H2 » H

Scoville and Sanders 1987

Molecule or Atom?

The Central Molecular Zone

CMZ

H2

H

H+

The great ocean of truth lay all undiscovered before us

Distribution of YSOs near the Galactic center

Takeshi Oka

DIB meeting, November 22, 2008

Ridgway, Carbon, Hall, Jewell, ApJS, 54, 177 (1984)

οCet M5e-M9e

R And S6-6e

TX Psc C7.2

Late-type stars are hopeless for IR spectroscopy

Nagata, Hyland, Straw, Sato, Kawara, ApJ, 406, 501 (1993)

Usable stars (hot, bright YSOs) are few

H – K ≥ 1.4

Eight stars from the center to 30 pc east

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

H3+ everywhere

The great ocean of truth lay all undiscovered before us

Spitzer IRAC survey if the Galactic center

Ramírez, Arendt, Sellgren, Stolovy, Cotera, Smith, Yusef-Zadeh, ApJS 175, 147 (2008)

3.6 μm (L), 4.5 μm, 5.8 μm, 8.0 μm

Two micron all sky survey (2MASS) 1.25 μm (J), 1.65 μm (H), 2.16 μm (K)

Sources of stars

Skrutskie et al. ApJ, 131, 1163 (2006)

> 106

L < 7.5

- 1.2º < ℓ < 1.2 - 0.1º < b < 0.1º

→ 1420 →

J – K ~ 5K – L ~ 1.5

~ 300

CO

UIST medium resolution CO spectrum