VLBI Activities in China an update Zhi-Qiang Shen Shanghai - - PowerPoint PPT Presentation

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VLBI Activities in China an update Zhi-Qiang Shen Shanghai - - PowerPoint PPT Presentation

Aug 05, 2023 187 likes •477 views

VLBI Activities in China an update Zhi-Qiang Shen Shanghai Astronomical Observatory Chinese Academy of Sciences 11th East Asia VLBI Workshop 2018 4-7 September 2018, PyeongChang, Korea Current VLBI facilities in China Major Facilities

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SLIDE 1

VLBI Activities in China： an update

Zhi-Qiang Shen Shanghai Astronomical Observatory Chinese Academy of Sciences

11th East Asia VLBI Workshop 2018 4-7 September 2018, PyeongChang, Korea

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SLIDE 2

Major Facilities for RA in China

Kashi hi 13m Sany nya 13m Jilin1 lin13m Lega gacy CVN Newly ly built ilt big g dish VGOS OS CDSN

Current VLBI facilities in China

Luonan 40m

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SLIDE 3

Activities at each site

  • FAST
  • Kunming
  • Urumqi
  • VGOS
  • Shanghai
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SLIDE 4

FAST - VLBI system installed

Test observations in planning

  • L band with Sh, Ur
  • Drift scan mode
  • Tracking mode
  • First light in 2019?

H-mas aser ROACH-2 Mark rk 6

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SLIDE 5

Kunming - VLBI system updated

Updated to CDAS2 DBBC2+MARK6 New H-maser FlexBuff coming soon!

S X C(new)

Frequency range 2150~2450 MHz 8200~900 0MHz 4000~8000 MHz Polarizatio n L&R L&R L&R LO 2000MHz 8100MHz

  • ptional

Tsys 50K(Room TEMP.) 70K(Coole d) 45K Efficiency ~60% ~45% ~50%

Good EM env (4040—7500 MHz)

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SLIDE 6

Urumqi – updated to 26m

Dish 25m -> 26m New Q-band Rx  30 GHz~50 GHz  Tsys < 65K DBBC2 backend Test observations in late of 2018

Tsys measurements LCP & RCP

Q-band receiver installing

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SLIDE 7

25 m

VGOS – NTSC+SHAO

13m diameter antenna Very high slew rates  12°/s in azimuth  6°/s in elevation Frequency range 1.2 ~ 9 GHz Efficiency > 50% Bandwidth: 1GHz *4 Commissioning since 2017 Sheshan VGOS

Fringes Dec. 2017

Tianma VGOS Sh

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SLIDE 8

Shanghai – update

FlexBuff installed  240 TB  e-VLBI & local disk e-VLBI up to 2Gbps under testing

EAVN 2018B open use CE-4 VLBI tracking

relay-sat in orbit

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SLIDE 9

Shanghai – VLBI Sci & Tech workshop

(18-19 May, 2018)

More than 100 participants from 20+ institutes and universities. 40+ presentations: covering VLBI facilities, astrophysics, astrometry, geodesy, deep space applications and technical development.

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SLIDE 10

Related scientific outputs

  • AGN studies
  • Pulsar astrometry, Survey
  • Lunar missions
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SLIDE 11

Study the compact structure in M81*

Tm

Ur

Sh

6.1km

~3250km VLBI detected jet component of M81* with CVN at X-band (Kawaguchi et al. 2015)

0.1 mas

The e first st VL VLBI BI Image ge of M81* 1* at 3.4 mm with VL VLBA

  • BA. (Ji

Jian ang g et al. 2018) 18)

Peak=45.3 mJy/beam RMS=0.34 mJy/beam Dynamic range ~ 130

s ∝ λ0.88

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Among 3321 sources (red+green) in the ecliptic plane, 556 sources detected (green).

VLBI Ecliptic Plane Survey (VEPS)

(Shu et al. 2017 )

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澳大利亚LBA干涉阵+昆明40 米望远镜

~13 arcsec, ~45 arcsec ~1 mJy, compact and flat spectrum calibrators

LB LBA+KM40：@2.3GHz；

Li et al, 2018

Improve the parallax of J0437-4715 Measure Gdot combined with timing results

Detection of nearby calibrators for MSP J0437-4715 with LBA+KM 40m

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SLIDE 14

Pulsar Astrometry with VLBA+TM

NAME PSRJ P0 DM S1400 B0458+46 J0502+4654 0.638565 s 42.19 cm^-3 pc 2.50 mJy B2334+61 J2337+6151 0.495370 s 58.41 cm^-3 pc 1.40 mJy (Yan et al. )

  • pulsar parallaxes via relative astrometry (differential

astrometry) astrometry) to to get get distances distances and and transverse transverse velocities velocities

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SLIDE 15

VLBI astrometry of white dwarf binary system AR Sco with EVN and CVN

PM_ra = 11.44 ± 0.33 mas/yr parallax=8.37 ± 0.19 mas

(Jiang, Cui, et al. )

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In collaborations with HartRAO, SHAO, UTAS etc. Fringe test on April 18, 2017 (Hart26m-TMRT). The first 24 h session already done on August 28, 2017!

K K ba band nd As Astrometr

  • metry
  • Corr. @

SHAO

2Gbps K-band fringe Hh-T6!

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Phase-reference results of CE-3 Rover

  • Target: Rover using the Lander as the Calibrator.
  • The accuracy of the relative position between Lander and Rover is ~1m (0.5mas).

Rover Lander

A B C D E E17

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SLIDE 18

Future

  • QTT110m
  • A 40-m RT at YBJ（Tibet）
  • Space VLBI
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SLIDE 19

QTT110m

150 MHz – 115 GHz (1st phase upto 30 GHz)

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SLIDE 20

Major Facilities for RA in China

Kashi hi 13m Sany nya 13m Jilin1 lin13m Lega gacy CVN Newly ly built ilt big g dish VGOS OS CDSN

Current VLBI facilities in China

Luonan 40m

YBJ 40m

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SLIDE 21

Space Millimeter VLBI Array

  • Main Scientific Objectives:
  • High-resolution imaging of emission structure surrounding super-massive

black hole (SMBH) to study

  • SMBH Shadow (e.g. M87)
  • Disk structure & dynamics, SMBH mass (water mega-masers)
  • Astrophysical Jet in Active Galactic Nuclei (AGN)
  • Specifications:
  • Two 10-m (in diameter) space antennas
  • Three frequency bands (8, 22 & 43 GHz)
  • Dual polarization (LCP/RCP)
  • Date rate (1.2 Gbps , or 2.4 Gbps)
  • Angular resolution: 20 micro-arc-second
  • Optimized orbits for a better (u,v) coverage
  • Apogee: 60,000 km
  • Perigee: 1,200 km
  • Inclination: 28.5 deg
  • Life time: 3 year
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Review Mtg in June 2016 @ CAST (China Academy of Space Technology)

High precision reflector: 10m diameter with a surface accuracy better than 0.4mm (RMS)

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Lunar orbit VLBI experiment （LOVE）

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  • Relay satellite antenna diameter: 4.2m （？）
  • Band: X (8-9 GHz), Cooled receiver, bandwidth: 512MHz
  • Orbit: 200 km x 8,500 km
  • Baseline: ~400,000km, unprecedented longest baseline
  • Ground telescope: Big Dishes of Ground VLBI Network，e.g. Tianma 65m、

GBT 110m，Effelsberg 100m，SRT 64m, et el.

conception of lunar orbit VLBI experiment

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  • Space antennas: 2 x 30 m
  • Orbit :

– Apogee (60-)90,000 km – Perigee 2,000 km – Inclination angle 28.5o

  • Frequency Bands:

– 30MHz, 74MHz, 330MHz, 1.7GHz

  • Weight: 1.5 Ton/satellite
  • Resolution :

– 20mas (30MHz), 8mas (74MHz), 2mas (300MHz), 0.36 mas (1.7GHz)

  • Sensitivity：

– BL sensitivity: sub-mJy (int. time =10min) – image sensitivity: 1 microJy/beam (1h, 1.7GHz)

  • Onboard Clocks : H maser or Rb standard

Space VLBI in FAST & SKA era -

‘microscope’ probing the Universe from nearby by exo xopla planets nets to SMBHs Hs in in C Cosmic ic Daw awn

Low Frequency Twin VLBI Stations in Space

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Operation modes

  • 1. Space-ground VLBI
  • Unprec

eced edent nted ed Super er VLBI I net etwor

  • rk consists of

Twin space-based VLBI Stations + ground large telescopes (SKA1, FAST, Arecibo, Effelsberg, GBT, GMRT, QTT......)

  • new electromagnetic spectrum window (30 - 300MHz) for space VLBI
  • 2. Space-space VLBI (single baseline)
  • Uniq

ique e space ce-based based VLBI, long integration time, fast response of super- burst of OH masers, auroral radiation from extrasolar systems

  • 3. Space-based single dish
  • EoR total power spectrum, pulsar timing array, planets......
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SLIDE 27

Scientific objectives

  • Eo

EoR and Cosmi smic c Dawn awn

  • Discovery of Jupit

iter er-ty type pe exoplan lanets ts, Solar flares in nearby stellar systems

  • Search for Dual AGN and SMBH

BH bin inari ries es in nearby massive galactic centers as remnants of mergers – nano Hz GW sources

  • BH

BH (AGN, XRB; Galactic transients) physics cs: jet launching, collimation, acceleration; GRB, FRB

  • Pulsar

lsar : accurate astrometry, parallax distance, radiation mechanism; giant pulse

  • Pla

lanets ts radio emission

  • …

30MHz 74MHz 330MHz 1670MHz

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SLIDE 28

Thank you for your attention!

Welcome collaboration from all of you!