  Local low metallicity dwarf galaxies are relics of the early universe and
hold clues into the origins of supermassive black holes (SMBHs). In recent
work, coronal lines have been used to unveil a population of candidate
accreting black holes in dwarf galaxies with gas phase metallicities and
stellar masses well below the host galaxies of any previously known AGNs. Using
MUSE/VLT observations, we report the detection of [Fe X] $\lambda$6374 coronal
line emission and a broad H$\alpha$ line in the nucleus of SDSS
J094401.87$-$003832.1, a nearby ($z=0.0049$) metal poor dwarf galaxy almost 500
times less massive than the LMC. The [Fe X] $\lambda$6374 emission is compact
and centered on the brightest nuclear source, with a spatial extent of
$\approx$100 pc. The [Fe X] luminosity is $\approx 10^{37}$ erg s$^{-1}$,
within the range seen in previously identified AGNs in the dwarf galaxy
population. This line has never been observed in gas ionized by hot stars.
While it can be produced in supernova ejecta, the [Fe X] flux from SDSS
J094401.87$-$003832.1 has persisted over the ~19 year time period between the
SDSS and MUSE observations, ruling out supernovae as the origin for the
emission. The black hole mass measured from the broad H$\alpha$ FWHM and
luminosity is $\approx 3150$ M$_\odot$, in line with its stellar mass if virial
mass relations and black hole-galaxy scaling relations apply in this mass
regime. These observations, together with previously reported multi-wavelength
observations, can most plausibly be explained by the presence of an accreting
intermediate mass black hole in a primordial galaxy analog. However, we cannot
rule out the possibility that current stellar population models of metal poor
stars significantly under-predict the stellar ionizing photon flux, and that
metal poor stars can produce an extreme ionizing spectrum similar to that
produced by AGNs.
