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The (3, 3) metastable rotational level of H 3 +

The (3, 3) metastable rotational level of H 3 +. Takeshi Oka. Department of Chemistry and Department of Astronomy and Astrophysics The Enrico Fermi Institute, The University of Chicago. New Horizon of Astrochemistry and Laboratory Spectroscopy March 16, 9 am, 2006.

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The (3, 3) metastable rotational level of H 3 +

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  1. The (3, 3) metastable rotational level ofH3+ Takeshi Oka Department of Chemistry and Department of Astronomy and Astrophysics The Enrico Fermi Institute, The University of Chicago New Horizon of Astrochemistry and Laboratory Spectroscopy March 16, 9 am, 2006 I am looking for a postdoc, Laboratory or Observatory

  2. Metastable rotational levels J NH3 3 2 1 K 0 0 1 2 3

  3. Lifetime of the Universe ?

  4. Metastable rotational levels J NH3 3 2 1 K 0 0 1 2 3

  5. selection rules Breakdown of symmetry Geometry C3 Permutation (123) ΔK = 0 ΔK = 3

  6. Metastable rotational levels J NH3 3 人 生 五 十 年 50 years 2 μ 200 years 1 Δk = 3 0 T. Oka, F. O. Shimizu, T. Shimizu, J. K. G. Watson, ApJ 165, L15 (1971) F. Y. Chu, T. Oka, J. Chem. Phys. 60, 4612 (1974) PH3 AsH3

  7. H3+ is simpler Non-polar H3+ J No inversion 3 2 1 0 Δk = 3

  8. The ideal energy levels ofH3+ H3+ + H2→ (H5+)* → H3+ + H2 Δk = ± 3 forbidden transitions (J, K) J Ncrit ~ 200 cm-3 (3, 3) metastable level 361 K (2, 2) unstable level 27.2 days (1, 0) (1, 1) ground level 32.9 K K Pan, Oka, ApJ 305, 518 (1986) 0 ±1 ±2 ±3 k

  9. Discovery of metastable interstellar H3+ (3, 3) metastable (1, 1) ground level Subaru telescope Goto, McCall, Geballe, Usuda, Kobayashi, Terada, Oka PASJ, 54, 951 (2002)

  10. Sightline toward the Galactic center The Central Molecular Zone

  11. Thermalization ofH3+ H3+ + H2→ (H5+)* → H3+ + H2 (J, K) J Ncrit ~ 200 cm-3 (3, 3) metastable level 361 K (2, 2) unstable level 27.2 days (1, 0) (1, 1) ground level 32.9 K K 0 ±1 ±2 ±3 k

  12. Elementary processes Radiation Collision Reaction Ψ’ ψ C A A A B B D B Rigorous Selection Rules Approximate Rules Random ortho  para ΔI = 0 ortho  para ΔI = 0 ΔItotal = 0 Trad  3 K « Tkin

  13. Rate Equations Cosmic ray ionization 10-17 s-1 Steady State 0 = Production Spontaneous emission 4  10-7 s-1 Collision n(H2) 100 cm-3 10-7 s-1 Destruction 10-9 s-1 10-7 cm3 s-1 10-9 cm3 s-1 Proton hop reaction Dissociative recombination Detailed balance H3+ + H2 (H5+)*  H3+ + H2 Oka, Epp ApJ, 613, 349 (2004)

  14. Discovery of hot and diffuseclouds Oka, Epp, ApJ 613,349 (2004) Oka, Geballe, Goto, Usuda, McCall, ApJ 632, 882 (2005)

  15. Enter Gemini South Observatory (1, 1) ground level CMZ and spiral arms (3, 3) metastable level All CMZ High temperature (2, 2) unstable level Neither Low density CO Mostly spiral arms

  16. The Expanding Molecular Ring Kaifu, Kato, Iguchi, Nature (1972) Scoville, ApJ (1972) Whiteoak, Gardner, MNRAS (1979)

  17. The central 30 pc of the CMZ The Quituplet Nagata et al. (1990) Okuda et al. (1990) Yusef-Zadeh, Morris, AJ (1987)

  18. Other stars Oka, Geballe, Goto, Usuda, McCall, ApJ (2005)

  19. Controversies No hot gas in the Expanding Molecular Ring T. Oka F. Le Petit Diffuse gas cannot be that hot J. Black Infrared pumping (2, 0) F. Yusef-Zadeh 4 categories of gases ApJ 637, L101 (2006) (3, 3) (3, 0) (1, 0)

  20. The Galactic center The Central Molecular Zone (CMZ) The treasure house of H3+ Discovery of metastable H3+ Revelation ofwarm and diffuse gas H3+ CO, CS Radio diffraction X-ray Cold 30 K >104 cm-3 Warm 250 K ~102 cm-3 Hot 104 K ~102 cm-3 Ultrahot 107-8 K ~0.3 cm-3 0.1 0.5 - 1 ~ 0.5 «1 0.01 Volume filling factor f

  21. Extragalactic H3+ Z = 0.05821 Geballe, Goto, Usuda, Oka, McCall ApJ in press

  22. The (3, 3) metastable rotational level ofH3+ Takeshi Oka Department of Chemistry and Department of Astronomy and Astrophysics The Enrico Fermi Institute, The University of Chicago New Horizon of Astrochemistry and Laboratory Spectroscopy March 16, 9 am, 2006 I am looking for a postdoc, Laboratory or Observatory

  23. Surprise!!H3+more abundant in diffuse clouds!! Dense clouds McCall, Geballe, Hinkle Oka, ApJ 522,338(1999) N(H3+) ~ 3.6 ×1012 cm-2 AV N(H3+) ~ 4.4 ×1013 cm-2 AV Diffuse clouds McCall, Hinkle, Geballe, Moriarty-Schieven, Evans, Kawaguchi, Takano, Smith, Oka, ApJ 567, 391 (2002)  Per

  24. Central Molecular Zone, the treasure house ofH3+ M ~ 5 ×107 M⊙ Dominantly molecular Dense clouds, n(H2) > 104 cm-4 Volume filling factor 0.1 Hot gas T ~ 300 K High velocity dispersion Low dust temperature T ~ 20-30 K Morris, Serabyn, ARA&A (1996) CMZ Mezger, Duschl, Zylka, A&A Rev. (1996)

  25. Sightlines toward the CMZ

  26. Extraordinary radio emission • Radio Arc • Arched filaments • Nonthermal filaments • Sgr A* Yusef-Zadeh, Morris, AJ (1987)

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