1. LARGE PICTURE OF THE GALACTIC CENTER STUDIED BY H3+:
HIGH IONIZATION RATE,
PREVAILING WARM AND DIFFUSE GAS,
AND NON-ROTATING EXPANDING MOLECULAR RING
Takeshi Oka,
Department of Astronomy and Astrophysics and Department of Chemistry,
The Enrico Fermi Institute, University of Chicago,
Thomas R. Geballe, Gemini Observatory
Nick Indriolo, Department of Physics and Astronomy, Johns Hopkins University
Miwa Goto, Universitäts-Sternwarte München, Germany
June 18, 2013, Columbus meeting

2. The Longitude – Velocity (l – v) Diagram
Face-on view v
Rotating ring
Expanding and Rotating
Expanding ring
Sun

3. The Story of Two Rings Rotating Molecular Ring (RMR)
Expanding Molecular Ring (EMR) OH HI
OH Sgr A
Kaifu et al. 1972
13CO
120 pc Ring
Bolton et al. 1964
Rougoor & Oort 1960
Oort 1977
Bally et al. 1987
Sofue 1995
H2CO
Scoville 1972
Kormendy & Kennicutt, 2004
Binney et al. 1991
Athannasoula 1992
Rodriguez-Fernandez et al. 2006
Sofue 1995

4. 47 Stars for H3+ Spectroscopy
140 pc East B2 B1
140 pc West D λ C A* α κ ι δ θ γ β

5. Symmetric (l – v) Diagram → Purely Expanding Ring

6. Sofue 1995, PASJ, 47, 551

7. Expanding Ring cannot be explained by Gravitation

8. RMR of Dense Gas + EMR of Diffuse Gas
Double Ring
RMR of Dense Gas + EMR of Diffuse Gas
~100 pc km/s
~140 pc km/s
(1055 – 1056 erg) Kaifu et al.
(4 × 1054, 2 × 1055 erg) Scoville
(2 × 1054 erg) Sofue