Space-VLBI observations of M87 with RadioAstron

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Darrell Parsons
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1 Space-VLBI observations of M87 with RadioAstron Tuomas Savolainen Aalto University Metsähovi Radio Observatory, Finland Max-Planck-Institut für Radioastronomie, Germany and The RadioAstron Nearby AGN Key Science Program team

2 RadioAstron Nearby AGN KSP team T. Savolainen (PI; Aalto University) G.Giovannini, M.Giroletti, M.Orienti (INAF Bologna) Y.Y.Kovalev, K.V.Sokolovsky, P.Voitsik (ASC-Lebedev) G.Bruni, T.Krichbaum, A.Lobanov, J.A.Zensus (MPIfR) C.Reynolds, S. Tingay (Curtin Uni.) K.Hada, H.Nagai, M. Honma (NAOJ) J.Hodgson, M.Kino, S.S.Lee, B.W.Sohn (KASI) J. Anderson (GFZ Potsdam) D. Meier (JPL) P. Edwards (CSIRO)

RadioAstron Space-VLBI Project Kardashev+ 2013 10-m orbiting antenna (Space Radio Telescope; SRT) launched in 2011 Together with ground radio telescopes forms an ultra-high resolution interferometer

3 RadioAstron Space-VLBI Project Kardashev m orbiting antenna (Space Radio Telescope; SRT) launched in 2011 Together with ground radio telescopes forms an ultra-high resolution interferometer Highly elliptical orbit: perigee ~ km, apogee ~ km. 10x max baseline length of VSOP. Receivers onboard: 0.33, 1.6, 5 and GHz Max. angular resolution: 7 µas Project led by the Astro Space Center of Lebedev Physical Institute, Russia

collimation zone. 5 GHz VSOP 0.83 x 0.68 mas M87 (D=16 Mpc) 1 mas = 0.08pc = 140R S (M BH = 6 10 9 M Sol ) Walker et al.

4 RadioAstron Nearby AGN Key Science Program Near-perigee RadioAstron imaging observations of nearby radio galaxies. Target sources are at distances of 4-75 Mpc aiming at high spatial resolution (down to a few R S ) for studying the jet acceleration and collimation zone. 5 GHz VSOP 0.83 x 0.68 mas M87 (D=16 Mpc) 1 mas = 0.08pc = 140R S (M BH = M Sol ) Walker et al VLBA 43 GHz Horiuchi et al. (2006) Cen A (D=3.8 Mpc) 1 mas = pc = 3100 R S (M BH = M Sol ) (Nagai et al. 2014) 3C84 (D=75 Mpc) 1 mas = 0.34 pc = 4500R S (M BH = M Sol )

5 M87 RadioAstron observations 5/22 GHz in Feb ground telescopes divided in two arrays EVN+VLBA+LBA+KVN+Gb+Kl RadioAstron K-band Feb GHz in Jun ground telescopes in a single array EVN+VLBA+LBA+Ar+Kl RadioAstron L-band June 2014 Data correlated with modified DiFX correlator in Bonn (Bruni et al. 2015).

6 Space fringes detected Baseline-based fringe detections (PIMA) SNR > 5.7 Global fringe fitting using multiple baseline combinations and fully calibrated ground array data + source model yielded further detections up to 5 D earth at L-band.

7 M87 at 18cm 26 ground radio telescopes Natural weighting Beam: 3.3x4.5 mas 900 mas 10 4 R s

8 VLA 2cm Biretta et al. (1995) Helical filaments in arcsec and milliarcsec scales

9 M87 at 18cm including RadioAstron Natural weighting Beam: 2.3x3.4 mas 10 4 R s

10 M87 at 18cm outer mas Asada et al. (2014)

11 (Super)uniform weighting Beam: 0.86x1.56 mas M87 at 18cm inner 100 mas 10 3 R s

(2016) 10 3 R s Edge-brightened core structure visible at both 1.

12 (Super)uniform weighting Beam: 0.9x0.9 mas Jun 2014 M87 at 18cm core region 86 GHz VLBA+GBT Feb 2014 Hada et al. (2016) 10 3 R s Edge-brightened core structure visible at both 1.6 GHz RadioAstron and 86 GHz VLBA+GBT images Counter-jet visible Kink at 2-3 mas from the core at 1.6 GHz? 43 GHz VLBA Jan 2013 Walker et al.

M87 at 18cm core region (Super)uniform weighting Beam: 0.9x0.9 mas Jun 2014 1.6 GHz VSOP Dodson et al.

13 M87 at 18cm core region (Super)uniform weighting Beam: 0.9x0.9 mas Jun GHz VSOP Dodson et al. (2006) 10 3 R s VSOP (Dodson et al. 2006): haze around the core in the 18cm RadioAstron: low-intensity emission around the conical core sheath? Width ~ 5mas ~ 700 R S

3C84 RA observations in Sep 13 22 GHz image Core 1 mas 0.35 pc Hot spot Mach disk / reverse shock? Beam: 0.15x0.075 mas Longest baseline with fringes (7.6ED) corresponds to 27µas resolution, i.e., ~120 R s.

14 3C84 RA observations in Sep GHz image Core 1 mas 0.35 pc Hot spot Mach disk / reverse shock? Beam: 0.15x0.075 mas Longest baseline with fringes (7.6ED) corresponds to 27µas resolution, i.e., ~120 R s. Clearly edge-brightened jet: Hollow jet? Velocity structure? Counter-jet visible Hot spot inside the moving feature C3 the structure resembles that commonly seen in simulations of a working surface between jet and ambient medium, as already suggested by Nagai et al. (2014).

15 3C84 RA observations in Sep GHz image 0.3 mas 0.1 pc Core resolved in direction transverse to the jet Edge-brightened emission upstream of the core Very wide opening angle at first (>100 deg), then rapid collimation to an almost cylindrical jet Beam: 0.075x0.075mas Giovannini et al. in prep. Savolainen et al. in prep.

16 3C84 Jet collimation profile at 22 GHz Giovannini et al. in prep. z r 5.9 M 87 profile, z r 1.7 (Asada & Nakamura 2012) Very shallow collimation profile beyond 400R s : z r 5.9. Differs from M87. Jet is wide: ~600 R s peak-to-peak at 400R s from the 22 GHz core 22GHz core size ~50μas ~210R s ; quasi-simultaneous GMVA observations give a similar core size at 86 GHz The visible counter-jet limits the possible core-shift Edge-brightened part of the jet is launched from the disk? Viewing angle of 18 deg assumed (Tavecchio & Ghisellini 2014)

17 Summary Nearby radio galaxies 3C84, M87 and Cen A were observed with the RadioAstron at 1.6, 5 and 22GHz. Fringes on space baselines have been detected so far for M87 (up to 5 ED baseline lengths) and 3C84 (up to 7.7 ED). Key results: 1.6 GHz image of M87 shows a lot of internal structure, including helical filaments in mas-scale scale jet The core of M87 has similar structure in 1.6 GHz space-vlbi image and in 86 GHz VLBA+GBT image There is low-intensity emission around the core at 1.6 GHz sheath / disk wind? 22 GHz image of 3C84 shows a very different jet collimation profile compared to M87: wide initial opening angle together with rapid collimation to almost cylindrical jet 3C84 seems to have large initial jet width is the edge-brightened part of the jet launched from the disk?

Space-VLBI with RadioAstron pushing the limit of angular resolution in the radio band

Space-VLBI with RadioAstron pushing the limit of angular resolution in the radio band Gabriele Bruni Max Planck Institute for Radioastronomy S AGN 11, Trieste 23-26/09/2014 Very Long Baseline Interferometry