DiFX Vol. 32, No PROGRESS IN ASTRONOMY Nov., doi: /j.issn VLBI. DiFX VLBI VLBI. VLBI DiFX P228.

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1 32 4 Vol. 32, No PROGRESS IN ASTRONOMY Nov., 2014 doi: /j.issn DiFX CVN 1,2,3 1,2 1,2 1 1,2 1,2 ( ) VLBI DiFX DiFX DiFX VLBI (CVN DiFX CVN VLBI VLBI DiFX P228.6 A 1 VLBI VLBI ( ) [1] VLBI VLBI [2, 3] ( ) ( ) jiangwu@shao.ac.cn

2 4 DiFX CVN DiFX DiFX (Distributed FX Correlator) Adam Deller 2006 ( VLBA Haystack ) [3 5] DiFX VLBI IRA KVN DiFX DiFX Mark5 VLBA DiFX Mark5 40 Gb Infiniband VLBA 10 MPIfR DiFX Mark5 505 TB 20 Gb Infiniband 10 IVS KVN DiFX TB TB 56 Gb Infiniband 11 TFLOPS DiFX 1 vex log Mark5 machine DiFX v2d input Mark5 SWIN FITS Mark4 DiFX FFTW Inter IPP OpenMPI FFTW C MPI Intel IPP Intel cpu OpenMPI 1 DiFX

3 DiFX FX FX FFT zoom binconfig UV (UV-shifting) VLBI [6] FITS Mark4 CIRA VLBA MPIfR DiFX DiFX DiFX1.0 DiFX1.5 DiFX2.0 DiFX 2.3 DiFX DiFX 2.2 CVN CVN m 65 m 50 m 40 m 25 m CVN 3000 km 2000 km S/X L C VLBI CDAS [7] Mark5B [8] internet Mark5 [9 13] CVN VLBI IVS APSG 500 m FAST 110 m VLBI VLBI 2.3 SHAO-DiFX (SHAO) [14] [15] DiFX CVN 2009 CVN PSR B DiFX CVN [16] 4 DiFX Intel E GHz CPU 2 8 Intel E GHz CPU 6 Mark5 Mark5 1 Gb/s

4 4 DiFX CVN TB DiFX2.2 DiFX2.3 HOPS3.8, HOPS3.9 [17] Mb s 1 / Mb s 1 / 50% DiFX DiFX DiFX 3 DiFX 3 Mark5 VDIF [18] DiFX Mark5 Mark5 VSN Mark5 Mark5 jive5ab [19] Mark5 [3, 4] sched skd sked vex log DiFX v2d 1 DiFX errmon m5mon Mark5 1 DiFX 1 vex2difx v2d, vex calc, input, machine, threads 2 calcif2 calc im 3 Startdifx input, machine, threads, im difx 4 difx2fits/difx2mark4 difx, vex, input FITS/Mark4 FITS Mark4 DiFX HOPS difxsniff HOPS/fourfit HOPS/fourfit type-ii fourfit difx2mark4 Mark4 fourfit pt c

5 cf /No0001 pt c cf 1234 cf /No0001 Mark4 scan 3.1 DiFX ZOOM ZOOM v2d addzoomfreq [4] VLBI v2d addphasecentre [6] UV DiFX 2.5 DiFX DiFX [16, 20] VLBI (1) Tempo Tempo2 [21] (2) 3 5 (1) bin bin FITS AIPS FITS [16, 22] (2) DiFX profile CVN J CVN 25 m 40 m 25 m 8.5 h S MHz 2 bit 1024 Mb s 1 J MHz 13 mjy J MHz 10 mjy 3 DiFX profile profile J binconfig binconfig 40 bin 1 SRUNCH FALSE bin 2 (a) J (b) J AIPS [22, 23]

6 4 DiFX CVN h39min38s (RA) (Dec) Parkes 19h39min38s.5614 (RA) (Dec) CVN [24] 2 (a) Profile J (b) J CVN (beam size= mas) DiFX DiFX VLBI (bin) 3.2 DiFX Mark4 IVS DiFX IVS VLBI CVN IVS DiFX 2013 CVN HOPS DiFX Calc/Solve PCAL PCAL DiFX1.5 PCAL PCAL PCAL Mark4 IVS HOPS fourfit alist aedit [17] 3 (a) 3 (b) fourfit

7 HOPS/fourfit (Kunming) (Seshan25) (a) S 6 (b) X 8 3 (a) 3 (b) 3 ( ) ( ) ( ) ( ) ( ) ( ) ( ) PCAL S X S 6 X MHz 1 bit 256 Mb s 1 24 h Mark5 DiFX 5.8 h 3 S 6 X S X PCAL PCAL PCAL PCAL fourfit 3 (a) 3 (b)

8 4 DiFX CVN DiFX VLBI DiFX DiFX VLBI DiFX DiFX DiFX CVN J h 256 Mb s h DiFX HOPS IVS Mark4 VLBI VLBI DiFX VLBI DiFX VLBI IVS DiFX [25] VLBI DiFX VLBI VLBI DiFX DiFX Adam Deller Walter Brisken DiFX [1] Thompson A R, Moran J M, Swenson Jr G W. Interferometry and synthesis in radio astronomy. Berlin:Wiley-VCH, 2004: 304 [2] Deller A T, Tingay S J, Bailes M, et al. PASP, 2007, 119: 318 [3] Deller A T, Brisken W F, Phillips C J, et al. PASP, 2011, 123: 275 [4] Brisken W. A Guide to the DiFX Software Correlator, version fetch.php/difx/difxuserguide.pdf, 2013 [5] Alef W, Rottmann H, Bertarini A, et al. Proceedings of the 20th EVGA Meeting. Alef W, Bernhart S, Nothnagel A, eds. Bonn:MPIfR. 2011, 1: 57 [6] Morgan J S, Mantovani F, Deller A T, et al. A&A, 2011, 526: A140 [7],,,., 2011, 29: 207

9 [8] Whitney A R. ASPC, 2003, 306: 123 [9] Li J L, Guo L, Zhang B. Proceedings of the International Astronomical Union. Jin W J, Platais I, Perryman M A C, eds. Cambridge: Cambridge University Press, 2007, 248: 182 [10],,., 2013, 38: 386 [11] Zhang X Z, Zhu X Y, Kong D Q, et al.research in Astronomy and Astrophysics, 2009, 9: 367 [12] Hao L F, Wang M, Yang J. Research in Astronomy and Astrophysics, 2010, 10: 805 [13] Yusup A, Liu X, Zhang M. IVS 2011 Annual Report. Baver K D, Behrend D, eds. Washington:NASA, 2012: 115 [14],,,., 2001, 19: 312 [15],,., 2008, 29:18 [16],,., 2011, 29: 309 [17] [18] Whitney A R, Kettenis M, Chris P, et al. IVS 2010 General Meeting Proceedings, Behrend D, Baver K D, eds. Washington: NASA, 2010: 192 [19] verkout/evlbi/,2013. [20] Guo L, Zheng X W, Zhang B, et al. Science China Physics, Mechanics and Astronomy, 2010, 53: 1559 [21] Hobbs G B, Edwards R T, Manchester R N. MNRAS, 2006, 369: 655 [22] Greisen E W. Astrophysics and Space Science Library, 2003, 285: 109 [23] Shepherd M C. ASPC, 1997, 125: 77 [24] Verbiest J P W, Bailes M, Coles W A, et al. MNRAS, 2009, 400: 957 [25] Lanyi G, Border J, Benson J, et al. IPN Progress Report California: JPL, 2005: 1 The Progress of Adapting DiFX Correlator for Chinese VLBI Network JIANG Wu 1,2,3, SHEN Zhi-qiang 1,2, SHU Feng-chun 1,2, GUO Li 1, YAN Zhen 1,2, CHEN Zhong 1,2 (1. Shanghai Astronomical Observatory, Chinese Academy of Sciences, Shanghai , China; 2. Key Laboratory of Radio Astronomy, Chinese Academy of Sciences, Shanghai , China; 3. University of Chinese Academy of Sciences, Beijing , China) Abstract: The correlator is crucial in the data processing of VLBI observations. Its output can be used for astronomical imaging, reduction of geodetic measurements and radiometry of spacecraft. DiFX is a well-known software correlator operating in a distributed computing and shared memory environment. The status of the DiFX platform in Shanghai Astronomical Observatory and its progress in the correlation of CVN sessions were reported in the paper. The platform can be used for data correlation of CVN and international VLBI observations. We hope this report could provide some valuable reference to the researchers related. Key words: radio astronomy; VLBI; DiFX; pulsar; geodesy