Astronomy and Astrophysics – Astronomy
Scientific paper
Dec 1992
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1992aas...181.6007b&link_type=abstract
American Astronomical Society, 181st AAS Meeting, #60.07; Bulletin of the American Astronomical Society, Vol. 24, p.1217
Astronomy and Astrophysics
Astronomy
Scientific paper
We discuss the observability of isolated neutron stars (NSs) accreting interstellar material as sources of quiescent and transient UV and X-ray radiation. We study their spatial and kinematic properties in the solar neighborhood through Monte Carlo simulations of 10(5) orbits in the Galactic potential. We present a much faster semi-analytic technique which is capable of reproducing the full kinematic properties of the local NS population in remarkable agreement with the Monte Carlo results. We derive the accretion rate distributions associated with the various phases of the interstellar medium (ISM). Assuming blackbody emission and 10(9) NSs in the Galaxy, we estimate that, in the case of isotropic (polar cap) accretion, of order 2000 (10000) old NSs should be observed as X-ray sources in the ROSAT-XRT all-sky survey, with up to 600 (100) of them showing up at longer wavelengths in the ROSAT-WFC survey. The number of detectable NSs in the forthcoming EUVE all-sky survey should be close to 200 (20). If old NSs are magnetized, we estimate that an additional 1000 sources located in giant molecular clouds should be observed in the ROSAT-XRT survey. NSs detected by ROSAT-XRT will be strongly concentrated towards the Galactic plane. Isolated NSs in the local cavity can contribute only 0.1% of the SXRB at 100 eV. We argue, however, that the integrated emission from solitary NSs accreting material in the Galactic plane could give rise to the Galactic X-ray ridges observed by Exosat and HEAO A-2. We investigate the emission properties of accreting NSs moving supersonically in dense atomic and molecular clouds, and show that they will produce elongated, \lq`cometary" HII regions, a possible characteristic observational signature. Material accumulated by slow accretion onto the polar cap of magnetized NSs located in diffuse clouds might be unstable to nuclear burning and lead to X-ray bursts. We estimate a rate of 25 yr(-1) energetic, ~ 5times 10(37) ergs events within 1 kpc, which might be detectable by HETE. Such bursts may also be responsible for some of the fast X-ray transients observed by HEAO A-1.
Blaes Omer
Madau Piero
No associations
LandOfFree
Can We Observe Accreting, Isolated Neutron Stars? does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Can We Observe Accreting, Isolated Neutron Stars?, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Can We Observe Accreting, Isolated Neutron Stars? will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1111221