We derive the preshock density and scale length along the line of sight for the collisionless shock from a deep HST image that resolves the Hα filament in SN 1006 and updated model calculations. The very deep ACS high-resolution image of the Balmer line filament in the northwest quadrant shows that 0.25 cm -3 ≤ n 0 ≤ 0.4 cm -3 and that the scale along the line of sight is about 2 × 10 18 cm, while bright features within the filament correspond to ripples with radii of curvature less than 1/10 that size. The derived densities are within the broad range of earlier density estimates, and they agree well with the ionization timescale derived from the Chandra X-ray spectrum of a region just behind the optical filament. This provides a test for widely used models of the X-ray emission from SNR shocks. The scale and amplitude of the ripples are consistent with expectations for a shock propagating through interstellar gas with ∼20% density fluctuations on parsec scales as expected from studies of interstellar turbulence. One bulge in the filament corresponds to a knot of ejecta overtaking the blast wave, however. The interaction results from the rapid deceleration of the blast wave as it encounters an interstellar cloud. © 2007. The American Astronomical Society. All rights reserved.
CITATION STYLE
Raymond, J. C., Korreck, K. E., Sedlacek, Q. C., Blair, W. P., Ghavamian, P., & Sankrit, R. (2007). The Preshock Gas of SN 1006 from Hubble Space Telescope Advanced Camera for Surveys Observations. The Astrophysical Journal, 659(2), 1257–1264. https://doi.org/10.1086/512483
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