Understanding the Nature of an Unusual Post-Starburst Quasar with
  Exceptionally Strong Ne V Emission
  We present a $z = 0.94$ quasar, SDSS J004846.45-004611.9, discovered in the
SDSS-III BOSS survey. A visual analysis of this spectrum reveals highly
broadened and blueshifted narrow emission lines, in particular
[Ne~V]$\lambda3426$ and [O~III]$\lambda5007$, with outflow velocities of 4000
km s$^{-1}$, along with unusually large [Ne V]$\lambda3426$/[Ne
III]$\lambda3869$ ratios. The gas shows higher ionization at higher outflow
velocities, indicating a connection between the powerful outflow and the
unusual strength of the high ionization lines. The SED and the $i - \text{W3}$
color of the source reveal that it is likely a "core" Extremely Red Quasar
(core ERQ); a candidate population of young AGN that are violently "blowing
out" gas and dust from their centers. The dominance of host galaxy light in its
spectrum and its fortuitous position in the SDSS S82 region allows us to
measure its star formation history and investigate for variability for the
first time in an ERQ. Our analysis indicates that SDSS J004846.45-004611.9
underwent a short-lived starburst phase 400 Myr ago and was subsequently
quenched, possibly indicating a time-lag between star formation quenching and
the onset of AGN activity. We also find that the strong extinction can be
uniquely attributed to the AGN and does not persist in the host galaxy,
contradicting a scenario where the source has recently transitioned from being
a dusty sub-mm galaxy. In our relatively shallow photometric data, the source
does not appear to be variable at $0.24-2.4~\mu$m in the restframe, most likely
due to the dominant contribution of host galaxy starlight at these wavelengths.
