The Pierre Auger Observatory has gathered, in ten years of operation, an unprecedented number of extremely energetic cosmic-ray events. We present the latest results of searches for small to intermediate-scale anisotropies in the distribution of arrival directions of such events. We update the test based on the Véron-Cetty and Véron catalog, previously performed by the Pierre Auger Observatory on early data, and conclude that it does not yield a significant indication of anisotropy with the present data set. We then study the correlation of arrival directions with the position of nearby galaxies in the 2MRS catalog, of active galactic nuclei (AGNs) detected by Swift-BAT, of a sample of radio galaxies with jets and of the Centaurus A galaxy. None of the searches shows a statistically significant evidence of anisotropy. The two largest departures from isotropy found have a post-trial probability ∼1%. The first one is for cosmic rays with energy above 58 EeV that arrive within 18° of Swift-BAT AGNs closer than 130 Mpc and brighter than 1044 erg/s. The other one is for cosmic rays above the same energy threshold that arrive within 15° of the direction of Centaurus A.
|Titolo:||On ultra-high energy cosmic-ray arrival directions after ten years of operation of the Pierre Auger Observatory|
|Settore Scientifico Disciplinare:||Settore FIS/01 - Fisica Sperimentale|
Settore FIS/04 - Fisica Nucleare e Subnucleare
Settore FIS/05 - Astronomia e Astrofisica
|Data di pubblicazione:||2015|
|Appare nelle tipologie:||01 - Articolo su periodico|