1. Central Molecular Zone (CMZ): the Treasure House of H 3 + Takeshi Oka Thomas R. Geballe Gemini Observatory Miwa Goto Max Planck Institute for Astronomy Tomonori Usuda Subaru Telescope Benjamin J. McCall University of Illinois, Urbana-Champaign The Enrico Fermi Institute, the University of Chicago Tetsuya Nagata Kyoto University Tomoharu Oka University of Tokyo Farhad Yusef-Zadeh Northwestern University Harvey Liszt National Radio Astronomy Observatory EFI mini-symposium April 20, 2007 H 3 + : the novel probe of the CMZ

2. Central Molecular Zone Morris, Serabyn, ARA&A (1996) CMZ OH, H 2 CO, CO, CS, NH 3, HCN H3+H3+ Mezger, Duschl, Zylka, A&A Rev. (1996) R(1, 1) u R(1, 0) Geballe Phil. Trans. RSL A358, 2503 (2000) the treasure house of H 3 +

3. Inferred face-on view of the CMZ The Expanding Molecular Ring Oka, Hasegawa, Sato, Tsuboi, Miyazaki, ApJS 118, 455 (1998) Sawada, Hasegawa, Handa, Cohen, MNRAS 349, 1167 (2004) Scoville, ApJ 175, L127 (1972) 145 km s -1 200 pc 130 pc 100 km s -1 EMR

4. Lazio & Cordes, ApJ 505, 715 (1998) 0.8 10 7 K 0.1 10 6 K 10 cm -3 0.1 10 2 K 10 4 cm -3 Gas in the CMZ : pre-H 3 + 160 pc × 30 pc 7 × 10 7 K Suzaku Dec. 6, 2006 Koyama et al. PASJ 59, S245 (2007)

5. 27° × 40° The Galactic center

6. Quintuplet Arches 1° × 1° 140 pc × 140 pc The Quituplet Stars Central Binary pinwheel nebula, Science (2006) GCS 3-2

8. Telescope and spectrometer UKIRT 3.8 m CGS4 8 km s -1 Mauna Kea 1982 Subaru 8.2 m IRCS 15 km s -1 Mauna Kea 2000 Gemini South 8 m Phoenix 5 km s -1 Cerro Pachon 2003 VLT 8 m CRIRES ≤3 km s -1 Cerro Paranal 2006

9. Breaking Symmetry Interstellar NH 3 Oka, Shimizu, Shimizu, Watson, ApJ 165, L15 (1971) Interstellar H 3 + Pan, Oka, ApJ 305, 518 (1986) Metastable 27.2 days 20.4 days μ Critical Density 200 cm -3 Ortho I = 3/2 Para I = 1/2 J K Collision H 3 + + H 2 → (H 5 + ) * → H 3 + + H 2 16 hrs 8 hrs  ++ = uuu The ideal rotational levels of H 3 + (3,3) (2,2) Unstable (1,1) Ground 361 K

10. CO J = 1 (2,2) unstable (3,3) metastable (1,1) ground Spectroscopy Oka, Geballe, Goto, Usuda, McCall, ApJ 632, 882 (2005) 130 pc 100 km s -1

11. Discovery of high temperature (T ~ 250 K), low density (n ≤ 100 cm -3 ) clouds Oka & Epp, ApJ 613,349 (2004)

12. Dimension of the discovered gas ζL = 2 k e N(H 3 + ) (n C /n H ) SV R X / f 7.3 ×10 -8 cm 3 /s1.6 ×10 -4 1 3.1 ×10 15 cm -2 3 - 10 Sodroski et al ApJ 452, 262 (1995) ζL = (2.5 – 8.4) × 10 5 cm/s ζ (s -1 )L (pc) 10 -16 (0.8 - 2.1) k 10 -15 80 - 210 COBE DIRBE 120 pc 100 km s -1

13. Harvey Liszt Phil. Trans. R. Soc. A 364, 3049 (2006) ζ = 10 -17 s -1

14. Eight YSO’s within 30 pc of the GC Subaru Telescope (2,2) densitometer (3,3) thermometer (1,1) ground level (2,2) densitometer (3,3) thermometer (1,1) ground level

15. The warm and diffuse gas is ubiquitous and has a large volume filling factor T = 220 K – 400 K n ≤ 100 cm -3 L min ~ 80 – 120 pc R X = 3 - 10

16. Lazio & Cordes, ApJ 505, 715 (1998) 0.8 10 7 K 0.1 10 6 K 10 cm -3 0.1 10 2 K 10 4 cm -3 Gas in the CMZ : post-H 3 + Warm and diffuse gas250 K 10 2 cm -3 0.01 ? ?

17. Chandra 20 pc × 20 pc (0.5 – 8) keV Muno et al. ApJ 589, 225 (2003) Warwick, Sakano Decourchelle (2006) Revnivtsev et al. (2006)

18. Hyperstrong Radio-wave Scattering in the Galactic Center. II A Likelihood Analysis of Free Electrons in the Galactic Center Lazio & Cordes, ApJ 505, 715 (1998) 0.8 10 7 K 0.1 10 6 K 10 cm -3 0.1 10 2 K 10 4 cm -3 Gas in the CMZ : post-H 3 + Warm and diffuse gas250 K 10 2 cm -3 0.01 ? ? Folded Fields as the Source of Extreme Radio-wave Scattering in the Galactic Center Goldreich and Sridhar, ApJ 640, L159 (2006)

19. Extragalactic H 3 + in ULIRG Geballe, Goto, Usuda, Oka, McCall ApJ 644, 907 (2006) Z = 0.05821

20. Controversies T. Oka No hot gas in the Expanding Molecular Ring F. Le PetitDiffuse gas cannot be that hot J. BlackInfrared pumping (1, 0) (3, 0) (2, 0) (3, 3) F. Yusef-Zadeh 4 categories of gases ApJ 637, L101 (2006) Linnott & Rawlings Dynamically evolving cloud A&A 448, 425 (2006)

21. The Infrared Pumping 10.2 ms 25.3 ms 3.75 hrs V = 0 V 2 = 1 (1, 0) (3, 3) (3, 0) (2, 0) A new estimate of the Galactic interstellar radiation field between 0.1 μm and 1000 μm T. A. Porter & A. W. Strong, Cosmic Ray Conference Pune (2005) Pump rate (s -1 )Infrared photon flux (cm -2 s -1 Hz -1 )

22. Three Proton System + I = 3/2 ortho I = 1/2 para  ++ = uuu p = uud n = udd

23. H – K’ A V = [(H-K’) + 0.097]/0.051 Cotera, Simpson, Erickson, Colgan, Burton, Allen, ApJS 129, 123 (2000)

26. Harvey Liszt Phil. Trans. R. Soc. A 364, 3049 (2006)

27. Cotera, Simpson, Erickson, Colgan, Burton, Allen, ApJS 129, 123 (2000)

28. The Quintuplet Okuda et al. ApJ 351, 89 (1990)