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

2006 AUSAC Meeting

VLBI/eVLBI with the 305-m Arecibo Radio Telescope

Arecibo VLBI Group

Chris SalterTapasi Ghosh

Emmanuel MomjianArun Venkataraman

(Jon Hagen)

2006 AUSAC Meeting

VLBI Operations 2005-6• Telescope proposals: 28 (10 HSA, 15 Global/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

eVLBIAdvantages

• 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.

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.

2006 AUSAC Meeting

Data Path to JIVE

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.

DAR/Formatter

MK5

JIVE

in2net

2006 AUSAC Meeting

EXPReSObjectives: 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

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

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

High-Sensitivity VLBI Science - IIExtragalactic Supernova Remnants

SN2001em

18-cm eVLBI; Garrett et al.

3.5-cm HAS;Bietenholz &Bartel

Odd SN thought possibly to be an off-axis GRB.VLBI shows this to be unlikely as source is notExpanding relativistically.

SN1979C

6-cm HAS; Bartel & Beitenholz

Shell structure revealed in this SNR forThe first time.

Peak brightness = 230 Jy/beam

2006 AUSAC Meeting

High-Sensitivity VLBI Science - IIINuclei of ARP 220

18-cm Global; Lonsdale et al.

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.

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.

2006 AUSAC Meeting

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

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.