1. SKA Science Report (Mostly 2018-2019)
Contents
News from SKAO
SKAJ Science Activity
赤堀卓也
グループサイエンティスト/マネージャー
2019/9/2
SKA-Japanシンポジウム2019

2. 1. News from SKAO Welcome MeerKAT!
MeerKAT inauguration (開所式) was held in July 13, 2018
Some large projects and conditional open-use in progress in 2019
2019/9/2
SKA-Japanシンポジウム2019

3. 1. News from SKAO Science Highlights
★Source6
★Source8
★Source2
★Source3
★Source1
★Source4
★Source7
★Source5
Bowman+18, Nature
EDGES experience at MRO
A signal of HI absorption in CMB radiation at z=15-20?
Shannon+18, Nature
ASKAP 1.4GHz PAF
FRBs can be classified into “repeater” and “one-off”?
2019/9/2
SKA-Japanシンポジウム2019

4. 1. News from SKAO Science Community
Including
22JPs (2.5%)
SKA General Science Workshop UK
SKA Science Working Group membership has grown by a factor of four in the past 5 years. There ware about 300 registrants in the last SKA Science Workshop 2019.
Cosmology Redbook (2019) has been published
The 14th Group “Gravitational Wave” was established
2019/9/2
SKA-Japanシンポジウム2019

5. 1. News from SKA Office SKA Data Challenge (SDC) #1
Some 107 sources based on
T-RECS sky model (Bonaldi+18). 1
Oxford-ICRAR
/UK-AU 2
ICRAR/AU 3
EngageSKA
/Portugal 4
ARCIt-CACAO
/IT 5
hs/DE,
IITK/IN,
IPM/Iran, JLRAT/CN, Shanghai/CN
←8, ↑1000, 100→
Integration
Time (hr)
17 teams
registered
9 teams
submitted
To get the community familiar with SKA data product
To develop efficient methods for source finding & source characterization
2019/9/2
SKA-Japanシンポジウム2019

6. 1. News from SKAO SDP HPC Breakdown
SKA-TEL-SKO
DFT in ICAL
2019/9/2
SKA-Japanシンポジウム2019

7. 1. News from SKAO SKA Regional Center (SRC)
SKA-TEL-SKO
“京”=10PFLOPs
If 8TB=2万円,
1EB=25億円
PFLOPs 30 20 10
ExaByte 3 2 1
100Gbit/s, 5.2M€/yr (in operation cost)
Forecast SRC requirements
2019/9/2
SKA-Japanシンポジウム2019

8. 1. News from SKAO Beyond Band 5
Freq.
(GHz)
LOW
Band 1
Band 2
Band 3
Band 4
Band 5a
Band 5b
Band 5c/6
Band B
0.05
0.3
1.0
1.7 3 5 8 15
25~50
Solar System
Planet Formation
Astrochemistry & Life
Tomoya Hirota
Star Formation & Stellar Evolution
Tomoya Hirota/Toshihiro Handa/Takeru Murase/Yuushi Hirata/Hiroshi Imai/Koichiro Sugiyama
Galactic Structure
Hiroshi Imai/Toshihiro Handa/Tomoya Hirota
Nearby Galaxies
Kazuhiro Hada/Yuki Kudoh
History of the Universe
Takuya Akahori
Cosmology
Kohji Yoshikawa
Fundamental Physics
Transient Phenomena
Takuya Akahori/Sujin Eie/Haruka Sakemi/Mami Machida
13 Japanese people will contribute to use cases
Deadline
End of September 2019
2019/9/2
SKA-Japanシンポジウム2019

9. 2. SKAJ Science Section Risks of Calibration/Imaging
F: far sidelobe error, S: near sidelobe error,
P: Statistical pointing error, P’: instantaneous pointing error
Q: primary beam error, B: primary beam freq. error,
M: source model error
Clear Need a factor of several improvement
Need one order of magnitude improvement
All 10hr x 100 epochs
Shimwell+17, A&A, 598, A104
Q. Can a 1000 hr integration reach the thermal- noise limit?
Error budget analysis (SKA-TEL-SKO )
Large gain error. Must do self-calibration
Need good primary beam shape & pointing stability
Q. Can a dynamic range reach 50dB of the requirement?
Self-cal. using bright compact sources
LOFAR achieved 60dB (but depends highly on the sky)
Need intelligent high-speed pipeline
2019/9/2
SKA-Japanシンポジウム2019

10. 2. SKAJ Science Section Comparison with ALMA/ngVLA
Snow line of protoplanetary disk 5 AU = pc
150km
25GHz ≒ 18mas of ALMA B6
But the brightness-temperature sensitivity is limited. SKA’s targets are:
Inner/equatorial disk where ALMA bands are optically-thick
Jets, ionized wind, flare
Some molecular lines that are difficult to study at ALMA bands
In 2030s, SKA2 will exceed ngVLA. Can SKA extend up to 50 GHz?
Calc. by
H. Kobayashi
Good
Sensitivty
SKA2
Good
Ang. Resolution
2019/9/2
SKA-Japanシンポジウム2019

11. 2. SKAJ Science Section SKAJ SKA Regional Center Task Force
Mission
To list the services needed for us
To develop our participation plan for the SRC alliance
Particularly, China SRC
Evaluate the cost
Roadmap
Members
Name
Affiliate
Role
Tomoya Hirota
SKAJ
Chair, Cont., Line, Pol.
Takuya Akahori
SKAO, Magnetism
Yuuki Adachi
MVO
VERA
Misato Fukagawa
ALMA ARC
ALMA
Kohji Yoshikawa
Tsukuba U.
HPC, Cosmology
Kenji Hasegawa
Nagoya U.
HPC, EoR
2019.7
#1 MTG
Mission
Definition 9
#2 MTG
Learn SRC
Define AIs 11
@Shanghai
SKA-WPC 12
#3 MTG
WPC report
Resolve AIs
2020.3
#4 MTG 5 6
#5 MTG
2020.9
#6 MTG
Draft start 11
@Shanghai
Consultation 12
#7 MTG
First draft
2021.3
#8 MTG
Second draft
2021.6
#9 MTG
Final report
2019/9/2
SKA-Japanシンポジウム2019

12. Summary Report from SKAO SKAJ Science Activity
SKA Precursors/Pathfinders go well!
SKA Community is increasing significantly
Science Data Challenge: #1 closed, #2 on going
HPC and SRC forecasts
Beyond Band 5 use case
SKAJ Science Activity
Risks of calibration/imaging
Comparison with ALMA/ngVLA
SKAJ SRC Task Force
2019/9/2
SKA-Japanシンポジウム2019