Nota de FísicaPublicado
Gravitational Radiation and Gamma-Ray Bursts from Accreting Neutron Stars
Herman J. Mosquera Cuesta; J. C. N. de Araujo; O. D. Aguiar; J. E. Horvath
2000
Dados da publicação
- Autores
- Herman J. Mosquera Cuesta; J. C. N. de Araujo; O. D. Aguiar; J. E. Horvath
- Tipo
- Nota de Física
- Status
- Publicado
- Data de publicação
- 2000
- Descrição
- It is well known that hydrodynamic instabilities can be induced in rapidly rotating low magnetic field neutron stars, which accrete mass from a companion in both high and low mass X-ray binaries. The dynamical instability, in particular, takes place when the rotational to potential self-gravitational energy ratio, <math>\beta \equiv T/|W|</math>, overcomes a critical value <math>\beta \simeq 0.2738</math>. Besides the formation of a bar, spiral arms can also be formed, as well as mass can be ejected. In this paper we argue that after mass ejection from the unstable spinning neutron star, matter goes into the formation of a high-velocity disk-like thick accretion structure, which fragments into blobs driven by gravitational (Jean's) instability. The surrounding matter (blobs) is captured back onto the compact star in a short-scale highly dynamic transient passing through the formation of a disk-collapsed-star system. During the whole system evolution gravitational waves (GWs) in different frequency bands and with distinct waveforms are produced. We here pay attention in particular to two different sources of GWs not previously predicted: the inspiraling of the blobs before crashing the neutron star surface, and the blobs impact themselves. When the blobs impact on the neutron star surface a powerful gamma-ray burst (GRB) can be also produced. We found that during the GRB that we estimate to have an effective temperature of <math>\simeq 770</math> keV and energy of the order of <math>10^{51}</math> ergs, the characteristic amplitude and signal frequency are <math>h_c \sim 10^{-20}\!\,</math> and <math>f_{gw} \simeq</math> 676 Hz, respectively, for a source at 10 kpc. Even stronger signals are produced during the inspiraling phase of the blobs (<math>h \simeq 3.4 \times 10^{-19})</math>. Prospective detection of these GW bursts by resonant-mass detectors such the TIGAs network and also by interferometric observatories such as LIGO and VIRGO are discussed and found likely.
- Ano
- 2000
- Número
- CBPF-NF-083/00
- Vínculo com tese
- Não
- Vínculo com bolsa
- Não