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A VLA Study of the Expansion of Tycho's Supernova Remnant


Reynoso, EM and Moffett, DA and Goss, WM and Dubner, GM and Dickel, JR and Reynolds, SP and Giacani, EB, A VLA Study of the Expansion of Tycho's Supernova Remnant, The Astrophysical Journal, 491, (2) pp. 816-828. ISSN 0004-637X (1997) [Refereed Article]

DOI: doi:10.1086/304997


We have measured the expansion of Tycho's supernova remnant (SNR) over a 10 yr interval by comparing new VLA observations at 1375 MHz made in 1994 and 1995 with previous observations made in 1983 and 1984 using the same array configurations, bandwidths, calibrators, and integration times. To compute the expansion of the outer rim, we estimate the expansion rate for radial sectors of 4 degrees. The overall mean expansion obtained is 3." 05 but varies between 1 " and 5 " around the shell. The weighted average fractional expansion rate is 0.1126% yr(-1), corresponding to a power-law index (expansion parameter) v = dln R/dlnt = 0.471, with an error of similar to 6%. We also compute the expansion of interior features, and find a comparable global expansion parameter. The value of v obtained is in excess of the pure Sedov value of 0.4, indicating that Tycho's SNR is still in transition from an earlier phase to the Sedov adiabatic phase of evolution, and supporting expansion into a medium without a strong radial density gradient, as expected for a Type Ia supernova. In addition, the significant local variations that we observe suggest that a unique average expansion rate is an oversimplified description for Tycho. Both radio flux and polarization were found to remain almost constant during the intervening 10 years.

Item Details

Item Type:Refereed Article
Research Division:Physical Sciences
Research Group:Astronomical sciences
Research Field:Galactic astronomy
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the physical sciences
UTAS Author:Moffett, DA (Dr David Moffett)
ID Code:12447
Year Published:1997
Web of Science® Times Cited:91
Deposited By:Physics
Deposited On:1997-08-01
Last Modified:2011-08-15

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