Click on the images shown for the larger versions or, in some cases, links to the investigators' WWW page.
When you are using these images, please follow the ISAS data policy.
Also check out the "Pearson-Readhead survey from Space" VSOP program web page.
The X-ray Jet Source 0637-752
Early Chandra X-ray Observatory observations of PKS 0637-752 resulted
in the surprising detection of an X-ray jet in the object.
The image at left shows a VSOP observation of the inner jet region.
Click on the image to see the milli-arcsecond-scale VSOP image in
comparison with the arcsecond resolution Chandra (pixels) and
ATCA (lower contours) images.
This work is described in J. Lovell et al. Astrophysical Phenomena Revealed by Space VLBI, eds. H. Hirabayashi, P.G. Edwards and D.W. Murphy (ISAS) p. 215, which is available from here. Image courtesy:
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The superluminal quasar 3C345
The bright quasar 3C345 has been well-studied using the VLBI technique, with previous ground-based observations revealing that jet components travel in curved trajectories away from the core and at apparently superluminal speeds. Observations of this famous quasar at the highest 18cm and 6cm wavelength resolution provided by VSOP were one of the missions key science projects. 3C345 was observed eight times in the first three years of the mission, half the observations being at 18cm (1.6 GHz) and the other half at 6cm (5 GHz). An image of the core and inner jet region is shown in the figure at left. Clicking on the image leads to a comparison of an image made with only the ground radio telescopes (the VLBA, VLA, and Effelsberg), and an image made with the inclusion of the HALCA data, illustrating the gain in resolution achieved with the long baselines to the satellite. This work is described in J. Klare, J.A. Zensus, E.Ros and A.P. Lobanov (MPIfR), in Astrophysical Phenomena Revealed by Space VLBI, eds. H. Hirabayashi, P.G. Edwards and D.W. Murphy (ISAS) p. 21, which is available from here. Image courtesy:
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The bright quasar 1546+027
The relatively nearby (z=0.412) quasar 1546+027 was observed with HALCA and the Effelsberg, Noto, Torun and Hartebeesthoek ground radio telescopes at 5 GHz in August 2000. The source was selected as one of the brightest and most compact objects in the 5-GHz VLBA Prelaunch Survey (VLBApls). Its sub-milliarcsecond (sub-mas) scale radio structure is resolved with space VLBI. The image shows the prominent inner jet structure directed to the South. Radio flux density monitoring data taken over the last couple of years indicate that there was a dramatic outburst in 1996. If the jet component we see now separated by 0.8 mas from the core is associated with that outburst, the source could be a candidate for detecting superluminal motion with an apparent speed of about 3c. There is a misalignment of about 40 degrees between the inner and outer jets: the mas-scale, as well as the arcsecond-scale jet points to the South, while on 10 arcsecond scale a jet component is seen SE from the core. This work is described in L. Mosoni, S. Frey, Z. Paragi, I. Fejes (FÖMI SGO), P.G. Edwards (ISAS), E.B. Fomalont (NRAO), L.I. Gurvits (JIVE), W.K. Scott (U. Calgary), in Proceedings of the 6th European VLBI Network Symposium, eds. E. Ros , R.W. Porcas, A.P. Lobanov, and J.A. Zensus, (MPIfR, Bonn, Germany) p. 97. Image courtesy:
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Multi-epoch imaging of the quasar 1928+738
The relatively low-redshift quasar 1928+738 is located in a part of the sky that is always visible to HALCA, making the quasar well-suited to a detailed monitoring program of VSOP observations. Seven 5 GHz images are shown above, the first made in August 1997, the second in December 1997, and the last in September 2001. The horizontal spacing between images is proportional to the time between observations.
Image courtesy : D.W. Murphy, JPL
The extremely misaligned quasar 3C216
3C216 is a compact steep spectrum (CSS) source whose milliarcsecond (mas) scale jet is misaligned with respect to the more extended, arcsecond scale structure. The source was observed on 14 February 1999 at 5 GHz (6cm) with HALCA, the western part of the European VLBI Network and the US NRAO Green Bank 43m telescope. The image has been restored with a 0.5 mas circular beam. A comparison with the radio/optical arcsecond scale structure, the ground only image and more information can be found at the investigators' web pages Image courtesy:
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The gamma-ray source 1156+295
A 1.6 GHz image of the quasar 1156+295 was obtained from a 2.7 hour observation using the ten-element Very Long Baseline Array (VLBA) and HALCA on 4 June 1997. The quasar, at a distance of 6.3 billion light years, shows a compact bright `core' and an extended milli-arcsecond scale `jet' on one side of the core. The standard physical model for this structure is that the core contains a massive black hole and that symmetric relativistic jets, powered by accretion onto the black hole, are ejected from this core. In most cases only the jet moving towards us is seen due to substantial Doppler boosting (see Science 281, 1825 (1998)). |
The stationary component in 1548+056.
This 1.6 GHz VSOP image of the quasar 1548+056 (at a distance of 9.3 billion light years) was obtained using telescopes in Australia, Japan and China and HALCA on 20 August 1997. The brighter component is the core and fainter feature is a component in the jet. Comparison with ground-only VLBI images reveals the jet component has shown no discernible motion over the last twelve years. This may arise if the jet is ejected from the core at an appreciable angle to the line of sight, with the stationary component corresponding to a region where the jet bends towards our line of sight and the radiation is enhanced by Doppler boosting (see Science 281, 1825 (1998)). |
The ultra-luminous high-redshift quasar 0014+813.
0014+813 is one of the most luminous quasars known, lying at a distance of 13.6 billion light years. The 1.6 GHz image of 0014+813 shows a well-resolved core-jet structure. This observation was made with HALCA, six telescopes of the European VLBI Network and the NRAO Green Bank 43 m telescope (see Science 281, 1825 (1998)). |
The super-luminal quasar 0212+735.
A 5 GHz image of the quasar 0212+735 (about 12 billion light-years away) was obtained from a 14 hour observation on 6 September 1997 with HALCA and the VLBA. Components in the jet can be identified with components observed closer to the core in ground-only VLBI observations over the last 15 years. The extended feature on the left-hand side of the image was also evident 15 years ago but appears to have remained relatively stationary (see Science 281, 1825 (1998)). |
VSOP Space VLBI image of 3C 446 at
6 cm. The quasar 3C 446 was observed on 2 December 1997 with an array
consisting of HALCA, Ceduna (Australia), Mopra (Australia), Hartebeesthoek
(South Africa), Shanghai (China), and Usuda (Japan).
The (u,v)
coverage had projected baselines of nearly 500 million wavelengths,
giving resolution of about 0.25 mas in the East-West direction of the jet
in 3C 446.
At shorter wavelengths, the highly inverted core of 3C 446 is so dominant that it is difficult to see the inner part of the jet. However, this space VLBI observation at 6 cm reduces the strength of the core relative to the jet, enabling detection of the innermost jet component roughly 0.2 mas east of the core in this image. This image supplied courtesy of J.S. Ulvestad (NRAO-Socorro) |
PKS J2207-5346, a quasar at a redshift
of 1.2, was observed as part of the VSOP
AGN survey on 30 October 1997. HALCA and only two ground radio telescopes:
Hartebeesthoek and
Hobart,
were used in this observation, resulting in a sparse
(u,v)
coverage. However, a good signal-to-noise image was still possible
and, more importantly, the Earth-space baselines have allowed the core
to be resolved and its brightness temperature to be measured for the first
time.
Data reduction and imaging by Jim Lovell (ISAS) and Chris Flatters(NRAO). |
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VSOP Space VLBI image of 1413+135 at
6 cm. The radio source 1413+135 is remarkable for a number of reasons;
1) it is 18 times more variable at 3.6 cm (X band) wavelengths than at
13 cm (S band), 2) it is one of the few (5) sources where radio absorption
lines of (Carilli et al. 1992), CO, HCN and other molecules (Wiklind and
Combes 1994) have been detected in absorption, and 3) it appears to be
a young radio source.
The accompanying figures shows the HALCA plus VLBA image (top) of 1413+135 at C band. The image has approximately 3 times the resolution of the VLBA only image(bottom), as expected. Notice the components of the jet visible to the south west, which are not resolved in the VLBA only image. The synthesized beam for this image is 2.05 x 0.47 mas with position angle -26.31 degrees. The entire image above is smaller than a single pixel of the HST image. For more images and details see the web page: http://www.gb.nrao.edu/~glangsto/1413/. The people involved in this project are:
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Active galaxy PKS 1519-273. At
left, as seen with the ground-based VLBI network only (10 VLBA telescopes
plus phased VLA). At right, with the addition of data from the HALCA satellite.
This is the first VLBI image ever made using an orbiting radio-astronomy
satellite.
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