COSMIC-RAYS FROM ACCRETING ISOLATED NEUTRON-STARS

Interstellar matter that is accreted on to isolated magnetic neutron s tars in the Galaxy (similar to 10(9) by number) is accelerated and ref lected back by magnetohydrodynamic (MHD) shocks, which envelop the sta rs. The integrated power in the Galaxy, L(cr,ns), is greater than or s imilar to 10(40) erg s(-1), the energy distribution is a power law of spectral index > 2, and the particle energy can be raised to 10(6) GeV , consistent with the power and spectrum of primary cosmic rays in the Galaxy. The major contribution to L(cr,ns) comes from a minority of s imilar to 10(7) isolated neutron stars which are located within dense clouds. Sources in these clouds, which are generally spread within the Galactic disc, can explain the concentration of high-energy cosmic ra ys in the Galactic plane, as deduced from pion decay spectra in gamma- ray observations. The soft X-ray luminosity from these neutron stars i s consistent with the Galactic X-ray background. The accretion may be associated with ion-neutral bias, which is further enhanced by ion con finement in frozen-in magnetic fields which can raise the relative abu ndance of first ionization potential (FIP) elements in the cosmic rays .