The Cherenkov Telescope Array is a next generation ground-based gamma-ray observatory de- signed to detect photons in the 20 GeV to 300 TeV energy range. With a sensitivity improvement of up to one order of magnitude on the entire energy range with r
espect to currently operating facilities, coupled with significantly better angular resolution, the array will be used to address many open questions in high-energy astrophysics. In addition, CTA will explore the ultra-high energy (E >50 TeV) window with great sensitivity for the first time. CTA is expected to reveal a detailed picture of the Galactic plane at the highest energies, and to discover around one hundred new supernova remnants and many hundreds of pulsar wind nebulae, according to current population estimates. The ability of the observatory to resolve such a large number of Galactic sources is one of the challenges to be faced. In this paper, we will present the first simulated scan of the Galactic plane with a realistic observation strategy, with particular attention to the potential source confusion. We will also present prospects for morphological studies of extended sources, such as the young SNR RX J1713.7-39.
Gammapy is a Python package for high-level gamma-ray data analysis built on Numpy, Scipy and Astropy. It enables us to analyze gamma-ray data and to create sky images, spectra and lightcurves, from event lists and instrument response information, and
to determine the position, morphology and spectra of gamma-ray sources. So far Gammapy has mostly been used to analyze data from H.E.S.S. and Fermi-LAT, and is now being used for the simulation and analysis of observations from the Cherenkov Telescope Array (CTA). We have proposed Gammapy as a prototype for the CTA science tools. This contribution gives an overview of the Gammapy package and project and shows an analysis application example with simulated CTA data.
The last six years have witnessed major revisions of our knowledge about the Crab Pulsar. The consensus scenario for the origin of the high-energy pulsed emission has been challenged with the discovery of a very-high-energy power law tail extending u
p to 400 GeV, above the expected spectral cut off at a few GeV. Now, new measurements obtained by the MAGIC collaboration extend the energy spectrum of the Crab Pulsar even further, on the TeV regime. Above 400 GeV the pulsed emission comes mainly from the inter-pulse, which becomes more prominent with energy due to a harder spectral index. These findings require gamma-ray production via inverse Compton scattering close to or beyond the light cylinder radius by an underlying particle population with Lorentz factors greater than 5 times 106. We will present those new results and discuss the implications in our current knowledge concerning pulsar environments.
Aims: Probe the high-energy ($>$60 MeV) emission from the black hole X-ray binary system, Cygnus X-1, and investigate its origin. Methods: We analysed 7.5 yr of data by Fermi/LAT with the latest PASS8 software version. Results: We report the detectio
n of a signal at $sim$8 $sigma$ statistical significance spatially coincident with Cygnus X-1 and a luminosity above 60 MeV of 5.5$times$10$^{33}$ erg s$^{-1}$. The signal is correlated with the hard X-ray flux: the source is observed at high energies only during the hard X-ray spectral state, when the source is known to display persistent, relativistic radio emitting jets. The energy spectrum, extending up to $sim$20 GeV without any sign of spectral break, is well fitted by a power-law function with a photon index of 2.3$pm$0.2. There is a hint of orbital flux variability, with high-energy emission mostly coming around the superior conjunction. Conclusions: We detected GeV emission from Cygnus X-1 and probed that the emission is most likely associated with the relativistic jets. The evidence of flux orbital variability points to the anisotropic inverse Compton on stellar photons as the mechanism at work, thus constraining the emission region to a distance $10^{11}-10^{13}$ cm from the black hole.
A new method for analyzing the returns of the custom-made micro-LIDAR system, which is operated along with the two MAGIC telescopes, allows to apply atmospheric corrections in the MAGIC data analysis chain. Such corrections make it possible to extend
the effective observation time of MAGIC under adverse atmospheric conditions and reduce the systematic errors of energy and flux in the data analysis. LIDAR provides a range-resolved atmospheric backscatter profile from which the extinction of Cherenkov light from air shower events can be estimated. Knowledge of the extinction can allow to reconstruct the true image parameters, including energy and flux. Our final goal is to recover the source-intrinsic energy spectrum also for data affected by atmospheric extinction from aerosol layers, such as clouds.
