Shinya Komugi NAOJ Chile Observatory+ Rie Miura, Sachiko Onodera, Tomoka Tosaki, Nario Kuno+ many (NRO Legacy MAGiC team, ASTE team, AzTEC team)

NRO UM Jul. 25 2013

MAGiC IV : 星間物質の基本平面

Star formation relation within M33

Increased scatter at 100pc scaleEffect of GMC evolution ?(e.g., Kawamura et al. 2009, Onodera et al. 2010)

Onodera et al. 2010

・ All but 1 SF region are 7Myr old・ gas=CO@OVRO, sfr=Paα@TAO

log SFR=0.95 logΣvar(H2)-8.23

・ small dispersion @ 700pcσ ＝ 0.1 for

varying Xcoc.f. σ = 0.5 in M51 (Liu+11)GMCs (SF regions) at a similar Evolution stage give tight SK laws

Star formation relation within Taffy I(Komugi+ 2012)

J=blue、 H=green、 Ks=red

Star formation

InterstellarRadiation

Field

Molecular gas

(CO)

Dust

Opt.-Near IR

“Dense” gas

Xco

metallicitytemperature

emissivity

heating

K-S law

Gas/dust ratio

IMF

UV input

extinction

The ISM at GMC scales

Hα, 24um

1.1 mm

12CO(J=1-0)

12CO(J=3-2)

2.1 um

+ time evolution

Interaction of ISM at 100pc in M33

12CO(J=1-0) @ NRO 45mTosaki et al. (2011)Catalog in progress

Interaction of ISM at 100pc in M33

12CO(J=3-2) map @ASTEMiura et al. (2012)

71 GMCs cataloguedLco, rmaj, rmin, σv, Tmb

Radius range 20 ~ 40

Interaction of ISM at 100pc in M33

1.1mm and dust temperature map ASTE and Spitzer 160umKomugi et al. (2011)

Interaction of ISM at 100pc in M33

57 GMCs at ~100pc resolution with 12CO(J=1-0) M10 : total

molecular gas 12CO(J=3-2) M32 : dense molecular gas

1.1mm Mdust : dust mass (using Tcold map and β=2)

Ks band K : measure of ISRF from old stellar pop.

Hα, 24um SFR : star formation rate (UV photon)

Type B, C, D : evolutionary stage

・ PC4 and PC5 have smallest variance, i.e. we can writePC4 = 0PC5 = 0・ SFR, K, Md contains 99.3% of the information in PC4

0.72 logSFR + 0.29 logK - 0.62 logMd = 0 ± 0.43 logSFR = (2.4 ± 0.3) logMdust – (0.23 ± 0.06) Kmag. + 0.15 ± 1.2

scatter = 0.4 dex・ SFR, M CO10, MCO32 contains 99.6% of the information in PC50.75 logMCO32 - 0.64 logMCO10 - 0.14 logSFR = 0 ± 0.29

logM32 = (0.86 ± 0.06) logM10 + (0.12 ± 0.02) logSFR + 1.0 ± 0.02scatter = 0.1 dex

PC5 : SFR-MCO32-MCO10 plane

log MCO32

(M◉ pc-2)

log MCO10

(M◉ pc-2)log SFR

(M◉ yr-1 pc-2)

• 3D version of SK law, but strongest correlation is between CO32 and CO10.

SK law at 100 pc is better expressed as “CO32/CO10 ratio is modulated by SFR” Consistent with “dense gas fraction is larger for

clouds with more active SF” (Onodera+ 2012)

PC5 : SFR-MCO32-MCO10 plane

PC4 : SFR-Mdust-KS plane

log Mdust

(M◉ pc-2)

log SFR(M◉ yr-1 pc-2)

ISRF(K band mag.)

• SFR-Mdust tighter than SFR-MCO32 or SFR-MCO10

Dust traces molecular gas better ??

• GMC evolution = movement in the plane; young GMC 2um dark, less dust, small SFR

< 10Myr GMC 2um bright, range of dust and SFR> 10Myr GMC intermediate in SFR, dust, 2um.

PC4 : SFR-Mdust- KS plane

summary• Multi-parameter analysis of GMC in M33• 2 most fundamental relations ;

“Classical” KS law can be explained by combining these

• PCA can be a powerful tool to interpret the entangled relations in the ISM

• Needs verification in other galaxies 12CO + Paα survey of NGC300 ongoing

logSFR = (2.4 ± 0.3) logMd – (0.23 ± 0.06) Kmag. + 0.15 ± 1.2scatter = 0.4 dex

logMCO32 = (0.86 ± 0.06) logMCO10 + (0.12 ± 0.02) logSFR + 1.0 ± 0.02 scatter = 0.1 dex