano Covino,Markus Garczarczyk,Angelo Antonelli,Denis Bastieri,Antonio La Barbera,Josefa Becerra-Gonzalez,Alessandro Carosi,Nicola Galante,Francesco Longo,Valeria Scapin,Susanna Spiro,for the MAGIC Collaboration
Physics , 2009,
Abstract: On January 2, the MAGIC-I Telescope observed GRB090102 (z=1.55) under particularly good observation conditions. Using the recently upgraded MAGIC-1 sum trigger system, upper limits down to below 50 GeV have been obtained. This is the first time that the new trigger system was fully exploited for a Gamma-ray Burst (GRB) observation and shows the capabilities of the MAGIC observatory for future follow-up observations.
GRB Observations with the MAGIC Telescopes
Markus Garczarczyk,Markus Gaug,Angelo Antonelli,Denis Bastieri,Josefa Becerra-Gonzalez,Stefano Covino,Antonio La Barbera,Alessandro Carosi,Nicola Galante,Francesco Longo,Valeria Scapin,Susanna Spiro,for the MAGIC Collaboration
Physics , 2009,
Abstract: MAGIC is currently the most suitable instrument to perform observations of the prompt an early afterglow emission from Gamma Ray Bursts (GRBs) at energies above 25 GeV. The instrument is designed to have the lowest possible energy threshold and fastest reaction time to GRB Coordinates Network (GCN) alerts. The MAGIC-I telescope started to follow-up GCN alerts in the beginning of 2005. Since then, more than 50 GRB candidates were observed. Just now MAGIC-II, the second telescope has started to operate. Both telescopes together will have a factor of three better sensitivity.
Instrumentation for comparing night sky quality and atmospheric conditions of CTA site candidates
Christian Fruck,Markus Gaug,Jean-Pierre Ernenwein,Du?an Mandát,Thomas Schweizer,Dennis H?fner,Tomasz Bulik,Marek Cieslar,Heide Costantini,Michal Dominik,Jan Ebr,Markus Garczarczyk,Eckart Lorentz,Giovanni Pareschi,Miroslav Pech,Irene Puerto-Giménez,Masahiro Teshima
Physics , 2015, DOI: 10.1088/1748-0221/10/04/P04012
Abstract: Many atmospheric and climatic criteria have to be taken into account for the selection of a suitable site for the next generation of imaging air-shower Cherenkov telescopes, the "Cherenkov Telescope Array" CTA. Such data are not available with sufficient precision, thus a comparison of the proposed sites and final decision based on a comprehensive characterization is impossible. Identical cross-calibrated instruments have been developed which allow for precise comparison between sites, the cross-validation of existing data, and the ground-validation of satellite data. The site characterization work package of the CTA consortium opted to construct and deploy 9 copies of an autonomous multi-purpose weather sensor, incorporating an infrared cloud sensor, a newly developed sensor for measuring the light of the night sky, and an All-Sky-Camera, the whole referred to as Autonomous Tool for Measuring Observatory Site COnditions PrEcisely (ATMOSCOPE). We present here the hardware that was combined into the ATMOSCOPE and characterize its performance.
Gamma-Ray Burst Science in the Era of the Cherenkov Telescope Array
Susumu Inoue,Jonathan Granot,Paul T. O'Brien,Katsuaki Asano,Aurelien Bouvier,Alessandro Carosi,Valerie Connaughton,Markus Garczarczyk,Rudy Gilmore,Jim Hinton,Yoshiyuki Inoue,Kunihito Ioka,Jun Kakuwa,Sera Markoff,Kohta Murase,Julian P. Osborne,A. Nepomuk Otte,Rhaana Starling,Hiroyasu Tajima,Masahiro Teshima,Kenji Toma,Stefan Wagner,Ralph A. M. J. Wijers,David A. Williams,Tokonatsu Yamamoto,Ryo Yamazaki,for the CTA Consortium
Physics , 2013, DOI: 10.1016/j.astropartphys.2013.01.004
Abstract: We outline the science prospects for gamma-ray bursts (GRBs) with the Cherenkov Telescope Array (CTA), the next-generation ground-based gamma-ray observatory operating at energies above few tens of GeV. With its low energy threshold, large effective area and rapid slewing capabilities, CTA will be able to measure the spectra and variability of GRBs at multi-GeV energies with unprecedented photon statistics, and thereby break new ground in elucidating the physics of GRBs, which is still poorly understood. Such measurements will also provide crucial diagnostics of ultra-high-energy cosmic ray and neutrino production in GRBs, advance observational cosmology by probing the high-redshift extragalactic background light and intergalactic magnetic fields, and contribute to fundamental physics by testing Lorentz invariance violation with high precision. Aiming to quantify these goals, we present some simulated observations of GRB spectra and light curves, together with estimates of their detection rates with CTA. Although the expected detection rate is modest, of order a few GRBs per year, hundreds or more high-energy photons per burst may be attainable once they are detected. We also address various issues related to following up alerts from satellites and other facilities with CTA, as well as follow-up observations at other wavelengths. The possibility of discovering and observing GRBs from their onset including short GRBs during a wide-field survey mode is also briefly discussed.
On the Ontology of Structural Realism  [PDF]
Markus Fischer
Open Journal of Political Science (OJPS) , 2019, DOI: 10.4236/ojps.2019.91008
Abstract: Due to its systemic approach, structural realism (or neorealism) can be subsumed under methodological holism, which takes social phenomena to be wholes that cannot be reduced to their parts. The wholes posited by structural realism are the state and the international structure. Recent developments in the philosophy of social science suggest that methodological holism ought to be limited to causal explanation and complemented by ontological individualism, which requires an account of how social wholes derive from individuals. Structural realism lacks such an account because it takes the state as an empirical given, mistaking for a fact what is really a concept in need of deductive derivation from individuals. To bring the theory methodologically up to date, this essay undertakes such a derivation of the state from individuals, proceeding in the deductive manner of political theory. It thus provides structural realism with a methodologically valid ontology, which, in turn, enables the theory to better defend itself against liberal and constructivist critics who reduce the state to a transient phenomenon.
Discretisation of stochastic control problems for continuous time dynamics with delay
Markus Fischer,Markus Reiss
Mathematics , 2006,
Abstract: As a main step in the numerical solution of control problems in continuous time, the controlled process is approximated by sequences of controlled Markov chains, thus discretising time and space. A new feature in this context is to allow for delay in the dynamics. The existence of an optimal strategy with respect to the cost functional can be guaranteed in the class of relaxed controls. Weak convergence of the approximating extended Markov chains to the original process together with convergence of the associated optimal strategies is established.
Spectral covolatility estimation from noisy observations using local weights
Markus Bibinger,Markus Rei?
Statistics , 2011,
Abstract: We propose localized spectral estimators for the quadratic covariation and the spot covolatility of diffusion processes which are observed discretely with additive observation noise. The eligibility of this approach to lead to an appropriate estimation for time-varying volatilities stems from an asymptotic equivalence of the underlying statistical model to a white noise model with correlation and volatility processes being constant over small intervals. The asymptotic equivalence of the continuous-time and the discrete-time experiments are proved by a construction with linear interpolation in one direction and local means for the other. The new estimator outperforms earlier nonparametric approaches in the considered model. We investigate its finite sample size characteristics in simulations and draw a comparison between the various proposed methods.
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