Gravitational waves and core-collapse supernovae

Abstract

A mechanism of formation of gravitational waves in the Universe is considered for a nonspherical collapse of matter. Nonspherical collapse results are presented for a uniform spheroid of dust and a finite-entropy spheroid. Numerical simulation results on core-collapse supernova explosions are presented for the neutrino and magneto-rotational models. These results are used to estimate the dimensionless amplitude of the gravitational wave with a frequency ν ~ 1300 Hz, radiated during the collapse of the rotating core of a pre-supernova with a mass of 1.2 M ⊙ (calculated by the authors in 2D). This estimate agrees well with many other calculations (presented in this paper) that have been done in 2D and 3D settings and which rely on more exact and sophisticated calculations of the gravitational wave amplitude. The formation of the large-scale structure of the Universe in the Zel’dovich pancake model involves the emission of very long-wavelength gravitational waves. The average amplitude of these waves is calculated from the simulation, in the uniform spheroid approximation, of the nonspherical collapse of noncollisional dust matter, which imitates dark matter. It is noted that a gravitational wave radiated during a core-collapse supernova explosion in our Galaxy has a sufficient amplitude to be detected by existing gravitational wave telescopes.

GW Interferometer Euro-Asian Network: Detection Characteristics for Signals of Known Shape

“…If we take that a rate of events for collapsing star appearing coincides with the rate of events for supernova explosion, it turns out to be at least two orders of magnitude higher than the frequency of the binaries merger per galaxy, namely it is estimated as 0.01 year −1 . The estimation of the expected amplitude of the GW burst from the collapse is 10 −20 -10 −22 for a source in the center of our galaxy [30], which is in the zone of current sensitivity of interferometers LIGO and VIRGO. Interest in recording the signals from the collapse is increased by the existence of parallel neutrino radiation, i.e., the possibility of implementing the multi-messenger astronomy.…”

“…Apparently, the signals of both radiations contain much richer physics than the gravitational bursts (chirps) emitted by the merger of relativistic binaries [14] (the latter is well described already in the Newtonian theory of paragraph 3, and the fine relativistic PPN details of the chirps are not yet resolved). The interconnected temporal structure of neutrino and gravitational bursts from collapsing stars can serve as a unique indicator of the nuclear processes occurring in it [30][31][32]. In particular, bounds in the process of monotonic compression indicate a change in the equations of nuclear matter state with increasing density, temperature, etc.…”

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“…On the contrary, the temporal structure of neutrino and gravitational bursts from a collapsing star is just an indicator of the nuclear processes taking place in it. 17,20,22 In particular, bounces in the monotonic compression course indicate a change in the equation of state of nuclear matter with increasing density, temperature, etc. This argument is the main motive of the BNO INR RAS program for the two-channel search for collapsars in the Galaxy.…”

“…According to the papers (Refs. 17,20) all such processes are developing inside of very short time on the order on ∼ 1 s. However there are other scenarios of multi -stage collapse 21,22 forecasting of multi-radiation flux during of a total collapse duration ∼ 20 s. In our analysis below we take it into account. The numerical modeling of GW radiation from non-spherical collapse 21,22 gives of the enough complex pulse form (Fig.…”

Gravitational waves and core-collapse supernovae

“…According to [14] k ∼ 0.01. We roughly estimate the gravitational wave power from our simulations done in [15] for the core mass is 1.2 M ⊙ [16].…”