VLBA & HALCA Images of Quasar 1156+295

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About this Image

The quasar B2 1156+295 as seen using the HALCA satellite in conjunction with the VLBA. The left-hand panel is an image of the quasar made at 1665 MHz with the VLBA. The right-hand panel is the same image as on the left, except that interferometer baselines between the VLBA antennas and the HALCA spacecraft have been included; these longer baselines provide the higher angular resolution apparent here. This right-hand image shows the quasar's core, bottom right, and a stream of radio emission emmitted by a jet of subatomic particles emerging from the core toward the top left. The observations were conducted on June 5, 1997, approximately four months after the launch of the HALCA satellite. This is the second image ever made using a space-based radio telescope, and the first to show appreciable structure. Astronomers and computer scientists used a special-purpose computer to digitally combine the signals from the satellite and the ground telescopes to make them all work together as a single, giant radio telescope. This dedicated machine, the VLBA Correlator, built as part of the VLBA instrument, was modified over the previous four years to allow it to incorporate data from the satellite.

Investigator(s):  Jim Ulvestad, Jonathan Romney

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Technical Data

    Telescope VLBA 
    Date of Observation 1997-06-05 
    Type of Observation Continuum Observations 
    Center of Image RA: 11:59:31.83, Dec: 29:14:43.80  
    Field of View 0.0002 x 0.0002 degrees  
    Technical Caption HALCA, launched on Feb. 11 1997 by Japan\'s Institute of Space and Astronautical Science (ISAS), is the first satellite designed for radio astronomy imaging. It is part of an international collaboration led by ISAS and backed by NRAO; Japan\'s National Astronomical Observatory; NASA\'s Jet Propulsion Laboratory (JPL); the Canadian Space Agency; the Australia Telescope National Facility; the European VLBI Network and the Joint Institute for Very Long Baseline Interferometry in Europe. The first observations with HALCA were conducted on May 22 1997, of the distant active galaxy PKS 1519-273. The second observation took place on June 5th 1997, when HALCA observed the quasar 1156+295.  

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