927 research outputs found
Blazar Flaring Patterns (B-FlaP): Classifying Blazar Candidates of Uncertain type in the third Fermi-LAT catalog by Artificial Neural Networks
The Fermi Large Area Telescope (LAT) is currently the most important facility
for investigating the GeV -ray sky. With Fermi LAT more than three
thousand -ray sources have been discovered so far. 1144 () of
the sources are active galaxies of the blazar class, and 573 () are
listed as Blazar Candidate of Uncertain type (BCU), or sources without a
conclusive classification. We use the Empirical Cumulative Distribution
Functions (ECDF) and the Artificial Neural Networks (ANN) for a fast method of
screening and classification for BCUs based on data collected at -ray
energies only, when rigorous multiwavelength analysis is not available. Based
on our method, we classify 342 BCUs as BL Lacs and 154 as FSRQs, while 77
objects remain uncertain. Moreover, radio analysis and direct observations in
ground-based optical observatories are used as counterparts to the statistical
classifications to validate the method. This approach is of interest because of
the increasing number of unclassified sources in Fermi catalogs and because
blazars and in particular their subclass High Synchrotron Peak (HSP) objects
are the main targets of atmospheric Cherenkov telescopes.Comment: 18 pages, 17 figures, accepted for publication on MNRA
Gamma-ray burst observations with new generation imaging atmospheric Cerenkov Telescopes in the FERMI era
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.Comment: 9 pages, two figures. Proceeding for the 6th "Science with the New
Generation of High Energy Gamma-Ray Experiments" worksho
Status and First Results of the MAGIC Telescope
The 17 m MAGIC Cherenkov telescope for gamma ray astronomy between 30 and 300
GeV started operations in its final configuration in October 2003 and is
currently well into its calibration phase. Here I report on its present status
and its first gamma ray source detections.Comment: Contribution to the proceedings of the II Workshop on Unidentified
Gamma-Ray Sources, Hong Kong, June 1-4, 200
Many-core applications to online track reconstruction in HEP experiments
Interest in parallel architectures applied to real time selections is growing
in High Energy Physics (HEP) experiments. In this paper we describe performance
measurements of Graphic Processing Units (GPUs) and Intel Many Integrated Core
architecture (MIC) when applied to a typical HEP online task: the selection of
events based on the trajectories of charged particles. We use as benchmark a
scaled-up version of the algorithm used at CDF experiment at Tevatron for
online track reconstruction - the SVT algorithm - as a realistic test-case for
low-latency trigger systems using new computing architectures for LHC
experiment. We examine the complexity/performance trade-off in porting existing
serial algorithms to many-core devices. Measurements of both data processing
and data transfer latency are shown, considering different I/O strategies
to/from the parallel devices.Comment: Proceedings for the 20th International Conference on Computing in
High Energy and Nuclear Physics (CHEP); missing acks adde
ASTRI SST-2M prototype and mini-array simulation chain, data reduction software, and archive in the framework of the Cherenkov Telescope Array
The Cherenkov Telescope Array (CTA) is a worldwide project aimed at building
the next-generation ground-based gamma-ray observatory. Within the CTA project,
the Italian National Institute for Astrophysics (INAF) is developing an
end-to-end prototype of the CTA Small-Size Telescopes with a dual-mirror
(SST-2M) Schwarzschild-Couder configuration. The prototype, named ASTRI SST-2M,
is located at the INAF "M.C. Fracastoro" observing station in Serra La Nave
(Mt. Etna, Sicily) and is currently in the scientific and performance
validation phase. A mini-array of (at least) nine ASTRI telescopes has been
then proposed to be deployed at the Southern CTA site, by means of a
collaborative effort carried out by institutes from Italy, Brazil, and
South-Africa. The CTA/ASTRI team is developing an end-to-end software package
for the reduction of the raw data acquired with both ASTRI SST-2M prototype and
mini-array, with the aim of actively contributing to the global ongoing
activities for the official data handling system of the CTA observatory. The
group is also undertaking a massive Monte Carlo simulation data production
using the detector Monte Carlo software adopted by the CTA consortium.
Simulated data are being used to validate the simulation chain and evaluate the
ASTRI SST-2M prototype and mini-array performance. Both activities are also
carried out in the framework of the European H2020-ASTERICS (Astronomy ESFRI
and Research Infrastructure Cluster) project. A data archiving system, for both
ASTRI SST-2M prototype and mini-array, has been also developed by the CTA/ASTRI
team, as a testbed for the scientific archive of CTA. In this contribution, we
present the main components of the ASTRI data handling systems and report the
status of their development.Comment: Proceedings of the 35th International Cosmic Ray Conference (ICRC
2017), Bexco, Busan, Korea. All CTA contributions at arXiv:1709.0348
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