scispace - formally typeset
Search or ask a question
Journal ArticleDOI

Runaway stars and the pulsars near the crab nebula.

TL;DR: Runaway stars and pulsars near Crab Nebula, discussing binary system explosion and remnant motion as discussed by the authors, discussing binary systems explosion and residual motion in the Crab Nebula and its surrounding area.
Abstract: Runaway stars and pulsars near Crab Nebula, discussing binary system explosion and remnant motion
Citations
More filters
Journal ArticleDOI
F. Curtis Michel1
TL;DR: In this article, a wide range of fundamental physical problems directly related to how pulsars function are discussed, some of which are independent of the specific pulsar mechanism and others relate directly to the physics of the pulsar and already shed some light on the properties of matter at high density and in strong magnetic fields.
Abstract: There is a wide range of fundamental physical problems directly related to how pulsars function. Some of these are independent of the specific pulsar mechanism. Others relate directly to the physics of the pulsar and already shed some light on the properties of matter at high density (\ensuremath{\sim}${10}^{15}$ g/cc) and in strong magnetic fields (\ensuremath{\sim}${10}^{12}$ G). Pulsars are assumed to be rotating neutron stars surrounded by strong magnetic fields and energetic particles. It is somewhere within this "magnetosphere" that the pulsar action is expected to take place. Currently there has been considerable difficulty in formulating an entirely self-consistent theory of the magnetospheric behavior and there may be rapid revisions in the near future, which is all the more surprising since many of the issues involve "elementary" problems in electromagnetism. One interesting discovery is that charge-separated plasmas apparently can support stable static discontinuities.

769 citations

Journal ArticleDOI
TL;DR: In this article, the authors investigated the birth and evolution of radio pulsars in the galaxy and found no evidence for multimodality of the distribution and favor one in which the absolute one-dimensional velocity components are exponentially distributed and with a threedimensional mean velocity of 380 km s-1.
Abstract: We investigate the birth and evolution of Galactic isolated radio pulsars. We begin by estimating their birth space velocity distribution from proper-motion measurements of Brisken and coworkers. We find no evidence for multimodality of the distribution and favor one in which the absolute one-dimensional velocity components are exponentially distributed and with a three-dimensional mean velocity of 380 km s-1. We then proceed with a Monte Carlo-based population synthesis, modeling the birth properties of the pulsars, their time evolution, and their detection in the Parkes and Swinburne Multibeam surveys. We present a population model that appears generally consistent with the observations. Our results suggest that pulsars are born in the spiral arms, with a galactocentric radial distribution that is well described by the functional form proposed by Yusifov & Kucuk, in which the pulsar surface density peaks at radius ~3 kpc. The birth spin period distribution extends to several hundred milliseconds, with no evidence of multimodality. Models that assume the radio luminosities of pulsars to be independent of the spin periods and period derivatives are inadequate, as they lead to the detection of too many old simulated pulsars in our simulations. Dithered radio luminosities proportional to the square root of the spin-down luminosity accommodate the observations well and provide a natural mechanism for the pulsars to dim uniformly as they approach the death line, avoiding an observed pileup on the latter. There is no evidence for significant torque decay (due to magnetic field decay or otherwise) over the lifetime of the pulsars as radio sources (~100 Myr). Finally, we estimate the pulsar birthrate and total number of pulsars in the Galaxy.

706 citations

Journal ArticleDOI
TL;DR: In this article, the authors present results of simulations of stellar collapse and explosions in spherical symmetry for progenitor stars in the 8-10 M ⊙ range with an O-Ne-Mg core.
Abstract: We present results of simulations of stellar collapse and explosions in spherical symmetry for progenitor stars in the 8-10 M ⊙ range with an O-Ne-Mg core. The simulations were continued until nearly one second after core bounce and were performed with the PROMETHEUS/VERTEX code with a variable Eddington factor solver for the neutrino transport, including a state-of-the-art treatment of neutrino-matter interactions. Particular effort was made to implement nuclear burning and electron capture rates with sufficient accuracy to ensure a smooth continuation, without transients, from the progenitor evolution to core collapse. Using two different nuclear equations of state (EoSs), a soft version of the Lattimer & Swesty EoS and the significantly stiffer Wolff & Hillebrandt EoS, we found no prompt explosions, but instead delayed explosions, powered by neutrino heating and the neutrino-driven baryonic wind which sets in about 200ms after bounce. The models eject little nickel (<0.015 M ⊙ ), explode with an energy of?0.1 x 10 51 erg, and leave behind neutron stars (NSs) with a baryonic mass near 1.36 M ⊙ . Different from previous models of such explosions, the ejecta during the first second have a proton-to-baryon ratio of Y e ? 0.46, which suggests a chemical composition that is not in conflict with galactic abundances. No low-entropy matter with Ye « 0.5 is ejected. This excludes such explosions as sites of a low-entropy r-process. The low explosion energy and nucleosynthetic implications are compatible with the observed properties of the Crab supernova, and the small nickel mass supports the possibility that our models explain some subluminous type II-P supernovae.

574 citations


Cites background from "Runaway stars and the pulsars near ..."

  • ...Also the Crab Nebula’s progenitor was proposed to be in this mass window (Gott et al. 1970; Arnett 1975; Woosley et al. 1980; Hillebrandt 1982)....

    [...]

Journal ArticleDOI
TL;DR: In this paper, the authors examined key interactions of double-neutron star (DNS) systems and evaluated their accretion history during the high-mass X-ray binary stage, the common envelope phase, and the subsequent Case BB mass transfer.
Abstract: Double neutron star (DNS) systems represent extreme physical objects and the endpoint of an exotic journey of stellar evolution and binary interactions. Large numbers of DNS systems and their mergers are anticipated to be discovered using the Square Kilometre Array searching for radio pulsars, and the high-frequency gravitational wave detectors (LIGO/VIRGO), respectively. Here we discuss all key properties of DNS systems, as well as selection effects, and combine the latest observational data with new theoretical progress on various physical processes with the aim of advancing our knowledge on their formation. We examine key interactions of their progenitor systems and evaluate their accretion history during the high-mass X-ray binary stage, the common envelope phase, and the subsequent Case BB mass transfer, and argue that the first-formed NSs have accreted at most $\sim 0.02\,{M}_{\odot }$. We investigate DNS masses, spins, and velocities, and in particular correlations between spin period, orbital period, and eccentricity. Numerous Monte Carlo simulations of the second supernova (SN) events are performed to extrapolate pre-SN stellar properties and probe the explosions. All known close-orbit DNS systems are consistent with ultra-stripped exploding stars. Although their resulting NS kicks are often small, we demonstrate a large spread in kick magnitudes that may, in general, depend on the past interaction history of the exploding star and thus correlate with the NS mass. We analyze and discuss NS kick directions based on our SN simulations. Finally, we discuss the terminal evolution of close-orbit DNS systems until they merge and possibly produce a short γ-ray burst.

478 citations

Journal ArticleDOI
TL;DR: The discovery of neutrino masses suggests the likely existence of gauge singlet fermions that participate in the neutrinos mass generation via the seesaw mechanism as discussed by the authors, which can play an important role in astrophysics and cosmology.

439 citations