H2S2
March 28-31, 1966, APS Durham, NC
April 22, 1966, Invitation to give a seminar
October, 1970
Scrutiny of the Central Parsec of the Galactic
Center by Infrared Spectra of H3+ and 13CO:
GCIRS 3 and GCIRS 1W
Miwa Goto, Max-Planck-Institute for Astronomy, Heidelberg
Tomonori Usuda, Subaru Telescope, Hilo
Thomas R. Geballe, Gemini Observatory, Hilo
Farhad Yusef-Zadeh, Northwestern University, Evanston
Nick Indriolo, and Ben J. McCall,
University of Illinois at Urbana-Champaign, Urbana
Takeshi Oka, University of Chicago, Chicago
Harvey Liszt, National Radio Astronomy Observatory
66th OSU International Symposium, June 21, 2011
T ~ 250 K
GCS 3-2
n < 100 cm-3
L > 2.2  105 cm/s
 = 2  10-15 s-1 L > 35 pc
η+
λ
Oka, Geballe, Goto, Usuda, McCall, 2005, ApJ, 632, 882
,  Geballe, Oka, 2010, ApJ, 709, L70
ε+
ε-
α+
θ+
θ-
δ+
Goto, Usuda, Nagata, Geballe, McCall, Indriolo,
Suto, Henning, Morong, Oka, 2008, ApJ, 688, 306
30 pc
Molecular face-on view of the GC
R ~ 180 pc
101 pc
130 pc
Reid, Menten, Zheng, Brunthaler, Xu, ApJ, 2009
The Expanding Molecular Ring
N. Z. Scoville, 1972
T. Sawada et al. 2001
T. Sawada et al. 2004
J. Kormendy & R. C. Kennicutt, 2004, ARA&A, 42, 603
The Central Cluster
8.4”
0.33 pc
The ISAAC L-band image of the Galactic center showing most of the
named sources (from Viehmann et al. 2005)
H3+ and 13CO spectra toward GCIRS 3 and GCIRS 1W
Warm and diffuse gas
(3,3)
(2,2)
27 days
(1,1)
361 K
H3+ and 13CO spectra toward GCIRS 3 and GCIRS 1W
Velocity profiles and radial location of gas
 140 km s-1
Subtract spiral arms
Expanding Mol. Ring
Inner Molecular gas
Dense cloud near Sgr A* toward GCIRS 3
N(1,1) = 1.89 ± 0.31 cm-2
N(2,2) = 2.05 ± 0.57 cm-2
N(3,3) = 2.78 ± 0.30 cm-2
T ~ 300 K
Ionization rate
 L = 2 ke N(H3+) (nC/nH)SV RX / f(H2)
1.8 ×10-9 cm3/s
1.6 ×10-4
1
 L = 2 kL N(H3+) (nC/nH)SV RX / f(H2)
1.0 ×1015 cm-2
3
~ 1700 cm s-1
if L = 0.5 pc,  = 1.1  10-15 s-1
Ubiquity of H3+
Sgr A* to 30 pc East
Goto, et al. 2008, ApJ, 688, 306
30 pc
GCS 4
1.00
NHS 21
0.95
NHS 25
0.90
NHS 42
0.85
FMM 361
0.80
0.75