Physics NotePublished
Gravitational-to-Electromagnetic Waves Conversion and Gamma-Ray Bursts Calorimetry: The GRB980425/SN1998bw erg Radio Emission
Herman J. Mosquera Cuesta
2001
Publication details
- Authors
- Herman J. Mosquera Cuesta
- Type
- Physics Note
- Status
- Published
- Publication date
- 2001
- Description
- The unusual features of supernova (SN) 1998bw and its apparent association with the gamma-ray burst (GRB) event GRB980425 were highlighted by Kulkarni et al. [1,2] . At its peak SN1998bw was anomalously superluminous in radio wavelengths with an inferred fluence: <math>E_{radio} \geq 10^{49}\,\!</math>erg [Kulkarni, S., et al., Nat. 395, 663 (1998)], while the apparent expansion velocity of its ejecta <math>(\sim 10^{-5}M_\odot)\,\!</math> suggests a shock wave moving relativistically <math>(V_{exp} \sim 2c)\,\!</math>. The SN1998bw unique properties strengthen the case for it to be linked with GRB980425. I present a consistent, novel mechanism to explain the peculiar event SN1998bw and similar phenomena in GRBs: Conversion of powerful, high frequency <math>(\sim 2kHz)\,\!</math> gravitational waves (GWs) into electromagnetic waves (EMWs) might have taken place during SN1998bw. Yet, conversion of GRB photons into GWs, as advanced in Johnston, Ruffini and Zerilli [Phys. Lett 49B, 185 (1974)], may also occur. These processes can produce GRBs depleted in <math> \gamma-rays \,\!</math> but enhanced in x-rays, for instance, or even more plausible to induce GRB, those with no optical afterglow. The class of GWs needed to drive these gamma-ray bursts' calorimetric changes may be generated by: a) the non-axisymmetric dynamics of a torus surrounding the hypernova (or failed supernova) magnetized stellar-mass black hole (BH) remnant, as in the van Putten's mechanism for driving long GRBs powered by the BH spin-energy [Phys. Rev. Lett. 87, 091101 (2001) [8], or in Van Putten and Ostriker [Astrophys. J. 552, L32 (2001)] mechanism for accounting for the bi-modal distribution in durations in GRBs, where the torus magneto-hydrodynamics may be dominated by either hyper-accretion on to a slowly spinning BH or suspended accretion on to a fast rotating BH. b) the just formed black hole with eletromagnetic structure (EMBH); as in the Ruffini et al. GRBs central engine mechanism [Astrophys. J. 555, L107 (2001); Astrophys. J. 555, L113 (2001)] [9], provided the issue concerning the origin of the black hole charge be suitably clarified. In both of these mechanisms the total energy radiated as GWs is about <math>\rm \Delta E_{GWs} \sim 10^{53}erg (\frac{M}{10 M_\odot})\,\!</math>, which for the conversion efficiency estimated here turns out to be enough to explain the superluminous radio wavelength emission from SN1998bw. Thus, I argue this process could have induced the enhancement in the radio-luminosity of SN1998bw as evidenced in its light curve (Figure 2 in Ref.[1]), and optical light curve of GRB980326 [Bloom et al., Nature 401, 453 (1998)] and GRB990712 [Björnsson et al., Astrophys. J. 552, L121 (2001)]. Moreover, GWs-driven plasma density perturbations moving at the speed of light may up(or down)-convert fireball photons [10], which could render further substancial modifications of the gamma-ray burst/supernovae calorimetry.}
- Year
- 2001
- Number
- CBPF-NF-058/01
- Linked to a thesis
- No
- Linked to a grant
- No