Central Molecular Zone CMZ the Treasure House of

Central Molecular Zone (CMZ): the Treasure House of H 3+: the novel probe of the CMZ H 3+ Takeshi Oka The Enrico Fermi Institute, the University of Chicago Thomas R. Geballe Miwa Goto Tomonori Usuda Benjamin J. Mc. Call Gemini Observatory Max Planck Institute for Astronomy Subaru Telescope University of Illinois, Urbana-Champaign 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

Central Molecular Zone the treasure house of H 3+ R(1, 1)u R(1, 0) Geballe Phil. Trans. RSL A 358, 2503 (2000) OH, H 2 CO, CS, NH 3, HCN CMZ H 3+ Morris, Serabyn, ARA&A (1996) Mezger, Duschl, Zylka, A&A Rev. (1996)

Inferred face-on view of the CMZ The Expanding Molecular Ring EMR 200 pc 145 km s-1 Scoville, Ap. J 175, L 127 (1972) 130 pc 100 km s-1 Oka, Hasegawa, Sato, Tsuboi, Miyazaki, Ap. JS 118, 455 (1998) Sawada, Hasegawa, Handa, Cohen, MNRAS 349, 1167 (2004)

Gas in the CMZ : pre-H 3+ 160 pc × 30 pc 7 × 107 K Suzaku Dec. 6, 2006 Koyama et al. PASJ 59, S 245 (2007) 0. 8 107 K 0. 1 106 K 10 cm-3 0. 1 102 K 104 cm-3 Lazio & Cordes, Ap. J 505, 715 (1998)

The Galactic center 27° × 40°

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

Telescope and spectrometer UKIRT 3. 8 m Subaru　 8. 2 m Gemini South 8 m VLT 8 m CGS 4 8 km s-1 IRCS 15 km s-1 Phoenix 5 km s-1 CRIRES ≤ 3 km s-1 Mauna Kea Cerro Pachon Cerro Paranal 1982 2000 2003 2006

The ideal rotational levels of H 3+ Ortho I = 3/2 Breaking Symmetry μ J Para I = 1/2 8 hrs 20. 4 days Unstable ++ = uuu 16 hrs (2, 2) (3, 3) 361 K 27. 2 days (1, 1) Metastable Ground Critical Density 200 cm-3 K Collision H 3+ + H 2 → (H 5+)* → H 3+ + H 2 Interstellar NH 3 Oka, Shimizu, Watson, Ap. J 165, L 15 (1971) Interstellar H 3+ Pan, Oka, Ap. J 305, 518 (1986)

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

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

Dimension of the discovered gas 7. 3 × 10 -8 cm 3/s 1. 6 × 10 -4 1 ζL = 2 ke N(H 3+) (n. C/n. H)SV RX / f 3. 1 × 1015 cm-2 3 - 10 COBE DIRBE Sodroski et al Ap. J 452, 262 (1995) ζL = (2. 5 – 8. 4) × 105 cm/s ζ (s-1) 120 pc 100 km s-1 10 -16 10 -15 L (pc) (0. 8 - 2. 1) k 80 - 210

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

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

The warm and diffuse gas is ubiquitous and has a large volume filling factor T = 220 K – 400 K n ≤ 100 cm-3 Lmin ~ 80 – 120 pc RX = 3 - 10

Gas in the CMZ : post-H 3+ ? ? 0. 8 107 K 0. 1 106 K 10 cm-3 0. 1 102 K 104 cm-3 0. 01 Lazio & Cordes, Ap. J 505, 715 (1998) 250 K 102 cm-3 Warm and diffuse gas

Chandra 20 pc × 20 pc (0. 5 – 8) ke. V Muno et al. Ap. J 589, 225 (2003) Warwick, Sakano Decourchelle (2006) Revnivtsev et al. (2006)

Gas in the CMZ : post-H 3+ ? ? 0. 8 107 K 0. 1 106 K 10 cm-3 0. 1 102 K 104 cm-3 0. 01 250 K 102 cm-3 Warm and diffuse gas Hyperstrong Radio-wave Scattering in the Galactic Center. II A Likelihood Analysis of Free Electrons in the Galactic Center Lazio & Cordes, Ap. J 505, 715 (1998) Folded Fields as the Source of Extreme Radio-wave Scattering in the Galactic Center Goldreich and Sridhar, Ap. J 640, L 159 (2006)

Extragalactic H 3+ in ULIRG Z = 0. 05821 Geballe, Goto, Usuda, Oka, Mc. Call Ap. J 644, 907 (2006)

Controversies T. Oka No hot gas in the Expanding Molecular Ring F. Le Petit J. Black Diffuse gas cannot be that hot Infrared pumping Linnott & Rawlings (2, 0) Dynamically evolving cloud A&A 448, 425 (2006) F. Yusef-Zadeh 4 categories of gases Ap. J 637, L 101 (2006) (3, 0) (1, 0) (3, 3)

The Infrared Pumping V 2 = 1 (2, 0) 25. 3 ms Pump rate (s-1) 10. 2 ms (3, 0) Infrared photon flux (cm-2 s-1 Hz-1) 3. 75 hrs (3, 3) V=0 (1, 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)

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

H – K’ AV = [(H-K’) + 0. 097]/0. 051 Cotera, Simpson, Erickson, Colgan, Burton, Allen, Ap. JS 129, 123 (2000)

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

Cotera, Simpson, Erickson, Colgan, Burton, Allen, Ap. JS 129, 123 (2000)

The Quintuplet Okuda et al. Ap. J 351, 89 (1990)