Mechanism for X-ray production in extars

Abstract

This presentation attempts to describe in very qualitative terms a theory of production of high energy radiation (soft and hard X-rays) in magnetoactive plasmas of astrophysical interest. Special emphasis has been placed on the application of our model to extars and in particular to Sco X-l. More rigorous arguments may be found else where [1] and the interested reader is urged to consult that reference for more details.Because the construction of our model for X-ray production is independent of evolutionary considerations, in the body of the paper we have steered clear of such admittedly important problems as the origin and nature of the forces holding an extar together. Nor have we dealt adequately with the ultimate source of energy in extars. Our guiding philosqphy has been somewhat akin to that taken by an earlier generation of astrophysicists in the context of stellar structures. It will be recalled that there too was an 'insurmountable problem', that of the energetics of stellar luminosities. Nevertheless the major results for a large class of stellar structures were obtained by applying rather elementary physical concepts. To this day, they stand relatively un changed by the discovery of nuclear synthesis as the source of stellar radiation. It is quite possible that the principles governing the origin and dynamics of extars as well as other new and strange objects in galactic and extragalactic space, such as quasars and pulsars, lie outside of contemporary physics. If that is so, then these recent astro nomical discoveries are bound to serve as a stimulus for a new synthesis in physics, much as other, long past astronomical discoveries led to past syntheses. Nonetheless it is tempting to apply some simple ideas stemming from contemporary physics, and see how well one can account for the observed properties of extars to date. It is this course that we propose to explore below.For reasons dealt with at great length elsewhere [1] our point of departure is that the bulk of extar radiation, viz. X-rays, is due to synchrotron emission by relativistic electrons in a preexisting magnetic field. For the present purposes we assume that the energy required to account for the luminosity of extars is that lodged in the magnetic field. In this context, it is irrelevant whether or not the energy content of this field is replenished by a more fundamental, underlying celestial body -here this consider ation would merely change the estimate of the effective lifetime of typical X-ray sources. What is important, however, is that a magnetic field is the only feasible means of storing significant amounts of energy in space without encountering unduly large * Present address: Visidyne, Inc.,