Proposal code

w048

Proposal title

Observing the evolution of the core of LS I +61°303

The

Investigators and their

Affiliations

P.I. A.R. Taylor University of Calgary
S.M. Dougherty University of Calgary/DRAO
M. Peracaula University of Calgary
J.M. Paredes Universitat de Barcelona

Proposal Abstract

The X-ray and gamma-ray binary LSI +61^\circ303 exhibits non-thermal radio outbursts every 26.51 days, rising in 48 hours from a quiesent flux of 20 mJy to a peak of ~300 mJy, followed by a slower decline. Unusual among massive X-ray binaries, this system is gamma-ray bright, yet has low X-ray luminosity. A number of models have been proposed to explain these properties, but no observations have yet been able to disriminate between them. Previous VLBI images reveal expansion and brightening on sub-mas scales. However, these observations fail to image the evolving outburst due to limited uv-coverage. Using HALCA with an array of sensitive GRT's, we can map the dynamical evolution of an outburst. The rapidly changing baseline orientation of HALCA provides the only means to effectively image the dynamical evolution of the outburst ejecta. The expansion velocity and shape of this ejecta are critical discriminants of the models.

The full Cover Sheets (compressed post-script, typically 50kbytes) can be retrieved. Note that many proposals were reduced in extent by the Scientific Review Committee (e.g. by reducing the number of experiments), however the Cover Sheets contain the full proposal as submitted. Also note that AO2 proposals were submitted in May 1998, and information such as affiliations and contact details has changed for some proposers since that time. The Cover Sheets (and the details on this page, which were derived from the Cover Sheets) may therefore have changed.