Collaborative Research: Exploring Gas throughout the Milky Way Galaxy and Magellanic System of Galaxies with the WHAM-South Telescope

University Of Wisconsin-Madison, Madison WI

Investigators

Abstract

The collaborators on this endeavor will use a telescope called WHAM to complete a long-term project to map the warm gas in the Milky Way Galaxy and nearby "satellite" galaxies known as the Magellanic Clouds. The telescope is a rather unusual design and was built specifically for this purpose. WHAM was constructed and has been maintained and operated for 20 years primarily with NSF funding. WHAM has led to Postdoctoral degrees and active careers in science for a large number of young researchers. After a decade at the Kitt Peak Observatory in Arizona the telescope is now located in Chile. It is operated remotely (over the internet) and can map the Milky Way in the light produced by different atoms and ions (charged atoms). Since this warm gas is an important component of the galaxy, astronomers can better understand how the galaxy is changing and can test theories of how it was formed and how it is evolving. Graduate and undergraduate students will continue to be involved in data collection and analysis as part of the operations team. This is a collaborative project from the University of Wisconsin-Madison and the Space Science Institute in Boulder that seeks to continue operations support for the Wisconsin H-Alpha Mapper (WHAM), a remotely controlled facility that is dedicated to the detection and study of faint optical emission lines in the disk and halo of the Milky Way.  The WHAM facility consists of a 15 cm aperture dual-etalon Fabry-Pérot spectrometer coupled to a 60 cm aperture siderostat, which together provide a one-degree field-of-view on the sky and produce a 12 km/s resolution spectrum across a 200 km/s spectral window.  A CCD camera serves as a multichannel detector, recording the spectrum as a Fabry-Pérot "ring image" without scanning. WHAM began operations on Kitt Peak in January 1997 from where it surveyed H-alpha emission throughout the entire northern sky (the WHAM-Sky Survey, or WHAM-SS). Complementary observations of various regions in other diagnostic emission lines were also obtained. WHAM has subsequently been refurbished and moved to Cerro Tololo, Chile, achieving first southern light in March 2009. The WHAM-SS has since been completed, and observations in other lines ([SII] and [NII]) have begun. With this award the team will complete mapping in [SII] and [NII], and extend the WHAM (H-alpha) survey to broader velocities. The overarching goal is to complete existing surveys and support current students through to the completion of existing projects. The combined datasets will be used to probe the composition, temperature, heating, and ionization of the Diffuse Ionized Gas (DIG) and Warm Ionized Medium (WIM). The team will investigate the relationship between these components and regions of active star formation. The WHAM facility can also be used to study the earth's atmosphere, comets, zodiacal dust, and lunar sodium.