2000/08/14 by S. B. Popov, С. Б. Попов, M. E. Prokhorov +13
Earth and Planetary Sciences · Physics and Astronomy · #Gamma-ray bursts and supernovae #Geophysics and Gravity Measurements #Pulsars and Gravitational Waves Research #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/0008199
7 pages, 3 PostScript figures, to be presented at the conference "Hot points in astrophysics", Dubna, August 22-26, 2000
arxiv created 2000/08/14 · arxiv updated 2009/12/01
In 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> ∼ (200-300) \rm km s-1. The same conclusion is reached for both a constant magnetic field (B∼ 1012 G) and for a magnetic field decaying exponentially with a timescale ∼ 109 yr. These results, moreover, constrain the fraction of low velocity stars, which could have escaped pulsar statistics, to ∼few percents. Then we show that the range of minimum value of magnetic moment, μb: ∼ 1029.5≥ μb ≥ 1028 \rm G \rm cm3, and the characteristic decay time, td: ∼ 108≥ td ≥ 107 \rm yrs, can be excluded assuming the standard initial magnetic momentum, μ0=1030 \rm G \rm cm3, 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 μ0. It is shown that old accreting INSs become more abundant than young cooling INSs at X-ray fluxes below ∼ 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 ∼ 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 ∼ 106 yr was much higher than inferred from radiopulsar observations.