e EVN science in Zsolt Paragi JIVE for the by boobygibson

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									e-EVN science in 2006-2007

Zsolt Paragi (JIVE),
for the EXPReS project
 What will e-VLBI offer for us one day?
     Several Gbps data rates/telescope, two orders of magnitude
     better sensitivity, “full” uv-coverage, flexibility…


 What the e-EVN can offer today:
• Limited sensitivity and resolution compared to EVN, but…
• Some flexibility for rapid response science
• Rapid feedback, you know if it works, you know what you observe…
• … enables quick decision about more observations (VLBI or other)
• Easy access, easy use – high level of PI support

2007 Sep 16-17            e-VLBI meeting, Bonn       Slide #2
The European VLBI Network (EVN)
• Some of the worlds greatest radio telescopes, e.g. Effelsberg 100m, Lovell 76m telescopes,
   Westerbork Synthesis Radio Telescope …
• Outside Europe includes Hartebeesthoek (South Africa), Urumqi and Shanghai (China)
• Several telescopes are being built that will join the EVN: Yebes 40m (this year), telescopes
  in Sardinia, Latvia, Ireland and China
• Operating in three observing sessions per year, sometimes jointly with MERLIN (UK) and
  the VLBA (USA) – global VLBI
• Observing wavelength ranges from 92cm to 1.3cm
• The most sensitive standalone VLBI array (now there is also the High Sensitivity Array,
   formed occasionally by the VLBA, VLA, GBT and Arecibo)
• The data are correlated in the EVN MkIV correlator at JIVE



                                                           http://www.evlbi.org/

                                                           http://www.jive.nl/


2007 Sep 16-17                    e-VLBI meeting, Bonn                Slide #3
The end of the tape era
  • Tape recording had limited performance (parity
  errors), and
  • limited data rate (256 Mbps; 512 Mbps with
     two write heads).
  • Tapes were expensive
  • Tape playback units were not easy to maintain



                                        • Disk based recording systems were developed at
                                          Haystack (Mark5A) and Metsahovi Radio
                                          Observatory (PC EVN)
                                        • And it worked!
                                        • The EVN is fully disk operational (Mark5A)
                                          since early 2004
                                        • Cheaper, off the shelf technology, perfect
                                          recording; data rate up to 1 Gbps
                                        http://www.haystack.edu/tech/vlbi/mark5/


2007 Sep 16-17                   e-VLBI meeting, Bonn                Slide #4
What is EXPReS?
• EXPReS = Express Production Real-time e-VLBI Service
• Three year project, started March 2006, funded by the European
  Commission (DG-INFSO), Sixth Framework Programme,
  Contract #026642
• Objective: to create a distributed, large-scale astronomical
  instrument of continental and inter-continental dimensions
• Means: high-speed communication networks operating in real-
  time and connecting some of the largest and most sensitive radio
  telescopes on the planet
• Initiated and formerly coordinated by Mike Garrett, now
  coordinated by Huib J. van Langevelde

                      http://www.expres-eu.org/


2007 Sep 16-17           e-VLBI meeting, Bonn      Slide #5
Participating EXPReS Telescopes




2007 Sep 16-17   e-VLBI meeting, Bonn   Slide #6
 VLBI / e-VLBI observation timelines




                                        Test cases: black holes in
                                        outburst
                                        • Data processing took 1-2
                                        weeks with first images within
                                        48 hours
                                        • Publication took less than 2
                                        months


2007 Sep 16-17   e-VLBI meeting, Bonn              Slide #7
 e-VLBI activities in 2006, early 2007
• Regular e-VLBI test observations in every six week (on average)
                   e-EVN, first 512 Mbps image
• 24h time is pre-allocated for science observation during each
e-VLBI test
• Observing proposals submitted up to two weeks before the
advertised date (CHANGED!…)
• Science operations at 1.6 and 5GHz at 128/256 Mbps
(Cm, Jb2, Mc, On, Tr, Wb)
• First 22 GHz test with Metsahovi in March 2007
• Fringes to all connected telescopes at 512 Mbps,
most recently to Torun
•More info at http://www.evlbi.org/evlbi/evlbi.html
2007 Sep 16-17           e-VLBI meeting, Bonn         Slide #8
 e-VLBI activities in mid-2007
• Keep regular e-VLBI runs but proposals must be submitted
for the normal EVN deadline
• Triggered as well as normal VLBI proposals are accepted
• Attempt to react to triggers (on fixed dates) within 24h
• First 6-station e-VLBI image at 512 Mbps
• Success with UDP-based transfer
• APAN test: fringes between European, Chinese and Australian
telescopes at 256 Mbps



2007 Sep 16-17            e-VLBI meeting, Bonn       Slide #9
Science projects in 2006/2007
     • Cyg X-3, 20 Apr/18 May, 128 Mbps, Tudose et al.
     • GRS1915+105, 20 Apr, 128 Mbps, Rushton et al.
     • LSI +61.303, 256 Mbps, 26 Oct, Perez-Torres et al.
     • Algol, 26 Oct/14 Dec, 256 Mbps, Paragi et al.
     • Calibrators near M81, 14 Dec, 256 Mbps, Brunthaler et al.
     • INTEGRAL microquasar candidates, 14 Dec, Pandey et al.
     • “double header” run, 15 XRBs, 29 Jan, Rushton & Spencer
     • Calibrators, 21 Feb, 256 Mbps, Tudose et al.
     • J2020+3631 microquasar candidate, 28 Mar, 256 Mbps, Martí et al.
     • Cyg X-3, 12-13(?) Jun, 256 Mbps, Tudose et al.
     • Stellar maser search, 22-23 Aug, 32 Mbps, Langevelde et al.
     • INTEGRAL source redo, 6-7 Sep, 256 Mbps, Pandey et al.
     • Type Ib/c SN 2007gr, 6-7 Sep, 256 Mbps, Paragi et al.

2007 Sep 16-17                  e-VLBI meeting, Bonn           Slide #10
First refereed journal papers:
                 Rushton et al. (2007), MNRAS 374, L47
                 Tudose et al. (2007), MNRAS 375, L11


Cyg X-3




2007 Sep 16-17                         e-VLBI meeting, Bonn   Slide #11
…also first detection of linear polarization
on VLBI scales in a microquasar




     Tudose et al. (2007), MNRAS 375, L11
2007 Sep 16-17                   e-VLBI meeting, Bonn   Slide #12
LSI 61+303 preliminary results:

                                        Gamma-detected XRB candidate;

                                        Recent VLBA observations
                                        (Mioduszewski et al.) suggest
                                        interacting pulsar wind source…

                                        e-EVN, MERLIN, CHANDRA
                                        Observations on 26 October 2006




                                          Perez-Torres et al. (in prep.)



2007 Sep 16-17   e-VLBI meeting, Bonn                    Slide #13
Algol, 14 December 2006 run:
                                  • Simultaneous optical photometry and e-EVN obs.
                                  (5 GHz, 256 Mbps) during secondary minimum
                                  • Source flared – total of such and circular polarization
                                Dedicated observations intensityflares
                                will be challanging even for e-VLBI and e-EVN data
                                  variations consistent between WSRT
                                  • Flare emission ~2 mas offset from the CP peak
                                                       • Detected proper motion during the
                                                       10 hours run –fitted orbital parameters
  Csizmadia et al. (in prep.)
                                                       of the AB close binary.




2007 Sep 16-17                  e-VLBI meeting, Bonn                Slide #14
IGR 17303-0601 results:
                                                              INTEGRAL source, with candidate
                                                              optical counterpart showing binary
                                                              nature, and associated(?) radio source
                                                              in NVSS.




e-VLBI confirms compactness, but measured
position is inconsistent with optical coords.
Not associated, radio source is not from
a microquasar jet – likely background AGN.

                 Pandey et al. (in prep.)

2007 Sep 16-17                         e-VLBI meeting, Bonn                    Slide #15
The first continuum e-EVN science result
 • SN2001em was discovered on 15 September                 Garrett et al. (2005)
 2001 in UGC11794 galaxy (Pepenkova 2001).
 • Redshift z~0.02 corresponding to a distance
 of 80~Mpc.
 • Filippenko and Chornok (2001) classified it
 as type Ib/c, most likely Ic.
 • Exceptional radio and X-ray luminosities
 (off axis GRB, developing late radio emission
 due to jet break?),
 • Not quite a 1 mJy radio source
 • EVN observations: Cm, Jb2, On, Tr, Wb
 (128Mbps), +Arecibo 300m (64 Mbps)
 at 18cm, on 2005 Mar 11
 • Tentative detection (4.5 σ) of the first real
 faint target with e-VLBI
 Paragi et al. (2005), MSAIt 76, 570
2007 Sep 16-17                      e-VLBI meeting, Bonn                  Slide #16
SN 2007gr ToO observations

 • SN2007gr was discovered on 15 Aug 2007
 with KAIT (CBET 1034); identified as
 Type Ib/c.
 • Distance is about 7.3 Mpc, 10x closer than
 SN 2001em was.
 • VLA discovers 610 microJy radio source
 (Soderberg 2007)
 • e-EVN observations: Da, Jb2, On, Tr, Wb
 (256Mbps), at 6cm, on 2007 Sep 6-7
 • Firm detection (5.6 σ) of the supernova
 within the VLA error box
 Paragi et al. (2007), ATel #1215




2007 Sep 16-17                      e-VLBI meeting, Bonn   Slide #17
                                        The first
                                        ATel message
                                        from the
                                        e-EVN




2007 Sep 16-17   e-VLBI meeting, Bonn    Slide #18
      What else astronomers want?
  • Better sensitivity and *resolution*
  • Will happen with new radio telescopes being connected soon:
    Arecibo 300m — 256 Mbps this fall
    Shanghai +2 new — 1 Gpbs available (not operationally yet)
    Effelsberg 100m — expected at the end of 2007
    Yebes 40m — expected at the end of 2007

  •     Better flexibility, not fixed dates, allow multiple epochs to
       follow up transients!!!
   in 2008 will get close to disk-recording VLBI resolution and
    sensitivity, and will be more flexible for ToOs

   will be challenging for telescopes as well as the correlator




2007 Sep 16-17                    e-VLBI meeting, Bonn             Slide #19
       SN 2007gr uv-coverage could have been…




2007 Sep 16-17       e-VLBI meeting, Bonn   Slide #20
       And we need e-MERLIN integrated

To image sources like this with
high fidelity, from 1-1000 mas scales




          Paragi et al., long time ago…




 2007 Sep 16-17                      e-VLBI meeting, Bonn   Slide #21
Want to propose e-VLBI observations?
e-EVN observations are scheduled ~10 times per year. Proposal deadlines are now
the normal VLBI deadlines: 1 Feb., 1 Jun., 1 Oct. Web-based proposal tool (Northstar):

                        http://proposal.jive.nl/
Since 1 June 2007, ToO projects are fully supported with a response time of 24 hours
(but only on fixed dates in 2007). May submit short observing requests up to three weeks
before the observing dates. e-VLBI proposals are just like other EVN proposals,
but you must take additional care to
• justify properly why urgency is needed
• give accurate coordinates if they are known in advance (sub-arcsecond accuracy)
• specify all the details of the proposed observations – schedule will be made by JIVE staff
• contact Bob Campbell (campbell@jive.nl), to find out if preferred correlation mode is OK
• keep in mind the limited resolution (~6*8 mas at 6cm), uv-coverage and sensitivity
  at the moment; resolution and sensitivity will greatly increase in 2008!
• Be ready to travel to JIVE for quick data processing
• Think creatively, find projects that make appropriate use of this unique service!
2007 Sep 16-17                     e-VLBI meeting, Bonn                Slide #22

								
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