Delaney, Tracey and Rudnick, Lawrence and Stage, M. D. and Smith, J. D. and Isensee, Karl and Rho, Jeonghee and Allen, Glenn E. and Gomez, Haley and Kozasa, Takashi and Reach, William T. and Davis, J. E. and Houck, J. C. (2010) The Three-dimensional Structure of Cassiopeia A. Astrophysical Journal, 725 (2). pp. 2038-2058. ISSN 0004-637X http://resolver.caltech.edu/CaltechAUTHORS:20110308-123057474
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We used the Spitzer Space Telescope’s Infrared Spectrograph to map nearly the entire extent of Cassiopeia A between 5 and 40μm. Using infrared and Chandra X-ray Doppler velocity measurements, along with the locations of optical ejecta beyond the forward shock, we constructed a three-dimensional model of the remnant. The structure of Cas A can be characterized into a spherical component, a tilted thick disk, and multiple ejecta jets/pistons and optical fast-moving knots all populating the thick disk plane. The Bright Ring in Cas A identifies the intersection between the thick plane/pistons and a roughly spherical reverse shock. The ejecta pistons indicate a radial velocity gradient in the explosion. Some ejecta pistons are bipolar with oppositely directed flows about the expansion center while some ejecta pistons show no such symmetry. Some ejecta pistons appear to maintain the integrity of the nuclear burning layers while others appear to have punched through the outer layers. The ejecta pistons indicate a radial velocity gradient in the explosion. In three dimensions, the Fe jet in the southeast occupies a “hole” in the Si-group emission and does not represent “overturning,” as previously thought. Although interaction with the circumstellar medium affects the detailed appearance of the remnant and may affect the visibility of the southeast Fe jet, the bulk of the symmetries and asymmetries in Cas A are intrinsic to the explosion.
|Additional Information:||© 2010 American Astronomical Society. Received 2009 August 11; accepted 2010 October 20; published 2010 December 3. This work is based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under NASA contract 1407. Partial support for this work was provided by NASA/JPL through award 1264030 to the University of Minnesota. This work is also based on observations made with the Chandra X-ray Observatory. Partial support for this work was provided by NASA through Chandra Award AR5-6008X to the University of Minnesota. During the course of this work, T.D. received partial support from NASA through SAO grant GO3-4063A while a post-doc at Harvard. At MIT, T.D. received support from NASA through SAO contract SV3-73016 to MIT for support of the Chandra X-ray Center and Science Instruments, which is operated by SAO for and on behalf of NASA under contract NAS8-03060. While at WV Wesleyan College, T.D. received partial support through a Faculty Research Enhancement Grant from the NASA-WV Space Grant Consortium. The three-dimensional graphics were made using the 3D Slicer program which is a medical imaging tool being adapted for astronomical use by the Astronomical Medicine Project which is a part of Harvard’s Initiative in Innovative Computing. 12 T.D. thanks Megan Watzke for connecting her with the Astronomical Medicine Project and Michelle Borkin for providing valuable assistance with 3D Slicer. T.D. also thanks Mike Noble for help with the three-dimensional PDF graphics and Dan Dewey for valuable conversations. T.D., L.R., and K.I. thank Alex Heger for guidance and valuable conversations concerning supernova models. Finally, we thank the referee for a thorough review of the manuscript which has resulted in significant improvements in the presentation of our results.|
|Subject Keywords:||infrared: ISM; ISM: individual objects (Cassiopeia A); ISM: supernova remnants; X-rays: ISM|
|Classification Code:||PACS: 98.38.Mz; 95.30.Gv; 97.60.Bw|
|Official Citation:||Tracey DeLaney et al. 2010 ApJ 725 2038 doi: 10.1088/0004-637X/725/2/2038|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Ruth Sustaita|
|Deposited On:||10 Mar 2011 16:09|
|Last Modified:||26 Dec 2012 13:00|
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