L. Petrov
The catalogue of positions of optically bright extragalactic radio sources OBRS-2

  It is anticipated that future space-born missions, such as Gaia, will be
able to determine in optical domain positions of more than 100,000 bright 
quasars with sub-mas accuracies that are comparable to very long baseline 
interferometry (VLBI) accuracies. Comparisons of coordinate systems from 
space-born missions and from VLBI will be very important, first for 
investigation of possible systematic errors, second for investigation 
of possible shift between centroids of radio and optical
emissions in active galaxy nuclea. In order to make such a comparison more
robust, a program of densification of the grid of radio sources detectable
with both VLBI and Gaia was launched in 2006. In the second observing
campaign a set of 290 objects from the list of 398 compact extragalactic radio 
sources with declinations >-10 degr was observed with the VLBA+EVN in 
2010-2011 with the primary goal of producing their images with milliarcsecond 
resolution. These sources are brighter than 18 magnitude at V band. In this 
paper coordinates of observed sources have been derived with milliarcsecond 
accuracies from analysis of these VLBI observations following the method 
of absolute astrometry and their images were produced. The catalogue 
of positions of 295 target sources and estimates of their correlated flux
densities at 2.2 and 8.4 GHz is presented. The accuracies of source
coordinates are in a range of 2 to 200 mas, with the median 3.2 mas.