| Title | The VLBA Imaging and Polarimetry Survey at 5 GHz |
| Authors | Helmboldt, J. F.; Taylor, G. B.; Tremblay, S.; Fassnacht, C. D.; Walker, R. C.; Myers, S. T.; Sjouwerman, L. O.; Pearson, T. J.; Readhead, A. C. S.; Weintraub, L.; Gehrels, N.; Romani, R. W.; Healey, S.; Michelson, P. F.; Blandford, R. D.; Cotter, G. |
| Bibcode | 2007ApJ...658..203H Search ADS ↗ |
| Abstract | We present the first results of the VLBA Imaging and Polarimetry Survey (VIPS), a 5 GHz VLBI survey of 1127 sources with flat radio spectra. Through automated data reduction and imaging routines, we have produced publicly available I, Q, and U images and have detected polarized flux density from 37% of the sources. We have also developed an algorithm to use each source's I image to automatically classify it as a pointlike source, a core jet, a compact symmetric object (CSO) candidate, or a complex source. Using data from the Sloan Digital Sky Survey (SDSS), we have found no significant trend between optical flux and 5 GHz flux density for any of the source categories. Using the velocity width of the Hβ emission line and the monochromatic luminosity at 5100 Å to estimate the central black hole mass, MBH, we have found a weak trend between MBH and 5 GHz luminosity density for objects with SDSS spectra. The mean ratio of the polarized to total 5 GHz flux density for VIPS sources with detected polarized flux density ranges from 1% to 20% with a median value of about 5%. We have also found significant evidence that the directions of the jets in core-jet systems tend to be perpendicular to the electric vector position angles (EVPAs). The data are consistent with a scenario in which ~24% of the polarized core jets have EVPAs that are antialigned with the directions of their jet components and that have a substantial amount of Faraday rotation. In addition to these initial results, plans for future follow-up observations are discussed. |
| Objects | 1119 Objects Search NED ↙ |
