Landing page for project RS003

We discovered transient radio emission in a unique "changing-look" AGN with repetitive outbursts, characterized by multiple synchrotron self-absorbed spectral components, likely originating from discrete jet ejections. At mas scales, we detected a marginally resolved structure with the EVN at 5GHz. By comparing with the VLBA observations at 1.6, 5 and 8 GHz, there is a positional offset of the emission peak by ~1.7 mas, the nature of which remains unclear. The recent VLA observations reveal a rising radio spectrum towards 25 GHz, providing a critical opportunity to study the properties of jet ejections at its earliest evolution phase. We hereby request timely EVN observation at C-band, with the immediate aim to confirm the resolved structure of radio emission at mas scale, and uncover the origin of positional offsets between EVN and VLBA. The new observation will enable to verify the novel scenario of fast jet ejections associated with the "changing-look" phenomenon, and constrain the superluminal motion velocity of jet or its upper limit, providing a new benchmark for future monitoring of the jet evolution.

This data is part of the archive of VLBI data maintained by JIVE on behalf of the EVN, a network of radio telescopes located primarily in Europe and Asia, with additional antennas in South Africa. The EVN archive itself has the DOI https://doi.org/10.17616/R3Z197