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arXiv · 1211.6443

X-ray Proper Motions and Shock Speeds along the Northwest Rim of SN 1006

Satoru Katsuda·Knox S. Long·Robert Petre·Stephen P. Reynolds·Brian J. Williams·P. Frank Winkler
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Abstract

We report the results of an X-ray proper motion measurement for the NW rim of SN1006, carried out by comparing Chandra observations from 2001 and 2012. The NW limb has predominantly thermal X-ray emission, and it is the only location in SN1006 with significant optical emission: a thin, Balmer-dominated filament. For most of the NW rim, the proper motion is about 0.30 arcsec/yr, essentially the same as has been measured from the H-alpha filament. Isolated regions of the NW limb are dominated by nonthermal emission, and here the proper motion is much higher, 0.49 arcsec/yr, close to the value measured in X-rays along the much brighter NE limb, where the X-rays are overwhelmingly nonthermal. At the 2.2 kpc distance to SN1006, the proper motions imply shock velocities of about 3000 km/s and 5000 km/s in the thermal and nonthermal regions, respectively. A lower velocity behind the H-alpha filament is consistent with the picture that SN1006 is encountering denser gas in the NW, as is also suggested by its overall morphology. In the thermally-dominated portion of the X-ray shell, we also see an offset in the radial profiles at different energies; the 0.5-0.6 keV peak dominated by O VII is closer to the shock front than that of the 0.8-3 keV emission--due to the longer times for heavier elements to reach ionization states where they produce strong X-ray emission.

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Satoru Katsuda, Knox S. Long, Robert Petre, Stephen P. Reynolds, Brian J. Williams, P. Frank Winkler. 2012-11-27. X-ray Proper Motions and Shock Speeds along the Northwest Rim of SN 1006. https://doi.org/10.1088/0004-637x%2F763%2F2%2F85

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