Hostname: page-component-cd9895bd7-7cvxr Total loading time: 0 Render date: 2024-12-26T04:10:06.695Z Has data issue: false hasContentIssue false
  • English
  • Français

Extreme Ultraviolet Emission from Neutron Stars

Published online by Cambridge University Press:  12 April 2016

R.S. Foster ,
J. Edelstein  and
S. Bowyer
R.S. Foster
Affiliation:
Remote Sensing Division, Code 7210, Naval Research Laboratory, Washington, DC 20375, USA
J. Edelstein
Affiliation:
Center for EUV Astrophysics, 2150 Kittredge Street, University of California, Berkeley, CA 94720-5030, USA
S. Bowyer
Affiliation:
Center for EUV Astrophysics, 2150 Kittredge Street, University of California, Berkeley, CA 94720-5030, USA

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

We summarize the detections of extreme ultraviolet (EUV) emission from neutron stars. Three firm detections have been made of spin-powered pulsars: the aged millisecond pulsar PSR J0437−4715, the middle-aged X-ray pulsar Geminga, and the radio pulsar PSR B0656+14. These observations allow us to evaluate both power-law and thermal-law emission models as the source of the EUV flux. For the case of PSR B0656+14 the lack of flux modulation with pulse period argues that the EUV radiation originates from the cooling neutron star surface rather than from a hot polar cap. If the emission is from a thermalized neutron star surface, then limits can be placed on the surface temperature. For the case of Geminga we can explain the observed EUV flux using thermal models that are consistent with standard neutron cooling scenarios. We also have a weak indication that the EUV emission from Geminga is pulsed in a manner consistent with the lowest energy channel observed with Rosat. For the case of the millisecond pulsar PSR J0437−4715 standard neutron star cooling models require surface re-heating. We compare different heating models to the data on this object. We rule out re-heating by crust-core friction, and find that models for the accretion from the interstellar medium, accretion from the white dwarf companion and a particle-wind nebula do not account for the EUV luminosity. Models of pulsar re-heating by magnetic monopole catalysis of nucleon decay are used to establish new limits to the flux of monopoles in the Galaxy. A single power-law source with properties derived from X-ray data cannot explain the EUV flux from PSR J0437−4715. The strongest model for explaining the EUV emission consists of a large ~ 3 km2 polar cap heated from particle production in the pulsar magnetic field. We consider the prospects for detecting other neutron stars in the extreme ultraviolet.

Type
IX. Neutron Stars
Information
International Astronomical Union Colloquium , Volume 152: Astrophysics in the Extreme Ultraviolet , 1996 , pp. 437 - 442
Copyright
Copyright © Kluwer 1996

References

Arons, J. & Tavani, M. 1993, High-energy emission from the eclipsing millisecond pulsai PSR 1957+20, ApJ, 403, 249 Google Scholar
Becker, W. & Trumper, J. 1993, Detection of pulsed X-rays from the binary millisecond pulsar J0437—4715, Nature, 356, 528 Google Scholar
Edelstein, J., Foster, R.S., & Bowyer, S. 1995, Extreme Ultraviolet Emission from the Millisecond Pulsar J0437—4715, ApJ, in pressGoogle Scholar
Freese, K., Turner, M., & Schramm, D.N. 1983, Monopole catalysis of nucleon decay in old pulsars, Phys. Rev. L., 51, 1625 Google Scholar
Halpern, J.P. & Holt, S.S. 1992, Discovery of soft X-ray pulsations from the gamma-ray source Geminga, Nature, 357, 222 Google Scholar
Halpern, J.P. & Ruderman, M. 1993, Soft X-ray properties of the Geminga pulsar, ApJ, 415, 286 Google Scholar
Johnston, S., et al. 1993, Discovery of a very bright, nearby binary millisecond pulsar, Nature, 361, 613 Google Scholar
Kolb, E. & Turner, M. 1984, Limits from the soft X-ray background on the temperature of old neutron stars and on the flux of superheavy magnetic monopoles, ApJ, 286, 702 Google Scholar
Page, D. & Applegate, J.H. 1992, The cooling of neutron stars by the direct Urea process, ApJL, 394, L17 Google Scholar
Shemi, A. 1995, Are Unidentified EUV Sources the Closest Neutron Stars?, MNRAS, submittedGoogle Scholar
Taylor, J.H., Manchester, R.N., & Lyne, A.G. 1993, Catalog of 558 pulsars, ApJS, 88, 529 Google Scholar
Taylor, J.H., Manchester, D.N., Lyne, A.G., & Camilo, F. 1995, in preparationGoogle Scholar
Vrtilek, S.D. et al. 1994, Multiwavelength observations of Hercules X-l/HZ Hercules, ApJL, 436, L9 Google Scholar