Presentation on theme: "E-EVN science projects (2006-2008) Zsolt Paragi (JIVE), for the EXPReS project."— Presentation transcript:
e-EVN science projects ( ) Zsolt Paragi (JIVE), for the EXPReS project
2008 June th e-VLBI Workshop, ShanghaiSlide #2 What will e-VLBI offer for us one day? Several Gbps data rates/telescope, greatly increased sensitivity, full uv-coverage, flexibility… What the e-EVN can do by the end of 2008: Open for users, regular observing sessions (10-12/year ) Sensitivity and resolution comparable to disk recording Already more 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
2008 June th e-VLBI Workshop, ShanghaiSlide #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, 17 Jy/beam, ~6 mas (10 Jy, ~1 mas with Arecibo, Hh, Sh, Ur at lower data rates) Full EVN (no Ar), 1024 Mbps, 12 Jy/beam, ~1 mas VLBA, 512 Mbps, 30 Jy/beam, ~1 mas VLBA+GBT, 512 Mbps, 12 Jy/beam
2008 June th e-VLBI Workshop, ShanghaiSlide #4 … and how far can we go Sensitivity Great 1 Gbps test results; 10 Gbps technology is available Max. 1 Gbps with current EVN; 4 Gbps upgrade is investigated Resolution/imaging Sh tested in 2007; Ar, Hh, Ur 512 Mbps coming soon Besides do not we do science (just few days year) with a more global array including Australian and Japanese telescopes??? Flexibility Limited e-EVN ToO is possible on previously unscheduled dates, but flexibility is still an issue
2008 June th e-VLBI Workshop, ShanghaiSlide #5 e-VLBI operations and test results Regular e-VLBI test observations in every six week (on average) 24h time is pre-allocated for science observation during tests Accepts normal and triggered proposals, more ToOs are supported Science operations (so far) at 1.6 and 5 GHz, max. 512 Mbps with Cm, Ef - new, Jb2, Mc, On, Tr, Wb; Mh - possible Tests (more by Arpad, Harro, Paul): With packet dropping near 1 Gbps Mixed data rate mode demonstrated Ar, Hh, Sh, Ur can join science obs! Four-continent fringes
2008 June th e-VLBI Workshop, ShanghaiSlide #6 The two newest members of the e-EVN in 2008 (AJPoD by Stefanie Muhle)
2008 June th e-VLBI Workshop, ShanghaiSlide #7 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
2008 June th e-VLBI Workshop, ShanghaiSlide #8 And with VLBI… Highest resolution image of SN1987A so far (first VLBI!) – not bad for a three telescope array. Countours shows an earlier ATCA image. Various fits to the data to measure the size of the expanding remnant. Tingay et al., (in prep.)
2008 June th e-VLBI Workshop, ShanghaiSlide #9 e-EVN science projects in 2006/2007 Cyg X-3, 20 Apr/18 May 2006, 128 Mbps, Tudose et al. GRS , 20 Apr 2006, 128 Mbps, Rushton et al. LSI , 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. J microquasar candidate, 28 Mar 2007, 256 Mbps, Martí et al. Cyg X-3, Jun 2007, 256 Mbps, Tudose et al. Stellar maser search, 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.
2008 June th e-VLBI Workshop, ShanghaiSlide #10 First refereed journal papers: GRS : 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 PIs really need is to be able to monitor these events in (1) closely spaced monitoring observations, (2) when they happen, not on fixed dates.
2008 June th e-VLBI Workshop, ShanghaiSlide #11 LSI 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
2008 June th e-VLBI Workshop, ShanghaiSlide #12 …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/
2008 June th e-VLBI Workshop, ShanghaiSlide #13 IGR results: M. Pandey, Z. Paragi, P. Durouchoux, H. Bignall, PoS(Dynamic2007)041 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.
2008 June th e-VLBI Workshop, ShanghaiSlide #14 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. Artists impression on the close binary system from the web. The K-subgiant is the source of radio activity.
2008 June th e-VLBI Workshop, ShanghaiSlide #15 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
2008 June th e-VLBI Workshop, ShanghaiSlide #16 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, Comparable or better accuracy than HIPPARCOS! Paragi et al., submitted to PoS (Manchester MRU proceedings) Csizmadia et al. (refereed paper in prep.)
2008 June th e-VLBI Workshop, ShanghaiSlide #17 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 Detected proper motion during the 10 hours run –fitted orbital parameters of the AB close binary, but… Dedicated observations of such flares will be challenging even for e-VLBI +
2008 June th e-VLBI Workshop, ShanghaiSlide #18 Supernovae: and old story with e-EVN 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 Garrett et al. (2005)
2008 June th e-VLBI Workshop, ShanghaiSlide #19 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
2008 June th e-VLBI Workshop, ShanghaiSlide #20 The first ATel message from the e-EVN
2008 June th e-VLBI Workshop, ShanghaiSlide #21 Science projects in 2008 A number of exploratory runs Supernovae in IC694, member of the famous Arp299 galaxy merger system. PI Perez-Torres. (MERLIN image from Antonis Polatidis)... record breaking correlaton job! On 8-9 April 2008, the first real triggered observations: Cyg X-3 in an X-ray states change. Followed by a huge outburst and three ToO epochs, first e-EVN observations outside the fixed dates. e-VLBI flexibility: could not do it with disks because stations were short of them!
2008 June th e-VLBI Workshop, ShanghaiSlide #22 Cyg X-3 giant flare (preliminary) The Cyg X-3 puzzle; preliminary maps by the PI, Valeriu Tudose
2008 June th e-VLBI Workshop, ShanghaiSlide #23 What science would benefit from e-VLBI? Transients obviously, from quick turnaround mostly Surveys of a large sample of weak sources, detection not 100% guaranteed (but likely) 1) can follow up quickly the detected sources only, at other frequencies 2) big surveys not limited by recording media capacity Projects requiring dynamic scheduling Others???, e.g. support to VSOP-2 Survey, quick compactness check of highly variable sources (also in size!) before space VLBI observations? How could we best support X-ray and gamma missions, for example GLAST? The highest redshift radio-detected quasar, with the EVN at 1.6 GHz - CSO at the edge of the visible Universe! (Frey et al. 2008) J , z=6.12
2008 June th e-VLBI Workshop, ShanghaiSlide #24 Synergy with other (e-)instruments e-MERLIN will be complementary in resolution to the e-EVN; short spacings LOFAR will be an exceptional instrument for finding new transients Wide FoV focal plane array considered for the WSRT - could also serve as a trigger instrument LOFAR (up) and DIGESTIF on the WSRT (left); from Astron web GLAST
2008 June th e-VLBI Workshop, ShanghaiSlide #25 Finishing thoughts... As Steven pointed out yesterday, e-VLBI is technologial pathfinder to SKA. Specific developments in EXPReS definitely make the e-EVN an SKA pathfinder. But do not think just the technology! We are looking for new ways of doing VLBI research, especially in the area of transients, which could soon transform our field considerably. e-EVN matured a great deal during the first two years of EXPReS, now it is time to harvest the results. EXPReS eVSAG (e-VLBI Science Advisory Group) will address this within a few days.