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

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 for RA in China Jilin1 lin13m Luonan 40m Kashi hi 13m Newly ly built ilt big g dish Lega gacy CVN VGOS OS CDSN Sany nya 13m

Activities at each site  FAST  Kunming  Urumqi  VGOS  Shanghai

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 Mark rk 6 ROACH-2

Kunming - VLBI system updated S X C(new) Updated to CDAS2 Frequency 2150~2450 8200~900 4000~8000 range MHz 0MHz MHz DBBC2+MARK6 Polarizatio L&R L&R L&R New H-maser n LO 2000MHz 8100MHz optional FlexBuff coming soon! Tsys 50K(Room 70K(Coole 45K TEMP.) d) Efficiency ~60% ~45% ~50% Good EM env (4040 — 7500 MHz)

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

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% Sh Bandwidth: 1GHz *4 Commissioning since 2017 Tianma VGOS Sheshan VGOS 25 m Fringes Dec. 2017

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

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.

Related scientific outputs  AGN studies  Pulsar astrometry, Survey  Lunar missions

Study the compact structure in M81* VLBI detected jet component of M81* with CVN at X-band (Kawaguchi et al. 2015) Ur ~3250km Sh Tm 6.1km 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 ∝ λ 0.88 0.1 mas

VLBI Ecliptic Plane Survey (VEPS) Among 3321 sources (red+green) in the ecliptic plane, 556 sources detected (green). (Shu et al. 2017 )

Detection of nearby calibrators for MSP J0437-4715 with LBA+KM 40m LBA+KM40 ： @2.3GHz ； LB 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  Improve the parallax of J0437-4715  Measure Gdot combined with timing results Li et al, 2018

Pulsar Astrometry with VLBA+TM  pulsar parallaxes via relative astrometry (differential astrometry) astrometry) to to get get distances distances and and transverse transverse velocities velocities 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. )

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. )

K K ba band nd As Astrometr ometry 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! Corr. @ SHAO 2Gbps K-band fringe Hh-T6!

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). A Rover B Lander C D E17 E

Future  QTT110m  A 40-m RT at YBJ （ Tibet ）  Space VLBI

QTT110m 150 MHz – 115 GHz (1 st phase upto 30 GHz)

Current VLBI facilities in China Major Facilities for RA in China Jilin1 lin13m Luonan 40m Kashi hi 13m YBJ 40m Newly ly built ilt big g dish Lega gacy CVN VGOS OS CDSN Sany nya 13m

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

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)

Lunar orbit VLBI experiment （ LOVE ）

conception of lunar orbit VLBI experiment • 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.

Low Frequency Twin VLBI Stations in Space Space VLBI in FAST & SKA era - • Space antennas: 2 x 30 m ‘microscope’ probing the Universe from nearby by exo xopla planets nets to SMBHs Hs in in C Cosmic ic • Orbit : Daw awn – Apogee (60-)90,000 km – Perigee 2,000 km – Inclination angle 28.5 o • 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

Operation modes 1. Space-ground VLBI • Unprec eced edent nted ed Super er VLBI I net etwor ork 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......

Scientific objectives • Eo EoR and Cosmi smic c Dawn awn 30MHz • 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 74MHz in nearby massive galactic centers as remnants of mergers – nano Hz GW sources 330MHz • BH BH (AGN, XRB; Galactic transients) physics cs: jet launching, collimation, acceleration; GRB, FRB 1670MHz • Pulsar lsar : accurate astrometry, parallax distance, radiation mechanism; giant pulse • Pla lanets ts radio emission • …

Welcome collaboration from all of you! Thank you for your attention!