EAVW 2019/9/24-26 @ Ibaraki

JVN UPDATEKENTA FUJISAWA (YAMAGUCHI UNIVERSITY), JVN COLLABORATION• Collaboration• NAOJ (VERA)• Ibaraki, Tsukuba, Gifu, Osaka-Pref, Yamaguchi,
Kagoshima universities• JAXA, NICT

• Specifications• 11 telescopes (11m ~ 64m)
• 6~7 active telescopes• Baseline 50 - 2500 km• Frequency 6.7/8/22 GHz• Sensitivities (8 GHz, 2 Gbps) 3 mJy• Operation•

200hr/yr, 30 observations/yr• Tomakomai 11m (Hokudai) stopped at 2016March• Tsukuba 32m (GSI) stopped at 2017 January• Kashima 34m (NICT) stopped at 2019
September

Japanese VLBI Network (JVN)TOPICS IN 2018 – 2019
• Contribution to EAVN : Ibaraki & Yamaguchi• Takahagi 32m (Ibaraki) will participate at 22 GHz• C-band test observation, under processing• Ibaraki & Yamaguchi will join EAVN C-band from 2020B• Ibaraki – Yamaguchi – Kashima Observation• High sensitivity, No image• Fringe detection/survey mode

JVN OBSERVATION
2018 OCT – 2019 SEPband# of obs.

Obs. time (hr)C-band42130

X-band50268

Sum92398• Imaging Observation• Methanol maser imaging• EAVN test observation• Ibaraki - Yamaguchi observation• High-z AGN (Furuya)• Extremely compact HII region (Motogi, Ogura)• Galactic compact sources• Flare star

IBARAKI – YAMAGUCHI OBSERVATION• Detection VLBI
• Ibaraki-Yamaguchi-Kashima• Non-imaging, fringe detection• 32/34m high sensitivity• a few mJy @ 6/8 GHz• Different baseline length• Source size / brightness• Long observation time• 200~300 hr/yr (up to 1000 hr infuture)• Correlation by universities

Massive VLBI database construction for various
class of radio sourceIBARAKI-YAMAGUCHI-KASHIMA OBSERVATIONEXTREMELY COMPACT HII REGION SURVEY(Motogi & Ogura)• To find candidates of very firststage of high-mass star as
extremely compact HII region• VLBI survey of thermal object withTarget distribution

Tb ~ 104 K• Observation• Ibaraki – Kashima• 662 sources from CORNISH• 390 sources done
Flux density of the targets

IBARAKI-YAMAGUCHI OBSERVATIONGAMMA-RAY EMITTING AGN SURVEY• To find candidate AGNs in the field of Fermi unassociated γ-ray sources• Observation• > 1000 sources in two years (2019 – 2020)• Ibaraki – Yamaguchi, X-band• Pre-study• Fujinaga, Niinuma et al.
(2016) PASJ, 68, 70• Surveyed gamma-ray
unidentified 845 sources inthe Fermi catalog• Found 28 new gamma-ray
AGNs (→)

SINGLE-DISH AND SHORT BASELINEINTERFEROMETER IN JVN• Large-scale Single-Dish and VLBI
Monitoring of 6.7 GHz methanol
maser by Ibaraki University• HR1099 (RS CVn type binary)monitoring with Hitachi – TakahagiInterferometer• X-ray binary GRS1915+105
monitoring with YamaguchiInterferometer

LARGE-SCALE SINGLE-DISH AND VLBI MONITORING OF 6.7 GHZ
METHANOL MASER BY IBARAKI UNIVERSITY• Goals• Mass accretion process of high-mass YSOs
• At 1000au - 10au with theoretical background• Method• To find new periodic sources by daily – monthly monitoring for 400 sources• To test if there is a Period-Luminosity relation for high-mass YSOs

New periodic source discovered at Ibaraki

Period – Luminosity relation of HMYSOs

A serendipitous result

DISCOVERY OF ANACCRETION BURST:
G358.93-00.03
THE ASTRONOMER'S TELEGRAM, NO.
12446, JANUARY 2019

• Bursting activity of the 6.668GHz CH3OH maser detected in
G 358.93-00.03 using theHitachi 32-m

• Sugiyama, K., Saito, Y.,
Yonekura, Y., Momose, M.

X-RAY BINARY GRS 1915+105 MONITORING BY MAXI (X-RAY) AND
YAMAGUCHI INTERFEROMETER (RADIO)
0.716• Results• Radio detection at quiet phasewith flux density of ~5mJy• Radio flare of ~100mJy wasdetected after X-ray flare• Fast variability with timescale ofa few hours• After X-ray became quiet, radio●2-20keV[ph/s/cm2]
MAXI
8.448 GHz [Jy]● YI0.6

122-20 keV [ph/s/cm 2]• Yamaguchi Interferometer• 8 GHz (8192-8704 MHz)
• Sensitivity ~5 mJy (5sigma)• Period 2019 Feb. to Sep.

14Radio activity
continues while X-ray
becomea quiet

100.50.4

860.3Radio flare after
X-ray flare

0.2

420.1

Detection at ~5mJy !

058500

58550

58600

58650

58700

058750

MJD

activity continues

108.448 GHz [Jy]• Observation

SUMMARY• Imaging Observation• C and X-bands steady observation• Participation to EAVN from 2020B• 100 hrs

• Ibaraki – Yamaguchi observation• Intensively doing to create a new field of VLBI

• Single-dish and short baseline interferometer• Ibaraki, Yamaguchi