The statistics of slow interstellar accretion onto neutron stars

Blaes, Omer; Rajagopal, M.

doi:10.1086/170642

Cited by 24 publications

(23 citation statements)

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“…The authors of [116] are motivated by a discussion on the nature of gamma-ray bursts. Their PS study has a goal to calculate the distribution of masses accreted onto isolated NSs in the solar neighborhood.…”

Section: Neutron Star Census and Isolated Accretorsmentioning

confidence: 99%

Population synthesis in astrophysics

Попов

Прохоров

2007

Phys.-Usp.

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Section: Neutron Star Census and Isolated Accretorsmentioning

confidence: 99%

Population synthesis in astrophysics

Попов

Прохоров

2007

Phys.-Usp.

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“…We consider galaxies with four masses, expressed in the units of Milky Way mass (M MW ¼ 1:5 Â 10 11 M ): 1.0, 0.1, 0.01, and 0:001 Â M MW . For a Milky Way-mass galaxy the bulge potential (i ¼ 1) is described by a 1 ¼ 0 kpc, b 1 ¼ 0:277 kpc, and M 1 ¼ 1:12 Â 10 10 M ; the disk potential (i ¼ 2) is described by a 2 ¼ 4:2 kpc, b 2 ¼ 0:198 kpc, and M 2 ¼ 8:78 Â 10 10 M ; the halo potential is described by r c ¼ 6:0 kpc and M h ¼ 5:0 Â 10 10 M ; and r cut ¼ 100 kpc (Paczyń ski 1990;Blaes & Rajagopal 1991).To obtain the potential of a galaxy with the mass M MW we rescale all the masses by the factor of and the distances a i , b i , r c , R, and z by 1/3 . Such scaling keeps the galaxy density constant, and we made sure that our model galaxies have flat rotation curves.…”

Section: Dynamical Evolution Of Stars In Model Galaxiesmentioning

confidence: 99%

Study of Gamma‐Ray Burst Binary Progenitors

Belczyński

Bulik

Rudak

2002

ApJ

162

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Recently much work in studying gamma-ray bursts (GRBs) has been devoted to revealing the nature of outburst mechanisms and to studies of GRB afterglows. These issues have also been closely followed by the quest to identify GRB progenitors. Several types of progenitors have been proposed for GRBs: the most promising objects seem to be collapsars, compact object binaries, mergers of compact objects with helium cores of evolved stars in common envelope episodes, and also the recently discussed connection of GRBs with supernovae. In this paper we consider the binary star progenitors of GRBs: white dwarf-neutron star (WD-NS) binaries, white dwarf-black hole (WD-BH) binaries, helium core-neutron star (He-NS) mergers, helium core-black hole (He-BH) mergers, and double neutron star (NS-NS) and neutron star-black hole binaries (NS-BH). Using population synthesis methods we calculate merger rates of these binary progenitors and compare them to the observed BATSE GRB rate. For the binaries considered, we also calculate the distribution of merger sites around host galaxies and compare them to the observed locations of GRB afterglows with respect to their hosts. We find that the rates of binary GRB progenitors in our standard model are lower than the observed GRB rates if GRBs are highly collimated. However, the uncertainty in the population synthesis results is too large to make this a firm conclusion. Although some observational signatures seem to point to collapsars as progenitors of long GRBs, we find that mergers of WD-NS, He-NS, He-BH, and NS-NS systems also trace the star formation regions of their host galaxies, as it is observed for long GRBs. We also speculate about possible progenitors of short-duration GRBs. For these, the most likely candidates are still mergers of compact objects. We find that the locations of NS-NS and NS-BH mergers with respect to their hosts are significantly different. This may allow us to distinguish between these two progenitor models once current and near future missions, such as HETE-2 or Swift, measure the locations of short GRBs.

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“…The NS orbits in the Galactic gravitational potential were also investigated by Blaes & Rajagopal (1991), Blaes & Madau (1993), Zane et al (1995), Popov & Prokhorov (1998), and Popov et al (2000, hereafter BR, BM, Z95, PP98, and P00, respectively) in order to constrain the number of nearby NSs accreting from the interstellar medium (ISM, see Treves et al 2000, and references therein). BR, BM, and Z95 adopted initial conditions similar to those of P90 except the distribution of birth velocities, which, following Narayan & Ostriker (1990), was assumed to be Maxwellian with a dispersion of 60 km s −1 .…”

Section: Introductionmentioning

confidence: 99%

Galactic neutron stars

Sartore¹,

Ripamonti

Treves³

et al. 2010

A&A

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Aims. Neutron stars (NSs) produced in the Milky Way are supposedly ten to the eighth -ten to the ninth -of which only ∼2 × 10 3 are observed. Constraining the phase space distribution of NSs may help to characterize the yet undetected population of stellar remnants. Methods. We performed Monte Carlo simulations of NS orbits, under different assumptions concerning the Galactic potential and the distribution of progenitors and birth velocities. We study the resulting phase space distributions, focusing on the statistical properties of the NS populations in the disk and in the solar neighbourhood. Results. It is shown that ∼80 percent of NSs are in bound orbits. The fraction of NSs located in a disk of radius 20 kpc and width 0.4 kpc is < ∼ 20 percent. Therefore the majority of NSs populate the halo. Fits for the surface density of the disk, the distribution of heights on the Galactic plane and the velocity distribution of the disk are given. We also provide sky maps of the projected number density in heliocentric Galactic coordinates (l, b). Our results are compared with previous ones reported in the literature. Conclusions. Obvious applications of our modeling are in the revisiting of accretion luminosities of old isolated NSs, the issue of the observability of the nearest NS and the NS optical depth for microlensing events. These will be the scope of further studies.

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The statistics of slow interstellar accretion onto neutron stars

Cited by 24 publications

References 0 publications

Population synthesis in astrophysics

Population synthesis in astrophysics

Study of Gamma‐Ray Burst Binary Progenitors

Galactic neutron stars

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