Gamma-ray lines from neutron stars as probes of fundamental physics
Abstract
The detection of gamma-ray lines produced at the surface of neutron stars will serve to test both the strong and gravitational interactions under conditions unavailable in terrestrial laboratories. Observation of a single redshifted gamma-ray line, combined with an estimate of the mass of the star will serve as a strong constraint on allowable equations of state of matter at supernuclear densities. Detection of two redshifted lines arising from different physical processes at the neutron star surface can provide a test of the strong principle of equivalence. Expected fluxes of nuclear gamma-ray lines from accreting neutron stars were calculated, including threshold, radiative transfer and redshift effects. The most promising probes of neutron star structure are the deuterium formation line and the positron annihilation line. Detection of sharp redshifted gamma-ray lines from X-ray sources such as Cyg X-1 would argue strongly in favor of a neutron star rather than black hole identification for the object.
- Publication:
-
Gamma Ray Spectroscopy in Astrophysics
- Pub Date:
- August 1978
- Bibcode:
- 1978grsa.rept..275B
- Keywords:
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- Astronomical Spectroscopy;
- Emission Spectra;
- Gamma Rays;
- Line Spectra;
- Neutron Stars;
- Physics;
- Stellar Radiation;
- Equations Of State;
- Equivalence;
- Positron Annihilation;
- Radiative Transfer;
- Red Shift;
- Space Radiation