THE H-2 LINE-PROFILES IN THE CYGNUS LOOP - EVIDENCE FOR J-SHOCKS WITH MAGNETIC PRECURSORS

We have obtained infrared Fabry-Perot spectra at almost-equal-to 25 km s-1 resolution of the H-2 line emission associated with the fast shocks to the NE of the Cygnus Loop supernova remnant. Profiles of the 1-0 S(1) H-2 emission associated with both the optically bright radiative shocks and the faint nonradiative shocks have been observed. The profiles are resolved and have deconvolved widths of almost-equal-to 20 km s-1. This result favors excitation of the H-2 emission in a magnetic precursor over excitation by a radiative precursor. Shocks with precursors may play an important role in Herbig-Haro objects, and in star-forming cloud cores.