Star Formation Legacy Project: Status and Results Shun Ishii - - PowerPoint PPT Presentation

Shun Ishii (NAOJ/JAO) Fumitaka Nakamura(NAOJ)

Star Formation Legacy Project: Status and Results

Kong et. al.,2018

NAOJ

• Fumitaka Nakamura(PI), Ryohei Kawabe, Chihomi Hara, Takashi Tsukagoshi, Shun Ishii,

Shuri Oyamada (Japan Women Univ.), Takayoshi Kusune (PD), Hideaki Takemura(M1) Tokyo Gakugei University

• Tomomi Shimoikura, Asha Hirose, Kazuhito Dobashi

Ibaraki Univ.

• Yoshihiro Tanabe (D3), Munetake Momose

Niigata Univ.

• Umiko Urasawa, Kazushige Sasaki, Ryoichi Nishi

National Thing Hua Univ.

• Shih-Ping Lai, Sheng-Jun Lin, Vivien Chen

Others

• Koji Sugitani (Nagoya City Univ.), Sachiko Okumura (Japan Women Univ.), Yoshimi

Kitamura (JAXA), Yoshito Shimajiri (CEA/Sacley), Quang Nguyen Luong (KASI), Patricio Sanhueza (NAOJ) International Collaborators

• John Carpenter (JAO), Hector Arce (Yale), Shuo Kong (PD, Yale), Jonathan Tan (Florida),

Wanggi Lim (D3, Florida), Peter Schlike, Sümeyye Suri (D3,Cologne), Paul Goldsmith, Peregrine McGehe (Caltech), Jens Kauffman, Thusuhara Pillai (MPI), John Bally (Colorado), Ralf Klessen, Rowan Smith (Heidelberg), Paolo Padoan (Barcelona), Alyssa Goodman (CfA), Andrea Isella (Rice), Doug Johnstone (HEA, Canada) et al. + CARMA consortium, Alvaro Hacar (Leiden), Zhi-Yun Li (Virginia)

Project members and collaborators

Outline

✴ Motivation and Science goals ✴ Project overview ✴ Observations ✴ Result from Orion A Observations ✴ Summary

Why is star formation so inefficient?

✴Star formation may be suppressed by turbulence, magnetic field, and

stellar feedback.

✴Towards a full understanding of the roles of these processes in star

formation, we characterize the cloud structure and dynamics by wide-field mapping observations with multiple lines.

✴Wide-field mapping observations are important to understand the effects of

stellar feedback and external events like large-scale shocks because they potentially affect cloud properties and structures in a cloud scale, 1−10 pc

✴12CO, 13CO, C18O, N2H+ observations cover the density range from 102 cm−3

to 105 cm−3.

✴Maps of nearby clouds by NRO 45m telescope can be directly compared

with the maps of the molecular clouds within a few kpc by ALMA in a comparable spatial resolution of a few thousand au.

NRO 45 m Star Formation Legacy Project

✴ Using the new receiver FOREST, we carried out wide-field mapping observations

toward nearby star forming regions in 12CO (1-0), 13CO (1-0), C18O (1-0), N2H+ (1-0), covering the density range of 100 to 105 cm-3.

✴ http://th.nao.ac.jp/MEMBER/nakamrfm/sflegacy/sflegacy.html ✴ three year project: 400 hours x 3 years ~ 1200 hours ✴ Targets ✴ Orion A (400 pc): 2-3 square degree ✴ Aquila Rift (415 pc): 1 square degree ✴ M17 (2000 pc): 1 square degree

M17 Aquila Rift Orion A

10 pc Povich et al., 2010

Orion A

13CO 12CO

C18O N2H+ H2 Column density

Aquila Rift

13CO 12CO

C18O N2H+ Spitzer CCS

W40 Serpens South

M17

13CO 12CO

N2H+ Spitzer C18O

Publication Plan

Initial Results will be presented mainly in the PASJ special issue (March, 2019)

• 1. Nobeyama Mapping Observations toward Nearby Molecular Clouds, Orion A, Aquila Rift, and

M17, Nakamura et al., submitted

• 2. Nobeyama Mapping Observations toward Orion A. I. A New Method of Molecular Outflow Search,

Tanabe et al., submitted

• 3. Nobeyama Mapping Observations toward Orion A. II. Classification of Cloud Structures and

Variation of the 13CO/C18O Abundance Ratio due to far-UV Radiation, Ishii et al., submitted

• 4. Nobeyama Mapping Observations toward Orion A. III. Initial Results of NH+ Core Survey,

Nakamura et al., accepted

• 5. Nobeyama Mapping Observations toward Orion A. IV. Multi-Line Observations toward an

Outflow-shocked Region, OMC-2, FIR 3/4/5, in prep.

• 6. Nobeyama Mapping Observations toward Aquila Rift. I. Cloud Structure, Shimoikura et al.

(2019)

• 7. Nobeyama Mapping Observations toward Aquila Rift. II. Effect of the W40 HII region,

Shimoikura et al. (2019)

• 8. Nobeyama Mapping Observations toward Aquila Rift. III. Relationship between Magnetic Field

and Cloud Structure, Kusune et al. (2019)

• 9. Nobeyama Mapping Observations toward M17. I. Cloud Structure, Dobashi et al. in prep.
• 10. Nobeyama Mapping Observations toward M17. I. N2H+ Clump Survey, Hirose et al. in prep.
• 11. Nobeyama Mapping Observations toward M17. II. Relationship between Magnetic Field and

Cloud Structure, Sugitani et al. (2019) Other papers (Orion A, CARMA+45m) (a) The CARMA Orion Survey, Kong et al. (2018) (b) Expanding Carbon Monoxide Shells in the Orion A Molecular Cloud, Feddersen et al. (2018) (c) Star Formation in the Orion A Molecular Cloud I. Properties of Filaments as Seen in 13CO (1-0) and C18O (1-0) Emission, Suri et al. (2018) ………

+ CMF in Orion A: see Takemura-san’s poster

Final combined map is more than 3 times of this image.

~20” ~5” ~5”

CARMA-NRO Orion maps

CARMA-NRO Orion maps

red: 9.8 - 12.1 km/s blue: 7.3 - 9.6 km/s green: 4.8 - 7.1 km/s

Kong et al. (2018)

12CO(J=1-0) 12CO(J=1-0)

A result from Orion Observations

Classification of Cloud Structures and Variation of the 13CO/C18O Abundance Ratio due to far-UV Radiation

13CO Column density

Cloud identification using 13CO data

✴ 13CO(J=1-0) is a good tracer to internal

structures through entire molecular clouds

✴ 12CO(J=1-0): optically thick, Tex ✴ C18O(J=1-0): traces dense gas ✴ We use the columns density cube fo 13CO to

analyze cloud structures

C18O Column density

Identification of Cloud Structures by SCIMES

Result

✴ 78 clouds identified ✴ Well-known subregions are naturally

identified as independent structures

✴ Diffuse clouds outsides of the integral

shaped filament are also detected

✴ Small clouds appear to overlap with

larger clouds. Analysis:

✴ Cloud identification by SCIMES

(Colombo et al.,2015)

Identification of Cloud Structures by SCIMES

Result

✴ 78 clouds identified ✴ Well-known subregions are naturally

identified as independent structures

✴ Diffuse clouds outsides of the integral

shaped filament are also detected

✴ Small clouds appear to overlap with

larger clouds. Analysis:

✴ Cloud identification by SCIMES

(Colombo et al.,2015) OMC-1 OMC-2/3 OMC-4 OMC-5 L1641N DLSF

Identification of Cloud Structures by SCIMES

Group1: Clouds in the integrate-shaped filament(ISF) Group2: Clouds in south and east/west side of ISF Group3: DLSF and diffuse clouds

Identification of Cloud Structures by SCIMES

Group1: Clouds in the integrate-shaped filament(ISF) Group2: Clouds in south and east/west side of ISF Group3: DLSF and diffuse clouds These clouds are isolated from

• thers in the

dendrogram

Identification of Cloud Structures by SCIMES

Group1: Clouds in the integrate-shaped filament(ISF) Group2: Clouds in south and east/west side of ISF Group3: DLSF and diffuse clouds →interacting with HII regions These clouds are isolated from

• thers in the

dendrogram

Environmental effect on the abundance ratio

The abundance ratio between 13CO and C18O has significant variation over Orion A X(13CO)/X(C18O) Shimajiri et al., 2014 Selective dissociation of C18O on the edge on PDR?

• The FUV emission selectively dissociates CO isotopes
• C18O molecules are expected to be selectively

dissociated by UV photons. (Lada et al. 1994, Shimajiri et al. 2014)

Environmental effect on the abundance ratio

The abundance ratio between 13CO and C18O has significant variation over Orion A → large variation by clouds and within a cloud especially on edges →the ratio changes along the velocity axis X(13CO)/X(C18O) Position-velocity diagram

• f X(13CO)/X(C18O)

Environmental effect on the abundance ratio

X(13CO)/X(C18O) Dust extinction AV FUV field intensity G0 The abundance ratio between 13CO and C18O has significant variation over Orion A →large variation by clouds and within a cloud →the ratio changes along the velocity axis →we compare with the dust extinction and FUV field derived by Herschel data

X(13CO)/C18O - Av by clouds

✴ High ratio clouds: ✴ the abundance ratio decreases with N(13CO) and Av ✴ Clouds are irradiated by strong FUV ✴ Low ratio clouds: ✴ the abundance ratio is almost independent ✴ FUV field is (relatively) low

h i g h X (13 C O ) / C18 O low X(13CO)/C18O

X(13CO)/C18O - FUV by clouds

G0 N(13CO) or Av

✴ Selective dissociation of C18O is enhanced on the surface of clouds that

are irradiated by FUV and it is suppressed under low FUV environment.

✴ 78 molecular clouds are identified by SCIMES. ✴ Well-known internal clouds are naturally identified as independent

structures in Orion A.

✴ Isolated structures in the dendrogram are likely to be produced by

interaction with HII regions.

✴ A large deviation of the abundance ratio X(13CO)/X(C18O) is found

among identified clouds in the position-position-velocity space.

✴ The results support that selective dissociation of C18O on the surfaces

• f clouds irradiated by FUV.

Cloud Structures in Orion A: Summary

Start Formation Legacy Project: Summary

✴ We have completed 3-year Star Formation Legacy project towards a

full understanding of the roles of these processes in star formation.

✴ 3 star-forming regions (Orion A, Aquila Rift, and M17) were mapped

with multiple lines thanks to wide-field and high sensitivity capabilities

• f FOREST.

✴ The data is now available at JVO ✴ We are writing publications from several points of view such as

• utflow, cloud structures, core survey, and stellar feedback.

Publication Plan

Initial Results will be presented mainly in the PASJ special issue (March, 2019)

• 1. Nobeyama Mapping Observations toward Nearby Molecular Clouds, Orion A, Aquila Rift, and

M17, Nakamura et al., submitted

• 2. Nobeyama Mapping Observations toward Orion A. I. A New Method of Molecular Outflow Search,

Tanabe et al., submitted

• 3. Nobeyama Mapping Observations toward Orion A. II. Classification of Cloud Structures and

Variation of the 13CO/C18O Abundance Ratio due to far-UV Radiation, Ishii et al., submitted

• 4. Nobeyama Mapping Observations toward Orion A. III. Initial Results of NH+ Core Survey,

Nakamura et al., accepted

• 5. Nobeyama Mapping Observations toward Orion A. IV. Multi-Line Observations toward an

Outflow-shocked Region, OMC-2, FIR 3/4/5, in prep.

• 6. Nobeyama Mapping Observations toward Aquila Rift. I. Cloud Structure, Shimoikura et al.

(2019)

• 7. Nobeyama Mapping Observations toward Aquila Rift. II. Effect of the W40 HII region,

Shimoikura et al. (2019)

• 8. Nobeyama Mapping Observations toward Aquila Rift. III. Relationship between Magnetic Field

and Cloud Structure, Kusune et al. (2019)

• 9. Nobeyama Mapping Observations toward M17. I. Cloud Structure, Dobashi et al. in prep.
• 10. Nobeyama Mapping Observations toward M17. I. N2H+ Clump Survey, Hirose et al. in prep.
• 11. Nobeyama Mapping Observations toward M17. II. Relationship between Magnetic Field and

Cloud Structure, Sugitani et al. (2019) Other papers (Orion A, CARMA+45m) (a) The CARMA Orion Survey, Kong et al. (2018) (b) Expanding Carbon Monoxide Shells in the Orion A Molecular Cloud, Feddersen et al. (2018) (c) Star Formation in the Orion A Molecular Cloud I. Properties of Filaments as Seen in 13CO (1-0) and C18O (1-0) Emission, Suri et al. (2018) ………

+ CMF in Orion A: see Takemura-san’s poster