561 research outputs found
Solid state bistable power switch
Tin and copper provide high current and switching time capabilities for high-current resettable fuses. They show the best performance for trip current and degree of reliability, and have low coefficients of thermal expansion
Solid state bistable power switch study
Feasibility of transforming solid state switches into high current resettable fuse
Study of the performance and capability of the new ultra-fast 2 GSample/s FADC data acquisition system of the MAGIC telescope
In February 2007 the MAGIC Air Cherenkov Telescope for gamma-ray astronomy
was fully upgraded with an ultra fast 2 GSamples/s digitization system. Since
the Cherenkov light flashes are very short, a fast readout can minimize the
influence of the background from the light of the night sky. Also, the time
structure of the event is an additional parameter to reduce the background from
unwanted hadronic showers. An overview of the performance of the new system and
its impact on the sensitivity of the MAGIC instrument will be presented.Comment: Contribution to the 30th ICRC, Merida Mexico, July 2007 on behalf of
the MAGIC Collaboratio
Observation of Galactic Sources of Very High Energy Gamma-Rays with the MAGIC Telescope
The MAGIC telescope with its 17m diameter mirror is today the largest
operating single-dish Imaging Air Cherenkov Telescope (IACT). It is located on
the Canary Island La Palma, at an altitude of 2200m above sea level, as part of
the Roque de los Muchachos European Northern Observatory. The MAGIC telescope
detects celestial very high energy gamma-radiation in the energy band between
about 50 GeV and 10 TeV. Since the autumn of 2004 MAGIC has been taking data
routinely, observing various objects, like supernova remnants (SNRs), gamma-ray
binaries, Pulsars, Active Galactic Nuclei (AGN) and Gamma-ray Bursts (GRB). We
briefly describe the observational strategy, the procedure implemented for the
data analysis, and discuss the results of observations of Galactic Sources.Comment: Brief Review, to be pulished in: Mod. Phys. Lett.
The orbit of the star S2 around SgrA* from VLT and Keck data
Two recent papers (Ghez et al. 2008, Gillessen et al. 2009) have estimated
the mass of and the distance to the massive black hole in the center of the
Milky Way using stellar orbits. The two astrometric data sets are independent
and yielded consistent results, even though the measured positions do not match
when simply overplotting the two sets. In this letter we show that the two sets
can be brought to excellent agreement with each other when allowing for a small
offset in the definition of the reference frame of the two data sets. The
required offsets in the coordinates and velocities of the origin of the
reference frames are consistent with the uncertainties given in Ghez et al.
(2008). The so combined data set allows for a moderate improvement of the
statistical errors of mass of and distance to Sgr A*, but the overall
accuracies of these numbers are dominated by systematic errors and the
long-term calibration of the reference frame. We obtain R0 = 8.28 +- 0.15(stat)
+- 0.29(sys) kpc and M(MBH) = 4.30 +- 0.20(stat) +- 0.30(sys) x 10^6 Msun as
best estimates from a multi-star fit.Comment: submitted to ApJ
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