The Centaurus A Ultrahigh-energy Cosmic-Ray Excess and the Local Extragalactic Magnetic Field
Abstract
The ultrahigh-energy cosmic-ray (UHECR) anisotropies discovered by the Pierre Auger Observatory provide the potential to finally address both the particle origins and properties of the nearby extragalactic magnetic field (EGMF). We examine the implications of the excess of ~10^(20) eV events around the nearby radio galaxy Centaurus A. We find that, if Cen A is the source of these cosmic rays, the angular distribution of events constrains the EGMF strength within several Mpc of the Milky Way to ≳ 20 nG for an assumed primary proton composition. Our conclusions suggest that either the observed excess is a statistical anomaly or the local EGMF is stronger than conventionally thought. We discuss several implications, including UHECR scattering from more distant sources, time delays from transient sources, and the possibility of using magnetic lensing signatures to attain tighter constraints.
Additional Information
© 2012 American Astronomical Society. Received 2012 March 28; accepted 2012 August 3; published 2012 September 20. We thank Stirling Colgate, Dan Holz, Hui Li, and especially Matteo Murgia for discussions and comments. H.Y. is supported by the LANL LDRD program, T.S. is supported by DOE Grant DE-FG02-91ER40626, M.D.K. acknowledges support provided by NASA through the Einstein Fellowship Program, grant PF0-110074, and P.P.K. acknowledges support from an NSERC (Canada) Discovery Grant A5713.Attached Files
Published - 0004-637X_758_1_16.pdf
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Additional details
- Eprint ID
- 35365
- Resolver ID
- CaltechAUTHORS:20121108-113603320
- LANL-LDRD Program
- DE-FG02-91ER40626
- Department of Energy (DOE)
- PF0-110074
- NASA Einstein Fellowship Program
- A5713
- Natural Sciences and Engineering Research Council of Canada (NSERC)
- Created
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2012-11-09Created from EPrint's datestamp field
- Updated
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2021-11-09Created from EPrint's last_modified field