1. Targeting transient phenomena with e-VLBI Zsolt Paragi (JIVE), for the EXPReS project

2. 2007 June 12-15Bursts, Pulses and Flickering...Slide #2 What does e-VLBI mean to the observer? Rapid response, ideal for observing transients Rapid feedback, you know if it works, you know what you observe… … enables quick decision about more observations (VLBI or other) Even if real-time correlation is not strictly justified, prompt results (on timescales similar to instruments in other wavebands) is very attractive to users! – why not let them enjoy these benefits? Easy access, easy use – high level of PI support  VLBI accessible for a wider community – but we have to promote! Makes new types of VLBI research possible!

3. 2007 June 12-15Bursts, Pulses and Flickering...Slide #3 Test cases: black holes in outburst Data processing took 1-2 weeks with first images within 48 hours Publication took less than 2 months VLBI / e-VLBI observation timelines

4. 2007 June 12-15Bursts, Pulses and Flickering...Slide #4 Why do we need e-VLBI: ToO projects An example: the huge flare of SGR1806-20 SGR1806-20 is a soft gamma-ray repeater a neutron star with very strong magnetic fields, a magnetar Produced the greatest explosion witnessed by humans in our Galaxy, on 27 December 2004 Observations with various instruments, also VLBI (with the VLBA array) Could not image reliably because of lack of known calibrator in the vicinity of the target! Is there a way to do these projects more efficiently? Is there a way to get the data and analyze them quickly??? Fender et al. (2005), MNRAS 367, L6

5. 2007 June 12-15Bursts, Pulses and Flickering...Slide #5 Another example: SS433 during outburst Compact jet quenched during outbursts in SS433, just like in other XRBs. Can we observe these systems in good time to follow this process right from the beginning? VLBA, 5 GHz Paragi et al. 1999 New A.R. 43, 553

6. 2007 June 12-15Bursts, Pulses and Flickering...Slide #6 e-VLBI: data rate improvements

7. 2007 June 12-15Bursts, Pulses and Flickering...Slide #7 e-VLBI activities in 2006/2007 Regular e-VLBI test observations in every six week (on average) 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.htmlhttp://www.evlbi.org/evlbi/evlbi.html e-EVN, first 512 Mbps image

8. 2007 June 12-15Bursts, Pulses and Flickering...Slide #8 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. (see poster) Calibrators near M81, 14 Dec, 256 Mbps, Brunthaler et al. INTEGRAL microquasar candidates, 14 Dec, Pandey et al. (see poster) “double header” run, 15 XRBs, 29 Jan, Rushton & Spencer (see poster) Calibrators, 21 Feb, 256 Mbps, Tudose et al. J2020+3631 microquasar candidate, 28 Mar, 256 Mbps, Martí et al.

9. 2007 June 12-15Bursts, Pulses and Flickering...Slide #9 Westerbork  e-EVN as a unique instrument Westerbork Synthesis Array data may help in calibration (amplitude, linear and circular polarization; linear feeds!) May help to confirm detection/non-detection of weak targets Could be used as a ‘built-in’ alert instrument for the e-EVN Wb can help improving coordinates of new transients… (note that there are cases when we cannot afford time to get this information from an external instrument, e.g. the VLA) …with adaptive scheduling, this could be immediately used for the VLBI array; with adaptive scheduling, Wb could quickly trigger observations of ~hours stellar flares Not to mention the additional information on the very large-scale structure (which we normally waste when we do not reduce Wb data along with the EVN)

10. 2007 June 12-15Bursts, Pulses and Flickering...Slide #10 GRB high frequency follow-up (>5 GHz) Science goal: is fireball model correct? Response time: within a week Monitoring: 1-2 week, every 3-4 days Trigger: Swift, GLAST, +radio ID Coordinates: IRAM, Ryle, VLA, MERLIN VLBI resources needed: min. 512 Mbps, 22 GHz, Ef! (+GBT,Usuda64?) e-VLBI benefit: significant

11. 2007 June 12-15Bursts, Pulses and Flickering...Slide #11 GRB high frequency follow-up (1-5 GHz) Science goal: afterglow evolution at late times Response time: 3-4 weeks? Monitoring: order of a year, every 2-4 months Trigger: Swift, GLAST, +radio ID Coordinates: WSRT, VLA, MERLIN VLBI resources needed: min. 512 Mbps, 1.6-5 GHz, Ef+Wb+LT+Chinese e-VLBI benefit: ?

12. 2007 June 12-15Bursts, Pulses and Flickering...Slide #12 GLAST gamma flares from blazars Science goal: jet models, high energy emission IC/SSC …? Response time: months Monitoring: years, half yearly Trigger: GLAST Coordinates: known VLBI resources needed: min. 256 Mbps, 0.6-22 GHz e-VLBI benefit: no

13. 2007 June 12-15Bursts, Pulses and Flickering...Slide #13 GLAST gamma flares from LLAGN Science goal: jet models Response time: months Monitoring: years, half yearly Trigger: GLAST Coordinates: VLA, MERLIN VLBI resources needed: 512 Mbps, 1.6-5 GHz, Ef+Wb+LT+Chinese e-VLBI benefit: little – search for calibs?

14. 2007 June 12-15Bursts, Pulses and Flickering...Slide #14 SN Type Ib/c “off axis” GRBs Science goal: SN/GRB connection; is fireball model correct? Response time: 1-2 weeks Monitoring: months, monthly Trigger: optical, +radio ID Coordinates: optical or radio (e.g. WSRT) VLBI resources needed: min. 512 Mbps, 1.6/5 GHz, Ef+WB+LT+Chinese e-VLBI benefit: some

15. 2007 June 12-15Bursts, Pulses and Flickering...Slide #15 Early evolution of SNe Science goal: early SN evolution, testing environment Response time: days Monitoring: 2-3 weeks, every 3-4 days? Trigger: optical, +radio ID (e.g. WSRT) Coordinates: IRAM, Ryle, VLA, MERLIN VLBI resources needed: min. 512 Mbps, 5/22 GHz, Ef! e-VLBI benefit: significant

16. 2007 June 12-15Bursts, Pulses and Flickering...Slide #16 Known transients flaring (uQSO, SGR) Science goal: jet prod mechanism; jets from non-NH/NS systems? Response time: within a day, or as soon as possible Monitoring: 1 week, every 1-3 days Trigger: RATAN, Ryle… -may be triggered from other wavebands? Coordinates: known VLBI resources needed: min. 256 Mbps, 5 GHz (+S/X?) e-VLBI benefit: significant

17. 2007 June 12-15Bursts, Pulses and Flickering...Slide #17 Known transients, special trigger Science goal: various, e.g. jet composition Response time: within a day! Monitoring: 1 week, every 1-3 days Trigger: Wb, or e-VLBI Coordinates: known VLBI resources needed: 256/512 Mbps, 1.6/5 GHz, Ef+Wb+LT+Ar; polcal e-VLBI benefit: only Wb+e-EVN can do this

18. 2007 June 12-15Bursts, Pulses and Flickering...Slide #18 Unknown Galactic transients flaring Science goal: nature of new transients Response time: within a day, if possible; sometimes evolve on longer timescales (depending on type of source) Monitoring: depends on what we see!!! Trigger: RXTE, Swift, GLAST, INTEGRAL+radio ID Coordinates: Swift and GLAST ~ok; WSRT prior to VLBI run VLBI resources needed: 512 Mbps, 1.6/5 GHz, Ef+Wb+LT e-VLBI benefit: only WB+e-EVN can do this very quick

19. 2007 June 12-15Bursts, Pulses and Flickering...Slide #19 Extragalactic (stellar) transients flaring Science goal: accurate location of transient?- will not be resolved Response time: within a day, or days Monitoring: yes, but probably not with VLBI Trigger: RXTE, Swift, GLAST, +WSRT quick check Coordinates: Swift, GLAST ~ok/ WSRT VLBI resources needed: min. 512 Mbps, 5 GHz, Ef+WB+LT (+Ar) e-VLBI benefit: only WB+e-EVN can do this when quick position update is necessary

20. 2007 June 12-15Bursts, Pulses and Flickering...Slide #20 Other Galactic variable sources Science goal: stellar flare localization and physics Response time: within hours! Monitoring: single epoch, full track Trigger: Wb/e-VLBI Coordinates: known VLBI resources needed: 256-512 Mbps, 5 GHz, Ef+Wb+Chinese, polcal! e-VLBI benefit: only Wb-e-EVN can do this (Wb observes a sample of sources => e-EVN a selected, active one)

21. 2007 June 12-15Bursts, Pulses and Flickering...Slide #21 LOFAR transients Science goal: nature if these transients Response time: hours? Monitoring: ? Trigger: LOFAR Coordinates: LOFAR +quick WSRT VLBI resources needed: ? e-VLBI benefit: only WB+e-EVN can get quick coord. update

22. 2007 June 12-15Bursts, Pulses and Flickering...Slide #22 XRB low/hard state jet proper motion (a case for “special trigger” obs) Science goal: jet production/acceleration models Response time: - Monitoring: 2-3 days Trigger: e-VLBI Coordinates: known VLBI resources needed: Ar+Ef+Wb+LT, 1.6/5 GHz, min. 512 Mbps e-VLBI benefit: only Ar+e-EVN can do this

23. 2007 June 12-15Bursts, Pulses and Flickering...Slide #23 e-VLBI Summary First of all, it works! Significantly reduces science turnaround time e-VLBI is easy and practical for users with little or no experience with VLBI. Data analysis pipeline does most of the work! Additional PI support is available at JIVE Westerbork + e-EVN is/will be a unique instrument: calibration, WSRT alert for e-VLBI, position information on new transients; e-MERLIN may play a similar role later These developments are mainly driven by technical/logistical considerations, but there is the possibility of doing new type of VLBI science... …especially when adaptive scheduling is becoming a reality Ideal for Galactic transient observations: classic microquasars, magnetars, X-ray flare transients, pulsars?, dMe stellar “super-flares” (talk by Rachel Osten)… PLEASE CONTRIBUTE TO THE SCIENCE CASE!