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Interstellar X-Ray Absorption Spectroscopy of the Crab Pulsar with the LETGSWe study the interstellar X-ray absorption along the line of sight to the Crab Pulsar. The Crab was observed with the Low Energy Transmission Grating Spectrometer on the Chandra X-ray Observatory, and the pulsar, a point source, produces a full resolution spectrum. The continuum spectrum appears smooth, and we compare its parameters with other measurements of the pulsar spectrum. The spectrum clearly shows absorption edges due to interstellar Ne, Fe, and O. The O edge shows spectral structure that is probably due to O bound in molecules or dust. We search for near-edge structure (EXAFS) in the O absorption spectrum. The Fe L absorption spectrum is largely due to a set of unresolved discrete n=2-3 transitions in neutral or near-neutral Fe, and we analyze it using a new set of dedicated atomic structure calculations, which provide absolute cross sections. In addition to being interesting in its own right, the ISM absorption needs to be understood in quantitative detail in order to derive spectroscopic constraints on possible soft thermal radiation from the pulsar.
Document ID
20020022507
Acquisition Source
Marshall Space Flight Center
Document Type
Preprint (Draft being sent to journal)
Authors
Paerels, Frits
Weisskopf, Martin C.
Tennant, Allyn F.
ODell, Stephen L.
Swartz, Douglas A.
Kahn, Steven M.
Behar, Ehud
Becker, Werner
Whitaker, Ann F.
Date Acquired
August 20, 2013
Publication Date
January 1, 2001
Subject Category
Astronomy
Meeting Information
Meeting: Two Years of Science with Chandra Symposium
Location: Washington, DC
Country: United States
Start Date: September 5, 2001
End Date: September 7, 2001
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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