Schedule Feb 10, 2006
Arcsecond-Scale Spectroscopy of Cas A and the Implications for Cosmic-Ray Acceleration
Glenn Allen (MIT)

G. E. Allen (MIT), M. D. Stage (UMass), J. C. Houck (MIT) and J. E. Davis (MIT)We present the results of spectroscopic analyses of 1.1 megaseconds of Chandra ACIS X-ray data for the supernova remnant Cas A. The analyses were performed by extracting spectra from 1\"x1\" to 7\"x7\" overlapping boxes at each point on a rectangular grid with 1\" spacing. Each set of spectra and spatially-dependent responses was fitted with a simple thermal model. The results of this analysis suggest that some, if not all, of the regions in which the X-ray synchrotron emission is produced can be identified. These regions have relatively high fitted electron temperatures and relatively low elemental abundances. The regions whose X-ray emission is dominated by synchrotron radiation seem be distributed around the forward shock, except, perhaps, for portions of the southwestern face of the remnant. The data for these regions were subsequently fitted with a synchrotron emission model. The fitted critical frequencies associated with the highest-energy electrons vary from about 10^16-10^18 Hz. This variation indicates that the cut-off energy of the electron spectrum varies by as much as one order of magnitude and/or the magnetic field strength varies by as much as two orders of magnitude. In the regions with the highest critical frequencies, the electrons must be accelerated about as fast as possible (i.e. have diffusion coefficients comparable to the Bohm coefficient).

Begin streaming QuickTime of the whole talk (high bandwidth).
(Or, right-click to download the movie.) (Or, right-click to download the podcast.)

Begin streaming RealMedia for the whole talk: high bandwidth or medium bandwidth.
Or, stream audio only for the whole talk: high bandwidth or low bandwidth. (Or, right-click to download the whole audio file.)

To begin viewing slides, click on the first slide below. (Or, view as pdf.)

[01] [02] [03] [04] [05] [06] [07] [08] [09] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] [21] [22] [23] [24] [25] [26] [27] [28] [29] [30]

Author entry (protected)