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

3. Very Long Baseline Interfero- metry Space

4. SVLBI in principle: ground-space baseline

5. 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 VSOP (VLBI Space Observatory Programme) http://www.vsop.isas.ac.jp/ ISAS (Japan) HALCA start: February 12, 1997 (new M-V rocket)

6. Highly Advanced Laboratory for Communications and Astronomy

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

8. 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

9. 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

10. Fomalont et al. (2000), ApJS 131, 95

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

12. 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 Research 26, 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 Japan 52, No. 6 (2000)

13. Orion-KL water maser outburst the only VSOP image @ 22 GHz peak: 1.3  10 5 Jy/beam elongated structure + VLBA monitoring: overlapping maser spots? Kobayashi et al. 2000, VSOP Symp., 109

14. 1519–273 at 1.6 GHz the first-ever SVLBI image, June 1997 VLBA & VLA HALCA added

15. M87 (Virgo A) VLA VSOP 1.6 GHz Reid 1998, Science 281, 1815 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

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

17. 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 Murphy et al. 2000, VSOP Symp., 47 1928+734 (z=0.3) monitoring core 1997 Aug 22 1997 Dec 16 1998 Apr 29 1998 Jul 9

18. VSOP 5 GHz Chandra X-ray (color) Australia Telescope Compact Array (8.4 GHz, contours) 0637–752 quasar (z=0.65) Lovell et al. 2000, VSOP Symp., 215 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

19. The most distant radio-loud quasars (z>3) 2215+020 (z=3.57) VLBA+EVN ground-only @ 1.6 GHz + baselines to HALCA included resolved jet cross-section  ~4·10 9 M o estimated cental black hole mass J4 Lobanov et al. 2001, ApJ 547, 714

20. 1351-018 (z=3.71) earlier VLBA @ 5 GHz Frey et al. 1997, A&A 325, 511 SVLBI @ 5 GHz: dramatic change in jet direction between sub-mas and ~10 mas scale

21. … 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 VSOP phase-referencing HALCA cannot switch rapidly between sources... Guirado et al. 2001, A&A 371, 766 Porcas et al. 2000, VSOP Symp., 245

22. 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, PASJ 52, 1055

23. 0235+164 a highly variable BL Lac VSOP @ 5 GHz: the highest brightness temperature measured with VSOP T B > 5.8  10 13 K Frey et al. 2000, PASJ 52, 975

24. The Pearson-Readhead Survey from Space Lister et al. 2001, ApJ 554, 948 HALCA + VLBA + EVN imaging of 27 sources from the P-R survey (Pearson & Readhead 1988, ApJ 328, 114) original sample: 65 sources (  >35 , S 5 >1.3 Jy,  b  >10  ) sub-sample for SVLBI: S corr >0.4 Jy on ground baseliness 2200+420 (BL Lac) @ 5 GHz ground-only SVLBI

25. imaging: true dynamic range typically 30:1 … 100:1 Tingay et al. 2001, ApJ 549, L55 The Pearson-Readhead Survey from Space: results brightness temperature distribution: a significant proportion has T B >10 12 K relation between high T B and IDV activity source properties: correlation analysis (morphology, IDV, core dominance, optical polarization, emission line equivalent width, etc.)  support to the beaming model Lister et al. 2001, ApJ 554, 948 Lister et al. 2001, ApJ 554, 964

26. The VSOP Survey Program: preliminary results Hirabayashi et al. 2000, PASJ 52, 997 sample: among 402 sources (S 5 >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 (T B ) distribution shows apparent violation of inverse Compton limit (~10 12 K)  relativistic beaming is common

27. 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)

28. SVLBI: technically feasible, scientifically interesting  next generation satellites with improved performance (sensitivity, frequency coverage, etc.) Next generation Space VLBI VSOP-2 is being proposed at ISAS in Japan 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 ?

29. ARISE (Advanced Radio Interferometry between Space and Earth) http://arise.jpl.nasa.gov/ 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 ?.