Revelation of a vast amount of warm and diffuse gas
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Revelation of a vast amount of warm and diffuse gas and high ionization rate in the Central Molecular Zone of the Galactic center by the Infrared Spectrum of H 3 + Takeshi Oka Department of Astronomy and Astrophysics and Department of Chemistry

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Revelation of a vast amount of warm and diffuse gas and high ionization rate

Revelation of a vast amount of warm and diffuse gas

and high ionization rate

in the Central Molecular Zone of the Galactic center

by the Infrared Spectrum of

H3+

Takeshi Oka

Department of Astronomy and Astrophysics

and Department of Chemistry

The Enrico Fermi Institute, University of Chicago

Tom Geballe Gemini Observatory

Miwa Goto Max-Planck Institut für Astronomie

Ben McCall University of Illinois at U-C

Informal talk at Onsala Observatory: March 24, 2011

March 19, 1981


Revelation of a vast amount of warm and diffuse gas and high ionization rate

C60

1973

Watson

Herbst and Klemperer

Black and Dalgarno

Harry Kroto

H–C≡C–C≡C–C≡C–C≡C–C≡N

H–C≡C–C≡C–C≡C–C≡N

H–C≡C–C≡C–C≡N

1975

X-ogen

1970

H3+

Buhl, Snyder, Klemperer


Revelation of a vast amount of warm and diffuse gas and high ionization rate

H3+, the new astrophysical probe

H

1975HC5N, HC7N, HC9N

1951

1980

Laboratory Spectrum

Oka, Phys. Rev. Lett. 45, 531

T.G.

H2

1989 - 95

1970

1973

1996

Interstellar H3+, Discovery, Dense Clouds

Geballe, Oka, Nature 384, 334

1999 High H3+ abundance in the Galactic center

H3+

2002 Metastable H3+, Discovery, Galactic center

Goto, McCall, Geballe, Oka, et al. PASJ 54, 951

1996

+

  • Revelation of warm and diffuse gass near GC

  • Oka, Geballe, Goto, Usuda, McCall, ApJ 632, 882

2008 Ubiquity Central 30 pc of the Galactic center

Goto, Geballe, Oka, et al. ApJ 688, 306

2010 Exploring wider regions of the Galactic center

Geballe, Oka, ApJ, 709, L70


Telescopes and spectrometers

Telescopes and spectrometers

Telescope D Spectrom. λ/Δλ

UKIRT 3.8 m CGS4 40,000 Mauna Kea 1982

Subaru8.2 m IRCS 20,000Mauna Kea 2000

Gemini South 8 m Phoenix 60,000Cerro 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


High abundance of h 3 in the cmz

High abundance of H3+ in the CMZ

R(1, 1)u R(1, 0)

3 × 1014 cm-2

10-5

10%

T. R. Geballe, Phil. Trans. Roy. Soc. Lond. A358, 2503 (2000)

CMZ

400 pc


Revelation of a vast amount of warm and diffuse gas and high ionization rate

Super-massive clusters

Quintuplet

Cluster

GCS 3-2

1° × 1° 140 pc × 140 pc


Revelation of a vast amount of warm and diffuse gas and high ionization rate

(J, K) = (3,3) metastable H3+, the fingerprint of GC

Goto, McCall, Geballe, Usuda, Kobayashi, Terada, Oka, 2002, PASJ 54, 951

Spontaneous breakdown of symmetry

(1,1) ground

ParaI = 1/2

J

OrthoI = 3/2

(3,3)metastable

T ~ 250 K

8 hrs

Metastable

(3,3)

16 hrs

(2,2) unstable

n ≤ 100 cm-3

(2,2)

361 K

20.4 days

(1,0)

27.2 days

CO J = 1

(1,1)

K

Pan and Oka, 1987, ApJ, 305, 518

Oka and Epp, 2004, ApJ, 613, 349

Oka, Geballe, Goto, Usuda, McCall, 2005, ApJ, 632, 882


Revelation of a vast amount of warm and diffuse gas and high ionization rate

Ubiquity of H3+

Sgr A* to 30 pc East

30 pc


Revelation of a vast amount of warm and diffuse gas and high ionization rate

Simple chemistry of H3+: N(H3+) → ·L

ProductionH2→H2+ + e H2++ H2 →H + H3+

dn(H3+)/dt = n(H2)

= ken(H3+)n(e)

DestructionH3+ + e → H + H + H

7.3 ×10-8 cm3/s

1.6 ×10-4

1

L = 2 keN(H3+) (nC/nH)SV RX / f(H2)

(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-140 - 140 pc

Goto, Usuda, Nagata, Geballe, Indriolo, McCall, Suto, Henning, Morong, and Oka, ApJ, 668, 306 (2008)


Revelation of a vast amount of warm and diffuse gas and high ionization rate

Super-massive clusters

1° × 1° 140 pc × 140 pc


Revelation of a vast amount of warm and diffuse gas and high ionization rate

Search for bright and hot stars in the CMZ

GLIMPSE 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 band̲s

Skrutskie et al. 2006, AJ, 131, 1163

- 1.2º < ℓ - ℓº < 1.2º

- 0.1º < b - bº < 0.1º

~ 2,000,000 stars

brightness

L < 7.5

~ 3,000 stars

youth

J - K > 5

K - L > 1.5

(J –K)/(K – L)< 2.5

~ 300 stars

smoothness

Low res. CO first overtone, 2.2 – 2.4μm

Candidate stars

location

High res. H3+ and CO spectroscopy

Selected stars


Revelation of a vast amount of warm and diffuse gas and high ionization rate

The CO test

Most old (late-type) cool stars are useless

Bright dust-embedded stars with smooth spectrum are scarce


Revelation of a vast amount of warm and diffuse gas and high ionization rate

New bright dust-embedded stars

suitable for H3+ spectroscopy


Revelation of a vast amount of warm and diffuse gas and high ionization rate

Two sightlines with remarkable H3+ spectrum

Quintuplet,α, ι

0 – 30 pc East

α

ι

Geballe and Oka, ApJ, 709, L70-73 (2010)


Revelation of a vast amount of warm and diffuse gas and high ionization rate

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. 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. Zaal21

3 kpc

Scutum

Sgittarius

H2O+ 110← 101

H3+ R(1,1)l

H2O+ 111← 000

A&A June 22 2010

E. Falgarone et al. 2010

Geballe & Oka, 2010, ApJ, 709, L70

17 pc


Revelation of a vast amount of warm and diffuse gas and high ionization rate

New category of gas in the CMZ

Previous concept drastically changed

T ~ 250 K

n ~ 100 cm-3

L ~ 60 pc f ~30%

~ 1.5 × 1015 s-1

Schultheis et al. ApJ 495, 157 (2009)

f:

80% 107-8 K

?

10% 104-6 K ne10 cm-3

Lazio & Cordes,

ApJ, 505, 715 (1998)

10% 50 K 104 cm-3

2%


Revelation of a vast amount of warm and diffuse gas and high ionization rate

X-ray: Chandra comes to rescue

Chandra 20 pc × 20 pc (0.5 – 8) keV Muno et al. ApJ 589, 225 (2003)

Warwick, Sakano Decourchelle (2006) Revnivtsev et al. (2006)


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