* Astronomy

Title: Observation of the Cosmic Ray Moon shadowing effect with the ARGO-YBJ experiment
Authors: G. Di Sciascio, R. Iuppa, for the ARGO-YBJ collaboration

Cosmic rays are hampered by the Moon and a deficit in its direction is expected (the so-called Moon shadow). The Moon shadow is an important tool to determine the performance of an air shower array. In fact, the displacement of the shadow center, due to the bending effect of the Geomagnetic field on the propagation of cosmic rays, allows to set the energy scale of the primary particles inducing the showers observed by the detector. The shape of the shadow permits to determine the detector point spread function. The position of the deficit at high energy allows evaluating its pointing accuracy. Here we present the observation of the cosmic ray Moon shadowing effect carried out by the ARGO-YBJ experiment (Yangbajing Cosmic Ray Laboratory, Tibet, P.R. China, 4300 m a.s.l., 606 g/cm²) in the multi-TeV energy region with high statistical significance (70 standard deviations). By means of an accurate Monte Carlo simulation of the cosmic rays propagation in the Earth-Moon system we have studied the role of the Geomagnetic field and of the detector point spread function on the observed shadow.

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Chinese and German scientists are establishing an astronomical observatory in a Tibetan county 4,300 meters above sea level.
Construction of the observatory began on Monday in Yangbajain Township, of Damxung County in the suburbs of Tibet's regional capital Lhasa, said project leader Wang Junjie Tuesday.
The observatory would be operational in early 2011, after a state-of-the-art telescope was moved to the Tibet plateau from its current site in the Swiss Alps, said Wang, a researcher with the National Astronomical Observatories of the Chinese Academy of Sciences (CAS), in Beijing.

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A mysterious surplus of energetic particles called cosmic rays is striking the Earth from the direction of the constellation Cygnus, suggests a controversial new study. If confirmed, the detection of this excess may help scientists figure out what produces these enigmatic high-speed particles.
Cosmic rays are speeding charged particles that appear to hit Earth in roughly equal numbers from all directions. Lower energy cosmic rays are thought to come from the shock waves around supernovae, but the source of the higher energy ones is still a mystery.
When a cosmic ray hits Earth's atmosphere, it produces a burst of charged particles and light. Sensitive detectors on the ground measure either the secondary particles or the light to try to determine the direction from which each cosmic ray came.
However, no one has been able to unequivocally trace cosmic rays to a specific object like the expanding shell of a supernova.
Now, observations have revealed what appears to be a broad area of enhanced cosmic ray activity in the sky. The data comes from the Tibet Air Shower Arrays, which detects the secondary particles produced when cosmic rays or high-energy radiation slams into the atmosphere.

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