Large scale anisotropy studies with the Pierre Auger Observatory
18 Apr 2011
1RWTH Aachen University, Phys. Inst. IIIA, Aachen, Germany
2Observatorio Pierre Auger, Av. San Martín Norte 304, (5613) Malargüe, Mendoza, Argentina
*Full author list: http://www.auger.org/archive/authors_2010_10.html
Abstract. The Pierre Auger Observatory in Argentina measures air showers initiated by cosmic rays at EeV energy scales (1 EeV = 1018 eV). An important goal of the collaboration is to study the distribution of arrival directions of the primary particles and quantify potential anisotropies therein. Using data collected by the surface detector (SD) array of the Pierre Auger Observatory since 1 January 2004, we study large scale anisotropies in different energy windows.
Modulations of the event rate within the period of a sidereal day are studied by means of a periodicity analysis accounting for local effects which may induce an artificial anisotropy. We present results for the event rate modulation in right ascension and derive upper limits for the equatorial component of a dipole amplitude (Auger Coll., 2011; Bonino, 2009).