[CI] mapping of the super star cluster RCW38 (ASTE [CI] Demo - - PowerPoint PPT Presentation

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[CI] mapping of the super star cluster RCW38 (ASTE [CI] Demo Science Project) Natsuko Izumi (NAOJ) Yasuo Fukui, Kengo Tachihara, Shinji Fujita (Nagoya U), Kazofumi Torii, Takeshi Kamazaki, Hiroyuki Kaneko, Takeshi Nakazato George Kosugi, Jun

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[CI] mapping of the super star cluster RCW38

(ASTE [CI] Demo Science Project)

Natsuko Izumi (NAOJ) Yasuo Fukui, Kengo Tachihara, Shinji Fujita (Nagoya U), Kazofumi Torii, Takeshi Kamazaki, Hiroyuki Kaneko, Takeshi Nakazato George Kosugi, Jun Maekawa, Shigeru Takahashi, Akira Yoshiko, Daisuke Iono (NAOJ), Kanako Sugimoto (NRAO) and ASTE team

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❖Target: Super Star Cluster RCW38

Spitzer (r: 8.0 um, g: 4.5 um, b: 3.6 um) VLT (r: 2.2 um, g: 1.65 um, b: 1.25 um)

Wolk et al. 2006

1. INTRODUCTION

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❖Target: Super Star Cluster RCW38

VLT (r: 2.2 um, g: 1.65 um, b: 1.25 um)

Distance : ~ 1.7 kpc
Youngest super star cluster

in the Milky Way

~ 0.1 Myr
~ 10,000 star

(~ 20 O stars)

2 IR peaks
IRS1: ridge structure
IRS2: O5.5 binary

Wolk et al. 2006 e.g. Fukui et al. 2016

1. INTRODUCTION

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CO mapping observation with Mopra

Fukui et al. 2016

12CO(1-0)

Ring Finger Ring Finger

Two molecular clouds (Δv ~ 12 km/s)
Ring cloud: blue-shifted (vLSR = -8.3 - 9.1 km/s), NH2 > 1023 cm-2
Finger cloud: red-shifted (vLSR = 9.1 - 17.5 km/s), NH2 ~ 1022 cm-2
Bridging feature between two clouds

Bridge

❖Triggered Star formation by Cloud-cloud collision

Haworth et al. 2015a,b

1. INTRODUCTION

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CO mapping observation with Mopra

Fukui et al. 2016

12CO(1-0)

Ring Finger Ring Finger

Two molecular clouds (Δv ~ 12 km/s)
Ring cloud: blue-shifted (vLSR = -8.3 - 9.1 km/s), NH2 > 1023 cm-2
Finger cloud: red-shifted (vLSR = 9.1 - 17.5 km/s), NH2 ~ 1022 cm-2
Bridging feature between two clouds

Bridge

❖Triggered Star formation by Cloud-cloud collision

Haworth et al. 2015a,b

1. INTRODUCTION

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Obs. date

2016/11/26 Receiver Band 8 Spectrometer MAC Mode OTF mapping Frequency 492.1607 GHz Bandwidth 512 MHz Spectral resolution 1 MHz (~0.6 km/s) HPBW ~17’’ (~ 0.14pc) Mapping area 6’ × 8’ Total mapping time ~ 6 hrs Tsys 800 ~ 1400 K PWV ~0.5 Opacity (220 GHz) 0.02 ~ 0.07 RMS noise ~ 0.46 K (Tmb)

❖[CI] mapping observation with Band8 receiver

6’ 8’ Mapping area IRS1 IRS2 Spitzer (r: 8.0 um, g: 4.5 um, b: 3.6 um)

2. OBSERVATION

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❖Software

The raw data, final cube data, and detailed analysis procedures are already published on the ASTE web page

https://sites.google.com/site/ asteobservation/home/reduction#TOC- DEMO-SCIENCE-DATA-REDUCTION- GUIDE

Data reduction with NOSTAR and CASA
NOSTAR: Mainly used for OTF mapping data from NRO 45m

and ASTE

CASA: Mainly used for data from ALMA,

VLA

3. DATA REDUCTION

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❖Ring-like structure

4. RESULT

6’ 6’ 8’ Mapping area IRS1 IRS2 Spitzer (r: 8.0 um, g: 4.5 um, b: 3.6 um)

IRS1 IRS2

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❖Two velocity component

4. RESULT
Similar structure to CO clouds
Ring cloud: blue-shifted (vLSR = -8.3 - 9.1 km/s) , N[CI] ~1018 cm-2
Finger cloud: red-shifted (vLSR = 9.1 - 17.5 km/s) , N[CI] ~1017 cm-2

[CI]

Ring Finger Ring Finger Fukui et al. 2016

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5. DISCUSSION
Past studies reported that [CI] distribution is similar to

13CO(1-0) distribution

Orion (e.g. Ikeda et al. 2002, Shimajiri et al. 2013)
Southern Milky Way (Oka et al. 2005)
Carina nebula (e.g. Kramer et al. 2008)

❖Relation between [CI] and 13CO in RCW38

Ikeda et al. 2002

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❖Relation between [CI] and 13CO in RCW38

5. DISCUSSION

[CI] (ASTE)

13CO(1-0)

(Mopra)

Ring Finger Ring Finger Fukui et al. 2016

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❖Relation between [CI] and 13CO in RCW38

5. DISCUSSION

Fukui et al. 2016

[CI] (ASTE)

13CO(1-0)

(Mopra) [CI] distribution is very similar to 13CO distribution !!

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❖[CI] / 13CO ratio in RCW38

5. DISCUSSION
[CI]/13CO ratio in Finger cloud is higher than that in Ring cloud
Ring cloud: ~ 1.5
Finger cloud: ~ 1.0 - 5.0

W[CI] (K km/s)/ W13CO (K km/s) Contour: [CI]

Ring Finger Ring Finger

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❖[CI] / 13CO ratio in RCW38

5. DISCUSSION

I[CI](K) vs. I13CO(K)

I13CO = I[CI] Finger: I13CO = 0.49 I[CI] Ring: I13CO = 0.64 I[CI] Orion: I13CO = 0.62 I[CI] (Shimajiri et al. 2013)

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❖Relation between [CI] / CO and NH2 (Av)

5. DISCUSSION
N[CI]/NCO (~ [CI]/[CO]) is constant (~ 0.1) at AV ~ 10 - 100

Finger: NCO = -1.3×10-23N[CI] + 0.3 Ring: NCO = -3.1×10-27N[CI] + 0.09

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❖Relation between [CI] / CO and NH2 (Av)

5. DISCUSSION
N[CI]/NCO (~ [CI]/[CO]) is constant (~ 0.1) at AV ~ 10 - 100

Finger: NCO = -1.3×10-23N[CI] + 0.3 Ring: NCO = -3.1×10-27N[CI] + 0.09

Difficult to explain by Layered PDR model

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❖Relation between [CI] / CO and NH2 (Av)

5. DISCUSSION
N[CI]/NCO (~ [CI]/[CO]) is constant (~ 0.1) at AV ~ 10 - 100

Finger: NCO = -1.3×10-23N[CI] + 0.3 Ring: NCO = -3.1×10-27N[CI] + 0.09 Layered PDR model (CLOUDY): UV from 05.5 star, nH2 = 104 cm-3

Difficult to explain by Layered PDR model

Rolling et al, 2007 Ferland et al. 2003

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❖Relation between [CI] / CO and NH2 (Av)

5. DISCUSSION
N[CI]/NCO (~ [CI]/[CO]) is constant (~ 0.1) at AV ~ 10 - 100

Finger: NCO = -1.3×10-23N[CI] + 0.3 Ring: NCO = -3.1×10-27N[CI] + 0.09 PDR model (CLOUDY): UV from 05.5 star, nH2 = 104 cm-3

Difficult to explain by Layered PDR model

Rolling et al, 2007 Ferland et al. 2003

Suggest clumpy PDR model?? We need follow-up observation..

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❖[CI] mapping toward the RCW38

6. SUMMARY
Detect two velocity component
Ring cloud: blue-shifted (vLSR = -8.3 - 9.1 km/s) , N[CI] ~1018 cm-2
Finger cloud: red-shifted (vLSR = 9.1 - 17.5 km/s) , N[CI] ~1017 cm-2
[CI] distribution is very similar to 13CO distribution
Same result as past studies (e.g. Orion, Carina nebula)
N[CI]/NCO (~ [CI]/[CO]) is constant (~ 0.1) at AV ~ 10 - 100
Difficult to explain by Layered PDR model

We plan to follow up observation with ALMA !! → Suggest clumpy PDR model ??