1. The Survey for Ionized Gas in the Galaxy, Made with Arecibo SIGGMA – the ALFA RRL Survey Robert Minchin

2. What? ALFA survey for Hydrogen, Helium and Carbon Radio Recombination Lines: – H163α – H174α – He163α – He174α – C163α – C174α Commensal with P-ALFA in the inner Galaxy Lead project (supporting P-ALFA and ALFA ZOA) in the outer Galaxy

3. Where? Milky Way image: NASA/JPL-Caltech/R. Hurt Inner Galaxy 30° < l < 75° Outer Galaxy 175° < l 207°

4. Why? Identification of H II regions Measure electron temperatures (via line to continuum ratio) Probe properties of nebular Photo- Dissociation Regions (withcarbon RRLs) Look for extended emission from the Warm Interstellar Medium

5. When? Observations started in 2010 Currently on-going How? ‘Leapfrog’ mapping based on the P-ALFA tiling pattern Co-addition of the H, He and C lines within the 300 MHz ALFA bandpass

6. Who? Loren Anderson (WVU) – PI Robert Minchin (Arecibo) Yervant Terzian (Cornell) Ed Churchwell (UWM) Bin Liu (NAO/CAS) Anish Roshi (NRAO) Logan Hough (WVU)

7. Results?