1 / 21

e-EVN science in 2006-2007

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:.

nayda-griffith
Download Presentation

e-EVN science in 2006-2007

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. e-EVN science in 2006-2007 Zsolt Paragi (JIVE), for the EXPReS project

  2. 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 EXPReS Progress meeting, Utrecht

  3. Where are we now in capabilities… • Sensitivity and resolution in typical observations, 5 GHz • e-EVN in 2007, 256 Mbps: 50 uJy/beam, ~6 mas • e-EVN, 512 Mbps: 35 uJy/beam, ~6 mas • e-EVN in 2008, 512 Mbps, 10 uJy/beam, ~6 mas (~1 mas with Ar) • Full EVN (no Ar), 1024 Mbps, 12 uJy/beam, ~1 mas • VLBA, 512 Mbps, 30 uJy/beam, ~1 mas • VLBA+GBT, 512 Mbps, 12 uJy/beam • The e-EVN is reaching very competitive sensitivity in 2008, but resolution remains an issue. EXPReS Progress meeting, Utrecht

  4. … and how far can we go • Sensitivity • Great 1 Gbps test results; 10 Gbps technology is coming • Stuck with max. 1 Gbps with current EVN! => actions by CBD • Resolution/imaging • It would be crucial to get long baselines other than Ar and Sh • Besides EVN telescopes, can we initiate a more global array including Australian and Japanese telescopes? • Flexibility • Is it possible at all to make the EVN respond to some triggers on previously unscheduled dates? What needs to be done to achieve this??? EXPReS Progress meeting, Utrecht

  5. e-VLBI activities in 2007 • Regular e-VLBI test observations in every six week (on average) • 24h time is pre-allocated for science observation during tests • Observing proposals now must be sent to normal EVN deadlines; a new type of triggered proposal class, normal and spectral projects supported • Science operations at 1.6 and 5GHz, up to 256 Mbps • (Cm, Jb2, Mc, On, Tr, Wb) • First 22 GHz test with Metsahovi in March 2007 • Australia and Shanghai demos, great success!; 512 Mbps in Australia science demo observations, with small number of tels. • Most recently: robust 512 Mbps operations, and 1 Gbps fringes!!! EXPReS Progress meeting, Utrecht

  6. Science results from the ‘Oz-demo’ ATCA, Mopra and Parkes observations at 512 Mbps, correlated at JIVE. Target: the nearby supernova in the LMC, only visible from the South. One of the breathtaking Hubble Space Telescope images of SN1987A EXPReS Progress meeting, Utrecht

  7. And with VLBI… Various fits to the data to measure the size of the expanding remnant. Tingay et al., (in prep.) Highest resolution image of SN1987A so far (first VLBI!) – not bad for a three telescope array. Countours shows an earlier ATCA image. EXPReS Progress meeting, Utrecht

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

  9. First refereed journal papers: GRS 1915+105: Rushton et al. (2007), MNRAS 374, L47 Cyg X-3: Tudose et al. (2007), MNRAS 375, L11 Cyg X-3 Aftermath of a huge outburst -first detection of polarisation on VLBI scales in a microquasar What PI’s really need is to be able to monitor these events in (1) closely spaced monitoring observations, (2) when they happen, not on fixed dates. EXPReS Progress meeting, Utrecht

  10. LSI 61+303 campaign: • Binary XRB system, also source of very energetic gamma rays; • What is the source of these? Earlier hypothesis: microquasar jet. • Recent VLBA observations (Mioduszewski et al.) suggest an • interacting pulsar wind source instead • MAGIC collaboration observations including e-EVN, VLBA, MERLIN, CHANDRA in October 2006 The MAGIC telescope and a view of its surroundings in La Palma. It is capable of detecting very high energy gamma rays. The telescope is operated by the MAGIC collaboration of 17 institutes since 2004. http://wwwmagic.mppmu.mpg.de/ EXPReS Progress meeting, Utrecht

  11. …and the results • no ultimate answer on the nature of the binary yet • radio and X-rays originate from a different population • of electrons, but • there is indication for temporal correlation between • X rays and gamma rays • Albert et al. (2008), Astrophys. J. (accepted), • astro-ph/0801.3150 EXPReS Progress meeting, Utrecht

  12. 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. M. Pandey, Z. Paragi, P. Durouchoux, H. Bignall, PoS(Dynamic2007)041 EXPReS Progress meeting, Utrecht

  13. CHARA and e-VLBI observations of Algol Algol is one of the most famous variable stars, also known as beta Persei. It is very nearby, only 26 parsecs away, ideal for optical/radio interferometry studies. Algol is active from radio to the X-ray bands, besides the optical variations due to regular eclipses. Artist’s impression on the close binary system from the web. The K-subgiant is the source of radio activity. EXPReS Progress meeting, Utrecht

  14. The CHARA array The CHARA array is located at Mount Wilson in California, USA, and is operated by the Center for High Angular Resolution for Astronomy http://www.chara.gsu.edu/CHARA/ EXPReS Progress meeting, Utrecht

  15. CHARA results CHARA fringes before and after processing. Resulted visibility amplitudes vs. baseline length are shown below. Fitted orbital parameters to the data, found geometry of the system. Determined distance: 26.1±0.4 pc, More accurate than HIPPARCOS! Paragi et al., submitted to PoS (Manchester MRU proceedings) Csizmadia et al. (refereed paper in prep.) EXPReS Progress meeting, Utrecht

  16. Algol, 14 December 2006 e-EVN run: • Simultaneous optical photometry and e-EVN obs. • (5 GHz, 256 Mbps) during secondary minimum • Source flared – total intensity and circular polarization • variations consistent between WSRT and e-EVN data • Flare emission ~2 mas offset from the CP peak Dedicated observations of such flares will be challenging even for e-VLBI + • Detected proper motion during the • 10 hours run –fitted orbital parameters • of the AB close binary, but… EXPReS Progress meeting, Utrecht

  17. Supernovae: and old story with e-EVN Garrett et al. (2005) • SN2001em was discovered on 15 September 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 ) of the first real faint target with e-VLBI • Paragi et al. (2005), MSAIt 76, 570 EXPReS Progress meeting, Utrecht

  18. 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 ) of the supernova • within the VLA error box • Paragi et al. (2007), ATel #1215 EXPReS Progress meeting, Utrecht

  19. The first ATel message from the e-EVN EXPReS Progress meeting, Utrecht

  20. The e-EVN has participated in a variety of science observations, contributed to results carried out in ambitious multi-waveband projects. We ‘used’ the e-VLBI developments to stir a bit of noise around the EVN, and attract new users. But more is needed to make e-EVN a very competitive, unique instrument. Conclusion EXPReS Progress meeting, Utrecht

  21. Better sensitivity and *resolution* Will happen with new radio telescopes being connected soon: Arecibo 300m — 256 Mbps spring 2008 Shanghai +2 new — 1 Gpbs available (not operationally yet) Effelsberg 100m — expected spring 2008 Yebes 40m — expected in 2008 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 What else astronomers want? EXPReS Progress meeting, Utrecht

More Related