1. Next Space VLBI mission: VSOP-2
Y.Murata (ISAS/JAXA)
Next Generation Space VLBI WG
H.Hirabayashi, M.Natori, P.G.Edwards, Y.Asaki, N.Mochizuki, T.Toda, … (ISAS/JAXA),
M.Inoue, S.Kameno, M.Tsuboi, Y.Kono, K.Asada, A.Doi, H.Nagai, H.Kobayashi, K.Bushimata, N.Kawaguchi, S.Iguchi, … (NAOJ)
T.Kondo, Y.Koyama (NICT)
K.Fujisawa (Univ. of Yamaguchi),
T.Omodaka(Univ.of Kagoshima),
H.Sudo (Univ. of Gifu), K.Wajima (KVN)
T.Kasuga (Hosei Univ.), S.Sawada-Sato (ASIAA)
International collaborators
JPL, NRAO, ATNF, DRAO, JIVE/EVN, China, ..
I’m a member of VSOP group in ISAS Japan.
Today, I talk about a next generation space-VLBI mission, we call VSOP-2.

2. VSOP

3. 34,000 km HALCA and VSOP 1.6 GHz (18 cm) 5 GHz (6 cm)
VLBI Space Observatory Programme
HALCA and VSOP
Highly Advanced Laboratory for Communications and Astronomy
1.6 GHz (18 cm)
5 GHz (6 cm)
x[ 22 GHz (1.3cm)]
34,000 km
Launch:
Feb. 1997
ISAS M-V rocket
Resolution of
360 μarcseconds
　 at λ= 6 cm

4. Resolution of current & future telescopes in all wavelength
Present
status
ＶＳＯＰ
Lobanov, A.P. 2003, SKA Memo 38

5. VSOP observation results
FIRST Space VLBI Mission
Physics of the Active Galactic Nuclear (AGN)
Structure and motion of the AGN jets
Torus around the AGN core
Extremely high brightness temperature objects
(TB=1014 K)
Beamwidth 100 Rs
at 5 GHz for M87
Jet Structure
Plasma torus
Plasma Torus
in absorption
ISAS and international partners have succeeded VSOP which is the first VLBI imaging mission.
So, we could studies about AGN jet environment and jet physics:
As you know….
Structure …
Time variation of jet in high resolution.
And HALCA is still living,
NGC4261 parsec-scale structure by free-free absorption Jones et al. (2000)
year monitering observation. Murphy
AGNのジェットと核周物質の物理の解明
活動銀河核からのジェットの構造、運動
吸収による銀河中心部のトーラス構造の解明
高輝度温度天体の存在を示す。
5-years jet monitor of

6. VSOP publications PASJ VSOP issue Advances In Space Research
VSOP symposium

7. Success of large scale International Collaboration
HALCA Tracking Stations:
NASA DSN (Goldstone, Tidbinbilla, Madrid),
NRAO Green Bank, Usuda (ISAS)
Navigation:
NASA JPL, ISAS
Correlators
VLBA (NRAO), Penticton (DRAO, Canada), Mitaka (NAOJ)
Radio Telescopes:
VLBA, VLA, Green Bank 140 ft (NRAO), Arecibo,
DSN 70m (GO, TI, RO), Jodrell Bank, Westerbork, Onsala,
Effelsberg, Torun, Noto, Metsahovi, Kalyazin, Shanghai,
Hartebeesthoek, ATCA, Hobart, Ceduna, Mopra, Usuda,
Kashima (14 countries, 32 telescopes)

8. VSOP-2

9. Phase-referencing capability
VSOP-2 Mission
VSOP-2 is the upgraded space VLBI mission following the VSOP mission.
10 times higher sensitivity.
10 times higher frequency
observation
10 times higher resolution with ～ 40 μarcseconds　(43 GHz).
Observing band 8, 22, 43 GHz (Wavelength of 3.8, 1.3 and 0.7 cm)
Dual polarization
Phase-referencing capability

10. Resolution of current & future telescopes in all wavelength
Present
status
ＶＳＯＰ
ＶＳＯＰ－２
Lobanov, A.P. 2003, SKA Memo 38

11. Characteristics of the future radio telescopes
Sensitivity
SKA
(Square Kilometer Array)
ALMA
Higher
Frequency
Resolution
VSOP-2

12. Launcher and orbit Launcher : M-V rocket by JAXA Orbit : (cf HALCA)
Apogee 25,000 km (21,300 km) Perigee 1,000 km (560 km)
inclination ° (31 °)
period hour (6.3 hour)
Mass kg (831 kg)
Power ,800 W (700 W)
Launch : 2011 in earliest caes
For the launcher, we are assuming the rocket to be M-V.
The possibility of launching satellite with HII still remains, too.
If so, we can get additional mass budget, fairing space and apogee height.
But for now, M-V is more realistic.

13. VSOP-2 Science Targets Key science :
Jet structure, collimation and acceleration
Structure of plasma tori, accretion disks, BHs in active galactic nucleus (AGN)
Structure of magnetosphere in protostars
Other science targets:
Galactic masers in star-forming region
Extragalactic Megamasers
Radio quiet quasars
X-ray binaries, SNR, gravitational lenses etc.
Following these success of VSOP, science targets of VSOP-2 approach the central region of AGN.
studies of accretion disks and jets in AGN
studies of non-thermal emission from YSOs
And we revenge the maser observations.
the highest resolution studies of Galactic masers and extragalactic megamasers.
And the capability of other observations have been discussing.

14. Look at the BLACK HOLE !? (Takahashi et al. 2004) a-c: inclination 20°
　　　20°
g-I: inclination
　　　45°
　Model
VSOP-2
image
Imaging of Accretion Disk
　ADAF、TB= K　　
（Standard Disk = 105K ）
Black Hole
10 Rg resolution
@ M87 distance
(Takahashi et al. 2004)
Schwartschild………………...…..Extreme Kerr

15. Magneto-HydroDynamic Simulation (Meier et al. 2001)
Rotating accretion disk + Magnetic Fiels
Polarization Image by
VSOP
VSOP-2 enables
full-polarization Image

16. Dynamics of galaxies and the star forming regions using maser emission
Mega-maser in NGC4258 type galaxies
Measurement of the proper motion in short timescale
Doppler shift measurement
3 dimensional dynamics
Estimation of the central mass
Star Forming Region
Late Type Stars
NGC4258 Miyoshi et al. 1995

17. VSOP-2 satellite 9-m offset Cassegrain antenna with modular structure
Light weight

18. VSOP-2 engineering developments
Large deployable antenna for λ=7 mm
High data rate sampling of the data
1 Gbps data transmission
Cooled low noise amplifiers on board.
Development of the phase-referencing
Switching capability
Total satellite system design
Mass budget
Power budget
Heat control system
Attitude control system
Power supply system
Structure fit to the M-V fairing
Observing frequencies of VSOP-2 are these. We revenge the 22GHz of HALCA.
For now, 22 and 43 GHz receivers are cooled. But 8GHz is not cooled because of the restriction of mass and power budget.
Wide band data downlink is one of technical challenges.
These bring the improvement of sensitivity.
Apogee height is about 25000km, so we can get the resolution of 75 mas for 22GHz and…
And other option are these.
Phase-ref brings more higher sensitivity and astrometric observation.
Dual polarization bring us the studies of magnetic field.

19. Deployment mechanism of the Modular antenna structure
Launch 2006 ?
ETS-VIII(JAXA)
Same deployment mechanism as ETSVIII
modular antenna structure
Deployment image of ETS-VIII
We use …
NASDA HPでcheck!
Deployment test of ETS-VIII

20. Development of a high accuracy antenna module
図中を英語に
Antenna surface of ETS-VIII is cable ****
We need a surface accuracy of 0.4mm for 43GHz observation.
Now, may be this or next week, mesh will be stretched on the surface

21. Deployment of the module
Deployment system test.
Confirmed mechanical structure

22. Radiation test of the high speed A/D LSI
Total dose test (April 2001)
Single event test （August 2001)
1:16 DEMUX
10 Gbps 1 bit A/D
Heavy ion beam
Correlator

23. Solution of high torque actuator
4 reaction wheels and 2 CMG for rapid switching
CMG
changes the direction of the spin axis set by the reaction wheels
Simulations
Assuming :
Switching cycle 1 minute
Amplitude 3.5 °
Flexible structure body
CMG control test
separation angle < 3°
will allow rapid switching for phase referencing
Switching cycle < 1min.
Attitude error < 0.005°

24. International Collaborations
International collaboration based on VSOP experience
Correlators, tracking stations, orbit determination
Ground telescopes commitments based on GVWG (Global VLBI Working Group) discussion.
Many new Ground Telescopes
VERA 4 stations, Yamaguchi, Uchinoura ,
KVN 3 stations,
Urumqi, Delingha, Beijing
Sardinia, Yebes
GBT
Possibility of SKA with VSOP-2

25. Status of VSOP-2 JAXA/ISAS Developments are going.
The VSOP-2 mission proposal was submitted to ISAS Science Steering Committee in October, 2003, but could not go to the budget request.
Revised version of the proposal will be submitted soon as an M-V 2011
3 missions are the candidates to be approved.
NAOJ
Space VLBI project office for VSOP-2 is started from last April
NAOJ and ISAS will be core institute for the VSOP-2 mission, as we did in the VSOP mission.