Sep 26 2017, TGS2017,Tsukuba

Mapping the Milky Way in Sub-millimeter
Wavelengths Emission Lines
Masumichi Seta
（KwanseiGakuin Univ.）

Contents• Molecular cloud• Survey observations of the Milky Way• Emission lines in sub-mm wavelengths• Astronomy from Antarctica

• Inter Stellar Medium
Gas+Dust• Classification on ISM
HI cloud

Temperature

Molecular cloud (MC)Formation ofMolecular cloud
100K
Condensation
10K
High massstar

HII region
HI cloud
Molecularcloud101

HII region

Super nova
Explosion Heatingacceleration(Myers 1978)

density（/cc)

103

Importance of molecular cloud•Forming stars• Energy source of Active Galactic Nuclei
Formation and evolution of
MC is a hot research topic

Probe for Observing Molecular Cloudl No emission from main constituent H2
Thermal emission from dust grains
Emission lines of molecule and atoml What is good probe?
Gas (molecule, atom)
Abundance
Dust Grain[He]/[H]〜 0.1[O]/[H] 〜5×10-4[C]/[H] 〜3×10-4
UV・cosmic ray change state
Ionization of H2 >13.6 eV
Molecular cloud
Ionization of C > 11.3eV
Dissociation of H2 >14.7 eV
Dissociation of CO >11.1eV
Critical density n optical depth
Cosmic RayUV
CO J=1-0 n〜1×103/cc
CO J=4-3 n〜4×104/cc

CO has been used. Atomic carbon may be good probe.

History of Mapping the Milky Way
I

Bell Lab7m 13CO 1-0 (Stark+ IAU Stmp. 1987)
Masschusetts-Stony Brook
FCRAO 14m 12CO 1-0 45” 3’grid

G35.04-0.50(V= 52)
CO AT V= 40- 53 KM/S [ 5K KM/S](Sanders+ApJS 1986, Scoville+,ApJS 1987)

CfA 1.2m 1２CO 1-0
9’ 4deg<full beam
(Dame+ ApJ 1987, 2001 )ZFig. 13 —8MC exists in the form of GMC (40pc、 105Mo)
Concentrated in a ring between 4<r<8 kpc from the Galactic center

Velocity of Molecular Cloud
Velocity

Doppler ShiftMCRadioTelescope

Relative motion→Shift in Frequency(f0 →fd )Rest frequency f0 :Structure ofmolecule&Atomfd

f0Frequency

Δf→Velocity of MC

Distance to MC
Galactic rotation

1987ApJ...322..706D

Molecular Cloud around Sun(Dame+ 1987)

High Resolution Galactic Plane Survey

FOREST Unbiased Galactic plane Imaging survey withNobeyama 45m telescope(FUGIN(Umemoto+ Publ 17)
Publications of the Astronomical Society of Japan (2017), Vol. 00, No. 0(resolution 20”）
12CO 1-0

13CO 1-0

C18O 1-07

Advances in the Survey Obs.

60cm telescope@ChileTsukuba
30cm in Chilel Higher angular resolution

NRO 45m FUGIN
Nagoya Univ. NANTEN2 4m

l Higher frequency
Univ. Tokyo-NRO 60cm CO 2-1 9’
Osaka Prefect. Univ. 1.8m 3’
12CO 13CO C18O 2-1
Univ. of Tsukuba 30cm 9’
CO 4-3 CI
9’Intensity ratio (I 4-3/1-0）→physical condition
Mt. Fuji 1.2m CO 4-3
JCMT 15m CO 3-2(Dempsey+ ApJS 2013)

Orion MC(Ishi+ 2016)

Filamental structure of Dust
Ph. André et al.: The Herschel Gould Belt Survey

Fig. 1.Andre+Column density
A&A maps
10 of two subfields in Aquila (left) and Polaris (right) derived from our SPIRE/PACS data. The contrast of the filamewith respect to the non-filamentary background has been enhanced using a curvelet transform as described in Appendix A. Given the typical wi∼10 000 AU of the filaments, these column density maps are equivalent to maps of the mass per unit length along the filaments. The color sc
shown on the right of each panel is given in approximate units of70-500um
the critical line mass of Inutsuka & Miyama (1997) as discussed in Sect

〜0.1pc width

Colum density （Hershel SPIRE/PACS

Emission Lines from Atom and Molecule
Change in internal energy

Energy States of moleculeEu

Eu − EL = hνEL

E = Eelectron + Evibration + Erotation
Rotational transition of CO
CO J=1-0 115GHz

CO J=4-3 460GHz

Fine structure line of atomic carbon (CI)Interaction between angular momentum of electron and spin
3

P2 − 3P1

809.34GHz (370um)

33492.16GHz (609um)

P1 − P0

CI in the Milky Way
MW surveyCOBE(7°）
FIXSEN, by
BENNETT,& MATHER(Fixsexen+1999, Wright,et al. ApJ,1991)
Vol. 526

Atomic carbon (CI) is detected at PDR
Photo Dissociation Region(PDR)
Simulation(Hollenbach & TienenRev. Mod. Phys.1999)

Observation of PDR
Taurus Molecular Cloud(Orr, et al., ApJ, 2014)

PDR model well explains the results

CII 1.9THz
CI 492GHzHIFI 44”@492GHz

CI 809GHz
12CO 1-0

FCRAO14m 45”
13CO 1-0

C I Peak behind CO
PDR in dark cloud L1688
Mt Fuji 1.2m
Distribution of CI is similar to that of 13CO
C18O core is closer to exciting starLow density PDR or Chemically young core
CI color（Kamegai et al., ApJ 2003）

C IICIC18OCI

13CO Red contour

CII contour

C18OCII

Chemical Evolution and CI
Chemical compositions change with time

(Suzuki et al.,ApJ 1992)

Sub-mm Observation is difficult• No detector→THz detector is available
Camera MKIDS TESHeterodyne SIS, HEB• Absorption by atmosphere(Water vapor & Oxygen)↓lHigh Altitude ,Dry site
Maunakea （Hawaii）

Atacama desert in Chile

High Plateau in Antarctical Best site for sub-mm Astronomy• High altitude（3000m以上)• Low temp. (Min-80℃、Av-55℃）
1000kmᘓタሙᡤ

Pressure䝁䞁䝁䝹䝕䜲䜰ᇶᆅ 䠜䝗䞊䝮(⡿)

Temperature䝪䝇䝖䞊䜽(㟢)(3488m)

䞉䝣䝷䞁䝇䞉䜲䝍䝸䜰䛜ඹ䞉㉺෤ᇶᆅ䠄ᐃဨ16ྡ䞉タഛ䞉㐠⏝䛜㠀ᖖ䛻䞉㔜ᶵ䠄130䝖䞁䜽䝺䞊䞁(௖ఀ)⁥ᐟἩ◊✲ᲷWind speed⌧ᆅㄪᰝ(஺᥮⛉Ꮫ⪅)
2016ᖺ1᭶䡚2᭶䠄ᅜ❧ᴟᆅ◊✲ᡤ䛾⤂௓䠅

10mᮃ㐲㙾ᘓタೃ⿵ᆅ

10m Telescope in Antarctica
10m Reflector

Heterodyne receiverHigh frequency resolution
Radio Observational band
450GHz CO 4-3 [CI] 3P1-3P0Camera
3800GHz1CO 7-6 [CI] P2-3P1
1.0 THz CO 8-7
1.3THz CO 11-10
1.5THz NIIAtmosphericTransparency(simu   lation)

0.8

Heterodyne
Receiver

0.6
0.4
0.2
00.4

0.8

1.2





1.62

Summary• Molecular cloud is important– Energy source of Active Galactic Nuclei– Stars are born in Molecular cloud• CI at 492 GHz & 809 GHz may be good probe for revealing
formation and evolution of molecular cloud.
• Sub-mm Astronomy is difficult due to strong absorption ofatmospheric water vapor.
• Antarctic plateau is best site on earth for Sub-mmAstronomy.
• We have plan to build 10m class telescope in Antarctica