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Model Simulations Of A Shock‐Cloud Interaction In The Cygnus Loop, Daniel J. Patnaude, Robert A. Fesen

Dartmouth Scholarship

We present optical observations and two-dimensional hydrodynamic modeling of an isolated shocked ISM cloud. Hα images taken in 1992.6 and 2003.7 of a small optical emission cloud along the southwestern limb of the Cygnus Loop were used to measure positional displacements of ~01 yr^-1 for surrounding Balmer-dominated emission filaments and 0025-0055 yr^-1 for internal cloud emission features. These measurements imply transverse velocities of 250 and 80-140 km s^-1 for ambient ISM and internal cloud shocks, respectively. A lack of observed turbulent gas stripping at the cloud-ISM boundary in the Hα images suggests that there is not an …