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VLBI/eVLBI with the 305-m Arecibo Radio Telescope

VLBI/eVLBI with the 305-m Arecibo Radio Telescope. Arecibo VLBI Group Chris Salter Tapasi Ghosh Emmanuel Momjian Arun Venkataraman (Jon Hagen). VLBI Operations 2005-6. Telescope proposals: 28 ( 10 HSA , 15 Global/EVN , 3 e-VLBI )

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VLBI/eVLBI with the 305-m Arecibo Radio Telescope

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  1. VLBI/eVLBI with the 305-m Arecibo Radio Telescope Arecibo VLBI Group Chris Salter Tapasi Ghosh Emmanuel Momjian Arun Venkataraman (Jon Hagen) 2006 AUSAC Meeting

  2. VLBI Operations 2005-6 • Telescope proposals: 28 (10 HSA, 15Global/EVN, 3 e-VLBI) • Observing Runs : 40 (14 HSA, 18 Global/EVN, 5 eVLBI, 3 NME) • Standard Operations at 1Gbit/s from Feb-2005 • Operations at 327 MHz, L-, C-, and X-bands • No. of VLBI runs: 2001=12, 2002=15, 2003=16, 2004=24, 2005=36. eVLBI in 2005-6 • eVLBI continuum demonstrator on March 05 • Sustained operations at 32 Mb/s (occasional fringes at 64Mb/s) • Joined EXPReS Consortium (funded Oct. 05) • Demonstration of eVLBI to E.C. Science Commissioner, July 05 2006 AUSAC Meeting

  3. eVLBI Disadvantages • Fear of single point failure. • No multi-pass correlation. • Loss of low bandwidth stations. • Presently lower max bit rate than disks. • Capital and recurring costs of links. Advantages • No need for disks/tapes. • Speed at which results are obtained. • Target of Opportunity. • Real-time monitor of Station reliability. • Reduced manpower at VLBI station. • No longer observing blind. 2006 AUSAC Meeting

  4. Data Path to JIVE MK5 in2net DAR/Formatter • PRISANET (PR) of the Arecibo Obs./UPR. • AMPATH (US) of Florida Intl. Univ. • Abilene (US) of Internet 2. • SURFnet (NL) of SURFnet BV. Data rate: 32 Mbps. JIVE 2006 AUSAC Meeting

  5. EXPReS Objectives: 1) Create production-level e-VLBI service. 2) Reliable telescope connection to the JIVE correlator via Internet. 3) Data flow of up to 16 Gb/s into correlator via infrastructure of trans-continental dimensions and capability of generating real-time cosmic radio source images. 4) Design and prototype hardware, software and data transport services to support future e-VLBI facilities with net data flows of hundreds of Gb/s. 2006 AUSAC Meeting

  6. e-VLBI Plans & Possibilities • Need to upgrade Mark-5 system (~$5k). • Faster CPU • Gb/s ethernet • Present link from AO is shared OC-3 (155 Mb/s) • Cannot sustain > 32 Mb/s to JIVE • In near term focus on optimizing OC-3 link • Reserve bandwidth (at a cost) • More efficient protocols (TCP variants) • Update observatory switch to be OC-12 (655 MB/s) compatible (~$20k). • If available, OC-12 may cost $200k/month at present. Cheaper fiber expected after communication link to St. Croix established. 2006 AUSAC Meeting

  7. High-SensitivityVLBI Science - I D. Hough (Trinity U. Tx.) & C. Aars (Angelo State U, Tx) Search for pc-scale jets in extremely faint FRII Radio Galaxy Nuclei. RMS noise =10 Jy/beam Peak flux=1.5 mJy (3C34), 4 mJy (3C132) 2006 AUSAC Meeting

  8. High-Sensitivity VLBI Science - II Extragalactic Supernova Remnants SN2001em SN1979C 3.5-cm HAS; Bietenholz & Bartel 18-cm eVLBI; Garrett et al. 6-cm HAS; Bartel & Beitenholz Odd SN thought possibly to be an off-axis GRB. VLBI shows this to be unlikely as source is not Expanding relativistically. Shell structure revealed in this SNR for The first time. Peak brightness = 230 Jy/beam 2006 AUSAC Meeting

  9. High-Sensitivity VLBI Science - III Nuclei of ARP 220 18-cm Global; Lonsdale et al. 6-cm 1Gbps EVN; Parra & Conway Observed Arp220 for 10 min (rms=30 Jy/beam) as part of 100 source ULIRG sample. First two 5-GHz detections in Arp220, neither coincident with 18-cm compact sources. Western detection confirmed with VLBA archive data & 18-cm ToO data, believed to be ultra-luminous SNs similar to SN1986J. RMS=5.5 Jy /beam; Linear resolution ~ 1 pc Detect 49 point sources with 60 Jy < S < 1.2 mJy. Four of the sources are new, implying an SN-rate of 4  2 per year in ARP220. 2006 AUSAC Meeting

  10. Current & Near-Future Activities • Continue support of HSA and Global/EVN arrays. • For 2005, five e-VLBI tests scheduled, starting 16 March. • Purchase more Mark-5 disc packs. • Offer has been made to host the next EVN Technical Operation Group (TOG) meeting of EVN at Arecibo. • When available, upgrade to Mark-5B. • Explore options for a supplementary antenna to improve efficiency of phase-referenced VLBI, etc. 2006 AUSAC Meeting

  11. Timeline • The post-upgrade 305 m Arecibo radio telescope became a part of the VLBI network in late 1990s for the HALCA mission of the Japanese VSOP project (S2 recorder). • In 2001, Arecibo acquired its hybrid tape-based VLBA-Mark IV (VLBA4) recording system. • In 2004, the Observatory procured its Mark 5A disk-based recording system, enabling the largest telescope in the world to become electronically connected to other radio telescopes in the world in real time via eVLBI observations. 2006 AUSAC Meeting

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