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Sándor Frey FÖMI Satellite Geodetic Observatory P.O. Box 546, H-1373 Budapest, Hungary frey@sgo.fomi.hu http://www.sgo.f

Space VLBI. Sándor Frey FÖMI Satellite Geodetic Observatory P.O. Box 546, H-1373 Budapest, Hungary frey@sgo.fomi.hu http://www.sgo.fomi.hu/vlbi/. S pace. V ery L ong B aseline I nterfero- metry. SVLBI in principle: ground-space baseline. VSOP (VLBI Space Observatory Programme).

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Sándor Frey FÖMI Satellite Geodetic Observatory P.O. Box 546, H-1373 Budapest, Hungary frey@sgo.fomi.hu http://www.sgo.f

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  1. Space VLBI Sándor Frey FÖMI Satellite Geodetic Observatory P.O. Box 546, H-1373 Budapest, Hungary frey@sgo.fomi.hu http://www.sgo.fomi.hu/vlbi/

  2. Space Very Long Baseline Interfero- metry

  3. SVLBI in principle: ground-space baseline

  4. VSOP (VLBI Space Observatory Programme) ISAS (Japan) HALCA start: February 12, 1997 (new M-V rocket) 8-m parabolic antenna on board HALCA observing frequencies: 1.6 and 5 GHz recording data rate:128 Mbps bandwidth: 32 MHz orbital period:6.3 h 21 400km (apogee) 560 km (perigee) baselines: up to ~30 000 km http://www.vsop.isas.ac.jp/

  5. Highly Advanced Laboratory for Communications and Astronomy

  6. Usuda 64 m a truly global VLBI: >40 ground radio telescopes from all over the world 5 ground tracking stations (USA, Japan, Australia, Spain) Usuda 10 m 3 correlators (USA, Canada, Japan)

  7. VSOP scientific program • General Observing Time (~50% of operational time) • open for the scientific community via peer-reviewed proposals • (deadlines now coincide with ground VLBI deadlines, • 3 times per year) • a few declared key science programs: • blazars • high brightness temperature / intra-day variability • jet motions (3C 273, 3C 279 and 3C 345) • key sources (NGC 4258, Centaurus A and Virgo A) • nearby AGN • absorption in AGN • stars

  8. VSOP scientific program (cont.) • VSOP Survey Program (~25%) • led by the mission at ISAS • coordinated by the international Survey Working Group • ~200 brightest, pre-selected AGN to be imaged at 5 GHz • limited ground resources (typically 3-5 GRTs) • mainly S2 recording + “extractions” from GOT experiments • homogeneous information on sub-mas structures, • for statistical studies • data base will be publicly available

  9. Fomalont et al. (2000), ApJS131, 95

  10. Selected VSOP scientific results Selection criteria for inclusion in this talk: interesting important spectacular certain people in this room are involved... … including myself

  11. Large collections of various VSOP-related papers: "VSOP Results and the Future of Space VLBI", Proc. COSPAR Symposium, Nagoya, Japan, July 1998, eds. Hirabayashi H., Preston R.A. & Gurvits L.I., Advances in Space Research26, No. 4 (2000) "Astrophysical Phenomena Revealed by Space VLBI", Proc. VSOP Symposium, Sagamihara, Japan, January 2000, eds. Hirabayashi H., Edwards P.G. & Murphy D.W., ISAS (2000) VSOP Special Issue, Publications of the Astronomical Society of Japan52, No. 6 (2000)

  12. Orion-KL water maser outburst the only VSOP image @ 22 GHz peak: 1.3  105 Jy/beam elongated structure + VLBA monitoring: overlapping maser spots? Kobayashi et al. 2000, VSOP Symp., 109

  13. 1519–273 at 1.6 GHz the first-ever SVLBI image, June 1997 VLBA & VLA HALCA added

  14. M87 (Virgo A) VLA No proper motion is detected in 1.5 years VSOP monitoring @ 5 GHz (in contrast with superluminal motion at VLA & HST scales) Junor et al. 2000, VSOP Symp., 13 VSOP 1.6 GHz Reid 1998, Science281, 1815

  15. the impact of improved angular resolution: transverse jet structure resolved edge-brightening regular, oscillating patterns: instabilities propagating along the jet Lobanov et al. 2000, AdSpR 26, 669 Lobanov et al. 2000, VSOP Symp., 239

  16. 1928+734 (z=0.3) monitoring core Murphy et al. 2000, VSOP Symp., 47 1997 Aug 22 1997 Dec 16 1998 Apr 29 1998 Jul 9 circumpolar superluminal quasar, ideal for VSOP monitoring substantial changes near the core on ~months time scale a variety of different phenomena, inconsistent with a simple straight jet model

  17. first Chandra target, thought to be unresolved  luminous kpc-scale X-ray jet 1999 Aug: coordinated VSOP and Chandra observations radio (ATCA) vs. X-ray jet structure: striking coincidence and radio jet bending polarization E-vectors perpendicular to the jet until X-rays detected to W, then begin to be parallel with the jet simple synchrotron model is not sufficient to explain all data (incl. HST optical) VSOP/VLBI: mas-scale jet direction, ~11c superluminal motion 0637–752 quasar (z=0.65) VSOP 5 GHz Australia Telescope Compact Array (8.4 GHz, contours) Chandra X-ray (color) Lovell et al. 2000, VSOP Symp., 215

  18. The most distant radio-loud quasars (z>3) 2215+020 (z=3.57) VLBA+EVN ground-only @ 1.6 GHz J4 + baselines to HALCA included resolved jet cross-section  ~4·109 Mo estimated cental black hole mass Lobanov et al. 2001, ApJ547, 714

  19. 1351-018 (z=3.71) earlier VLBA @ 5 GHz Frey et al. 1997, A&A325, 511 SVLBI @ 5 GHz: dramatic change in jet direction between sub-mas and ~10 mas scale

  20. VSOP phase-referencing HALCA cannot switch rapidly between sources ... … but: 1308+326 / 1308+328 quasar pair (14.3 arcmin separation) HALCA primary beam: 26 arcmin @ 5 GHz VLBA + Effelsberg switched between the sources phase reference mapping, relative astrometry with VSOP 1342+662 / 1342+663 quasar pair (4.8 arcsec separation) sources lie within the primary beam of HALCA & VLBA antennas it works! satellite orbit reconstruction error ~3 m Porcas et al. 2000, VSOP Symp., 245 Guirado et al. 2001, A&A371, 766

  21. VSOP polarization HALCA receives only left-circularly polarized radiation ... … but: despite the other complications (lower sensitivity, difficult polarization calibration), it is technically feasible to obtain high-resolution polarization images test observations with the VLBA and VLA @ 1.6 and 5 GHz of sources with sufficiently high correlated polarized flux density good perspectives for next-generation SVLBI Kemball et al. 2000, PASJ52, 1055

  22. 0235+164 a highly variable BL Lac VSOP @ 5 GHz: the highest brightness temperature measured with VSOP TB > 5.8  1013 K Frey et al. 2000, PASJ52, 975

  23. The Pearson-Readhead Survey from Space HALCA + VLBA + EVN imaging of 27 sources from the P-R survey (Pearson & Readhead 1988, ApJ 328, 114) original sample: 65 sources (>35, S5>1.3 Jy, b>10) sub-sample for SVLBI: Scorr>0.4 Jy on ground baseliness 2200+420 (BL Lac) @ 5 GHz ground-only SVLBI Lister et al. 2001, ApJ554, 948

  24. The Pearson-Readhead Survey from Space: results imaging: true dynamic range typically 30:1 … 100:1 Lister et al. 2001, ApJ554, 948 source properties: correlation analysis (morphology, IDV, core dominance, optical polarization, emission line equivalent width, etc.)  support to the beaming model Lister et al. 2001, ApJ554, 964 brightness temperature distribution: a significant proportion has TB>1012 K relation between high TB and IDV activity Tingay et al. 2001, ApJ 549, L55

  25. The VSOP Survey Program: preliminary results sample: among 402 sources (S5>0.95 Jy, >–0.45,b>10), 289 sources sufficiently compact for VSOP @ 5 GHz ~half of the data sets reduced, even more observed rest-frame brightness temperature (TB) distribution shows apparent violation of inverse Compton limit (~1012 K)  relativistic beaming is common Hirabayashi et al. 2000, PASJ52, 997

  26. VSOP proposals, observations and data reduction • open proposals; deadlines: 1 February, 1 June & 1 October • all info at: www.vsop.isas.ac.jp/obs/AO.html • Proposers’ Guide, cumulative observation list, etc. • severe observing constraints (on-board equipment, tracking, • ground network availability, etc.) • assistance: user software, sample (u,v)-coverages • schedule is done by the VSOP mission • data reduction: AIPS and Difmap are available • calibration information on the VSOP web • general info: e-mail newsletter (also on the web, with some • delay)

  27. Next generation Space VLBI SVLBI: technically feasible, scientifically interesting  next generation satellites with improved performance (sensitivity, frequency coverage, etc.) • 10 increase over VSOP sensitivity • 20-40 000 km apogee • 10-m antenna • frequencies: (1.6?), 5(8), 22, 43, (86?) GHz • data rate: 1 (2?) Gbit/s • launch vehicle: modified M-V • launch: 2008 ? VSOP-2 is being proposed at ISAS in Japan

  28. ARISE(Advanced Radio Interferometry between Space and Earth) • 5 ground-based resolution • (max. 10-20 as) • 50 VSOP sensitivity • 40-50 000 km apogee • 25-m inflatable antenna • frequencies: 5(8), 22, 43, 86 GHz • single-dish: 60 GHz • data rate: 8 Gbit/s • lifetime  3 years • launch: 2008 ? . http://arise.jpl.nasa.gov/

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