1. H3+H3+

2. Search for hot and bright stars for H 3 + spectroscopy Near the Galactic center Takeshi Oka Department of Astronomy and Astrophysics and Department of Chemistry The Enrico Fermi Institute, University of Chicago and T. R. Geballe Gemini Observatory OSU international symposium on molecular spectroscopy, June 25, 2009

3. (2,2) (3,3) (1,1) (2,2) (3,3) (1,1) 8 stars within 30 pc from GC all show the warm and diffuse gas T = 220 - 400 K n ≤ 100 cm -3 Goto, Usuda, Nagata, Geballe, McCall, Indriolo, Suto, Henning, Morong, Oka, ApJ, 688, 306 (2008)

4. A lucky summer at the Gemini South Observatory

5. The great ocean of truth lay all undiscovered before us We must find hot and bright young stars ! Long pathlength of H 3 +

6. Old (late-type) stars are useless

7. Nagata, Hyland, Straw, Sato, Kawara, ApJ, 406, 501 (1993) Bright and hot young stars are scarce

8. Search for bright and hot stars in the CMZ GLIMPSE Point Source Catalogue of the Spitzer Space Telescope, L to M Ramírez et al. 2008, ApJS, 175, 147 2MASS photometry at J, H, and K bands Skrutskie et al. 2006, AJ, 131, 1163 ~ 2,000,000 stars L < 7.5 ~ 3,000 stars (J – K)/(K – L) < 2.5K - L > 1.5J - K > 5 ~ 300 stars Low res. CO first overtone, 2.2 – 2.4μm Candidate stars Selected stars High res. H 3 + and CO spectroscopy 83 stars so far 10 new stars and 5 known stars Star L J – K K – L (J – K)/(K – L) GCS3-2 3.03 7.33 3.16 2.32 GCS4 3.71 7.65 3.45 2.22 NHS21 4.62 7.03 2.76 2.55* NHS25 6.24 4.81* 1.27* 3.79* brightness youth hotness location

9. Typical hot young star and cool old star (both very bright!) HotCool Spectra taken by UIST spectrometer of the UKIRT CO 2 – 0 3 – 1 4 – 2 5 – 3

10. Medium resolution spectroscopy at UKIRT using UIST spectrometer

12. # Star Spectrum location 1 J 17432173 728_24 K=6.5 L=3.8 132 pc West 2 J 17432988 808_56 K=8.8 L=4.5 127 pc West 3 J 17441867 728_28 K=10.0 L=6.4 80 pc West ? 4 J 17444083 731_64 K=9.4 L=6.4 45 pc West 5 J 17450483 815_33 K=9.0 L=6.5 30 pc West 6 J 17452861 815_71 K=9.2 L=6.6 10 pc out of plane 7 J 17461514 731_68 K=10.1 L=5.6 Close to Quint. 8 J 17461783 731_72 K=7.8 L=5.5 Close to Quint. 9 J 17463219 728_40 K=9.2 L=6.4 43 pc East 10 J 17470264 808_143 K=10.2 L=6.5 ?? 11 J 17470898 815_79 K=10.4 L=6.6 84 pc East. 12 J 17474486 731_76 K=10.3 L=4.7 96 pc East Candidate stars

13. High resolution spectroscpy for radial location

14. The central 2 pc Circum nuclear disk Adaptive Optics needed VLT, Subaru The central 30 pc Super-massive clusters Velocity analysis GS Whole CMZ Hunting stars UKIRT Observation Subaru, GS Tons of work ahead of us → IRTF → SOAR

15. Radio CO, CS, HCN, CH emission H 3 + IR abs. Understanding a monster X-rayγ-ray HII region Radio recomb. Fine structure Radio continuum H 2 FIR H 2 IR emission CO IR abs

16. H3+H3+