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X-RAY NOVAE AND THE EVIDENCE FOR BLACK HOLE EVENT HORIZONS (2001)
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BibTeX
@MISC{Narayan01x-raynovae,
author = {Ramesh Narayan and Michael R. Garcia and Jeffrey E. Mcclintock},
title = {X-RAY NOVAE AND THE EVIDENCE FOR BLACK HOLE EVENT HORIZONS},
year = {2001}
}
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Abstract
We discuss new observations of X-ray novae which provide strong evidence that black holes have event horizons. Optical observations of 13 X-ray novae indicate that these binary stars contain collapsed objects too heavy to be stable neutron stars. The objects have been identified as black hole candidates. X-ray observations of several of these X-ray novae in quiescence with the Chandra X-ray Observatory show that the systems are approximately 100 times fainter than nearly identical X-ray novae containing neutron stars. The advection-dominated accretion flow model provides a natural explanation for the difference. In this model, the accreting gas reaches the accretor at the center with a large amount of thermal energy. If the accretor is a black hole, the thermal energy will disappear through the event horizon, and the object will be very dim. If the accretor is a neutron star or any other object with a surface, the energy will be radiated from the surface, and the object will be bright. We discuss alternate interpretations of the data that eliminate the need for advection-dominated accretion. Most of these alternatives still require an event horizon to explain the unusually low X-ray luminosities of the black hole candidates. Some of the alternatives are also inconsistent with observations. 1
Keyphrases
x-ray nova evidence black hole event horizon event horizon neutron star black hole thermal energy black hole candidate advection-dominated accretion flow model binary star collapsed object natural explanation strong evidence advection-dominated accretion chandra x-ray observatory show low x-ray luminosity new observation stable neutron star alternate interpretation identical x-ray nova optical observation x-ray observation large amount
