Evidence from the Very Long Baseline Array that J1502SE/SW are Double
  Hotspots, not a Supermassive Binary Black Hole
  SDSS J150243.09+111557.3 is a merging system at z = 0.39 that hosts two
confirmed AGN, one unobscured and one dust-obscured, offset by several
kiloparsecs. Deane et al. recently reported evidence from the European VLBI
Network (EVN) that the dust-obscured AGN exhibits two flat-spectrum radio
sources, J1502SE/SW, offset by 26 mas (140 pc), with each source being
energized by its own supermassive black hole (BH). This intriguing
interpretation of a close binary BH was reached after ruling out a
double-hotspot scenario, wherein both hotspots are energized by a single,
central BH, a configuration occuring in the well-studied Compact Symmetric
Objects. When observed with sufficient sensitivity and resolution, an object
with double hotspots should have an edge-brightened structure. We report
evidence from the Very Long Baseline Array (VLBA) for just such a structure in
an image of the obscured AGN with higher sensitivity and resolution than the
EVN images. We thus conclude that a double-hotspot scenario should be
reconsidered as a viable interpretation for J1502SE/SW, and suggest further
VLBA tests of that scenario. A double-hotspot scenario could have broad
implications for feedback in obscured AGNs. We also report a VLBA detection of
high-brightness-temperature emssion from the unobscured AGN that is offset
several kiloparsecs from J1502SE/SW.
