2. Further studies of λ 5797.1 Diffuse Interstellar Band Takeshi Oka, Lew M. Hobbs, Daniel E. Welty, Donald G. York Department of Astronomy and Astrophysics, University of Chicago Julie Dahlstrom Department of Physics and Astronomy Carthage College Adolf N. Witt Department of Physics and Astronomy University of Toledo June 25, 2015, International Symposium on Molecular Spectroscopy, University of Illinois at Urbana Champaign

3. The Diffuse Interstellar Bands (DIBs) Ben McCall Don York Apache point observatory

4. 414 bands 380 bands Two contrasting sightlines, C 2 C 3 rich and poor HD 204827 Highest N(C 2 ) and N(C 3 ) HD 183143 C 2, C 3 not detected

5. Our previous work on λ 5797.1 DIB x-axis Stars ~ 300 (SDSS > 5000) y-axis DIBs ~ 500 Herschel 36 λ 5797 DIB From Don York October 8, 2011 Her 38 rotational excitation high T r ~ 90 K B´ ‒ B < 0 linear molecule polar molecule n ≤ 7 Polar molecule Parallel band of prolate top T r = 2.73 K 5 ≤ n ≤ 7 AAT R ~ 600,000

6. Vibronic satellites of λ 5797.1 DIB 5797.2 HD 183143 73 DIBs HD 204827 120 DIBs 5545.15494.2 5797.1 Å 17250.12 cm -1

7. Correlations between DIBs × ×

8. 0.943 (77) 0.941 (77) 0.903 (109) Vibronic bands 1147 cm -1 602 cm -1 5797.1 Å 17250.12 cm -1 5545.1 Å 18034.1 cm -1 5494.1 Å 18201.3 cm -1 784.0cm -1 951.2 cm -1

9. Correlations: 5797.1 vs 5494 and 5545 r = 0.941 77 starsr = 0.943 77 stars HD 21389 HD 229059 Hobbs et al. (2009)

10. Line shape ESO LaSilla 3.6-m telescope R = 115,000

11. II. 5797 DIB and RR 5800 by the same molecule

12. Emission and Absorption Herschel 36 T r ~ 90 K Red Rectangle 3000 K

13. Draine, Ann. Rev. Astron. Astrophys. 41, 241 (2003) III Anomalous microwave emission

14. A&A 565, A103 (2014) ApJ 460, 1 (1996)

15. I am scared and mystified High column density 10 13 cm -2 Snow & McCall, ARAA, 44, 367 (2004) PAH C 60