EVN Phase-Referenced Observations of 1308+328

Astrometric accuracy of phase-referenced observations with the VLBA and EVN

Astrometric accuracy of complex modern VLBI arrays cannot be calculated analytically. We study the astrometric accuracy of phasereferenced VLBI observations for the VLBA, EVN and global VLBI array by simulating VLBI data for targets at declinations −25◦, 0◦, 25◦, 50◦, 75◦ and 85◦. The systematic error components considered in this study are calibrator position, station coordinate, Earth orienta...

Phase-Referenced VLBA Observations of OH Masers at 4765 MHz

We report VLBA observations of maser emission from the rotationally excited Π1/2, J = 1/2 state of OH at 4765 MHz. We made phase-referenced observations of W3(OH) at both 4765 MHz and 1720 MHz and found emission in three fields within a ∼2000 AU diameter region and verified that in two of the three fields, 4765 MHz and 1720 MHz emission arise from the same position to within ∼4 mas (∼8 AU). We ...

EVN observations of candidate Compact Symmetric Objects

We present pc-scale images of ten Compact Symmetric Objects (CSO) candidates observed with the European VLBI network (EVN). Five radio sources have been observed at 1.6 GHz, and five more at 2.3/8.4 GHz, the latter subsample with the inclusion in the VLBI array of 3 antennae normally used for geodesy. These objects were selected from existing samples of GHz Peaked Spectrum (GPS) radio sources w...

0 EVN Observations of GRS 1915 +

EVN , MERLIN , and VLA Observations of NRAO 530

Abstract. We present images of NRAO530 observed with the EVN (VLBI) at 5 GHz, the MERLIN at 1 .6 and 5 GHz, and the VLA at 5 and 8 GHz showing the complex morphology on scales from pc to kpc. The VLBI image shows a core-jet structure indicating a somehow oscillation trajectory on a scale of 30 mas, north to the strongest compact component (core). A core-jet structure extended to several hundred...