Nearby, isolated, old neutron stars (IONSs) accreting interstellar material might be detectable as sources of UV and soft X-ray radiation. We investigate the interaction between this radiation field and the surrounding medium, assumed to consist of purely hydrogen and helium. This interaction results in a cometary H II region around the star which we model in detail by including all the relevant time-dependent ionization, recombination, heating, and cooling processes. We find that preheating of the ambient gas to temperatures higher than 104 K may significantly quench the accretion rate onto these neutron stars, thereby reducing the IONS number counts in the EUV and soft X-ray bands predicted by previous investigations. However, the reprocessing of hard radiation by the surrounding H II regions may enhance the detectability of IONSs at optical wavelengths. Searches for nearby accreting IONSs are currently being undertaken.

Blaes, O., Warren, O., Madau, P. (1995). Accreting, isolated neutron stars. III. Preheating of infalling gas and cometary H II regions. THE ASTROPHYSICAL JOURNAL, 454(1), 370-381 [10.1086/176488].

Accreting, isolated neutron stars. III. Preheating of infalling gas and cometary H II regions

Madau, P
1995

Abstract

Nearby, isolated, old neutron stars (IONSs) accreting interstellar material might be detectable as sources of UV and soft X-ray radiation. We investigate the interaction between this radiation field and the surrounding medium, assumed to consist of purely hydrogen and helium. This interaction results in a cometary H II region around the star which we model in detail by including all the relevant time-dependent ionization, recombination, heating, and cooling processes. We find that preheating of the ambient gas to temperatures higher than 104 K may significantly quench the accretion rate onto these neutron stars, thereby reducing the IONS number counts in the EUV and soft X-ray bands predicted by previous investigations. However, the reprocessing of hard radiation by the surrounding H II regions may enhance the detectability of IONSs at optical wavelengths. Searches for nearby accreting IONSs are currently being undertaken.
Articolo in rivista - Articolo scientifico
Accretion: accretion disks; H ii regions; Stars: neutron; Ultraviolet: stars; X-rays: stars;
English
1995
454
1
370
381
none
Blaes, O., Warren, O., Madau, P. (1995). Accreting, isolated neutron stars. III. Preheating of infalling gas and cometary H II regions. THE ASTROPHYSICAL JOURNAL, 454(1), 370-381 [10.1086/176488].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/454146
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