revelation of a vast amount of warm (~ 250 k) and diffuse (≤ 100 cm -3 ) gas and high ionization...
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Revelation of a vast amount of warm (~ 250 K) and diffuse (≤ 100 cm-3) gas and high ionization rate (ζ > 10-15 s-1)
in the Central Molecular Zone by the Infrared Spectrum of
H3+
Takeshi Oka
Department of Astronomy and Astrophysics and Department of Chemistry
The Enrico Fermi Institute, University of Chicago
Star formation under extreme conditions: the Galactic center
at the Besançon Observatory, December 7, 2010
Tom Geballe Gemini ObservatoryMiwa Goto Max-Planck Institut für Astronomie
2005 Revelation of warm and diffuse gass near GC Oka, Geballe, Goto, Usuda, McCall, ApJ 632, 882
1999 High H3+ abundance in the Galactic center
H3+, the new astrophysical probe
+
1951
19701973
1996
1980 Oka, Phys. Rev. Lett. 45, 531Laboratory Spectrum
1996Geballe, Oka, Nature 384, 334
Interstellar H3+, Discovery, Dense Clouds
H
H2
H3+
1989 - 95
2002 Metastable H3+, Discovery, Galactic center
Goto, McCall, Geballe, Oka, et al. PASJ 54, 951
1975 HC5N, HC7N, HC9N
2008 Ubiquity Central 30 pc of the Galactic center Goto, Geballe, Oka, et al. ApJ 688, 306
T.G.
2010 Exploring wider regions of the Galactic center Geballe, Oka, ApJ, 709, L70
92
10~
a
Telescopes and spectrometersTelescope D Spectrom. λ/Δλ UKIRT 3.8 m CGS4 40,000 Mauna Kea 1982 Subaru 8.2 m IRCS 20,000 Mauna Kea 2000Gemini South 8 m Phoenix 60,000 Cerro Pachon 2003VLT 8.2 m CRIRES 100,000 Cerro Paranal 2006 Gemini North 8 m GENIRS 18,000 Mauna Kea 2011
Subaru UKIRTGemini South
VLT
Gemini North
High abundance of H3+ in the CMZ
CMZ
R(1, 1)u R(1, 0)
T. R. Geballe, Phil. Trans. Roy. Soc. Lond. A358, 2503 (2000)
3 × 1014 cm-2
10-5
10%
400 pc
(J, K) = (3, 3) metastable H3+, the fingerprint of GC
Metastable
27.2 days
20.4 days
Ortho I = 3/2
Para I = 1/2J
K
16 hrs8 hrs (3,3)
(2,2)
(1,1)
Pan and Oka, 1987, ApJ, 305, 518
(1,0)
Goto, McCall, Geballe, Usuda, Kobayashi, Terada, Oka, 2002, PASJ 54, 951
361 K
CO J = 1
(2,2) unstable
(3,3) metastable
(1,1) ground
T ~ 250 K
n ≤ 100 cm-3
Oka, Geballe, Goto, Usuda, McCall, 2005, ApJ, 632, 882
Spontaneous breakdown of symmetry
Search for bright and hot stars in the CMZGLIMPSE Point Source Catalogue of the Spitzer Space Telescope, L to M Ramírez et al. 2008, ApJS, 175, 147
2MASS photometry at J, H, and K bandM sSkrutskie et al. 2006, AJ, 131, 1163
~ 2,000,000 stars
L < 7.5
~ 3,000 stars
(J – K)/(K – L) < 2.5K - L > 1.5J - K > 5
~ 300 stars
Low res. CO first overtone, 2.2 – 2.4μm
Candidate stars
Selected stars
High res. H3+ and CO spectroscopy
brightness
youth
hotness
location
- 1.2º < ℓ - ℓº < 1.2º - 0.1º < b - bº < 1.0º
New bright and hot dust embedded stars suitable for H3
+ spectroscopy
Geballe and Oka, ApJ, 709, L70-73 (2010)
Two sightlines with remarkable H3+ spectrum
α
ι
Geballe and Oka, ApJ, 709, L70-73 (2010)
0 – 30 pc EastQuintuplet, α, ι
Simple chemistry of H3+ → ·L
Destruction H3+ + e → H + H + H
10-9
10-8
10-7
10-6
10-5
10-4
10-3
10-2
10-1
100
101
102
103
104
105
106
n(X
)
10-1
100
101
102
103
104
105
106
n(H)
Dense Clouds Diffuse Clouds
H2
HCO
C+H3
+
Production H2 → H2+ + e H2
+ + H2 →H + H3+
L = 2 ke N(H3+) (nC/nH)SV RX / f
7.3 ×10-8 cm3/s 1.6 ×10-4 1
(1.8-6.1) ×1015 cm-2 3
( L)min = (1.3 – 4.3) ×105 cm/s
L
10-16 s-1 (0.4 – 1.4) kpc 10-15 s-1 40 - 140 pc
Goto, Usuda, Nagata, Geballe, Indriolo, McCall, Suto, Henning, Morong, and Oka, ApJ, 668, 306 (2008)
dn(H3+)/dt = n(H2)
= ken(H3+)n(e)
Lazio & Cordes, ApJ, 505, 715 (1998)
80% 107-8 K
10% 104-6 K ne 10 cm-3
10% 50 K 104 cm-3
New category of gas in the CMZ
f:
Previous concept drastically changedT ~ 250 Kn ~ 100 cm-3
L ~ 60 pc f ~30%
~ 1.5 × 1015 s-1
Schultheis et al. ApJ 495, 157 (2009)
2%
Chandra 20 pc × 20 pc (0.5 – 8) keV Muno et al. ApJ 589, 225 (2003)
Warwick, Sakano Decourchelle (2006) Revnivtsev et al. (2006)
X-ray: Chandra comes to rescue
Remarkable similarity between velocity profilesof H3
+ toward Iota and H2O+, CH+ toward Sgr B2 Herschel observations of ortho- and para-oxidaniumyl (H2O+) in spiral arm clouds toward Sgr B2(M) ⋆
P. Schilke,1,2 C. Comito,2 H. S. P. M¨uller,1 E. A. Bergin,3 E. Herbst,14 D. C. Lis,4 D. A. Neufeld,20 T. G. Phillips,4 T. A. Bell,4 G.A. Blake5 E. Caux,6,7 C. Ceccarelli,8 J. Cernicharo,9 N. R. Crockett,3 F. Daniel,9,10 M.-L. Dubernet,11,12 M. Emprechtinger,4 P. Encrenaz,10 M. Gerin,10 T. F. Giesen,1 J. R. Goicoechea,9 P. F. Goldsmith,13 H. Gupta,13 C. Joblin,6,7 D. Johnstone,15 W. D. Langer13 W. B. Latter16 S. D. Lord,16 S. Maret,8 P. G. Martin,17 G. J. Melnick,18 K. M. Menten,2 P. Morris,16 J. A. Murphy,19 V. Ossenkopf,12,21 J. C. Pearson,13 M. P´erault,10 R. Plume,22 S.-L. Qin,13 S. Schlemmer,1 J. Stutzki,1 N. Trappe,19 F. F. S. van der Tak,21 C. Vastel,6,7 S. Wang,3 H. W. Yorke,13 S. Yu,13 N.Erickson,25 F.W. Maiwald,13 J. Kooi,4 A. Karpov,4 J. Zmuidzinas,4 A. Boogert,4 R. Schieder,1 and P. Zaal21A&A June 22 2010
Geballe & Oka, 2010, ApJ, 709, L70
H3+ R(1,1)l
H2O+ 111← 000
H2O+ 110← 101
17 pc
3 kpc ScutumSgittarius
E. Falgarone et al. 2010
Metastable rotational levels
0
1
2
3
JNH3
μ
T. Oka, F. O. Shimizu, T. Shimizu, J. K. G. Watson, ApJ 165, L15 (1971)
50 years
Δk = 3 2
00 years