H3 , the new probe for ionization rate ?

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H3, the new probe for ionization rate ?
the cosmic ray
Takeshi Oka Department of Astronomy and
Astrophysics and Department of Chemistry The
Enrico Fermi Institute, University of Chicago
Tom Geballe Gemini Observatory Nick Indriolo,
Ben McCall University of Illinois,
Urbana-Champaign
Cosmic Ray Interactions Bridging High and Low
Energy Astrophysics Leiden, March 14, 2011
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Astronomers Periodic Table
6
H
He
Ne
C
N
O
Si
S
Ar
Mg
Fe
Ben McCall
3
Hydrogenic Probes
5
H2
H
H3
10-7 ?10-8
H
H2
H?
H3
H
H2

Ewen Purcell 1951 Muller Oort 1951
Carruthers 1970 Spitzer et al. 1973
Geballe Oka 1996
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H3 the most direct probe for soft cosmic ray
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H3 the most direct probe for soft cosmic ray
Simple chemistry production
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H2
H
H3
OH, HD
H
H2
H2 ? H2 e
H2 H2 ? H H3
1.7 eV
? 10-18 10-14 s-1
R kLn(H2)
P. Langevin 1905 ? r-4
10-9 cm3 s-1
104 - 102 cm-3
dn(H3)/dt dn(H2)/dt ?n(H2)
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H3 the most direct probe for soft cosmic ray
Simple chemistry destruction
Dense Clouds (104 cm-3) C ? CO
H3 CO ? H2 HCO ? dn(H3)/dt
kLn(H3)n(CO)
10-9 cm3 s-1 ? r-4
Diffuse Clouds (102 cm-3) C ? C e?
10-7 cm3 s-1 ? r-1
H3 e? ? 3H, H2 H ? dn(H3)/dt
ken(H3)n(e?)
?n(H2)
Steady state
n(H3) n(H3)
N(H3)/L
(nH/nC)f(H2)/2

f(H2) 2n(H2)/nH
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H3 the most direct probe for soft cosmic ray ?
L ? N(H3)
Dense clouds
? L 2 kL N(H3) (nC/nH)?1.5
? L (0.6 2.3) ? 102 cm s-1
? 3 ? 10-17 s-1 L (0.6 2.3) pc
N(H3)obs (1.1 5.2) ? 1014 cm-2
McCall, Geballe, Hinkle, Oka, 1999, ApJ, 522, 338
Diffuse clouds
? L 2 ke N(H3) (nC/nH) / f(H2)
? L (0.4 4.4) ? 104 cm s-1
N(H3)obs (0.21 2.4) ? 1014 cm-2
? 4.5 ? 10-16 s-1 L (3 29) pc
Indriolo, Geballe, Oka, McCall, 2007, ApJ,
671,1736
Galactic center
? L 2 ke N(H3) (nC/nH)SV RC/H / f(H2)
? L gt (1.2 4.2) ? 105 cm s-1
? 1.5 ? 10-15 s-1 L gt (24 84) pc
N(H3)obs (1.8 6.1) ? 1015 cm-2
RC/H 3 6.7
Goto, Usuda, Nagata, Geballe, McCall, Indriolo,
Suto, Henning, Morong, Oka, 2008, ApJ, 688, 306
Rolleston et al. 2000, AA, 363, 557 Esteban et
al. 2005, ApJ, 618, L95
RX 3 10, gt 3
Sodroski, et al. 1995, ApJ 452, 262 Arima, Sofue,
Tsujimoto, 1996, PASJ 48, 275
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Telescopes and spectrometers

• Telescope D Spectrom. ?/??
• UKIRT 3.8 m CGS4 40,000
  Mauna Kea 1982
• Subaru 8.2 m IRCS 20,000
  Mauna Kea 2000
• Gemini South 8 m Phoenix 60,000
  Cerro Pachon 2003
• VLT 8.2 m CRIRES 100,000
  Cerro Paranal 2006
• Gemini North 8 m GENIRS 18,000
  Mauna Kea 2011

Gemini North
Gemini South
Subaru
UKIRT
VLT
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0
Remarkable similarity between velocity
profiles of 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. Muller,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. Perault,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. Zaal21
3 kpc
Scutum
Sgittarius
H2O 110? 101
H3 R(1,1)l
H2O 111? 000
AA June 22 2010
E. Falgarone et al. 2010
Geballe Oka, 2010, ApJ, 709, L70
17 pc