Central Molecular Zone (CMZ): the Treasure House of H3+
Takeshi Oka
Thomas R. Geballe Gemini Observatory
Miwa Goto Max Planck Institute for Astronomy
Tomonori Usuda Subaru Telescope
Benjamin J. McCall University of Illinois, Urbana-Champaign
The Enrico Fermi Institute, the University of Chicago
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
H3+: the novel probe of the CMZ
Central Molecular Zone
Morris, Serabyn, ARA&A (1996)CMZ
OH, H2CO, CO, CS, NH3, HCN H3+
Mezger, Duschl, Zylka, A&A Rev. (1996)
R(1, 1)u R(1, 0)
Geballe Phil. Trans. RSL A358, 2503 (2000)
the treasure house of H3+
Inferred face-on view of the CMZThe Expanding Molecular Ring
Oka, Hasegawa, Sato, Tsuboi, Miyazaki, ApJS 118, 455 (1998)Sawada, Hasegawa, Handa, Cohen, MNRAS 349, 1167 (2004)
Scoville, ApJ 175, L127 (1972)
145 km s-1
200 pc 130 pc
100 km s-1
EMR
Lazio & Cordes, ApJ 505, 715 (1998)
0.8 107 K
0.1 106 K 10 cm-3
0.1 102 K 104 cm-3
Gas in the CMZ : pre-H3+
160 pc × 30 pc
7 × 107 K
Suzaku Dec. 6, 2006
Koyama et al. PASJ 59, S245 (2007)
27° × 40°
The Galactic center
QuintupletArches
1° × 1° 140 pc × 140 pc
The Quituplet Stars
Central
Binary pinwheel nebula, Science (2006)
GCS 3-2
Telescope and spectrometer
UKIRT 3.8 m CGS4 8 km s-1 Mauna Kea 1982
Subaru 8.2 m IRCS 15 km s-1 Mauna Kea 2000
Gemini South 8 m Phoenix 5 km s-1 Cerro Pachon 2003
VLT 8 m CRIRES ≤3 km s-1 Cerro Paranal 2006
Breaking
Symmetry
Interstellar NH3 Oka, Shimizu, Shimizu, Watson, ApJ 165, L15 (1971)
Interstellar H3+ Pan, Oka, ApJ 305, 518 (1986)
Metastable
27.2 days
20.4 days
μ
Critical Density 200 cm-3
Ortho I = 3/2
Para I = 1/2J
KCollision H3
+ + H2 → (H5+)* → H3
+ + H2
16 hrs8 hrs
++ = uuu
The ideal rotational levels of H3+
(3,3)
(2,2)Unstable
(1,1)Ground
361 K
CO J = 1
(2,2) unstable
(3,3) metastable
(1,1) ground
Spectroscopy
Oka, Geballe, Goto, Usuda, McCall, ApJ 632, 882 (2005)
130 pc
100 km s-1
)2,2(
)3,3(
N
N
Discovery of high temperature (T ~ 250 K), low density (n ≤ 100 cm-3) clouds
)1,1(
)3,3(
N
N
Oka & Epp, ApJ 613,349 (2004)
Dimension of the discovered gas
ζL = 2 ke N(H3+) (nC/nH)SV RX / f
7.3 ×10-8 cm3/s 1.6 ×10-4 1
3.1 ×1015 cm-2 3 - 10
Sodroski et al ApJ 452, 262 (1995)
ζL = (2.5 – 8.4) ×105 cm/s
ζ (s-1) L (pc)
10-16 (0.8 - 2.1) k 10-15 80 - 210
COBE DIRBE
120 pc
100 km s-1
Harvey Liszt Phil. Trans. R. Soc. A 364, 3049 (2006)
ζ = 10-17s-1
ζ = 10-17s-1
Eight YSO’s within 30 pc of the GCSubaru Telescope
(2,2) densitometer
(3,3) thermometer
(1,1) ground level
(2,2) densitometer
(3,3) thermometer
(1,1) ground level
The warm and diffuse gas is ubiquitousand has a large volume filling factor
T = 220 K – 400 K n ≤ 100 cm-3 Lmin ~ 80 – 120 pc
RX = 3 - 10
Lazio & Cordes, ApJ 505, 715 (1998)
0.8 107 K
0.1 106 K 10 cm-3
0.1 102 K 104 cm-3
Gas in the CMZ : post-H3+
Warm and diffuse gas250 K 102 cm-3
0.01
??
Chandra 20 pc × 20 pc (0.5 – 8) keV Muno et al. ApJ 589, 225 (2003)
Warwick, Sakano Decourchelle (2006) Revnivtsev et al. (2006)
Hyperstrong Radio-wave Scattering in the Galactic Center. IIA Likelihood Analysis of Free Electrons in the Galactic Center
Lazio & Cordes, ApJ 505, 715 (1998)
0.8 107 K
0.1 106 K 10 cm-3
0.1 102 K 104 cm-3
Gas in the CMZ : post-H3+
Warm and diffuse gas250 K 102 cm-3
0.01
??
Folded Fields as the Source of Extreme Radio-wave Scattering in the Galactic CenterGoldreich and Sridhar, ApJ 640, L159 (2006)
Extragalactic H3+ in ULIRG
Geballe, Goto, Usuda, Oka, McCall ApJ 644, 907 (2006)
Z = 0.05821
Controversies
T. Oka No hot gas in the Expanding Molecular Ring
F. Le Petit Diffuse gas cannot be that hot
J. Black Infrared pumping
(1, 0)
(3, 0)
(2, 0)
(3, 3)
F. Yusef-Zadeh 4 categories of gases ApJ 637, L101 (2006)
Linnott & Rawlings Dynamically evolving cloud A&A 448, 425 (2006)
The Infrared Pumping
10.2 ms
25.3 ms
3.75 hrs
V = 0
V2 = 1
(1, 0)
(3, 3)
(3, 0)
(2, 0)2
75.27 108
W A
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)
Pump rate (s-1) Infrared photon flux(cm-2 s-1 Hz-1)
Three Proton System
+
I = 3/2 ortho
I = 1/2 para
++ = uuup = uudn = udd
H – K’
AV = [(H-K’) + 0.097]/0.051
Cotera, Simpson, Erickson, Colgan, Burton, Allen, ApJS 129, 123 (2000)
Harvey Liszt Phil. Trans. R. Soc. A 364, 3049 (2006)
Cotera, Simpson, Erickson, Colgan, Burton, Allen, ApJS 129, 123 (2000)
The Quintuplet
Okuda et al. ApJ 351, 89 (1990)