The MAGIC telescope reflecting surface Bigongiari, C.; Bastieri, D.; Galante, N. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
02/2004, Volume:
518, Issue:
1
Journal Article
Peer reviewed
The Major Atmospheric Gamma Imaging Cherenkov telescope will achieve an energy threshold lower than any other present IACT
(E
Th
∼30
Gev)
thanks to the largest reflecting surface, a
17
m
diameter, ...f/1, tessellated parabolic reflector. The tiles are
50
cm×50
cm
all-aluminum spherical mirrors with different radii of curvature to best fit the paraboloid. The technology used to make these mirrors and the method used to measure their optical properties, as the focal length, the spot size and the reflectivity, are described. The results of these measurements are shown.
The ASTRI (Astrofisica con Specchi a Tecnologia Replicante Italiana) Mini-Array will be composed of nine imaging atmospheric Cherenkov telescopes at the Observatorio del Teide site. The array will be ...best suited for astrophysical observations in the 0.3–200 TeV range with an angular resolution of few arc-minutes and an energy resolution of 10-15%. A core-science programme in the first four years will be devoted to a limited number of key targets, addressing the most important open scientific questions in the very-high energy domain. At the same time, thanks to a wide field of view of about 10∘, ASTRI Mini-Array will observe many additional field sources, which will constitute the basis for the long-term observatory programme that will eventually cover all the accessible sky. In this paper, we review different astrophysical Galactic environments, e.g. pulsar wind nebulae, supernova remnants, and gamma-ray binaries, and show the results from a set of ASTRI Mini-Array simulations of some of these field sources made to highlight the expected performance of the array (even at large offset angles) and the important additional observatory science that will complement the core-science program.
The ASTRI Mini-Array is a next-generation system of nine imaging atmospheric Cherenkov telescopes that is going to be built at the Observatorio del Teide site. After a first phase, in which the ...instrument will be operated as an experiment prioritizing a schedule of primary science cases, an observatory phase is foreseen in which other significant targets will be pointed. We focus on the observational feasibility of extragalactic sources and on astrophysical processes that best complement and expand the ASTRI Mini-Array core science, presenting the most relevant examples that are at reach of detection over long-term time scales and whose observation can provide breakthrough achievements in the very-high energy extragalactic science. Such examples cover a wide range of γ-ray emitters, including the study of AGN low states in the multi-TeV energy range, the possible detection of Seyfert galaxies with long exposures and the searches of dark matter lines above 10 TeV. Simulations of the presented objects show that the instrument performance will be competitive at multi-TeV energies with respect to current arrays of Cherenkov telescopes.
We present the first results from very-high-energy observations of the dwarf spheroidal satellite candidate Triangulum II with the MAGIC telescopes from 62.4 h of good-quality data taken between ...August 2016 and August 2017. We find no gamma-ray excess in the direction of Triangulum II, and upper limits on both the differential and integral gamma-ray flux are presented. Currently, the kinematics of Triangulum II are affected by large uncertainties leading to a bias in the determination of the properties of its dark matter halo. Using a scaling relation between the annihilation J-factor and heliocentric distance of well-known dwarf spheroidal galaxies, we estimate an annihilation J-factor for Triangulum II for WIMP dark matter of logJann(0.5°)∕GeV2cm−5=19.35±0.37. We also derive a dark matter density profile for the object relying on results from resolved simulations of Milky Way sized dark matter halos. We obtain 95% confidence-level limits on the thermally averaged annihilation cross section for WIMP annihilation into various Standard Model channels. The most stringent limits are obtained in the τ−τ+ final state, where a cross section for annihilation down to 〈σannv〉=3.05×10−24 cm3 s−1 is excluded.
ANTARES is a high-energy neutrino telescope installed in the Mediterranean Sea at a depth of 2475m. It consists of a three-dimensional array of optical modules, each containing a large ...photomultiplier tube. A total of 2700 front-end ASICs named analogue ring samplers (ARS) process the phototube signals, measure their arrival time, amplitude and shape as well as perform monitoring and calibration tasks. The ARS chip processes the analogue signals from the optical modules and converts information into digital data. All the information is transmitted to shore through further multiplexing electronics and an optical link. This paper describes the performance of the ARS chip; results from the functionality and characterization tests in the laboratory are summarized and the long-term performance in the apparatus is illustrated.
Gamma ray astronomy is now at the leading edge for studies related both to fundamental physics and astrophysics. The sensitivity of gamma detectors is limited by the huge amount of background, ...constituted by hadronic cosmic rays (typically two to three orders of magnitude more than the signal) and by the accidental background in the detectors. By using the information on the temporal evolution of the Cherenkov light, the background can be reduced. We will present here the results obtained within the MAGIC experiment using a new technique for the reduction of the background. Particle showers produced by gamma rays show a different temporal distribution with respect to showers produced by hadrons; the background due to accidental counts shows no dependence on time. Such novel strategy can increase the sensitivity of present instruments.
During its first data cycle, between 2005 and the beginning of 2006, the fast repositioning system of the MAGIC telescope allowed the observation of nine different gamma-ray bursts as possible ...sources of very high energy gamma -rays. These observations were triggered by alerts from Swift, HETE-2, and INTEGRAL; they started as quickly as possible after the alerts and lasted for several minutes, with an energy threshold varying between 80 and 200 GeV, depending on the zenith angle of the burst. No evidence for gamma signals was found, and upper limits for the flux were derived for all events using the standard analysis chain of MAGIC. For the bursts with measured redshifts, the upper limits are compatible with a power-law extrapolation, when the intrinsic fluxes are evaluated taking into account the attenuation due to the scattering in the metagalactic radiation field.
A two-level pattern trigger for the MAGIC telescope Bastieri, D.; Bettini, M.; Bigongiari, C. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2001, Volume:
461, Issue:
1
Journal Article
Peer reviewed
Open access
Strong scientific motivation are pushing the second generation of ground base Cherenkov telescopes to lower as much as possible their energy threshold. MAGIC will be the biggest single telescope, in ...terms of collection area (250 m
2), foreseen for the second-half of 2001. The large collection area, the new photodetector and the electronic design will allow the telescope to lower the energy threshold below 30
GeV. For this telescope a two-level pattern trigger is designed to work in severe high pixel rate. The MAGIC trigger architecture and its implementation is presented.
The MAGIC collaboration has studied the high-frequency-peaked BL Lac object 1ES 1218+30.4, at a redshift z = 0.182, using the MAGIC imaging air Cerenkov telescope located on the Canary Island of La ...Palma. A gamma-ray signal was observed with 6.4 s significance. The differential energy spectrum for an energy threshold of 120 GeV can be fitted by a simple power law, yielding F sub(E)(E) = (8.1 c 2.1) x 10 super(-7) E/(250 GeV) super(-3.0c0.4) TeV super(-1) m super(-2) s super(-1). During the 6 days of observation in 2005 January, no time variability on timescales of days was found within the statistical errors. The observed integral flux above 350 GeV is nearly a factor of 2 below the upper limit reported by the Whipple collaboration in 2003.
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