Mapping AG Carinae - Long-slit spectroscopy and coronographic imaging of the nebula and jet

Abstract

New high-resolution images of the nebula around the luminous blue variable AG Carinae have been obtained with the Johns Hopkins Adaptive Optics Coronograph at the Swope 40 inch (1 m) telescope, Las Campanas, in the light of H-alpha + forbidden N II and in a narrow V continuum. The images confirm the presence of highly axisymmetric features in AG Carinae's circumstellar environment. In addition, we present new, high signal-to-noise ratio long-slit spectroscopic data, in the spectral range (6363-7254 A), spatial resolution 0.89 arcsec/pixel, and spectral resolution 40 km/s, with full spatial coverage of the nebula. The radial velocity data are consistent with a hollow, expanding shell but also show noticeable deviations from spherical symmetry. Possible interpretations are examined, such as the presence of an equatorial disk due to stellar rotation or, possibly, to a close, undetected companion, the presence of a magnetic field sufficiently strong to drive the wind, or density and pressure gradients in the local interstellar environment.