Differences between the two anomalous X-ray pulsars: variations in the spin-down rate of 1E 1048.1-5937 and an extended interval of quiet spin-down in 1E 2259+586

Baykal, Altan and Strohmayer, Tod and Swank, Jean and Alpar, M. Ali and Stark, Michael J. (2000) Differences between the two anomalous X-ray pulsars: variations in the spin-down rate of 1E 1048.1-5937 and an extended interval of quiet spin-down in 1E 2259+586. Monthly Notices of the Royal Astronomical Society, 319 (1). pp. 205-208. ISSN 0035-8711

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Abstract

We analysed the Rossi X-ray Timing Explorer (RXTE) archival data of 1E 1048.1-5937 covering a time-span of more than one year. The spin-down rate of this source decreases by similar to 30 per cent during the observation. We could not resolve the X-ray flux variations because of contamination by eta Carinae. We find that the level of pulse frequency fluctuations of 1E 1048.1-5937 is consistent with typical noise levels of accretion-powered pulsars. Recent RXTE observations of 1E 2259+586 have shown a constant spin-down with a very low upper limit on timing noise. We used the RXTE archival X-ray observations of 1E 2259+586 to show that the intrinsic X-ray luminosity times-series is also stable, with an rms fractional variation of less than 15 per cent. The source could have been in a quiet phase of accretion with a constant X-ray luminosity and spin-down rate.
Item Type: Article
Uncontrolled Keywords: accretion, accretion discs; binaries : general; stars : individual : 1E 1048.1-5937; stars : individual : 1E 2259+586; stars : low-mass, brown dwarfs
Subjects: Q Science > QB Astronomy > QB460-466 Astrophysics
Q Science > QB Astronomy
Divisions: Faculty of Engineering and Natural Sciences > Basic Sciences > Physics
Faculty of Engineering and Natural Sciences
Depositing User: M. Ali Alpar
Date Deposited: 02 Jul 2010 12:03
Last Modified: 25 Jul 2019 10:51
URI: https://research.sabanciuniv.edu/id/eprint/14102

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