Program: GN-2012B-Q-127

Title:Testing the standard cosmology with Very Long Baseline Interferometry (VLBI)
PI:Oleg Titov
Co-I(s): Dick Hunstead, Helen Johnston, Dave Jauncey, Laura Stanford, Tapio Pursimo

Abstract

About 1200 radio quasars are observed regularly by the International VLBI Service, IVS, to define and maintain the International Celestial Reference Frame, ICRF. We have presented evidence for large scale proper motions. While the dipole effect is consistent with theoretical prediction, the quadrupole effect, at a level in excess of 10 muas/year, presents a serious challenge to the standard cosmologies. However, our estimates of the spherical harmonics may be influenced by the paucity of IVS quasars with known redshifts. We would like to continue ongoing program on spectroscopy of optically bright (m<21) radio strong radio sources to improve the statistics. We ask for observing time on the Gemini North telescope with GMOS-N to measure radio quasar redshifts. These quasars have unique optical identifications based on precise radio-optical position coincidence.

Publications using this program's data