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H 3 +. Search for hot and bright stars for H 3 + spectroscopy Near the Galactic center. Takeshi Oka. Department of Astronomy and Astrophysics and Department of Chemistry The Enrico Fermi Institute, University of Chicago. and T. R. Geballe. Gemini Observatory.

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H 3

H3+


H 3

Search for hot and bright stars for

H3+spectroscopy

Near the Galactic center

Takeshi Oka

Department of Astronomy and Astrophysics

and Department of Chemistry

The Enrico Fermi Institute, University of Chicago

and T. R. Geballe

Gemini Observatory

OSU international symposium on molecular spectroscopy, June 25, 2009


H 3

8 stars within 30 pc from GC

all show the warm and diffuse gas

(2,2)

(1,1)

(3,3)

(2,2)

(1,1)

(3,3)

T = 220 - 400 K

n≤ 100 cm-3

Goto, Usuda, Nagata, Geballe, McCall, Indriolo, Suto, Henning, Morong, Oka, ApJ, 688, 306 (2008)


H 3

A lucky summer at the Gemini South Observatory


H 3

The great ocean of truth lay

all undiscovered before us

Long pathlength of H3+

We must find hot and bright young stars !


H 3

Old (late-type) stars are useless


H 3

Bright and hot young stars are scarce

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


H 3

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 bands

Skrutskie et al. 2006, AJ, 131, 1163

Star LJ – KK – L (J – K)/(K – L)

GCS3-2 3.03 7.33 3.16 2.32

GCS4 3.71 7.65 3.45 2.22

NHS21 4.62 7.03 2.76 2.55*

NHS25 6.24 4.81*1.27*3.79*

~ 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

83 stars so far

hotness

Low res. CO first overtone, 2.2 – 2.4μm

Candidate stars

10 new stars and 5 known stars

location

High res. H3+ and CO spectroscopy

Selected stars


H 3

Typical hot young star and cool old star

(both very bright!)

Hot

Cool

CO 2 – 0

3 – 1

4 – 2

5 – 3

Spectra taken by UIST spectrometer of the UKIRT


H 3

Medium resolution spectroscopy at UKIRT

using UIST spectrometer


H 3

Candidate stars

# Star Spectrum location

1 J 17432173 728_24 K=6.5 L=3.8 132 pc West

2 J 17432988 808_56 K=8.8 L=4.5 127 pc West

3 J 17441867 728_28 K=10.0 L=6.4 80 pc West ?

4 J 17444083 731_64 K=9.4 L=6.4 45 pc West

5 J 17450483 815_33 K=9.0 L=6.5 30 pc West

6 J 17452861 815_71 K=9.2 L=6.6 10 pc out of plane

7 J 17461514 731_68 K=10.1 L=5.6 Close to Quint.

8 J 17461783 731_72 K=7.8 L=5.5 Close to Quint.

9 J 17463219 728_40 K=9.2 L=6.4 43 pc East

10 J 17470264 808_143 K=10.2 L=6.5 ??

11 J 17470898 815_79 K=10.4 L=6.6 84 pc East.

12 J 17474486 731_76 K=10.3 L=4.7 96 pc East


H 3

High resolution spectroscpy for radial location


H 3

Tons of work ahead of us

The central 2 pc Circum nuclear disk

Adaptive Optics needed VLT, Subaru

The central 30 pc Super-massive clusters

Velocity analysis GS

→ IRTF

Whole CMZ Hunting stars UKIRT

Observation Subaru, GS

→ SOAR


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Understanding a monster

X-ray

γ-ray

Radio continuum

HII region

Radio recomb.

Fine structure

H3+ IR abs.

CO IR abs

H2 FIR

H2 IR emission

Radio CO, CS, HCN, CH emission


H 3

H3+


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