The Wisconsin H-Alpha Mapper Sky Survey: A First Look at the Global Distribution of Diffuse Ionized Gas in the Milky Way

Type Conference Paper
Names Nitish Chopra, L. M. Haffner, R. J. Reynolds, G. J. Madsen, A. S. Hill, K. A. Barger, K. P. Jaehnig, E. J. Mierkiewicz, J. W. Percival, N. M. Pingel, D. T. Reese, M. C. Gostisha
Conference Name Bulletin of the American Astronomical Society
Volume 43
Pages 25107
Date January 1, 2011
Short Title The Wisconsin H-Alpha Mapper Sky Survey
Library Catalog NASA ADS
Abstract After a year of observations from its new location on Cerro Tololo, the Wisconsin Hα Mapper (WHAM) has nearly completed survey observations below δ < -30°. This new data combined with the Northern Sky Survey provides the first kinematic, all-sky survey of diffuse Hα from the Milky Way. Aside from many large-scale, locally-ionized regions, much of this emission arises from the Warm Ionized Medium (WIM), a diffuse but thick component of the ISM that extends several kiloparsecs into the Galactic halo. WHAM was designed primarily to study the WIM, delivering a spatially integrated spectrum from a one-degree beam on the sky covering 200 km s-1 with 12 km s-1 spectral resolution. The short exposures of the survey reach sensitivity levels of about 0.1 R (EM 0.2 pc cm-6) and reveal emission toward nearly every direction in the sky. Here, we present our early efforts at reducing this new southern dataset and offer a first look at the global distribution and kinematics of diffuse ionized gas throughout the Galaxy. WHAM and the research presented here are funded by NSF award AST-0607512. We also thank the excellent and responsive staff at CTIO in Chile for helping to keep our remote installation fully operational.
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