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The Distribution of Radioactive <sup>44</sup>Ti in Cassiopeia A [electronic resource].

Published
Washington, D.C. : United States. Dept. of Energy, 2016.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy
Physical Description
Article numbers 19 : digital, PDF file
Additional Creators
SLAC National Accelerator Laboratory, United States. Department of Energy, and United States. Department of Energy. Office of Scientific and Technical Information
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Summary
The distribution of elements produced in the inner-most layers of a supernova explosion is a key diagnostic for studying the collapse of massive stars. Here we present the results of a 2.4 Ms NuSTAR observing campaign aimed at studying the supernova remnant Cassiopeia A (Cas A). We perform spatially-resolved spectroscopic analyses of the 44Ti ejecta which we use to determine the Doppler shift and thus the three-dimensional (3D) velocities of the 44Ti ejecta. We nd an initial 44Ti mass of 1.54±0.21x10-4 M which has a present day average momentum direction of 340°±15° projected on to the plane of the sky (measured clockwise from Celestial North) and tilted by 58°±20° into the plane of the sky away from the observer, roughly opposite to the inferred direction of motion of the central compact object. We find some 44Ti ejecta that are clearly interior to the reverse shock and some that are clearly exterior to the reverse shock. Where we observe 44Ti ejecta exterior to the reverse shock we also see shock-heated iron; however, there are regions where we see iron but do not observe 44Ti. This suggests that the local conditions of the supernova shock during explosive nucleosynthesis varied enough to suppress the production of 44Ti in some regions by at least a factor of two, even in regions that are assumed to be the result of processes like α-rich freezeout that should produce both iron and titanium.
Report Numbers
E 1.99:1361151
Subject(s)
Note
Published through SciTech Connect.
12/27/2016.
The Astrophysical Journal (Online) 834 1 ISSN 1538-4357 AM
Brian W. Grefenstette; Chris L. Fryer; Fiona A. Harrison; Steven E. Boggs; Tracey DeLaney; J. Martin Laming; Stephen P. Reynolds; David M. Alexander; Didier Barret; Finn E. Christensen; William W. Craig; Karl Forster; Paolo Giommi; Charles J. Hailey; Alan Hornstrup; Takao Kitaguchi; J. E. Koglin; Laura Lopez; Peter H. Mao; Kristin K. Madsen; Hiromasa Miyasaka; Kaya Mori; Matteo Perri; Michael J. Pivovaroff; Simonetta Puccetti; et al.
Funding Information
AC02-76SF00515
View MARC record | catkey: 23494619