Two Sightlines toward the Galactic Center
with Remarkable H3+ and CO Spectra
Takeshi OkaDepartment of Astronomy and Astrophysics
and Department of Chemistry, The Enrico Fermi Institute, University of Chicago
June 24, Columbus Symposium
Tom Geballe Gemini Observatory
Geballe, T.R. & Oka, T. 2010, ApJ, 709, L70
Tomonori Usuda
Miwa Goto
Subaru Telescope
Max-Planck Institute for Astronomy
H3+ near the GC
Surprises
Huge column density; rich profile Geballe et al. ApJ 1999(3,3) metastable and (2,2) unstable H3
+ Goto et al. PASJ 2002Thermalization model analysis Oka & Epp ApJ 2004Revelation of warm and diffuse gas GS Oka et al. ApJ 2005Review Oka PNAS 2006From the center to 30 pc east Subaru Goto et al. ApJ 2008Scrutiny of the Central core VLT Goto et al. 2010Synthesis Gemini South Oka et al. 2011
30 pc
Lazio & Cordes, ApJ, 505, 715 (1998)
0.8 107-8 K
0.1 104-6 K 10 cm-3
0.1 50 K 104 cm-3
Previous concept of gas in the CMZneed to be drastically changed
Warm and diffuse gas250 K 102 cm-3
f: X-ray emittingUltrahot plasma
ζ·L
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 bandsSkrutskie 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
83 stars so far
10 new stars and 5 known stars
Star L J – K K – L (J – K)/(K – L)GCS3-2 3.03 7.33 3.16 2.32GCS4 3.71 7.65 3.45 2.22NHS21 4.62 7.03 2.76 2.55*NHS25 6.24 4.81* 1.27* 3.79*
brightness
youth
hotness
location
8
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
Geballe and Oka, ApJ 709, L70-73 (2010)
Iota, the Monster
“iota”, 85 pc East, Sgr B
High T
Low n
(3,3)
(2,2)
Subaru May 4, 2010
H3+ ν2←0 (2,2)l←(1,1)l
Iota 84.5 pc East 1.8 pc below
Gemini South
H2O+ 111←000 2B1
Sgr B2 101.1 pc East 1.4 pc above
HIFI
Ossenkoph et al. Astro-ph.1005, 2521, 2010
Two Monsters
“alpha”, 140 pc West, 2.7 pc below
Alpha, the elegant
Geballe and Oka, ApJ 709, L70-73 (2010) H. Liszt, ApJL, 82, 495 (1992)
13CO
Sgr E, 144 pc West, 20 pc above