Astron. Astrophys. 358, 605-611 (2000)

A deep search for the optical counterpart to the anomalous X-ray pulsar 1E 2259+58.6

F. Hulleman ¹, M.H. van Kerkwijk ¹, F.W.M. Verbunt ¹ and S.R. Kulkarni <sup>2

1</sup> Astronomical Institute, Utrecht University, P.O. Box 80000, 3508 TA Utrecht, The Netherlands
² Palomar Observatory, California Institute of Technology 105-24, Pasadena, CA 91125, USA

Received 10 January 2000 / Accepted 9 March 2000

Abstract

We present Keck R and I band images of the field of the anomalous X-ray pulsar 1E 2259+58.6. We derive an improved X-ray position from archival ROSAT HRI observations by correcting for systematic (boresight) errors. Within the corresponding error circle, no object is found on the Keck images, down to limiting magnitudes and . We discuss the constraints imposed by these limits, and conclude that it is unlikely that 1E 2259+58.6 is powered by accretion from a disk, irrespective of whether it is in a binary or not, unless the binary is extremely compact.

Key words: stars: pulsars: individual: 1E 2259+58.6 accretion, accretion disks stars: neutron stars: white dwarfs X-rays: stars

Send offprint requests to: F.Hulleman@astro.uu.nl

SIMBAD Objects

Contents

• 1. Introduction
• 2. 1E 2259+58.6
  • 2.1. Distance and reddening to 1E 2259+58.6
• 3. Improved X-ray position
• 4. Keck observations
• 5. Discussion
  • 5.1. An isolated object
  • 5.2. An isolated NS accreting from a disk
  • 5.3. A very low mass binary
• 6. Conclusions
• Acknowledgements
• References

© European Southern Observatory (ESO) 2000

Online publication: June 8, 2000
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