15min:

NICK INDRIOLO, Department of Astronomy, University of Illinois at Urbana-Champaign, Urbana, IL 61801; GEOFFREY A. BLAKE, Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125; MIWA GOTO, Max Planck Institute for Astronomy, Königstuhl 17, Heidelberg D-69117, Germany; TOMONORI USUDA, Subaru Telescope, Hilo, HI 96720; THOMAS R. GEBALLE, Gemini Observatory, Hilo, HI 96720; TAKESHI OKA, Department of Astronomy & Astrophysics and Department of Chemistry, University of Chicago, Chicago, IL 60637; BENJAMIN J. MCCALL, Departments of Chemistry and Astronomy, University of Illinois at Urbana-Champaign, Urbana, IL 61801.

It has long been theorized that supernova remnants (SNR) accelerate the majority of Galactic cosmic rays. Observations in the -ray, X-ray, and radio regimes support this theory, at least for cosmic rays with energies above a few GeV. However, there is no direct evidence that SNRs accelerate cosmic rays in the MeV--GeV range. These low-energy cosmic rays are of great importance, as they are the primary means by which H₂ is ionized in the interstellar medium. Collisions between H₂⁺ and H₂ will rapidly form H₃⁺, a molecule which can then be observed to infer the ionization rate of H₂. Using the Subaru and Keck telescopes, we have searched for H₃⁺ absorption in sight lines which probe molecular material known to be interacting with the SNR IC 443. By computing the ionization rate of H₂ in these sight lines, we constrain the flux of low-energy cosmic rays generated by this particular supernova remnant.