The Galactic Cosmic Ray Origins Project


The Galactic Cosmic Ray (GCR) project seeks to identify the type(s) of objects responsible for accelerating cosmic ray nuclei up to energies of ~1015 eV.

This project is made possible through a NASA Long Term Space Astrophysics grant to Yousaf Butt, the PI, who is based at the CfA/SAO. Other core members of this group include Dr. Trevor Weeks (SAO), Dr. Don Ellison (NCSU) and Jennifer West (CfA/SAO), together with many collaborators at CfA and other institutes.

Our research focuses on ±10° of the Galactic plane and uses high-quality gamma-ray (VERITAS, GLAST, SWIFT & INTEGRAL) and X-ray (Chandra, XMM) observations in coordination with the lower frequency window (Spitzer, various ground-based mm & radio observatories) as well as archival information. Such data allows us to set stringent constraints on the contribution of electronic (inverse Compton & bremsstralung) versus nucleonic (pion decay) interactions to the production of the detected high-energy gamma-ray emissions.

The high spatial resolutions and sensitivities of the space- and ground-based observatories in operation during the period of the proposed study (2005-2010) will also permit us a unique opportunity to precisely ascribe the origins of the energetic radiation to specific astrophysical sites. For example, GeV range gamma-radiation from a pulsar vs. nearby supernova shell-shocks will typically be resolvable by GLAST for the first time ever. In order to properly interpret the new data and to keep pace with the latest theoretical developments over the 5-year term of the proposed observational campaign, state-of-the-art GCR acceleration models are also being developed and their results cross-checked with broadband observational data.

We have studied a number of galactic supernovae and attempt to associate them with discrete sources of ( > 70 MeV) γ-rays, observed by the Energetic Gamma-ray Experiment Telescope (EGRET).

A table of EGRET sources and their potential supernova counterparts serves as an overview of the scope of the project, complete with links to images in all available energy bands, radio through gamma.

We have posted a 'living' notepad of TeV sources of possible GCR significance.

A periodically updated catalog of HESS sources is also available, as well as a list of gamma-ray and multiwavelength URLs of interest.

Note: These pages are permanently under construction! Questions or comments to Yousaf or Jennifer...