LARGE PICTURE OF THE GALACTIC CENTER STUDIED BY H3

+: HIGH IONIZATION RATE,

PREVAILING WARM AND DIFFUSE GAS, AND NON-ROTATING EXPANDING MOLECULAR RING

June 18, 2013, Columbus meeting

Miwa Goto, Universitäts-Sternwarte München, Germany

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

The Longitude – Velocity (l – v) Diagram

Rotating ring

Expanding ring

Face-on view(l – v) diagram

Sun

v

Expanding and Rotating

The Story of Two RingsRotating Molecular Ring (RMR) Expanding Molecular Ring (EMR)

Bally et al. 1987Sofue 1995

HI13CO120 pc Ring

Binney et al. 1991Athannasoula 1992

Rougoor & Oort 1960Oort 1977

Rodriguez-Fernandez et al. 2006

Kormendy & Kennicutt, 2004

OH Sgr A

Bolton et al. 1964

Kaifu et al. 1972

Scoville 1972

OH

H2CO

Sofue 1995

47 Stars for H3+ Spectroscopy

A*

B1B2D C

E

α

βγδθι

λ

κ

1.00

0.95

0.90

0.85

0.80

0.75

0.70

-200 -150 -100 -50 0 50 100

GCS 4

NHS 21

NHS 25

NHS 42

FMM 361

140 pc West140 pc East

Symmetric (l – v) Diagram → Purely Expanding Ring

Sofue 1995, PASJ, 47, 551

Expanding Ring cannot be explained by Gravitation

Double RingRMR of Dense Gas + EMR of Diffuse Gas

years10140km/s

pc140 6

~100 pc 100 km/s

~140 pc 140 km/s

(1055 – 1056 erg) Kaifu et al.

(4 × 1054, 2 × 1055 erg) Scoville

(2 × 1054 erg) Sofue