1. The “TOP” “SCOPE”: Follow-up surveys toward Planck Galactic cold clumps with ground-based radio telescopes
Tie Liu (KASI fellow)
Korea Astronomy and Space Science Institute
On behalf of the TOP-SCOPE team
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Tie Liu---IAU---Hawaii

2. 11/11/2018

3. We welcome new collaborators!
The team
Tie Liu (KASI, KR)
We welcome new collaborators!
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4. 53 New members since open enrollment
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5. Face-to-face workshop on Dec
Face-to-face workshop on Dec at Peking University
1. SOC:  Tie Liu; Mark Thompson; Sheng-Yuan Liu; Gary Fuller; Ken Tatematsu; Yuefang Wu; Di Li; James di Francesco; Kee-Tae Kim; Ke Wang; Isabelle Ristorcelli; Mika Juvela
2. LOC:  Zhiyuan Ren; Jinghua Yuan; Jinlong Xu; Jie Yao; Chao Zhang; Shuxian Li; Huawei Zhang; Yuefang Wu Tie Liu
3. Accommodations:  Please reserve your rooms at "Zhong Guan Xin Yuan Global Village PKU" hotel as soon as possible (before Oct. 15):
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6. 11/11/2018

7. Outline 1. Introduction 2. Joint surveys and follow-up observations
3. Preliminary results
4. Summary
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8. 1. Introduction
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9. What are Planck galactic cold clumps?
Planck is a third generation space based cosmic microwave background
experiment, operating at nine frequencies between 30 and 857 GHz
Planck Catalogue of Galactic Cold Clumps (PGCC), clumps
The early cold core (ECC) sample: 915 sample Td<14 K, SNR>15
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10. Summary from Planck collaborators et al. (2015)
“We believe that the PGCC catalogue, covering the whole sky, hence probing wildly different environments, represents a real goldmine for investigations of the early phases of star formation. These include, but are not limited to: i) studies of the evolution from molecular clouds to cores and the influence of the local conditions; ii) analysis of the extreme cold sources, such as the most massive clumps or those located at relatively high latitude; iii) characterization of the dust emission law in dense regions and the role of the environment.”
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11. Science topics
1. how dense cores form and how star formation varies as a function of environment
2. the universality of filaments in the cold ISM and their roles in generating dense cores
3. the existence of a density threshold for dense core formation
4. how dust properties change in different environments and, how dust properties affect the chemical evolution of dense cores
5. a comparison between some of the isolated Planck/JCMT cores and the clustered cores they have already found in the JCMT Gould Belt Survey.
6. Bright extragalactic sources
7. Core-YSO association
8. Magnetic Fields in ISM
9. HI-H2 Transition and cloud evolution
10. Collapsing and Oscillatory starless cores
11. Gas-grain chemistry, Dust grain properties and density profiles
12. Study of the cores with lower masses (e.g. brown dwarfs)
13. Search for the first hydrostatic core candidates
14. Core formation in Lamda Orion complex
15. Distance estimates
16. triggered star formation (HII regions, cloud-cloud collision)
17. …..
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12. 2. Joint surveys and follow-up observations
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13. Galactic distribution of targets
All-sky distribution of the PGCC sources (black dots) and the 2000 selected PGCC sources (open dots) overlaid on the 857 GHz Planck map (credit: M. Juvela).
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14. Summary of joint surveys
1. PMO/TRAO 13.7-m telescope survey in the J=1-0 transitions of CO isotopologues TRAO Observations of Planck cold clumps (TOP): 400hrs/yr for 3 years Goals: large scale structure & kinematics 2. SMT 10-m telescope survey in the J=2-1 transitions of CO isotoplogues (PI: Ke Wang, 600 hrs/3yrs). Goals: CO excitation, column density and depletion, kinematics 3. SCOPE: SCUBA-2 Continuum Observations of Pre-protostellar Evolution (300 hrs for first phase) Goals: dense cores and filaments 4. KVN 21-m telescope survey in dense gas tracers (e.g. HCN, HCO+, N2H+) (PI: Kee-Tae Kim, pilot survey done, 2016B proposal accepted; large proposal to be submitted soon) Goals: chemistry & kinematics of dense cores 5. NH3 follow-up survey with Effelsberg 100-m and TianMa 65-m (PI: Yuefang Wu, ~30 hrs at 100-m. Proposal to TianMa 65-m to be submitted by the end of this year) Goals: kinetic temperature & turbulence 6. HI survey with Arecibo 300-m and future FAST 500-m telescopes (PI : Di Li) Goals: HI abundance and chemical evolution of molecular clouds 7. Follow-up observations with NRO 45-m (PI: Ken Tatematsu, ~150 hrs in 2015B; 2016B proposal accepted) Goals: Chemistry 8. Follow-up observations with the SMA (four standard proposals submitted or accepted) Goals: Fragmentation and small scale structures/kinematics 9. Proposals to IRAM 30-m and SOFIA submitted
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15. TOP: TRAO Observations of Planck cold clumps
Targets: 2000 PGCCs
Tracers: 12CO (1-0) and 13CO (1-0)
Telescope: 13.7 m TRAO telescope (same as FCRAO, PMO)
Receiver: SEQUOIA is a cryogenic focal plane array designed for the GHz range.
32 pixels are arranged in a dual-polarized 4x4 array.
The noise temperature ranges from 50-80K over most of the band.
Tsys: ~250 K for 13CO (1-0) , ~500 K for 12CO (1-0)
Single pointing Obs:
3 minutes (on+off+cal) per source
Rms: < km/s for 13CO (1-0), <0.3 km/s for 12CO
Otf Mapping Obs：
~42 minutes per source for a 15arcmin*15arcmin map
Rms: ~ km/s for 13CO (1-0), <0.5 km/s for 12CO
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16. Status of “TOP”
Until end of May, ~150 fields have been mapped in 12CO/13CO (1-0). The mapping sizes range from 6arcmin*6arcmin to 30arcmin*30arcmin. Nearly all the Herschel fields observed at JCMT in 2016A have been mapped by “TOP”.
Below, I show an example of 13CO (1-0) map of a high-latitude cloud G Interestingly, the dense regions show very different velocities from the surroundings.
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17. With a diameter of 15m the James Clerk Maxwell Telescope (JCMT) operated by EAO is the largest astronomical telescope in the world designed specifically to operate in the submillimeter wavelength region of the spectrum. 
SCUBA-2 (Submillimetre Common-User Bolometer Array 2) is a 10,000 pixel bolometer camera operating simultaneously at 450 and 850 micron. The camera has in total eight TES arrays, four at each wavelength band. With each array having 32×40 = 1280 bolometers there are in total 5120 bolometers per wavelength. 
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18. constant velocity (CV) Daisy mode
15 minutes per source
6 mJy/beam within central 3 arcmin
10-30 mJy/beam in the map out to 12 arcmin
TRACK pattern
Exposure time map
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19. Why 850 micron?
1. Could be done under normal/bad weather conditions (grade 3 &4)
2. The SCUBA micron data are essential for constraining SED fits and determining dust emissivity (beta)
(beta map; Hersche+850 micron)
(beta map; Hershel only)
Perseus B1 clump: Sadavoy et al. 2013
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20. and high angular resolution mm/submm continuum survey.
When compared with previous continuum surveys, “SCOPE” is the first “all-sky” high sensitivity
and high angular resolution mm/submm continuum survey.
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21. Status of “SCOPE”
150 observed in pilot phase, 686 (65%) observed in “SCOPE”
PMO selected sources: 37/60
Herschel selected sources: 68/78
Lamda Orion region: 11/49
HINSA: 12/31
180 PGCCs in Galactic, ~100 observed, very high detection rate (>80%)
~530 PGCCs unbiased selected in Dec. -30 to 35 deg.
~20 papers in preparation
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22. 3. Preliminary results
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23. SCUBA-2 Dense core detection rate
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24. HINSA detections with Arecibo 300-m (Di Li)
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25. HINSA sources in “SCOPE”
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26. High-Latitude clouds (|b|>30 deg.)
Dense gas clumps revealed in PMO/TRAO survey. But most of them have no SCUBA-2 detections.
Density too low to form cores?
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27. Cold filaments
We detected several tens of very cold (T~10 K) and quiescent (starless) filaments
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(Henshaw et al. 2016)

28. PGCCs in Orion Lamda Orionis Orion A+B (Hee-weon Yi, in preparation)
(Blue: Halpha, Green, IRAS 100 micron, red/contours: Planck 353GHz
Black stars: PGCCs without SCUBA-2 detections
White stars: PGCCs with SCUBA-2 detections)
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(Hee-weon Yi, in preparation)

29. SCUBA-2 cores in Orion Planck SCUBA-2 SCUBA-2
Protostellar core fraction: Lamda Orionis (9/15), Orion A (30/73) , Orion B (9/28)
Lamda Orionis cores have higher temperature, lower beta, lower mass and lower column density than Orion A+B cores.
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30. brown-dwarf and very low-mass star formation (Liu+2016)
850 micron
1.3 mm
MIPS 70 micron
Green Contours:70 micron
Blue contours: 1.3 mm
Color: 24 micron
Extremely young Class 0:
G192N: M=0.43 Msun (JCMT); M=0.38 Msun (SMA); Lint=~0.2 Lsun
Proto-brown dwarf:
G192S: M=0.23 Msun (JCMT); M=0.02 Msun (SMA); Lint=~0.08 Lsun
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31. 1.3 mm continuum in color image and black contours; CO outflows in red and blue contours
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32. Chemistry or accretion gas flows as in VLA 1623A (Lai+)?
Color: WISE 22 micron
Contours: 850 micron
Gray image: 850 micron
Red contours: HC3N
Black contours: N2H+
(Tatematsu et al. 2016)
Chemistry or accretion gas flows as in VLA 1623A (Lai+)?
Need higher resolution obs!
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33. CCS-N2H+ configuration for prestellar core
SCUBA2 contours on WISE 22 micron image
Gray image: 850 micron continuum
Black contours: N2H+ (1-0)
Blue contours: CCS,
CCS is depleted toward the core
Red contours: HC3N
(Tatematsu, K. in preparing)
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34. Summary
 The Planck telescope has provided us with an unprecedented sample of “all-sky” pre-stellar object candidates. Planck cold clumps correspond to the coldest portion of the ISM where stars form, and can be used to characterize the earliest stages of star formation. In order to make significant progress in understanding the early evolution of molecular clouds and dense cores in a wide range of Galactic environments, we are carrying out unbiased “all-sky” surveys of Planck cold clumps in J=1-0 of CO/13CO lines with TRAO 14-m telescope and 850 µm continuum with the JCMT/SCUBA-2. We are also actively developing follow-up surveys/observations (SMT, KVN, FAST, NRO 45-m, SMA) for these legacy surveys, which will allow us to deepen the investigation of the dense core or star formation in widely different environments at their earliest evolutionary phases. Our survey will also provide a unique legacy database for such studies with other instruments, especially with ALMA.
Our observations have proved that Planck cold clumps are really interesting for studies of initial conditions of star formation at their earliest evolutionary stages in various environments. Our survey data could be used for various science topics related to star formation and cloud evolution.
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35. Thanks!
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