The Arcminute Morphology of the WIM Toward the Local Perseus Arm of the Galaxy

POSTER

Abstract

We used the Virginia Tech Spectral-Line Imaging Camera (SLIC) to image the warm ionized interstellar medium (WIM) toward the Local Perseus Arm. We obtained a series of images, each of which is 10$^\circ$-wide, and has arcminute-resolution. The images show three basic types of structures --- compact clouds with diameters greater than several degrees, those that are 1$^\circ$ or less in diameter, and extended filaments which span several degrees in length but have thicknesses of only a few tens of arcminutes. The data show that [S {\sc ii}]/H$\alpha$ ratios are, on average, nearly six times higher in the filaments than in the clouds, which indicates that emission from collisionally excited, singly-ionized S$^+$ is the dominant emission source within the filaments. In clouds, the lower [S {\sc ii}]/H$\alpha$ values are evidence that the H$\alpha$ recombination line of photoionized hydrogen dominates.

Authors

  • Phillip Nelson

    Roanoke College

  • John Simonetti

    Virginia Tech

  • Rahul Kulkarni

    Materials and Structures Laboratory, Tokyo Institute of Technology, Jefferson Lab, 12000 Jefferson Avenue, MS 58, Suite 17, Newport News, VA 23606, VirginiaTech, Department of Physics, University of South Alabama, New York University, University of Tennessee Knoxville, Georgia College, North Georgia College \& State Univ., North Carolina Central University, TUNL, James Madison University, Physics Department, Hollins University; JQI, University of Aarhus, University of Tennessee, UNC at Asheville, The College of New Jersey, CERN, Florida Institute of Technology, Mechanical Engineering Department, University of New Mexico, Department of Physics, Florida State University, JINR, Vanderbilt, Tsinghua University, LBNL, Vanderbilt and LBNL, Vanderbilt University, Vanderbilt University, Tsinghua University, Vanderbilt University, LBNL, NBPHS, Vanderbilt University, Dept. of Physics and Astronomy - James Madison University, National High Magnetic Field Laboratory, U. of South Alabama Dept. of Chemistry, U. of South Alabama Dept. of Physics, Ohio State University, Wright State University, Engineering Science and Mechanics, Virginia Tech, US, Department of Nanobio Materials and Electronics, GIST, Republic of Korea, Department of Physics, Virginia Tech