VLBI and optical astrometry of southern extragalactic radio sources and radio stars

Details VLBI and optical astrometry of southern extragalactic radio sources and radio stars VLBI and optical astrometry of southern extragalactic radio sources and radio stars

Jan 1990

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1990aj.....99..405w&link_type=abstract

Astronomical Journal (ISSN 0004-6256), vol. 99, Jan. 1990, p. 405-414. Research supported by CNRS.

Astronomy and Astrophysics

Astronomy

12

Astrometry, Extragalactic Radio Sources, Radio Stars, Southern Hemisphere, Very Long Base Interferometry, Active Galactic Nuclei, Astronomical Catalogs, Binary Stars, Quasars

Scientific paper

Mark III very long baseline interferometry (VLBI) has been used to determine the positions of ten compact extragalactic radio sources in the southern hemisphere. These positions are relative to the Jet Propulsion Laboratory VLBI celestial reference frame and are accurate at the 0.01 level, more than an order of magnitude improvement compared to their previous radio positions. First epoch VLBI positions have also been determined for two relatively weak radio stars in the southern hemisphere [the RS CVn close binaries HD 26337 (El Eri) and HD 77137 (TY Pyx)]. Optical positions relative to the Perth 70 Catalogue with rms uncertainties better than 0".2 have been found for the extragalactic sources by measurement of Schmidt plates. Optical positions with similar accuracy have been determined for the radio stars, and proper motions, with accuracy of ˜0".003/yr, have been found by measurement of Schmidt plates and reference to catalogs. Comparison of these optical and radio positions indicates that for the southern hemisphere area covered, there is no mean global bias larger than ˜0".05 between the VLBI radio reference frame and the "J2000.0 Perth 70 catalogue". In addition, there are no obvious regional effects larger than our optical measurement accuracy of ˜0".2. The VLBI positions of the ten extragalactic sources will help strengthen the southern extragalactic reference frame and the VLBI positions for the two optically bright radio stars will be useful for the link of the Hipparcos reference system to the extragalactic reference frame. We have determined the angular size of the radio-emitting region associated with HD 77137 to be ˜1 mas (milliarcsec), approximately the physical size of the binary system, or 7 times the radius of the individual stars. The corresponding brightness temperature is 3 × l09 K and is consistent with the gyrosynchrotron emission process.

Affiliated with

Also associated with

No associations

Rating

VLBI and optical astrometry of southern extragalactic radio sources and radio stars does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with VLBI and optical astrometry of southern extragalactic radio sources and radio stars, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and VLBI and optical astrometry of southern extragalactic radio sources and radio stars will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1560187