The East-Asian VLBI Network

Transcription

1 The East-Asian VLBI Network Zhi-Qiang Shen ( 沈志强 ) Shanghai Astronomical Observatory (SHAO) Chinese Academy of Sciences Hideyuki Kobayashi (NAOJ), Kiyoaki Wajima (KASI), Kenta Fujisawa (Yamaguchi Univ.), Wu Jiang (SHAO) The 10th East Asian Meeting on Astronomy (EAMA10) 2016 September Seoul National University, Seoul, KOREA

2 Outline 0. A bit of history 1. Current status of EAVN 2. Recent progress 3. Future plan

3 Outline 0. A bit of history 1. Current status of EAVN 2. Recent progress 3. Future plan

4 1967 First VLBI Experiments in USA and Canada spatial resolution: ~l/d x = u sina q s 0 a s 0 b s 0 u = bcosq u telescope 1 b telescope 2 V 1 V 2 V 1 V 2 V ( u, v) Ae I( l, m) e i 2 i( ul vm) spatial resolution: ~l/b dldm Single Dish Interferometer 4

5 Global VLBI Station Distribution EVN VLBA Not a complete list! 5

6 VLBA Ten 25m Antennas, 327 MHz - 86 GHz 6

7 European VLBI Network (EVN) 7 7

8 East Asian VLBI Network 2003 Nov. 3-5: Preparation Committee (PC) was formed during 1 st regional millimeter-vlbi workshop in Shanghai PC meeting during the AP-RASC 04 in Weihai 2004 Oct : East Asia VLBI Consortium was organized during the EAMA6 in Seoul Chair: H. Kobayashi (Japan) Co-Chair: M. H. Choi (Korea) Secretary: Z.-Q. Shen (China) 8

9 Responsibility of EA VLBI Consortium Organize VLBI observations in east Asia region with the existing VLBI facilities Exchange information of VLBI technique developments Promote education and training programs (ex. Summer/winter schools) 9

10 East Asian VLBI Network 2005 Nov : (J-K) VLBI Symposium at Ishigakijima 2006 March 7: 2 nd EACOA meeting in Tokyo 2006 May 22-23: 2 nd East Asia Millimeter-VLBI Science Workshop in Nanjing 2010 Oct. 13: EA VLBI Consortium Meeting during the EAMA8 in Shanghai 2013 June: The EAVN Tiger Team, chaired by Y. Hagiwara of NAOJ then and now K. Wajima of KASI, was organized To coordinate VLBI test observations To proceed data reduction of test observations To pave the road for future regular operation and open-use of the EAVN 10

11 East Asian VLBI Network 11

12 Outline 0. A bit of history 1. Current status of EAVN 2. Recent progress 3. Future plan

13 Existing VLBI stations in 2005 Japan(11) VERA(4), Kashima, Tsukuba, Yamaguchi, Nobeyama, Usuda, Tomakomai, Gifu Korea(1) Taejun, (+KVN (3)) China(2) Shanghai, Urumqi, (+Beijin, Kumming) 22 GHz: 8 stations 43 GHz: 7 stations 13

14 Japanese VLBI Network (JVN) led by Japanese Universities Collaboration NAOJ (VERA) Universities (Hokkaido, Ibaraki, Tsukuba, Gifu, Osaka-Pref, Yamaguchi, Kagoshima) JAXA, NICT, GSI Specifications 13 telescopes (11m ~ 64m) 6~7 active telescopes Baseline km Frequency 6.7/8/22 GHz JVN 13 Telescopes 14

15 Korean VLBI Network (KVN) Specifications 3 telescopes (21m) Baseline 300~500 km Frequency 22, 43, 86, 129 GHz (Simultaneous Multi-Frequency Obs.) 15

16 Chinese VLBI Network (CVN) Baseline length: 1115km to 3249km (Coverage: E-W:34 S-N:18 ) 1993(25m) 2006(50m) (25m) 2006(correlator) (65m) 2006(40m) 16

17 Science 2008 Dec. 5 17

18 Tamna 21 m Miyun 50 m KASI/KJJVC Sejong 22 m Yonsei 21 m Ulsan 21 m Gifu 11 m Usuda 64 m Mizusawa 20 m Nanshan 26 m Takahagi 32 m Tianma 65 m Hitachi 32 m Sheshan 25 m SHAO/DiFX Kunming 40 m Yamaguchi 32 m Ishigakijima 20 m Kashima 34 m (Image Credit: Reto Stöckli, NASA Earth Observatory) 6.7 GHz 8 GHz 22 GHz 43 GHz Iriki 20 m Ogasawara 20 m

19 EAVN: Specifications Number of (potential) telescopes: 19 (16 telescopes have participated in test observations one or more times) Korea: 4, China: 5, Japan: 10 (Possible) frequency coverage: 6.7 GHz (12 stations), 8 GHz (15), 22 GHz (16), 43 GHz (10) (Expected) angular resolution: 2.4 mas (6.7 GHz; Ogasawara Kunming) 1.5 mas (8 GHz; Ogasawara Nanshan) 0.6 mas(22 GHz; Ogasawara Nanshan) 0.7 mas (43 GHz; Ogasawara Tianma) Sensitivity for 7-σ fringe detection (τ = 60 s, B = 256 MHz): 1.6 mjy (8 GHz; Tianma KVN) 9.5 mjy (22 GHz; Tianma KVN) (Expected) recording rate: 2 Gbps (= 512 MHz BW) (Currently-used) correlator: KJCC (Korea): KJJVC and DiFX SHAO (China): DiFX 19

20 Total effective aperture and longest baseline length EAVN VLBA EVN No. of Stations Longest Baseline Length (km) Effective GHz (m 2 ) Effective GHz (m 2 ) Effective GHz (m 2 ) 5,000 8,000 2,000-8,000 9,000 3,700 9,800 4,900 3,200 4,900 1,400 2,900 1,800 20

21 Examples of (u, v) Coverage 22 GHz 10-hour duration array of 16 telescopes Beam size: 0.6 mas δ = +60 deg δ = +30 deg δ = +60 deg δ = 0 deg δ = 29 deg 21

22 KJCC Executive Board Daejeon Correlator DiFX Correlator on HPC 22

23 DiFX correlator at SHAO Astrophysics (200 CPUs). serve for CVN, EAVN (FT), international VLBI. Geodesy (200 CPUs). serve for CVN, IVS standard correlator. Features support MKIV, Mark5B, KVN5B, VDIF raw data format; support pulsar gating, multi-phase center, zoom spectrum etc. 400 CPUs, 432 TB storage, built in e-transfer links 23

24 Outline 0. A bit of history 1. Current status of EAVN 2. Recent progress 3. Future plan

25 EAVN: Fringe Test Experiments 8 times during 2013 September 2015 February: 2013 (2), 2014 (5), 2015 (1) Stations involved: 4 (2014 Sep) 11 (2013 Sep), 16 stations have participated in fringe tests one or more times (CN: 4, KR: 4, JP: 8) Observation duration: 1 hour (typical) Observing Frequency: 8, 22 GHz Observing mode: 256 MHz bandwidth (16 MHz 16 ch), data recording rate of 1 Gbps Polarization: RHCP (8 GHz), LHCP (22 GHz) Correlator: KJJVC (KASI), DiFX (KASI/SHAO) 25

26 EAVN: List of Fringe Test Observations # Date Frequency Antenna Source 8 22 KVN+ VERA JVN CVN YS UL TN SJ MZ IR OG IS YM TH HI TK SH TM UR KM Sep Nov Jan May , DA Sep 16 3C 273, W3OH Oct 18 3C 273, W49N Nov 11 3C 345, W49N Feb 12 BL Lac, 3C

27 EAVN: Observations since Dec 2015 # Date Frequency Antenna Target KVN VERA JVN CVN ATCA YS UL TN MZ IR OG IS YM TH HI TK TM KM NS AT Dec 13 4C Mar 20 M Mar 21 M Sep Sep (2 Gbps Fringe Test) 3C 273, M84, M87, RT Vir Sep 26 (BL Lac, 3C 454.3) Total observing time: 36 hours (6 sessions) Number of telescopes: 15 (KR: 3, CN: 3, JP: 8, AU: 1) Frequency: 8 GHz (1), 22 GHz (2), 43 GHz (3) Part of observations were conducted in collaboration with the KaVA AGN Large Program 27

28 ULS KUN TIA KUN ULS KUN TIA KUN MIZ KUN ULS TIA MIZ KUN ULS TIA MIZ ULS MIZ TIA MIZ ULS MIZ TIA Preliminary Results (2015 December 13) Source: 4C 39.25; telescope: VERA Mizusawa, KVN Ulsan, Tianma, Kunming τ = 60 s, bandpass correction NOT applied, a priori calibration NOT applied, amplitude correction by ACCOR, 180 < φ < +180 Raw data ACCOR, FRING applied 28

29 Preliminary Results (2016 March 20) First 43 GHz image of M87 by EAVN on 2016 Mar 20 Non-cooled receiver was used at Tianma station Indirect amplitude scaling was applied to the Tianma s visibilities KaVA KaVA+Tianma DR = 3238 σ = 0.24 mjy/b DR = 3540 σ = 0.22 mjy/b 29 (Image courtesy: Dr. Kazuhiro Hada (NAOJ))

30 Tianma-65m Q band fringes Cryogenic Rx VLBI Fringes to Tianma-KVN (2016 Sept.13) 30

31 Publ.Astron.Soc.Japan 66, 31 (2014) 31

32 The First Results of EAVN (6 sessions between 2010 and 2011) Usuda 64m Ibaraki 32m (Hitachi) Shanghai 25m VERA 20m x 4 Yamaguchi 32m 32

33 Different morphological categories: linear, elliptical, complex etc (Fujisawa et al. 2014) G Proper motions of CH 3 OH maser sources (Sugiyama et al. 2015) 33

34 Outline 0. A bit of history 1. Current status of EAVN 2. Recent progress 3. Future plan

35 Purposes Actions 9/10 Short- and Mid-Term Plan Year time fringe tests done FTP data transfer test Further fringe tests Imaging tests, performance evaluation Imaging tests Science commissioning observations at 8/22 GHz Fringe tests at 6.7/43 GHz (Late 2017) Risk-shared open-use at 8/22 GHz Performance evaluation and science commissioning at 6.7/43 GHz (Late 2017) Risk-shared open-use at 6.7/8/22/43 GHz Performance evaluation for extending observation modes (2-pol., wide-band, etc.) Freq. 8/22 GHz 8/22 GHz 6.7/8/22/43 GHz 6.7/8/22/43 GHz 6.7/8/22/43 GHz Fringe detection from some telescopes in EAVN Evaluation of array performance and imaging capability Evaluation of array performance and array operation commissioning Performance evaluation at 6.7/43 GHz Initial scientific outputs from EAVN Confirmation of performance at 6.7/43 GHz Regular operation of EAVN Conformation of performance for various observation 35 modes

36 Short- and Mid-Term Plan Re-organization of the Tiger Team and re-definition of tasks Re-organization of the task force for imaging tests (and the future open-use operation) Brushing up the items for imaging tests Fringe tests and imaging tests at 6.7 GHz EAVN observations at 6.7 GHz was carried out using the VSOP Terminal (with a recording rate of 128 Mbps) Fringe tests and imaging tests with the data rate of 2 Gbps The first 2 Gbps fringe test was conducted on 2016 September 13 Set of goals of science objective Organization of science sub-wgs on the basis of scientific activities by KaVA sub-wgs Acquirement of budget for regular operation 36

37 Long-Term Plan Collaboration with the Australian LBA ( short- or mid-term agenda?) Collaboration with the FAST Time schedule of installation of the VLBI backend system VLBI observations at 1.6/2 GHz? Collaboration with the Thai VLBI Network (TVN) Good to connect between EA and OZ Available in 2020+? (Boonrucksar Soonthornthum s talk) In synergy with ALMA (mm/sub-mm) amd SKA 37

38 EAO (Paul Ho s talk) EAVN? 38

39 East Asia VLBI Workshop 2008 March 20-22: 1 st EA VLBI WS in Shanghai 2009 March 18-20: 2 nd EA VLBI WS in Seoul 2010 April 22-24: 3 rd EA VLBI WS in Kagoshima 2011 April 18-20: 4 th EA VLBI WS in Lijiang 2012 May 30 June 1: 5 th EA VLBI WS in Taipei 2013 June 17-19: 6 th EA VLBI WS in Jeju 2014 Aug. 20: 7 th EA VLBI WS in Daejeon (as part of APRIM) 2015 July 8-10: 8 th EA VLBI WS in Sapporo 2016 Nov. 7-11: 9 th EA VLBI WS in Guiyang 39 39

40 Thank you for your attention!