TY - JOUR
T1 - Multiwavelength observations of isolated neutron stars as a tool to probe the properties of their surfaces
AU - Pavlov, G. G.
AU - Zavlin, V. E.
AU - Trümper, J.
AU - Neuhäuser, R.
N1 - Funding Information:
We thank Fred Walter, Werner Becker, Bernd Aschenbach, Stuart Bowyer, and the referee for useful discussions. The ROSAT project is supported by the BMBF and the Max-Planck-Society. G. P. is grateful to the Max-Planck-Institut fu‹r Extraterrestrische Physik for hospitality; his work was partially supported by NASA grant NAG5-2807 and INTAS grant 94-3834. V. Z. acknowledges Max-Planck fellowship and the INTAS grant.
PY - 1996
Y1 - 1996
N2 - We show that an analysis of multiwavelength observations of isolated neutron stars based on neutron star atmosphere models can be used not only to evaluate the neutron star effective temperature, but also to determine chemical composition of its surface. To demonstrate how this new method can be applied to a specific object, we chose the old isolated neutron star candidate RXJ 1856.5-3754, the soft X-ray radiation of which has been studied recently by Walter, Wolk, & Neuhäuser. We fitted the soft X-ray spectrum of this object with neutron star atmosphere models of different chemical compositions and used these fits to calculate the source spectrum over a broad wavelength range. We showed, in particular, that the optical/UV flux expected from this object depends drastically on the composition of its surface. In particular, the neutron star covered with hydrogen would be 5-6 mag brighter than the neutron star with an iron surface. The object should also be observable with EUVE; the EUV flux is expected to be almost twice higher for the iron surface than for the hydrogen one. Thus, multiwavelength observations of this object would enable one to examine, for the first time, chemical composition of the neutron star surface. The method proposed can be applied to other nearby isolated neutron stars.
AB - We show that an analysis of multiwavelength observations of isolated neutron stars based on neutron star atmosphere models can be used not only to evaluate the neutron star effective temperature, but also to determine chemical composition of its surface. To demonstrate how this new method can be applied to a specific object, we chose the old isolated neutron star candidate RXJ 1856.5-3754, the soft X-ray radiation of which has been studied recently by Walter, Wolk, & Neuhäuser. We fitted the soft X-ray spectrum of this object with neutron star atmosphere models of different chemical compositions and used these fits to calculate the source spectrum over a broad wavelength range. We showed, in particular, that the optical/UV flux expected from this object depends drastically on the composition of its surface. In particular, the neutron star covered with hydrogen would be 5-6 mag brighter than the neutron star with an iron surface. The object should also be observable with EUVE; the EUV flux is expected to be almost twice higher for the iron surface than for the hydrogen one. Thus, multiwavelength observations of this object would enable one to examine, for the first time, chemical composition of the neutron star surface. The method proposed can be applied to other nearby isolated neutron stars.
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U2 - 10.1086/310355
DO - 10.1086/310355
M3 - Article
AN - SCOPUS:33749175851
SN - 0004-637X
VL - 472
SP - L33-L36
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 1 PART II
ER -