Absorption line survey toward the Galactic center II

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Absorption line survey toward the Galactic center
II
Miwa Goto Max-Planck-Institut fuer
Astronomie Heidelberg, Germany
contribution from Subaru to the exploitation of
H3 in space
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Here is my acknowledgement to

• B. J. McCall (Univ. of Illinois)
• T. R. Geballe (Gemini Observatory)
• T. Oka (Univ. of Chicago)
• T. Usuda (Subaru Telescope)

Japan Society of Promotion of Science
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What is Subaru?
It is a Telescope.
Atop at Mauna Kea in Hawaii
8.2-m primary mirror
the world largest class
Joined the force of exploitation of H3 in the
ISM since 2000
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How to get there
Subaru Base facility in Hilo
London
Honolulu
Hilo
MaunaKea
Honolulu
Hilo
Subaru Telescope
Hilo
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What is so special about Subaru and its
spectrograph

• unlike with CO

it is particularly suited for absorption line
survey

• H3 so nasty scattered all over the 3um region

• Which requires wide wavelength coverage

• still needs high spectral resolution

• Velocity dispersion in interstellar cloud lt 10
  km/s

• Usually, these two are conflicting demands in
  observation.

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Subaru/IRCS selling point wide wavelength
coverage
IRCS(Infrared Camera and Spectrograph
Atmospheric transmission
H3 lines
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Subaru/IRCS selling point wide wavelength
coverage
Low dispersion
High dispersion
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Survey type observation

• Is powerful mean of observation when a new field
  is just open

Absorption line Survey
2-fold
- extend the series of lines for one object
Cross-dispersing spectrograph helps

• Detect lines in as many object

8-m primary helps
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Brief history
Pre Subaru
1996 detection in ISM ( If there is H3 in
space? )
(Geballe Oka 1996)
1998-1999 diffuse cloud enigma widely recognized
by community
(McCall et al. )
Subaru I
2002 metastable state
(Tom-sans talk yesterday)
(extension toward wavelength)
Subaru II
2005 R(3, 3)l is ubiquitous in the Galactic
center.
(Extension of sources.)
(Oka et al. 2005)
Subaru III
2006- What comes next?
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Subaru II
R(2,2)l
It is ubiquitous!
R(2,2)l -
R(3,3)l
R(3,3)l
R(1,0)l
At least in Galactic Center
But only in the Galactic Center
R(1,0)lR(1,1)u
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Subaru III How far the boundary extend?

• Dots

• Line

• Area

• -180 pc

Where R(3,3)l disappears?
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Trick to increase Absorption line survey

• Use late type stars. ( we know it is not clean)

• But See, Can use it.

R(1,1)
R(1,0)
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Thanks!!

• B. J. McCall (Univ. of Illinois)
• T. R. Geballe (Gemini Observatory)
• T. Oka (Univ. of Chicago)
• T. Usuda (Subaru Telescope)

Japan Society of Promotion of Science