2,763 research outputs found
A review of the past and present MAGIC dark matter search program and a glimpse at the future
No full textThe MAGIC TeV gamma-ray telescopes have devoted several hundreds hour of
observation time in about a decade, to hunt for particle dark matter indirect
signatures in gamma rays, from various candidate targets of interest in the
sky: the galactic center, satellite galaxies, galaxy clusters and unidentified
objects in other bands. Despite the effort, no hints are present in MAGIC data.
These observation are nevertheless not unusable. MAGIC indeed derived the most
robust upper limits in the TeV range than any other instrument. These results,
for the time being, only mildly constrain some classic dark matter models, but
are of use in the construction of dark matter models for the next searches,
that consider also the negative results from accelerator and direct-detection
experiments. In the contribution, we discuss and review MAGIC results, putting
them into context, and in perspective with the next generation of ground-based
Cherenkov telescopes. We will briefly inform about future MAGIC projects
regarding dark matter searches
CTA—A project for a new generation of Cherenkov telescopes
No full textGamma-rays provide a powerful insight into the non-thermal universe and perhaps a unique probe for new physics beyond the standard model. Current experiments are already giving results in the physics of acceleration of cosmic rays in supernova remnants, pulsar and active galactic nuclei with a 100 sources detected at very-high-energies so far. Despite its relatively recent appearance, very high-energy gamma-ray astronomy has proven to have reached a mature technology with fast assembling, relatively cheap and reliable telescopes. The goal of future installation is to increase the sensitivity by a factor 10 compared to current installations, and enlarge the energy domain from few 10s of GeV to a 100 TeV. Gamma-ray spectra of astrophysical origin are rather soft thus hardly one single size telescope can cover more than 1.5 decades in energy, therefore an array of telescopes of 2–3 different sizes is required. Hereafter, we present design considerations for a Cherenkov Telescope Array (CTA), a project for a new generation of highly automated telescopes for gamma-ray astronomy. The status of the project, technical solutions and an insight in the involved physics will be presented
Rare Events searches with Cherenkov Telescopes
No full textGround-based Imaging Cherenkov Telescope Arrays observe the Cherenkov radiation emitted in extended atmospheric showers generated by cosmic gamma rays in the TeV regime. The rate of these events is normally overwhelmed by 2–3 orders of magnitude more abundant cosmic rays induced showers. A large fraction of these “back-ground” events is vetoed at the on-line trigger level, but a substantial fraction still goes through data acquisition system and is saved for the off-line reconstruction. What kind of information those events carry, normally rejected in the analysis? Is there the possibility that an exotic signature is hidden in those data? In the contribution, some science cases, and the problems related to the event reconstruction for the current and future generation of these telescopes will be discussed
Photon–Photon Interactions and the Opacity of the Universe in Gamma Rays
No full textWe discuss the topic of the transparency of the Universe in gamma rays due to extragalactic background light, and its cosmological and physical implications. Rather than a review, this is a personal account on the development of 30 years of this branch of physical science. Extensive analysis of the currently available information appears to us as revealing a global coherence among the astrophysical, cosmological, and fundamental physics data, or, at least, no evident need so far of substantial modification of our present understanding. Deeper data from future experiments will verify to what extent and in which directions this conclusion should be modified
Toward a new generation of Cherenkov telescopes with CTA
No full textGamma-rays provide a powerful insight into the non-thermal uni- verse and a valid probe for new physics beyond the standard model. Despite its relatively recent appearance, very high energy (VHE) gamma-ray astronomy from the ground has proven to have reached a mature technology stage, with fast assem- bling, relatively cheap and reliable telescopes. The scientific outcome is impressive, with more than 140 sources discovered in few years, and several astrophysical sce- narios of particle acceleration and gamma-ray transport already disproved by VHE data.
The goal of future installation is to increase the sensitivity by a factor 10 compared to current installations, and enlarge the energy domain from few tens of GeV to several tens of TeV with unprecedented angular and energy resolution and a factor 3 larger field of view.
Hereafter, we present design considerations for the Cherenkov Telescope Array (CTA), a project for a new generation of highly automated telescopes for VHE gamma-ray astronomy
Reaching the lowest energy threshold of ground-based Cherenkov telescopes with MAGIC–stereo: A goal achieved
No full textThe MAGIC telescopes have been designed primarily to reach the lowest possible energy threshold with the ground-based Imaging Atmospheric Cherenkov technique, in order to fill the gap between MeV– GeV gamma-ray satellite experiments and TeV ground-based installations. With the construction of a second MAGIC telescope and the subsequent use of the stereoscopic operation mode, this goal has already been largely achieved. Astrophysical spectra of some active galactic nuclei and pulsar wind nebulae, for example, are now completely sampled in the high energy peak from MeV to TeV. Frequently, this was achieved in multi-wavelength campaigns covering many orders of magnitude in energy and permitting a deeper insight into the target physics. In addition, the sensitivity at low energies allows us to perform studies of pulsars, gamma-ray burst and other fundamental physics topics.
In this review, the improvement due to the stereoscopic upgrade will be briefly presented and discussed. The importance of low energy studies in astrophysics and fundamental physics searches will be exposed together with a selection of the most recent and sometimes conspicuous results obtained with the MAGIC-stereo experiment
A decade of dark matter searches with ground-based Cherenkov telescopes
No full textn the general scenario of Weakly Interacting Massive Particles (WIMP), dark matter (DM) can be observed via astrophysical gamma-rays because photons are produced in various DM annihilation or decay processes, either as broad-band or line emission, or because of the secondary processes of charged particles in the final stages of the annihilations or the decays. The energy range of the former processes is accessible by current ground-based Imaging Atmospheric Cherenkov telescopes (IACTs, like H.E.S.S., MAGIC and VERITAS). The strengths of this technique are: a) the expected DM gamma-ray spectra show peculiar features like bumps, spikes and cutoff that make them clearly distinguishable from the smoother astrophysical spectra, b) the expected DM spectrum is universal and therefore by observing two or more DM targets with the same spectrum, a clear identification (besides detection) of DM would be enabled. The role of IACTs may gain more importance in the future as the results from the LHC may hint to a DM particle with mass at the TeV or above, where the IACTs sensitivity is unsurpassed by other experiments. In this contribution, a review of the search for DM with the current generation of IACT will be presented
Technical Solutions for the MAGIC Telescope
No full textThe atmospheric Cherenkov telescope MAGIC for ground-based gamma-ray astronomy is operating since late 2003 on the Canarian island La Palma. The telescope’s 17 m diameter mirror is composed of 964 light weight, square all- aluminum mirrors of 234 m2 total area, which allows to lower the energy thresh- old to a value far beyond that of past generation of telescopes. The trigger sys- tem, based on ultra-fast decision logics (topological, time-coincidences, etc.) is designed to cope with very fast PMT signals (2 ns). Details of the MAGIC telescope will be presented, technical problems and solutions will be discussed as well as a report on three years of operations will be given
Novel Reflective Elements and Indirect Dark Matter Searches for MAGIC II and future IACTs.
No full textDuring the PhD I made my research following two principal research activities: a technological part relative to the development and the production of reflective units for the second MAGIC telescope and a second part more scientific, focused on strategy of indirect detection of dark matter with the MAGIC telescope.Durante la Scuola di Dottorato ho svolto la mia ricerca seguendo due attivita' principali: una parte tecnologica relativa allo sviluppo e la produzione di unita' riflettenti per il secondo telescopio MAGIC ed una parte maggiormente scientifica sulle strategie di rivelazione indiretta
di Materia Oscura con il Telescopio MAGIC
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