DOI

https://doi.org/10.48717/dtmt-n962

Project

EW039

Title

EW039A

Abstract

We recently discovered a surprising excess of FIRST/VLASS detection fraction in extremely stable quasars (ESQs, i.e., type 1 quasars in SDSS Stripe 82 with extremely weak variability in ugriz over 10 years), compared with control sample with matched redshift, luminosity, SMBH mass and Eddington ratio. These radio ESQs could be a rare population with strong magnetic field (an essential ingredient for jet launching) above a critical value which stabilizes the magnetorotational instability in the inner accretion disk and simultaneously launches the jet. The discovery makes ESQs distinct targets of multi-band observations to tackle the long-standing mystery of jet launching in quasars, and probe the physical processes under potentially extreme condition. As the 4.4 sigma excess of radio detection of ESQs only occurs at intermediate radio loudness (R < 60), we ask for EVN+eMERLIN observations of 12 radio relatively bright ESQs to directly confirm the presence of compact radio core or jet in these ESQs. We will also testify whether ESQs could be young radio AGNs, i.e., whether the beyond critical magnetic field may preferentially exist during the early stage of intermittent jet evolution. The requested observation time is 20 hours total.