The Three-dimensional Expansion of the Ejecta from Tycho's Supernova Remnant
- Space Telescope Science Institute, Baltimore, MD 21218 (United States)
- NASA Goddard Space Flight Center, X-ray Astrophysics Laboratory, Greenbelt, MD 20771 (United States)
- School of Physical, Environmental and Mathematical Sciences, University of New South Wales, Australian Defence Force Academy, Canberra, ACT 2600 (Australia)
- University of North Florida, Department of Physics, 1 UNF Drive, Jacksonville, FL 32224 (United States)
- Department of Physics, North Carolina State University, Raleigh, NC 27695 (United States)
- Department of Physics, Astronomy, and Geosciences, Towson University, Towson, MD 21252 (United States)
We present the first 3D measurements of the velocity of various ejecta knots in Tycho’s supernova remnant, known to result from a Type Ia explosion. Chandra X-ray observations over a 12 yr baseline from 2003 to 2015 allow us to measure the proper motion of nearly 60 “tufts” of Si-rich ejecta, giving us the velocity in the plane of the sky. For the line-of-sight velocity, we use two different methods: a nonequilibrium ionization model fit to the strong Si and S lines in the 1.2–2.8 keV regime, and a fit consisting of a series of Gaussian lines. These methods give consistent results, allowing us to determine the redshift or blueshift of each of the knots. Assuming a distance of 3.5 kpc, we find total velocities that range from 2400 to 6600 km s{sup −1}, with a mean of 4430 km s{sup −1}. We find several regions where the ejecta knots have overtaken the forward shock. These regions have proper motions in excess of 6000 km s{sup −1}. Some SN Ia explosion models predict a velocity asymmetry in the ejecta. We find no such velocity asymmetries in Tycho, and we discuss our findings in light of various explosion models, favoring those delayed-detonation models with relatively vigorous and symmetrical deflagrations. Finally, we compare measurements with models of the remnant’s evolution that include both smooth and clumpy ejecta profiles, finding that both ejecta profiles can be accommodated by the observations.
- OSTI ID:
- 22663524
- Journal Information:
- Astrophysical Journal, Vol. 842, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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