oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2019 ( 124 )

2018 ( 703 )

2017 ( 694 )

2016 ( 966 )

Custom range...

Search Results: 1 - 10 of 400785 matches for " M. Garczarczyk "
All listed articles are free for downloading (OA Articles)
Page 1 /400785
Display every page Item
Field test of the hybrid photodetector R9792U-40 on the MAGIC camera
T. Y. Saito,S. Sun,R. Orito,E. Lorenz,R. Mirzoyan,M. Teshima,M. Garczarczyk,for the MAGIC Collaboration
Physics , 2011, DOI: 10.7529/ICRC2011/V09/1212
Abstract: The hybrid photodetector (HPD) R9792U-40 has very high peak quantum efficiency ($>50$% at 500 nm), excellent charge resolution and very low after-pulsing probability (500 times less than that of currently used photomultipliers (PMTs)). These features will improve the sensitivity, the energy resolution and the energy threshold of the MAGIC telescope. On the other hand, its high photocathode voltage (-8 to -6 kV), relatively short photocathode lifetime, and relatively large temperature dependence of the gain need to be taken care of. In February 2010, 6 HPDs were installed in a corner of the MAGIC-II camera for a field test. Here we report the results of the field test and our future plans.
Gamma-ray burst observations with new generation imaging atmospheric Cerenkov Telescopes in the FERMI era
S. Covino,M. Garczarczyk,N. Galante,M. Gaug,A. Antonelli,D. Bastieri,S. Campana,F. Longo,V. Scapin
Physics , 2009, DOI: 10.1063/1.3125779
Abstract: After the launch and successful beginning of operations of the FERMI satellite, the topics related to high-energy observations of gamma-ray bursts have obtained a considerable attention by the scientific community. Undoubtedly, the diagnostic power of high-energy observations in constraining the emission processes and the physical conditions of gamma-ray burst is relevant. We briefly discuss how gamma-ray burst observations with ground-based imaging array Cerenkov telescopes, in the GeV-TeV range, can compete and cooperate with FERMI observations, in the MeV-GeV range, to allow researchers to obtain a more detailed and complete picture of the prompt and afterglow phases of gamma-ray bursts.
Atmospheric Monitoring for the MAGIC Telescopes
M. Gaug,O. Blanch,D. Dorner,M. Doro,Ll. Font,C. Fruck,M. Garczarczyk,D. Garrido,D. Hrupec,J. Hose,A. López-Oramas,G. Maneva,M. Martinez,R. Mirzoyan,P. Temnikov,R. Zanin
Physics , 2014,
Abstract: The monitoring of the atmosphere is very relevant for Imaging Atmospheric Cherenkov Telescopes. Adverse weather conditions (strong wind, high humidity, etc.) may damage the telescopes and must therefore be monitored continuously to guarantee a safe operation, and the presence of clouds and aerosols affects the transmission of the Cherenkov light and consequently the performance of the telescopes. The ATmospheric CAlibration (ATCA) technical working group of the MAGIC collaboration aims to cover all aspects related to atmosphere monitoring and calibration. In this paper we give an overview of the ATCA goals and activities, which include the set-up and maintenance of appropriate instrumentation, proper analysis of its data, the realization of MC studies, and the correction of real data taken under non-optimal atmospheric conditions. The final goal is to reduce the systematic uncertainties in the determination of the $\gamma$-ray flux and energy, and to increase the duty cycle of the telescopes by establishing optimized data analysis methods specific for real atmospheric conditions.
MAGIC low energy observation of GRB090102 afterglow
A. Carosi,L. A. Antonelli,U. Barres de Almeida,D. Bastieri,J. Becerra González,E. Colombo,M. Garczarczyk,S. Covino,A La Barbera,S. Spiro,A. Domínguez,M. Gaug,F. Longo,V. Scapin,for the MAGIC collaboration
Physics , 2011,
Abstract: Hints for a GeV component in the emission from GRBs are known since the EGRET observations during the '90s and they have been recently confirmed by the data of the Fermi satellite. These results have, however, shown that a fully satisfactory interpretative framework of the GRB phenomena is still lacking. The MAGIC telescope opens the possibility to extend the measurement of GRBs in the several tens up to hundreds of GeV energy range. From the theoretical point of view, both leptonic and hadronic processes have been suggested to explain the possible GeV/TeV counterpart of GRBs. Observations with ground-based telescopes of very high energy photons (E>30 GeV) from these sources are going to play a key role in discriminating among the different proposed emission mechanisms which are barely distinguishable at lower energies. MAGIC telescope observations of the GRB090102 (z=1.547) field from 03:14:52 UT to 06:54:01 UT are analyzed to derive upper limits to the GeV/TeV emission. We compare these results to the expected emissions evaluated for different processes in the framework of the standard fireball model. The results we obtained are compatible with the expected emission but cannot yet set further constraints on the theoretical scenario. However, the difficulty in modeling the low energy data for this event makes it difficult to fix in an unambiguous way the physical parameters which describe the fireball. Nonetheless, the MAGIC telescope, thanks to its low energy threshold and fast repositioning, is opening for the first time the possibility to fill the energy gap between space-based gamma detectors and the ground-based measurements. This will makes possible GRBs multiwavelength studies in the very high energy domain.
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.
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.
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.
Status of the technologies for the production of the Cherenkov Telescope Array (CTA) mirrors
G. Pareschi,T. Armstrong,H. Baba,J. B?hr,A. Bonardi,G. Bonnoli,P. Brun,R. Canestrari,P. Chadwick,M. Chikawa,P. -H. Carton,V. de Souza,J. Dipold,M. Doro,D. Durand,M. Dyrda,A. F?rster,M. Garczarczyk,E. Giro,J. -F. Glicenstein,Y. Hanabata,M. Hayashida,M. Hrabovski,C. Jeanney,M. Kagaya,H. Katagiri,L. Lessio,D. Mandat,M. Mariotti,C. Medina,J. Micha?owski,P. Micolon,D. Nakajima,J. Niemiec,A. Nozato,M. Palatka,M. Pech,B. Peyaud,G. Pühlhofer,M. Rataj,G. Rodeghiero,G. Rojas,J. Rousselle,R. Sakonaka,P. Schovanek,K. Seweryn,C. Schultz,S. Shu,F. Stinzing,M. Stodulski,M. Teshima,P. Travniczek,C. van Eldik,V. Vassiliev,?. Wi?niewski,A. W?rnlein,T. Yoshida
Physics , 2013, DOI: 10.1117/12.2025476
Abstract: The Cherenkov Telescope Array (CTA) is the next generation very high-energy gamma-ray observatory, with at least 10 times higher sensitivity than current instruments. CTA will comprise several tens of Imaging Atmospheric Cherenkov Telescopes (IACTs) operated in array-mode and divided into three size classes: large, medium and small telescopes. The total reflective surface could be up to 10,000 m2 requiring unprecedented technological efforts. The properties of the reflector directly influence the telescope performance and thus constitute a fundamental ingredient to improve and maintain the sensitivity. The R&D status of lightweight, reliable and cost-effective mirror facets for the CTA telescope reflectors for the different classes of telescopes is reviewed in this paper.
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.
Page 1 /400785
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.