A Proposal Constructingmm/sub-mm VLBI Network

by East-Asian Power

M. Miyoshi (NAOJ)

EAVN Symposium 　 Hokkaido Univ. 2015/07/10

1

Oct. 2014 　 VERA 　 UM @NAOJ-MitakaOct. 2014 J-VLBI Symp. @GSIDec. 2014 EA-RX- WS @ShimaMar. 2015 ASJ meeting @Osaka Univ.Jun. 2015 TDC Symp. @ KashimaJul. 2015 EA-VLBI WS ＠ Here Hokkaido Univ.

(0) As you seen, in THIS conference RECENT GOOD

jobs have been reported.

.

Adding ，we Asian researchers

　 have a long history

of Black Hole studyand mm-VLBI.

(1) The first black hole image in the world was

done in Japan by J. Fukue

using computer!

The First Black Hole Image by J. Fukue in 1988 at Osaka, Japan in East Asia.

Black hole shadow (horizon) was seen at the center of bright accretion disk. The disk was warped by strong gravity of black hole.http://quasar.cc.osaka-kyoiku.ac.jp/~fukue/

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(2) Nobeyama 45-m mm-wave

telescope joined in global mm-VLBI

during 1980’s

In 1991, the VLBI team forced to use the 45m though the surface panels were under replacement!

Global mm-VLBINetwork in 1980’s

NRO 45m still had the largest colleting area in the world with this status!

(3) East Asian astronomers have good jobs using VLBI since old days!

Shen et al. (2005) revealed the precise size of SgrA* using VLBA.

SgrA* 86GHz (3.5mm ）Shen et al. (Nature 2005)

１ｍａｓ The SgrA* image is broadened by scattering around circum-nuclear plasma. (Lo et al. 1998)

In 1995, MM, Inoue, Nakai, et al. got a decisive evidence of a super massive black hole in NGC 4258 from high velocity mega-maser using VLBA.

(5) Detailed investigationsfor imaging black holes were done more than 10 years ago in East Asia.

SgrA* 230GHzA model

Like VLBA location(North hemisphere)

Southern Hemisphere Horizon Telescope

For good imaging, we need 230GHz, 10-stations & 8000km wide dedicated array like the VLBA. For SgrA*, Array should be at southern hemisphere. (MM, Shen, Kameno ‘04)

250 as

(5a) A simple method of detecting black

hole shadow was also investigated.

(MM, Shen, Kameno et al. 2004,2007)

Noise level

Noise level

Krichbaum’s detection

(Miyohi et al. 2004,2007)

Noise level

Noise level

Krichbaum’s detectionDoeleman (2008)

kindly followed us and used our method in his observation.

(5b) VERICA:(Verification method of calibration)

We found a technique of verification of applied calibration both phase and amplitude.We need not worry about calibration!

Phase Amplitude

From checking if calibrated differential visibility shows thermal noise nature or not, we can verify the applied calibration both amplitude and phase. (MM 2014).

(6) Japan has a dedicated project plan, “Caravan-submm” at Andes.

“Caravan-submm” was　 openly discussed in 日本学術会議， the Astronomy and Astrophysics subcommittee of Science Council of Japan (SCJ) in 2012.

Mobile Station collects short u-v data, necessary for correct imaging

• The Caravan-submm and the Andes. The mobile radio telescope Caravan-submm moves around Andes. By changing positions of observations, we can obtain VLBI data from various baseline lengths and directions. In the data the null point should be contained, which is the strong evidence of the existence of a black hole horizon in the image. We plan to use multi mirror system for making a light weighted telescope. The Caravan-submm will contain at least three of trucks. One for antennas, another for mount, and the other is for electric power-supply and VLBI recording system and hydrogen maser. Though we suppose power supply for operating telescope is commercial base. The Peruvian and Bolivian Andes are the civilized regions. There are many cities and towns. Commercial based electric power supply is easily obtained. Also the main roads are developed along the Andes, therefore the movement of Caravan-submm telescope is quite easily preformed.

(7) The Most Important

East Asia has own 　radio telescopes suitable for mm/sub-mm VLBI!

JCMT15m(EAO)

SPART10m(Osaka Pref)

East Asian related institutions have own good sub-mm telescopes!ASTE10m(NAOJ)

GLT12m(ASIAA)

KVN:(max 129GHz now ）

Caravan-submm

+Open useALMA

JCMT15m(EAO)

SPART10m(Osaka Pref)

East Asian related institutions have own good sub-mm telescopes!ASTE10m(NAOJ)

GLT12m(ASIAA)

KVN:(max 129GHz now ）

Caravan-submm

+Open useALMA

We East Asia has a long history of the BH study, future plans, instruments and Own Powers!

Let’s construct a global sub-mm VLBI array by East Asian power!

East Asia must be the next leading force in the BH imaging.

Not only in computer, but also in observation, we East Asian Researchers have a chance to obtain the First Black Hole Image by own powers!

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