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Thurs., May 28
The GCT’s camera for the Cherenkov Telescope Array - Andrea De FrancoToggle Cloak Cloak The Gamma Cherenkov Telescope’s (GCT) camera is a development project involving UK, US, Japanese, French, Australian and Dutch institutes for the dual-mirror Small-Sized Telescopes (SST-2M) of the Cherenkov Telescope Array (CTA). Two GCT camera prototypes are fully funded. The first will be based on multi-anode photomultipliers (MAPMs) and the second on silicon photomultipliers (SiPMs). The camera is designed to record flashes of Cherenkov light lasting from a few to a hundred nanoseconds, with typical RMS image width and length of ~0.2° x 0.1° and has a 9° field of view. The physical camera geometry is dictated by the GCT telescope optics: a curved focal surface with radius of curvature 1 m and diameter 35 cm is required. The first prototype is now assembled and under extensive lab testing and meant to commissioned on field in the third quarter of this year. The SiPM based camera will follow shortly.
TeV pulsed emission from the Crab detected by MAGIC - Daniel GalindoToggle Cloak Cloak How and where pulsars accelerate particles have been long standing questions. The Crab pulsar, hosted inside its nebula, has been a test bench for any proposed pulsar emission scenario. The discovery of a power-law spectral component, above the cutoff measured by the LAT detector, on board of the Fermi satellite, and extending up to 400 GeV, has challenged the consensus view of the high-energy pulsars. The latest results obtained by the MAGIC collaboration, with more than 300 hours of observations, report the most energetic, ever detected, pulsed gamma rays coming from an astrophysical source, namely the Crab pulsar. The energy spectrum of the Crab pulsar extends up to ~2 TeV, connecting smoothly with the spectral points above 10 GeV measured by Fermi- LAT. Above 400 GeV the detected emission mainly comes from the interpulse, showing a pulse peak at a level of 6.5 sigma. The spectra of the two peaks follow two distinct power-law functions. These results imply that such energetic gamma rays are produced via Inverse Compton scattering in the vicinity of the light cylinder radius by an underlying particle population with Lorentz factors higher than 10^6. The exact site of gamma-ray production cannot be unequivocally assigned, given that none of the existing theories can reproduce all aspects of the observed measurements.
X-ray and gamma-ray studies of the supernova remnant (SNR) CTB 37B hosting a young magnetar - Harsha KumarToggle Cloak Cloak The supernova remnant (SNR) CTB 37B, located in a complicated region of CTB 37, is associated with the 3.82 s magnetar CXOU J171405.7-381031. We present a high-resolution study of the remnant using all available Chandra and XMM-Newton observations in order to characterize the spatial and spectral properties of the diffuse emission, to address the debated age of the SNR, as well as to infer the supernova explosion properties. Observations of the CTB 37 complex performed with the H.E.S.S. telescope array revealed HESS J1713-381, the first TeV source coincident with a magnetar. The origin of the TeV emission has been attributed primarily to the SNR shell, although it has been also suggested that the magnetar may contribute to the HESS source. The source has not yet been detected in any previous studies with the Fermi Large Array Telescope (LAT) that has allowed for successful detections of several SNRs in the MeV- GeV energy range. A further investigation using additional Fermi data to date would help reveal any possible gamma ray emission from this region in the GeV regime, as well as shed light on the nature of its multi-wavelength emission.
Sat., May 30
Searches for High-Energy Neutrinos from Gamma-Ray Bursts with the ANTARES Neutrino Telescope - Julia SchmidToggle Cloak Cloak ANTARES is the largest high-energy neutrino telescope in the Northern Hemisphere. Its main scientific purpose is the search for astrophysical muon neutrinos that are detected via their charged-current interaction in Earth and the subsequent Cherenkov emission of the secondary muon in the water of the Mediterranean Sea. Gamma-ray bursts are among the most promising candidates for the experiment as they are thought to accelerate not only electrons - leading to the observed gamma rays - but also protons, which would yield the emission of EeV neutrinos. Compelling evidence of a high-energy cosmic neutrino signal correlated with any astrophysical source would, for the first time, prove the acceleration of hadrons beyond any doubt, a hypothesis that cannot unambiguously be put to the test by pure electromagnetic observation. However, to explain the origin of cosmic rays at ultra-high energies, it is absolutely crucial to identify those processes in the universe that are capable of accelerating baryons to such energies. The recent searches for muon neutrinos from gamma-ray bursts using data of the ANTARES telescope will be presented. Several techniques to single out a neutrino signal from GRBs in the ANTARES data were developed, both in the search for simultaneous as well as a possibly time-shifted neutrino emission with respect to the photon signal. Data from multiple spacecraft and Earth-bound telescopes within the Gamma-ray burst Coordinates Network such as the Swift and Fermi satellites were used to search for correlated neutrinos in the data from the ANTARES telescope. The search could not identify any significant neutrino excess associated with gamma-ray bursts, yet the non-observation is still compatible with the realistic second-generation numerical predictions of neutrino emission. However, I could demonstrate that the future telescope KM3NeT will be capable of putting these models to the test with unprecedented sensitivity, allowing for the first time the neutrino flux as predicted by the realistic models to be detected, or the parameter space upon which they are based to be severely constrained. Bryce Carpenter
Pheneas Nkundabakura
Mark Wells
- Maxwell Jingo
Rachel Simoni
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