  The highly-accurate optical reference frame GCRF (Gaia Celestial Reference
Frame) is expected to be available in several years. By the same time, a new
version of radio reference frame ICRF (International Celestial Reference Frame)
will be also published. The link of GCRF to ICRF will be defined by means of
computation of the orientation angles between the two frames using the common
extragalactic objects observed in both radio (VLBI) and optics (Gaia). Taking
into account the expected accuracy of ICRF and GCRF of the first tens
microarcseconds, the link between them should be defined at a microarcsecond
level, which requires using the most accurate algorithms and models. One of
such models is the Galactic aberration in proper motions, which is not included
in the data processing yet. In this paper its impact on the ICRF-Gaia link is
estimated. Preliminary results showed that this impact is at a level of about 1
microarcsecond.

Instrumentation and Methods for Astrophysics;Cosmology and Nongalactic Astrophysics