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Soft X-ray emission from the radio pulsar PSR 0656 + 14A radio source with a flux density of a few mJy was found in the error region of the soft X-ray source E0656 + 14, and identified as the radio pulsar PSR 0656 + 14. The radio source has a steep, nonthermal spectrum and a high degree of linear (62 percent) and circular (19 percent) polarization. The X-ray spectrum of the pulsar is among the softest sources observed with the Einstein Observatory. The X-ray data taken with the Einstein imaging proportional counter (IPC) permit a range of blackbody temperatures of 3-6 x 10 to the 5th K, and an equivalent column density of hydrogen smaller than 4 x 10 to the 20th/sq cm. If the assumption is made that the X-ray flux is thermal radiation from surface of the neutron star, then the pulsar must be at a distance smaller than 550 pc, consistent with the low dispersion measure of PSR 0656 + 14. The X-ray timing data suggest that the X-ray emission is modulated at the pulsar's 0.385-s spin period with an amplitude of 18 percent + or - 6 percent, and that there is a 0.0002 probability that this is spurious. It was noted that PSR 0656 + 14 is close to the geometric center of a 20-deg diameter soft X-ray emitting ring called the Gemini-Monoceros enhancement. The close distance of the pulsar, together with its relatively young age of 1.1 x 10 to the 5th yr, makes it possible that the ring is a supernova remnant from the explosion of the pulsar's progenitor. A radio source extending over a region 1.2 to 3.3 arcmin south of the pulsar is a candidate for association with the pulsar.
Document ID
Document Type
Reprint (Version printed in journal)
External Source(s)
Cordova, F. A. (Los Alamos National Lab. NM, United States)
Middleditch, J. (Los Alamos National Laboratory NM, United States)
Hjellming, R. M. (National Radio Astronomy Observatory Socorro, NM, United States)
Mason, K. O. (London, University College, Dorking, United Kingdom)
Date Acquired
August 14, 2013
Publication Date
October 1, 1989
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 345
ISSN: 0004-637X
Subject Category
Distribution Limits