1. Warm and diffuse gas and high ionization rate in the Galactic center revealed by observation of H 3 + Takeshi Oka Department of Astronomy and Astrophysics and Department of Chemistry The Enrico Fermi Institute, University of Chicago NRAO April 21, 2011 Tom Geballe Gemini Observatory Ben McCall University of Illinois at U-C Miwa Goto Max-Planck Institut für Astronomie

2. 10458.634 MHz, 25 hrs 46 m Algonquin Telescope 14525.850 MHz, 18 hrs 43 m Green Bank Telescope H–C≡C–C≡C–C≡C–C≡C–C≡N H–C≡C–C≡C–C≡C–C≡N H–C≡C–C≡C–C≡N 1975 C 60 Herbst and Klemperer Watson 1973 TMC 1

3. 2005 Revelation of warm and diffuse gass near GC Oka, Geballe, Goto, Usuda, McCall, ApJ 632, 882 1999 High H 3 + abundance in the Galactic center H 3 +, the new astrophysical probe + 1951 1970 1973 1996 1980 Oka, Phys. Rev. Lett. 45, 531 Laboratory Spectrum 1996 Geballe, Oka, Nature 384, 334 Interstellar H 3 +, Discovery, Dense Clouds H H2H2 H3+H3+ 1989 - 95 2002 Metastable H 3 +, Discovery, Galactic center Goto, McCall, Geballe, Oka, et al. PASJ 54, 951 1975 HC 5 N, HC 7 N, HC 9 N 2008 Ubiquity Central 30 pc of the Galactic center Goto, Geballe, Oka, et al. ApJ 688, 306 T.G. 2010 Exploring wider regions of the Galactic center Geballe, Oka, ApJ, 709, L70

4. Telescopes and spectrometers Telescope D Spectrom. λ/Δλ UKIRT 3.8 m CGS4 40,000 Mauna Kea 1982 Subaru 8.2 m IRCS 20,000 Mauna Kea 2000 Gemini South 8 m Phoenix 60,000 Cerro Pachon 2003 VLT 8.2 m CRIRES 100,000 Cerro Paranal 2006 Gemini North 8 m GENIRS 18,000 Mauna Kea 2011 Subaru UKIRT Gemini South VLT Gemini North

5. Abundant H 3 + in the Central Molecular Zone CMZ R(1, 1) u R(1, 0) T. R. Geballe, Phil. Trans. Roy. Soc. Lond. 200, A358, 2503 3 × 10 14 cm -2 10 -5 10% 400 pc

6. Quintuplet Cluster 1° × 1° 140 pc × 140 pc Super-massive clusters GCS 3-2

7. (J, K) = (3, 3) metastable H 3 +, the fingerprint of GC Metastable 27.2 days 20.4 days Ortho I = 3/2 Para I = 1/2 J K 16 hrs 8 hrs (3,3) (2,2) (1,1) Pan and Oka, 1987, ApJ, 305, 518 Oka and Epp, 2004, ApJ, 613, 349 (1,0) Goto, McCall, Geballe, Usuda, Kobayashi, Terada, Oka, 2002, PASJ, 54, 951 361 K CO J = 1 (2,2) unstable (3,3) metastable (1,1) ground T ~ 250 K n ≤ 100 cm -3 Oka, Geballe, Goto, Usuda, McCall, 2005, ApJ, 632, 882 Spontaneous breakdown of symmetry

8. Simple chemistry of H 3 + : N(H 3 + ) →  ·L Destruction H 3 + + e → H + H + H Production H 2 → H 2 + + e H 2 + + H 2 → H + H 3 +   L = 2 k e N(H 3 + ) (n C /n H ) SV R X / f(H 2 ) 7.3 ×10 -8 cm 3 /s1.6 ×10 -4 < 1 3.1 ×10 15 cm -2 > 3  L > 2.2 ×10 5 cm/s  L 10 -16 s -1 > 700 pc 10 -15 s -1 > 70 pc dn(H 3 + )/dt =  n(H 2 ) = k e n(H 3 + )n(e)

9. Ubiquity of H 3 + Sgr A* to 30 pc East 30 pc Goto, et al. 2008, ApJ, 688, 306

10. 1° × 1° 140 pc × 140 pc Super-massive clusters

11. Search for bright dust-embedded stars for H 3 + spectra 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 band ̲ s 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 brightness youth ? smoothness location - 1.2º < ℓ - ℓº < 1.2º- 0.1º < b - bº < 0.1 º

12. The CO test Most old (late-type) cool stars are useless Bright dust-embedded stars with smooth spectrum are scarce

13. New bright dust-embedded stars suitable for H 3 + spectroscopy

14. Two sightlines with remarkable H 3 + spectrum α 140 pc West ι 68 pc East Geballe and Oka, 2010, ApJ, 709, L70-73 0 – 30 pc East Quintuplet, α, ι

15. H 3 + and CO α 140 pc West ι 68 pc East Geballe and Oka, 2010, ApJ, 709, L70-73

16. H2H2 H2+H2+ H- H- H3+H3+ (H 2 - ) Herschel Observatory

17. Remarkable similarity between velocity profiles of H 3 + toward Iota and H 2 O +, 13 CH + toward Sgr B2 Geballe & Oka, 2010, ApJ, 709, L70 H 3 + R(1,1) l H 2 O + 1 11 ← 0 00 H 2 O + 1 10 ← 1 01 E. Falgarone et al. 2011Schilke et al. 2011, A&A, 521, L11 H 3 + f(H 2 ) = 1 ? H 2 O + f(H 2 ) = 0.1 17 pc

18. 450 μm dust emission in the CMZ (Pierce-Price et al. 2000). Crosses show the stars toward which H 3 + has been observed (Goto et al 2008,, Geballe and Oka 2010).

19. Lazio & Cordes, 1998 ApJ, 505, 715 80 % 10 7-8 K 10 % 10 4-6 K n e 10 cm -3 10 % 50 K 10 4 cm -3 New category of gas in the CMZ Previous concept drastically changed T ~ 250 K n < 100 cm -3 L ~ 60 pc f ~30%  ~ 1.5 × 10 15 s -1 Schultheis et al. 2009, ApJ, 495, 157 1 % ?

20. Chandra 20 pc × 20 pc (0.5 – 8) keV Muno et al. 2003, ApJ, 589, 225 Warwick, Sakano Decourchelle (2006) Revnivtsev et al. (2006) X-ray: Chandra comes to rescue

21. Scrutiny at the core Lo and Claussen, 1983, Nature, 306, 647

22. Yusef-Zadeh, Wardle, Roy, 2007, ApJ, 665, L123 HCN

23. The ISAAC L-band image of the Galactic center showing most of the named sources (from Viehmann et al. 2005)

24. Galactic Disk Dense (molecular) clouds Diffuse clouds Galactic Center (the Central Molecular Zone) New category of gas Circum nuclear disk Extragalactic Object Ultraluminous IR galaxies Magellanic clouds Circumstellar Space Planetary nebulae Protoplanetary nebulae Planets Solar planets Proto-planet Exo-planet Treasure hunting IRAS 19312+190, CRL 618 HD 141569A

25. APCB High Resolution Spectroscopy Joseph von Fraunhofer 1787 – 1826 1814 HαHα NaFeHβHβ Fe,CaCa νt Δν  Δt ~ 1/2π David Brewster, William Herschel, John Herschel, William Draper, Anders Ångstrom, Armand Fizeau, William Huggins, Gustav Kirchhoff, Pierre Janssen, Norman Lockyer, Henry Draper, Herman Vogel, Arthur Schuster, Albert Michelson, Henri Deslandres, William Pickering, Annie Cannon, George Hale, Alfred Fowler, Ejnar Hertzsprung, Walter Adams, Henry Norris Russel, Edwin Hubble, 1. Spectroscopy and astronomy Gerhard Herzberg, Charlie Townes