Using multi-frequency VLBA and MERLIN observations of 32 compact radio sources within 30(deg) <= l <= 75(deg ) , mid bmid < 3(deg) , we test suggestions that the distribution of galactic electron-density fluctuations contains a spiral component. We derive Scattering Measure (SM = int CN(2) ds) values from scatter-broadening seen in the multi-frequency images of the sources. Lines of sight in this longitude range pass from the Sagittarius Arm, through an interarm region, into the Orion Arm and large, abrupt changes in the distribution of SM are expected if spiral structure is present in the electron-density fluctuations. Initial results do indeed show just such effects.
American Astronomical Society Meeting Abstracts
- Pub Date:
- December 1998