M. Graziani

Study of systematics in anisotropy searches with AMS-02

The search for anisotropies in cosmic ray arrival directions with space experiments like the Alpha Magnetic Spectrometer (AMS-02) on the International Space Station is subject to a number of time and energy dependent effects originating from the detector, its environment and the data selection that need to be corrected for. Different approaches to accommodate for these effects are motivated and presented. The impact of these effects on the interpretation of anisotropy is discussed.

Measurement of anisotropies in cosmic ray arrival directions with the Alpha Magnetic Spectrometer on the ISS

An analysis of anisotropies in the arrival directions of galactic protons, electrons and positrons has been performed with the Alpha Magnetic Spectrometer on the International Space Station using the first five years of data taking. Results on a dipole signal in Galactic coordinates are reported. The positron to proton and positron to electron ratio is consistent with isotropy. For energies above 16 GeV a limit of δ < 0.02 at the 95% confidence level is obtained. The electron to proton ratio is consistent with isotropy. For energies above 16 GeV a limit of δ < 0.004 at the 95% confidence level is obtained. The ratio of high rigidity protons to low rigidity protons is consistent with isotropy. For energies above 80 GV a limit of δ < 0.002 at the 95% confidence level is obtained. Limits on the absolute anisotropies in protons, electrons and positrons are consistent with the limits derived from the relative anisotropies. No indication of any time dependence is observed for all particle species within the present statistics.

Trajectory reconstruction in the Earth Magnetosphere using TS05 model and evaluation of geomagnetic cutoff in AMS-02 data

D. Grandi∗1, B. Bertucci45, M.J. Boschini13, M. Crispoltoni45, S. Della Torre1, F. Donnini45, M. Duranti45, D. D’Urso56, E. Fiandrini45, V. Formato5, G. La Vacca1, M. Gervasi12, M. Graziani45, F. Nozzoli56, S. Pensotti12, C. Pizzolotto 56, P.G. Rancoita1, D. Rozza12, M. Tacconi1, V. Vitale 56, M. Zannoni12 1 INFN, Sezione di Milano Bicocca, I20126 Milano, Italy 2 Università di Milano Bicocca, I-20126 Milano, Italy 3 CINECA, I20090 Segrate (MI) ITALY 4 University of Perugia, I06124 Perugia, Italy 5 INFN Perugia, I06124 Perugia, Italy 6 ASDC, ASI Science Data Center, I-00133 Roma, Italy E-mail: davide.grandi@mib.infn.it