1. Gas Detection in Galaxies and Techniques Comparisons Advisors: David Frayer and Ron Maddalena Teresa Ashcraft Rich Cosentino Lucas Hunt Karen Lee-Waddell Virginie Montes

2. Galaxies Selected IRAS 16504+0228 Seyfert 2 galaxy IRAS 12596-1529 IRAS 11257+5850 Interacting galaxy Galaxy 1Galaxy 2 Galaxy 3

3. Observation Procedure Two data sets and three techniques: – frequency switching – position switching – “brain-dead” Maddelena Magic!! (freq+position switch) Observation time: 45 min per galaxy

4. Methods Comparison: Galaxy 1 Three methods Position and Frequency-position switch RMS ps = 7.7x10 -3 RMS fsps = 6.6x10 -3

5. Methods Comparison RMS ps = 7.2x10 -3 RMS fsps = 5.8x10 -3 RMS ps = 8.4x10 -3 RMS fsps = 7.3x10 -3 Galaxy 2Galaxy 3 RMS improvement: expected = 1.6 and observed = 1.2

6. Baseline Comparison Position switchFrequency-position switch Galaxy 1 Galaxy 3

7. Baseline Comparison Position switch Frequency-position switch Galaxy 2 N HI = 1.7x10 20 cm -2 N HI = 1.6x10 20 cm -2

8. OH Spectral line Galaxy 1

9. OH Spectral line ARP 220 Expected OH 1665 : OH 1667 = 5:9 (LTE) Observed OH 1665 : OH 1667 = 1:4 (Maser IR pumping)