DOI

https://doi.org/10.48717/ek43-jw86

Project

RY009

Title

1ES1927+654

Abstract

We propose Target of Opportunity (ToO) observation of an unusual changing-look AGN 1ES 1927+654 (z=0.017) with EVN C-band receiver. The source underwent a changing-look event during 2018 and was captured during a spectral transition from Seyfert Type 2 to Type 1-like features (appearance of broad Balmer lines). Considering its ’naked’ nucleus, the changing look cannot be explained by the dramatic changing of the view angle, which alternatively indicates a new accretion episode in the central engine. The source has recently exhibited dramatic changes in the optical and X-ray light curves and spectra. Our previous VLBI observation revealed an outflowing jet structure, especially from the last year, the source starts to show a long-expected radio flux density increasing that is likely associated with the changing-look events. To fully understand the relationship between the multi-waveband appearance of the source, new sensitive VLBI observations are needed as soon as possible not to miss this unique opportunity to study the newly born outflow in this particularly interesting source. Before proposing monitoring observations in the regular semesters, we need one more VLBI observation to confirm the rising (or already declining) of the radio light curve.