Millisecond pulsars with extremely strong magnetic fields as a cosmological source of γ-ray bursts
TL;DR: In this article, a new model for γ-ray bursts at cosmological distances was proposed, based on the formation of rapidly rotating neutron stars with surface magnetic fields of the order of 1015.
Abstract: THE spatial and luminosity distribution of γ-ray bursts as observed by the BATSE instrument on the Compton Gamma Ray Observatory1,2 provides support for the revival of the idea3,4 that the burst sources are at cosmological distances5. I present here a new model for γ-ray bursts at cosmological distances, based on the formation of rapidly rotating neutron stars with surface magnetic fields of the order of 1015. Such objects could form by the gravitational collapse of accreting white dwarfs with anomalously high magnetic fields in binaries, as in magnetic cataclysmic binaries. Once formed, such rapidly rotating and strongly magnetized neutron stars would lose their rotational kinetic energy catastrophically, on a timescale of seconds or less: rotation of the magnetic field creates a strong electric field, and hence an electron–positron plasma, which I show to be optically thick and in quasi-thermodynamic equilibrium. This plasma flows away from the neutron star at relativistic speeds, and X-ray and γ-ray emission at the photosphere of this relativistic wind may then reproduce the observational characteristics of a γ-ray burst.
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TL;DR: In this paper, the authors used the observed time delay of $(+1.74\pm 0.05)\,{\rm{s}}$ between GRB 170817A and GW170817 to constrain the difference between the speed of gravity and speed of light to be between $-3
Abstract: On 2017 August 17, the gravitational-wave event GW170817 was observed by the Advanced LIGO and Virgo detectors, and the gamma-ray burst (GRB) GRB 170817A was observed independently by the Fermi Gamma-ray Burst Monitor, and the Anti-Coincidence Shield for the Spectrometer for the International Gamma-Ray Astrophysics Laboratory. The probability of the near-simultaneous temporal and spatial observation of GRB 170817A and GW170817 occurring by chance is $5.0\times {10}^{-8}$. We therefore confirm binary neutron star mergers as a progenitor of short GRBs. The association of GW170817 and GRB 170817A provides new insight into fundamental physics and the origin of short GRBs. We use the observed time delay of $(+1.74\pm 0.05)\,{\rm{s}}$ between GRB 170817A and GW170817 to: (i) constrain the difference between the speed of gravity and the speed of light to be between $-3\times {10}^{-15}$ and $+7\times {10}^{-16}$ times the speed of light, (ii) place new bounds on the violation of Lorentz invariance, (iii) present a new test of the equivalence principle by constraining the Shapiro delay between gravitational and electromagnetic radiation. We also use the time delay to constrain the size and bulk Lorentz factor of the region emitting the gamma-rays. GRB 170817A is the closest short GRB with a known distance, but is between 2 and 6 orders of magnitude less energetic than other bursts with measured redshift. A new generation of gamma-ray detectors, and subthreshold searches in existing detectors, will be essential to detect similar short bursts at greater distances. Finally, we predict a joint detection rate for the Fermi Gamma-ray Burst Monitor and the Advanced LIGO and Virgo detectors of 0.1–1.4 per year during the 2018–2019 observing run and 0.3–1.7 per year at design sensitivity.
2,633 citations
Cites background from "Millisecond pulsars with extremely ..."
...Within the fireball, kinetic energy is imparted to particles entrained in the outflow, although alternative models exist in which the energy outflow occurs mostly as Poynting flux (Usov 1992; Lyutikov & Blandford 2003)....
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TL;DR: A review of the current theoretical understanding of the physical processes believed to take place in GRB's can be found in this article, where the authors focus on the afterglow itself, the jet break in the light curve, and the optical flash that accompanies the GRB.
Abstract: Gamma-ray bursts (GRB's), short and intense pulses of low-energy $\ensuremath{\gamma}$ rays, have fascinated astronomers and astrophysicists since their unexpected discovery in the late sixties. During the last decade, several space missions---BATSE (Burst and Transient Source Experiment) on the Compton Gamma-Ray Observatory, BeppoSAX and now HETE II (High-Energy Transient Explorer)---together with ground-based optical, infrared, and radio observatories have revolutionized our understanding of GRB's, showing that they are cosmological, that they are accompanied by long-lasting afterglows, and that they are associated with core-collapse supernovae. At the same time a theoretical understanding has emerged in the form of the fireball internal-external shocks model. According to this model GRB's are produced when the kinetic energy of an ultrarelativistic flow is dissipated in internal collisions. The afterglow arises when the flow is slowed down by shocks with the surrounding circumburst matter. This model has had numerous successful predictions, like the predictions of the afterglow itself, of jet breaks in the afterglow light curve, and of the optical flash that accompanies the GRB's. This review focuses on the current theoretical understanding of the physical processes believed to take place in GRB's.
1,800 citations
TL;DR: In this article, it was shown that the inner engine that accelerates the relativistic flow is hidden from direct observations and therefore it is difficult to infer its structure directly from current observations.
1,405 citations
TL;DR: In this article, it was shown that most long-duration soft-spectrum gamma-ray bursts are accompanied by massive stellar explosions (GRB-SNe) and that most of the energy in the explosion is contained in nonrelativistic ejecta (producing the supernova) rather than in the relativistic jets responsible for making the burst and its afterglow.
Abstract: Observations show that at least some gamma-ray bursts (GRBs) happen simultaneously with core-collapse supernovae (SNe), thus linking by a common thread nature's two grandest explosions. We review here the growing evidence for and theoretical implications of this association, and conclude that most long-duration soft-spectrum GRBs are accompanied by massive stellar explosions (GRB-SNe). The kinetic energy and luminosity of well-studied GRB-SNe appear to be greater than those of ordinary SNe, but evidence exists, even in a limited sample, for considerable diversity. The existing sample also suggests that most of the energy in the explosion is contained in nonrelativistic ejecta (producing the supernova) rather than in the relativistic jets responsible for making the burst and its afterglow. Neither all SNe, nor even all SNe of Type Ibc produce GRBs. The degree of differential rotation in the collapsing iron core of massive stars when they die may be what makes the difference.
1,389 citations
TL;DR: In this article, a comprehensive sample of all gamma-ray burst (GRB) afterglows with known distances is presented, and their conical opening angles are derived based on observed broadband breaks in their light curves.
Abstract: We present a comprehensive sample of all gamma-ray burst (GRB) afterglows with known distances, and we derive their conical opening angles based on observed broadband breaks in their light curves. Within the framework of this conical jet model, we correct for the geometry and we find that the gamma-ray energy release is narrowly clustered around 5 × 10^(50) ergs. We draw three conclusions. First, the central engines of GRBs release energies that are comparable to ordinary supernovae. Second, the broad distribution in fluence and luminosity for GRBs is largely the result of a wide variation of opening angles. Third, only a small fraction of GRBs are visible to a given observer, and the true GRB rate is several hundred times larger than the observed rate.
1,225 citations
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TL;DR: In this paper, it was shown that the extraction of gauge invariants from a formally gauge invariant theory is ensured if one employs methods of solution that involve only gauge covariant quantities.
Abstract: This paper is based on the elementary remark that the extraction of gauge invariant results from a formally gauge invariant theory is ensured if one employs methods of solution that involve only gauge covariant quantities. We illustrate this statement in connection with the problem of vacuum polarization by a prescribed electromagnetic field. The vacuum current of a charged Dirac field, which can be expressed in terms of the Green's function of that field, implies an addition to the action integral of the electromagnetic field. Now these quantities can be related to the dynamical properties of a "particle" with space-time coordinates that depend upon a proper-time parameter. The proper-time equations of motion involve only electromagnetic field strengths, and provide a suitable gauge invariant basis for treating problems. Rigorous solutions of the equations of motion can be obtained for a constant field, and for a plane wave field. A renormalization of field strength and charge, applied to the modified lagrange function for constant fields, yields a finite, gauge invariant result which implies nonlinear properties for the electromagnetic field in the vacuum. The contribution of a zero spin charged field is also stated. After the same field strength renormalization, the modified physical quantities describing a plane wave in the vacuum reduce to just those of the maxwell field; there are no nonlinear phenomena for a single plane wave, of arbitrary strength and spectral composition. The results obtained for constant (that is, slowly varying fields), are then applied to treat the two-photon disintegration of a spin zero neutral meson arising from the polarization of the proton vacuum. We obtain approximate, gauge invariant expressions for the effective interaction between the meson and the electromagnetic field, in which the nuclear coupling may be scalar, pseudoscalar, or pseudovector in nature. The direct verification of equivalence between the pseudoscalar and pseudovector interactions only requires a proper statement of the limiting processes involved. For arbitrarily varying fields, perturbation methods can be applied to the equations of motion, as discussed in Appendix A, or one can employ an expansion in powers of the potential vector. The latter automatically yields gauge invariant results, provided only that the proper-time integration is reserved to the last. This indicates that the significant aspect of the proper-time method is its isolation of divergences in integrals with respect to the proper-time parameter, which is independent of the coordinate system and of the gauge. The connection between the proper-time method and the technique of "invariant regularization" is discussed. Incidentally, the probability of actual pair creation is obtained from the imaginary part of the electromagnetic field action integral. Finally, as an application of the Green's function for a constant field, we construct the mass operator of an electron in a weak, homogeneous external field, and derive the additional spin magnetic moment of $\frac{\ensuremath{\alpha}}{2\ensuremath{\pi}}$ magnetons by means of a perturbation calculation in which proper-mass plays the customary role of energy.
5,579 citations
1,927 citations
TL;DR: It has been shown that gamma-ray bursters are at cosmological distances, like quasars, with a redshift of about 1 or 2 as discussed by the authors, making them the brightest objects known in the universe.
Abstract: It is proposed that some, perhaps most, gamma-ray bursters are at cosmological distances, like quasars, with a redshift of about 1 or 2. This proposition requires a release of supernova-like energy of about 10 to the 51st ergs within less than 1 s, making gamma-ray bursters the brightest objects known in the universe, many orders of magnitude brighter than any quasars. This power must drive a highly relativistic outflow of electron-positron plasma and radiation from the source. It is proposed that three gamma-ray bursts, all with identical spectra, detected from B1900 + 14 by Mazets, Golenetskii, and Gur'yan and reported in 1979, were all due to a single event multiply imaged by a gravitational lens. The time intervals between the successive bursts, 10 hr to 3 days, were due to differences in the light travel time for different images.
1,467 citations
TL;DR: On montre que les sources Rγ peuvent etre optiquement epaisses a la creation de paires si la densite d'energie dans la region emettrice est suffisamment elevee as discussed by the authors.
Abstract: On montre que les sources Rγ peuvent etre optiquement epaisses a la creation de paires si la densite d'energie dans la region emettrice est suffisamment elevee. Les sources pourraient alors se situer a de grandes distances meme cosmologiques
807 citations