Fundamental Reference AGN Monitoring Experiment (FRAMEx) I: Jumping Out
  of the Plane with the VLBA
  We present the first results from the Fundamental Reference AGN Monitoring
Experiment (FRAMEx), an observational campaign dedicated to understanding the
physical processes that affect the apparent positions and morphologies of AGNs.
In this work, we obtained simultaneous Swift X-ray Telescope (XRT) and Very
Long Baseline Array (VLBA) radio observations for a snapshot campaign of 25
local AGNs that form a volume-complete sample with hard X-ray (14-195 keV)
luminosities above $10^{42}$erg s$^{-1}$, out to a distance of 40 Mpc. Despite
achieving an observation depth of $\sim20$ $\mu$Jy, we find that 16 of 25 AGNs
in our sample are not detected with the VLBA on milli-arcsecond (sub-parsec)
scales, and the corresponding core radio luminosity upper limits are
systematically below predictions from the Fundamental Plane of black hole
activity. Using archival Jansky Very Large Array (VLA) radio measurements, our
sample jumps back onto the Fundamental Plane, suggesting that extended radio
emission is responsible for the apparent correlation between radio emission,
X-ray emission, and black hole mass. We suggest that this discrepancy is likely
due to extra-nuclear radio emission produced via interactions between the AGN
and host environment. We compare VLBA observations of AGNs to VLA observations
of nearby Galactic black holes (GBHs) and we find a mass-independent
correlation between radio and X-ray luminosities of black holes of
$L_\mathrm{6cm}$/$L_\mathrm{2-10 keV}$ $\sim$ 10$^{-6}$, in line with
predictions for coronal emission, but allowing for the possibility of truly
radio silent AGNs.
