NEAR-INFRARED IMAGING POLARIMETRY OF BIPOLAR NEBULAE .2. GL-2591

High spatial resolution near-IR polarization and surface brightness images of the reflection nebulosity GL 2591 are presented. The J, H and K surface brightness images reveal two non-concentric 'loops' of nebulosity aligned with the high-velocity, blueshifted outflow from GL 2591 IRS. The polarization vector maps show a centro-symmetric pattern centred on GL 2591 IRS, indicating that it is illuminating a near-IR reflection nebula. Evidence is presented that implies GL 2591 IRS is surrounded by a dense disc or toroid of material. The observed increase in polarization with wavelength for the reflection nebulosity is interpreted as evidence for the presence of grains with a size distribution larger than that found in the diffuse ISM. Models giving the spatial dependence of linear polarization of scattered light for various scattering geometries are presented. A model for the blueshifted outflow, in which the two loops of nebulosity are the result of two discrete mass outbursts from GL 2591 IRS, is presented.