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Extraordinary line-emitting knots in the Crab NebulaExtraordinary, semistellar, line-emitting knots are apparent in images of the Crab Nebula which were obtained with the Goddard Fabry-Perot imager at the Michigan-Dartmouth-MIT Observatory. The knots are most prominent for (O III) lambda 5007 emission through a 5.3 A (Full Width at Half Maximum (FWHM)) bandpass centered at 5015.3 A, with representative fluxes of roughly 10(exp -14) ergs/sq cm. They are aligned in arcs, seven to the north and four to the south, from the pulsar. The northern group appears to be in a bounded corridor through the filamentary structure. Measurements over a 2 year baseline yield proper motions of order 0.1 sec/yr, corresponding to transverse velocities of order 900 km/s for a distance of 1830 pc. The knots are characterized by remarkably strong (Ar III) emission, possibly indicating high argon abundances, high gas temperatures, or anomalous physical processes.
Document ID
19950040580
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Macalpine, Gordon M.
(Univ. of Michigan, Ann Arbor, MI United States)
Lawrence, Stephen S.
(Univ. of Michigan, Ann Arbor, MI United States)
Brown, Beth A.
(Univ. of Michigan, Ann Arbor, MI United States)
Uomoto, Alan
(Johns Hopkins Univ. Baltimore, MD, United States)
Woodgate, Bruce E.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Brown, Larry W.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Oliversen, Ronald J.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Lowenthal, James D.
(Univ. of California, Santa Cruz, CA United States)
Liu, Charles
(Univ. of Arizona, Tucson, AZ United States)
Date Acquired
August 16, 2013
Publication Date
September 10, 1994
Publication Information
Publication: Astrophysical Journal, Part 2 - Letters
Volume: 432
Issue: 2
ISSN: 0004-637X
Subject Category
Astronomy
Accession Number
95A72179
Distribution Limits
Public
Copyright
Other

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