PoS(11th EVN Symposium)109 erse (6cm) and http://pos.sissa.it/ imply bright- ⊕ D ⊕ D ce. emperatures to resolve the dicated SPEKTR-R spacecraft, ferometry from space – Space- s. The current long-baseline fringe ated visibility measurements at the GN radio jets (with implications for s of a 92/18/6/1.35cm fringe survey of AGN radio emission, studying the GN) at baselines up to 25 Earth diam- ations, including Space-VLBI imaging. (18cm), BL Lac at 10 aya 84/32, 117997 Moscow, Russia ⊕ ing interstellar medium in our Galaxy) and D versitetsky 13, 119991 Moscow, Russia might indicate that the jet flow speed is often higher than b T ive Commons Attribution-NonCommercial-ShareAlike Licen K, about two orders of magnitude above the equipartition inv 13 10 ∼ (1.3cm). The 18 and 6cm-band fringe detections at 10 b T ⊕ ∗ D ). The survey goals include a search for extreme brightness t 126 at 4.3 ⊕ + D [email protected] Compton limit. These high values of eters ( RadioAstron is a project to use the 10m antenna on board the de launched on 2011 July 18,VLBI. to We perform describe the Very Long strategy and Baselineof highlight Inter some the of the first brighter result radio-loud Active Galactic Nuclei (A Speaker. the jet pattern speed. observed size distribution of the mosttheir compact intrinsic features structure in and the A properties ofselecting the promising scatter objects for detailed follow-upOur observ survey target selection islongest based ground-ground on baselines from the previous results VLBIdetections of survey with correl RadioAstron include OJ 287 at 10 Doppler factor crisis and to constrain possible mechanisms ness temperatures of B0748 ∗ Copyright owned by the author(s) under the terms of the Creat c E-mail: for the RadioAstron AGN Early Science Working Group Sternberg Astronomical Institute, Moscow University, Uni Kirill V. Sokolovsky Astro Space Center, Lebedev Physical Inst. RAS, Profsoyuzn RadioAstron Early Science Program Space-VLBI AGN survey: strategy and first results
11th European VLBI Network Symposium &October Users 9-12, Meeting, 2012 Bordeaux, France PoS(11th EVN Symposium)109 , b T tance and Kirill V. Sokolovsky 18 cm (1.7,GHz, L-band), launch from Baikonur (right). nstalled on board of the ded- , an on-board hydrogen maser, cted as part of the RadioAstron gure 1). The orbit was selected -hour period, 73 000 km perigee, nd station in real time. Currently, uct its position and velocity with y near Moscow, Russia serves as to a highly elliptical orbit on 2011 n data acquisition station is under servatory’s 43 m telescope at Green extreme brightness temperatures, gions during the mission lifespan. As echanisms of AGN radio emission [3], n AGN radio jets (with implications for f the Moon, to provide a wide range of by laser ranging, direct optical imaging ations, including space-VLBI imaging. , respectively. 1 ing in the interstellar medium in our Galaxy) − 2 2 cm s ± 500 m and ± inclination. Regular measurements of the spacecraft’s dis ◦ SPEKTR-R assembled at Lavochkin Association (left) and its The space telescope is equipped with 92 cm (324 MHz, P-band), The 10 m space radio telescope of the RadioAstron project is i A fringe detection survey of radio-bright AGN is being condu Figure 1: 6 cm (4.8 GHz, C-band) andand a 1.3 cm high-gain antenna (22.2 GHz, system to K-band)the downlink receivers 22 VLBI m data antenna to a ofthe grou the ground Pushchino data radio acquisition astronomyconstruction observator station. on the basis The of theBank, second National West Virginia, Radio RadioAstro USA. Astronomy Ob velocity using standard radiometric techniquesand supported VLBI state vector measurementsaccuracies typically [1] better allow than one to reconstr RadioAstron Space-VLBI AGN survey 1. The space radio telescope icated SPEKTR-R spacecraft. TheJuly spacecraft 18 was from launched the in Baikonurso Cosmodrome that by its a parameters Zenit-3F evolve rocketprojected under (Fi baselines the for gravitational pull VLBI observations o of of 2012 various October sky re 2, the281 SPEKTR-R 000 km orbital parameters apogee, were: and 206 79 to resolve the Doppler crisis [2]to and study to the constrain size possible distribution m oftheir the intrinsic most structure compact and features the i properties ofand the select scatter promising targets for detailed follow-up observ 2. AGN survey strategy Early Science Program. The survey goals include a search for PoS(11th EVN Symposium)109 , b 1 T the cor- (i) rces first to -coverage for ) v , u VSOP measured ( Kirill V. Sokolovsky ) and long projected (iii) ⊕ D ast one, over the whole ed in this catalog to set and of a Global 86 GHz 5 2 < d in the Radio Fundamental oup the Research and Development related visibility measurements m the ground is not decreasing also consulted the list of high– mme (VSOP) [15, 16, 17]. onstraints are met. An example revolutions, the plot represents a period of rather omparable unresolved flux densities urveys including the 13/3.6 cm (S/X- . Possible space-ground or ground telescopes, and availability of nce is given to sources for which -band) observations of the MOJAVE program u Figure 2: various sky positions computedorbital for revolution, 206 starting hours,00:00 one on UT with 2012 theLBA, December Arecibo, telescopes: GBT, Usuda. 15 Also RadioAstron, markedare: EVN, on the the plot Galactic Planethe (GP), satellite’s orbital Sun plane, avoidance the regions, perigee (P)and apogee (A), the direction perpendicular to the orbital plane. 3 we can obtain both short ( (ii) 1.3 cm. The space ra- there is a 3 mm detection. We try to schedule the preferred sou + (iv) -coverage computed with the above constraints, except the l ) plus a small solid angle centered K, and 18 cm or 6 v ◦ , . We used the “unresolved X-band flux density” parameter list + 12 u 3 ( 10 The results of many ground-based VLBI surveys are summarize http://www.physics.purdue.edu/astro/MOJAVE/ http://www.bu.edu/blazars/ http://astrogeo.org/rfc The survey target selection is based on the results of the cor All four RadioAstron bands (92, 18, 6, 1 2 3 > b sources observed at 6 cm by the VLBI Space Observatory Progra Catalog scheduling priorities for the sources.that satisfy Among RadioAstron visibility sources constraints, with prefere c related visibility at 13,rapidly 3.6, with 2 increasing cm baseline and length, 7 mm bands measured fro VLBI Survey of Compact Radio Sources [14], respectively. We RadioAstron Space-VLBI AGN survey on the longest ground-ground baselines fromband) existing VLBA VLBI Calibrator s Surveys (VCS) 1VLBA to program 6 (RDV) [4, [10, 5, 11, 6, 12, 7, 8, 13], 9] 2 cm and (K sky is presented on Figure 2, although it should be noted that T 7 mm (Q-) and 3 mm (W-band) results of the Boston University gr dio telescope observes simultaneously at two bands while thevided ground in telescopes two are sub-arraysthe di- or two switch bands between typical during AGN the survey observation experiment. consistsfour of scans, each A 10-minute long,source, on separated a from target other seriesby the of 40–60 scans minutes necessary to satisfyspacecraft’s the thermal constraints and slewthe to next target.the The scheduling main include: factors a affecting Sungle avoidance of an- 90 and 1.3 cm) are employed in thethe survey, main with focus onMost 18, 6, observations and are 1.3 done cmmode: in bands. 6 a dual-band on anti-solar direction, satellitethe visibility tracking to station (TS), TS visibilitysatellite’s to high-gain the antenna, targetground source telescopes visibility during f the time period when all the other c of the maximize the detection rate in the early stages of the survey space–ground baselines within one or a few SPEKTR-R orbital PoS(11th EVN Symposium)109 . The plot ⊕ D 3 erse Compton . imply brightness Kirill V. Sokolovsky ⊕ D m, Parkes 64 m, Mo- tions of pulsars, no 92 cm x25 m (Netherlands), Yebes nd LBA arrays. ogram observations include the m, Zelenchukskaya 32 m, Badary tempted. scales that were never before ac- s so far). This band was given a tections at 10 wever, detection of 18 cm fringes at vent low-frequency fringe detections rg 100 m (Germany), Evpatoria 70 m Interferometric signal from the quasar k 70 m (UK), Medicina 32 m and Noto the MASIV Survey [18]; BL Lac was 126 detected between RadioAstron and GBT nent at longer wavelengths and the angular + shows the signal to noiseual ratio delay as and a function ratefringe of after fitting. resid- delay-model subtraction and B0748 (1.3cm) at the projected baseline of 4 Figure 3: 4 126 and + for blazars ⊕ D K, about two orders of magnitude above the equipartition inv 126 at projected base- 13 + (Fig. 3). Some of the cur- 10 ⊕ ∼ D b T 126, OJ 287, and BL Lacertae. The suggests that interstellar scattering might not always pre + ⊕ While the first months of the survey Ground telescopes participating in the AGN Early Science Pr While the 92 cm band is actively used for RadioAstron observa The RadioAstron space interferometer is exploring angular D were marked byof correlation continuing techniques, development choosingspace optimal telescope observingbugging modes, the and satellite de- system, VLBI the data observations downlink duringnonetheless this provided period some record-breaking results. Fringes18 to and the 6 space cmjected telescope bands baselines at were of about detected 10 on pro- ground array consisted of Arecibo, GBT, and Effelsberg telescopes. At 1.3 cm, fringestween be- the space telescope and thedetected GBT were for B0748 B0748 lines up to 4.3 rent long-baseline fringe detections aresented pre- in Table 1. Both B0748 Arecibo 300 m and NRAOpra GBT 22 m, 100 Hobart m 26 m, (USA),(Ukraine), Tidbinbilla ATCA 70 Hartebeesthoek m tied-array 26 m (Australia), of (South Effelsbe Africa), 5x22 32 Jodrell m Ban (Italy), Shanghai 25 m and Urumqi32 25 m m (China), (Russia), Svetloe Torun 32 32 m40 m (Poland), and Usuda Robledo 70 64 m m (Spain), (Japan), as WSRT well 14 as the EVN, Kvazar-KVO, a 3. First results RadioAstron Space-VLBI AGN survey favorable observing conditions. OJ 287 exhibit interstellarnot scintillation included as in MASIV. determined in resolution is lower than that of other RadioAstron bands. Ho space–ground fringes on AGN havelow been priority because detected interstellar (few scattering is attempt most promi 10 at long baselines and more 92 cm AGN observations should be at 4. Summary cessible at centimeter wavelengths. The 18 and 6 cm fringe de temperatures PoS(11th EVN Symposium)109 of c ight. The ore, 306 0686 889 z . . . nd (5) – maxi- ed with the stan- g fringe detection Kirill V. Sokolovsky max 2013 B derived from ground- / δ oppler–boosted by a factor the velocity in units of λ λ ) (mas) 3 cm) / β . sic Research (projects 11-02- 6 cm) ted by Lavochkin Association λ 18 cm) 1 e observers and technicians at = max = = B λ is project possible. t indicate that the jet flow speed is λ skaya, Badary, Torun, Tidbinbilla, λ k, Hobart, Jodrell Bank, Medicina, (6) redshift (MOJAVE database). nt No. 8405). ademy of Sciences, and the Ministry IDE): a multidisciplinary enhancement ernational institutions. The RadioAs- t long baselines are planned to probe ) (M Calves, and T. Bocanegra Bahamon processes in galactic and extragalactic pical values of ⊕ max D B C-band ( L-band ( K-band ( measurements combined with the equipartition b 5 T is the bulk Lorentz factor, Ground telescope ( Γ , (2012) 696 GBT 100 m 4.3 4215 0.05 0 Arecibo 300 m 10 708 0.29 0 39 Effelsberg 100 m 10 2124 0.10 0 , 126 39th COSPAR Scientific Assembly. Held 14-22 July 2012, in Mys 100, where + , is the angle between the plasma flow direction and the line of s K. Surprisingly, interstellar scattering is not preventin ∼ θ 1 15 (1) source name and its alias (2), (3) ground telescope, (4) a Some of RadioAstron long-baseline detections as of January − − )] K [19]. These brightness temperature values may be reconcil 14 θ 11 10 derived from the RadioAstron cos 10 ∼ δ Table 1: β × b 2006 OJ 287 4216 BL Lac 1231 B0748 T − + + + incoherent synchrotron radiation model if the emission is D 1 ( Name Alias + e Γ / [ − J0854 J2202 J0750 e Planetary Radio Interferometry and Doppler Experimentof (PR space science missions India. Abstract C2.2-30-12, p.696 ≡ The RadioAstron Space Radio Telescope was build and is opera This research was supported by the Russian Foundation for Ba δ [1] Gurvits, L., S. V. Pogrebenko, G. Cimo, D. Duev, G. Molera Column designation: RadioAstron Space-VLBI AGN survey mum baseline at which fringes were found, (6) angular scale, limit of a few large values of based VLBI kinematic data [20,often 21]. higher than This the inconsistency jet migh the pattern range speed. of More observations a at long baselines even at 18 cm. Acknowledgements and Astro Space Center in collaborationtron with Russian AGN and Early int ScienceArecibo, Working Group ATCA, Effelsberg, is Evpatoria, deeplyNoto, GBT, grateful Mopra, Hartebeesthoe to Parkes, th Shanghai,Usuda, Urumqi, WSRT, Yebes, and Svetloe, Robledo Zelenchuk observatories for making th 00368 and 12-02-33101), the basic research programobjects” “Active of the Physical Sciencesof Division Education of and the Science Russian of Ac the Russian Federation (agreeme References dard of inverse Compton limit argument are inconsistent with the ty the emitting plasma, and PoS(11th EVN Symposium)109 , , , , , , AJ r , ults ApJ uclei BA ApJ The , , MASIV) rometric n , (2009) 1874 Kirill V. Sokolovsky 138 , (2008) 159 ton catastrophe , n Source Radiation AJ , (2009) 859 136 galactic Radio Jets , , 83 , AJ , The Second VLBA Calibrator f Blazar Jets llermann, Y. Y. Kovalev, E. Ros, llermann, Y. Y. Kovalev, and illan, E. B. Fomalont, and C. Ma d C. Ma Fomalont, R. C. Walker, and C. Carabajal Zensus, M. Bremer, A. Greve, and The Fourth VLBA Calibrator Survey: VCS4 The Fifth VLBA Calibrator Survey: VCS5 The Sixth VLBA Calibrator Survey: VCS6 , (2006) 185 The Third VLBA Calibrator Survey: VCS3 , (2002) 77 Journal of Geodesy , (1997) 95 19 , (2004) 110 , 640 , , 111 616 6 , , ApJ VLBA Observations of Radio Reference Frame Sources. , PASA , (2004) 33 , , (2008) 108 ApJ , (2002) 13 , (2008) 314 ApJS , 155 , 689 , 141 175 , , , Single-epoch VLBI imaging study of bright active galactic n ApJ The Micro-Arcsecond Scintillation-Induced Variability ( ApJS , , ApJS ApJS MOJAVE: Monitoring of Jets in Active Galactic Nuclei with VL The VSOP 5 GHz Active Galactic Nucleus Survey. III. Imaging The VSOP 5 GHz Active Galactic Nucleus Survey. IV. The Angula , (2012) A34 , The VSOP 5 GHz Active Galactic Nucleus Survey. V. Imaging Res , 544 , VLBA Observations of Radio Reference Frame Sources. II. Ast The Bulk Lorentz Factor Crisis of TeV Blazars: Evidence for a , (2003) 2562 A&A , Equipartition brightness temperature and the inverse Comp 126 Brightness Temperature Constraints to Compact Synchrotro , Relativistic Beaming and the Intrinsic Properties of Extra AJ , , (1996) 299 a Global 86 GHz VLBI Survey of Compact Radio Sources 105 , , (2006) 1872 , (2007) 1236 , (2008) 580 131 133 136 , (2005) 1163 , (2007) 232 , (1994) 51 ApJS , , , , VLBA Calibrator Survey-VCS1 129 Inhomogeneous Pileup Energy Distribution? Obtained from IDV and VLBI Observations AJ Survey: VCS2 AJ AJ I. Suitability Based on Observed Structure Precise geodesy with the Very Long Baseline Array at2 GHz and8 GHz Results for the First 102 Sources M. Grewing Size/Brightness Temperature Distribution 658 T. Savolainen, and J. A. Zensus Experiments. VI. Kinematics Analysis of a Complete Sample o for the Remaining 140 Sources Survey. II. The First Four Epochs 426 R. C. Vermeulen [4] Beasley, A. J., D. Gordon, A. B. Peck, L. Petrov, D. S. MacM [5] Fomalont, E. B., L. Petrov, D. S. MacMillan, D. Gordon, an [2] Henri, G. and L. Saugé [6] Petrov, L., Y. Y. Kovalev, E. Fomalont, and D. Gordon [3] Kellermann, K. I. [7] Petrov, L., Y. Y. Kovalev, E. B. Fomalont, and D. Gordon [8] Kovalev, Y. Y., L. Petrov, E. B. Fomalont, and D. Gordon [9] Petrov, L., Y. Y. Kovalev, E. B. Fomalont, and D. Gordon RadioAstron Space-VLBI AGN survey [10] Fey, A. L., A. W. Clegg, and E. B. Fomalont [11] Fey, A. L. and P. Charlot [13] Pushkarev, A. B. and Y. Y. Kovalev [12] Petrov, L., D. Gordon, J. Gipson, D. MacMillan, C. Ma, E. [15] Scott, W. K., and 19 colleagues [14] Lee, S.-S., A. P. Lobanov, T. P. Krichbaum, A. Witzel, A. [16] Horiuchi, S., and 11 colleagues [21] Lister, M. L., M. H. Cohen, D. C. Homan, M. Kadler, K. I. Ke [17] Dodson, R., and 23 colleagues [18] Lovell, J. E. J., and 10 colleagues [19] Readhead, A. C. S. [20] Cohen, M. H., M. L. Lister, D. C. Homan, M. Kadler, K. I. Ke