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Slide 12011年7月28日
New Results from NRO MaGiC Project : “GMC Evolution in M33”
“MAGiC” projectM33 All disk Survey of Giant molecular Clouds
Rie Miura
(The University of Tokyo/NAOJ ALMA)
N.Kuno, S.Sachiko, A.Hirota(NRO), T.Tomoka(Joetsu univ.), K.Muraoka(Osaka pref. Univ.) T.Minamidani (Hokkaido Univ.), S.K.Okumura,
S.Komugi, H.Narae, K.Nakanishi, T.Sawada(NAOJ) and K.Kohno (Tokyo univ.)
Slide 22011年7月28日
Massive Star Formation in Giant Molecular Clouds (GMC)
A large fraction of ISM in spiral galaxy is molegular gas.
GMCs comprises 80% of the molecular mass in Milkey Way (Williams & MacKee 1997)
Site of the Massive Star/Cluster Formation (Ladas & Lada 2003)
SFE:~10% of the mass of a GMC is converted to stars. (e.g.Williams & MacKee 1997)
I. GMC distribution :
II. GMC PropertiesGMC masses: 104—106 Mo,
sizes: 50—200 pc
III.Mass Function (MF) ranges from 1.55 to 2.49
IV.Lifetime: ~ 30 Myr (e.g. Williams & MacKee 1997, Yamaguchi et al,2001)Star formation occurs within ~4 Myr, Cloud's dispersal occurs within < 10 Myr. (Elmegreen 2000)
V. GMC Evolution No SF(TypeI)>only w HII(TypeII)>w HII & Cluster (TypeIII)
VI.Physical Properties, changes fromless dense&cold dense & warm →
Understanding “evolution of GMC” linked to SF both in MW in extragalaxies.
need more samples→ need wide field observations→ need high resolution obs.→
Slide 32011年7月28日
“MAGiC” project +M33 All disk Survey of Giant molecular Clouds
12CO(10) with 45m Onodera et al., 2010, ApJ Tosaki et al. 2011, PASJ Miura et al., in prep.
13CO(10) with 45m Muraoka et al. 2011 submitted to PASJ (村岡さんポスター参照)
Miura et al., in prep.
12CO(32) with ASTE Tosaki et al. 2007, ApJ Miura et al., in prep. (村岡さん講演)
Onodera et al. in prep. (村岡さん講演)
1.1mm continuum with ASTE/AzTECKomugi et al. 2011, PASJ
HCN & continuum with NMA Miura et al., 2010, ApJ
1212CO(1-0)CO(1-0)
Slide 42011年7月28日
Methodology
Step11: Identifying GMCs from NRO 12CO(10) image,
Step12:Identifying Young Clusteres and estimating their age by using the photometric data (Massey et al. 2006).
Step13:Classifying GMCs depending on age of the associated Young Cluster and the association with the HII regions.
Step 2: Investigating the variation of temperature and density for each M33 GMC with NRO 13CO(10), ASTE CO(32) data ,
Comparing to the GMC classifications.
GMC Cluster/
HII regions
associated?
Temperature ?Density ?
age?
Slide 52011年7月28日
step11. GMC Identifications
71 GMCs identified by the CPROPS (Rosolowsky & Leroy 2006)
GMC size range 52 – 400 pc, Mass ranges 1.6 – 38 × 105 Mo
14 GMCs among 71 GMCs are resolved into 2-3 smallerclouds.
Interestingly, most of the “GMC core”s which are identified in Rosolowsky et al. (2007) are located closer to the Halpha emitting region.
Slide 62011年7月28日
Step12: Cluster IdentificationYoung Stellar populations in M33
Padova model (Girardi et al. 2010 are ref. therein )
solar metalicityAv ~ 0.22 (Massey et al. 2006)
Blue dots: young stars (< 50 Myr)
Red dots: old stars (100 – 200 Myr)
Slide 72011年7月28日
Estimated Cluster Mass and Ages
Only the clusters within the extent of a GMC are treated as the associated clusters with a GMC.
Estimated Cluster ages are 10 – 20 Myr in GMC6.
Slide 82011年7月28日
GMC Types in M33
GMC Type Observed Signature M33 LMCI No Hii regions or young clusters 9 (14 %) 46 (24 %)II With Hii regions(s) 24 (34 %) 96 (50 %)
With Hii regions and stellar clusters (< 10 Myr) 15 (21 %) 49 (26 %)
With Hii regions and stellar clusters ( 10 -- 20 Myr) 20 (27 %) NAV With Hii regions and stellar clusters ( 20 -- 30 Myr) 5 (8 %) NA
III (confirm)
IV (candidate)
Type IGMC 13
Type IIGMC 18
Type III (<10 Myr)GMC 53
Type III (10--20 Myr)
GMC 41
Type IV(20--30 Myr)
GMC 2
This Implys.. Not like starbust but continuous star formation..
Slide 92011年7月28日
Properties in GMC Types
Type Mass(105 Mo)
Effective R (pc) SFR(10-5Mo/yr)
Max n*(/ 68pc box)
TypeI 3 36 – 65 0.5 – 20* 0
TypeII 4 – 38 32 – 119 0.9 – 160 0
TypeIII Type IV
4 – 32 35 – 108 3.7 – 190 29 – 67 (< 10Myr)5-35 (10-20Myr)
TypeV 2 – 18 30 – 65 4.0 – 110 5 – 25
Type IGMC 13
Type IIGMC 18
Type III (<10 Myr)GMC 53
Type III (10--20 Myr)
GMC 41
Type IV(20--30 Myr)
GMC 2
Slide 102011年7月28日
Summary: GMC Evolution?“Continuous” star formation
Type I (5/27, 19 %) Type II (10/27, 37%) Type III (10/27, 37 %) Type IV (2/27, 7%)
DIFFUSECOLDNO SF
DENSERDENSERCOLDNO SF
DENSEDENSECOLDSFSF
DENSEDENSEWARMWARMACTIVE SF ACTIVE SF
Contour 12COColor SFR(Ha+24um)
Type I(no SF)
Type II(/w HII regions)
Type III + Type IV(< 10 Myr-- 20Myr)
Type V(20-30Myr)
ACTIVE SFACTIVE SF
INTERMEDIATE INTERMEDIATE SFRSFR
DISPERSAL ?DISPERSAL ?
NOT ACTIVE NOT ACTIVE enough to enough to dispersedisperseContour 12CO
Color SFR(Ha+24um)
● Taking the lifetime of HII regions into account, star formation might last continuously in some GMCs, rather than starburst.
Slide 112011年7月28日
4. 13CO(1-0) Observations
Slide 122011年7月28日
13CO(1—0) data
In order to estimate physical state quantitatively, 13CO data was used for LVG analysis...
45 Molecular Clouds were observed in 13CO emission with the 45m telescope.
Note that this is not Mapping, but Pointed observations.
Slide 132011年7月28日
SFR vs. R13,R32
CO(32)/CO(10) line ratio is well correlated with the SFR, whilc 13CO/12CO line raito is slightly correlated, but not clear.
Line ratios of each GMC were measured at the peak in CO(10) emission.
SFR sensitivity is ~5x1011 Mo yr1 pc2
Slide 142011年7月28日
LVG Analysis using 13CO(1—0) data
Type R32
n(H2)
(cm-3)
Tk(K)
SFR*(10-8 Mo/yr)
TypeI 0.22 – 0.43 N/A N/A N/A
TypeII 0.22 – 0.54 6e+02 – 3e+03 ~10 0.2 – 0.6
TypeIII 0.3 – 1.17 5e+02 – 1e+06 10 – 200 0.6 – 26
TypeIV 0.35 – 0.65 2e+04 ~ 10 ~2
LVG code (Minamidani+2008)
Rotational levels up to J=40
Kinematic temperature Tkin
=5200K
Density n(H2)=10〜106cm3
CO fractional abundanceX(CO)=[CO]/[H
2]=1x104,1x105,3x106, 1x106, 1x107
Abundances 12CO/13CO=50
Slide 152011年7月28日
LVG Analysis using CO data
Temperature and Density seem to be correlated with SFR...
The molecular gas at the peak in the CO(10) emission shows mostly Tk~1020K, n~103 cm3
The molecular gas in Giant Hii region shows higher temperature and density.
Slide 162011年7月28日
Summary
We present new results from NRO MAGiC Project, showing high sensitivity, high resolution and wide field 12CO, 13CO data.
We identified 71 GMCs in M33 and classified into five groups depending on the association with young clusters or HII regions.This classification are interpreted “GMC evolutions”.
We also conduced 13CO observations in order to investigate the physical properties in M33 GMCs.By applying LVG analysis, the temperature and the density of 45 GMCs were estimated.As a result, there is a weak correlation between SFR and density, and also temprature.