Isolated Neutron Stars in the Galaxy

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dc.creatorPopov, S. B.
dc.creatorProkhorov, M. E.
dc.creatorColpi, M.
dc.creatorTreves, A.
dc.creatorTurolla, R.
dc.creatorLipunov, V. M.
dc.date2000-08-14
dc.date.accessioned2026-07-07T01:54:55Z
dc.date.available2026-07-07T01:54:55Z
dc.descriptionIn this article we briefly review our recent results on evolution and properties of isolated neutron stars (INSs) in the Galaxy. As the first step we calculate a {\it census} of INSs in our Galaxy. We infer a lower bound for the mean kick velocity of NSs, $ <V> \sim $(200-300) ${\rm km s^{-1}}$. The same conclusion is reached for both a constant magnetic field ($B\sim 10^{12}$ G) and for a magnetic field decaying exponentially with a timescale $\sim 10^9$ yr. These results, moreover, constrain the fraction of low velocity stars, which could have escaped pulsar statistics, to $\sim$few percents. Then we show that the range of minimum value of magnetic moment, $μ_b$: $\sim 10^{29.5}\ge μ_b \ge 10^{28} {\rm G} {\rm cm}^3$, and the characteristic decay time, $t_d$: $\sim 10^8\ge t_d \ge 10^7 {\rm yrs}$, can be excluded assuming the standard initial magnetic momentum, $μ_0=10^{30} {\rm G} {\rm cm}^3$, if accreting INSs are observed. For these parameters an INS would never reach the stage of accretion from the interstellar medium even for a low space velocity of the star and high density of the ambient plasma. The range of excluded parameters increases for lower values of $μ_0$. It is shown that old accreting INSs become more abundant than young cooling INSs at X-ray fluxes below $\sim 10^{-13}$ erg cm$^{-2}$ s$^{-1}$. We can predict that about one accreting INS per square degree should be observed at the {\it Chandra} and {\it Newton} flux limits of $\sim 10^{-16}$ erg cm$^{-2}$ s$^{-1}.$ The weak {\it ROSAT} sources, associated with INSs, can be young cooling objects, if the NSs birth rate in the solar vicinity during the last $\sim 10^6$ yr was much higher than inferred from radiopulsar observations.
dc.description7 pages, 3 PostScript figures, to be presented at the conference "Hot points in astrophysics", Dubna, August 22-26, 2000
dc.identifierhttps://arxiv.org/abs/astro-ph/0008199
dc.identifierhttp://arxiv.org/abs/astro-ph/0008199
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/1480
dc.subjectAstrophysics
dc.titleIsolated Neutron Stars in the Galaxy
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