Millimeter Transient Point Sources in the SPTpol 100 Square Degree
  Survey
  The millimeter transient sky is largely unexplored, with measurements limited
to follow-up of objects detected at other wavelengths. High-angular-resolution
telescopes designed for measurement of the cosmic microwave background offer
the possibility to discover new, unknown transient sources in this band,
particularly the afterglows of unobserved gamma-ray bursts. Here we use the
10-meter millimeter-wave South Pole Telescope, designed for the primary purpose
of observing the cosmic microwave background at arcminute and larger angular
scales, to conduct a search for such objects. During the 2012-2013 season, the
telescope was used to continuously observe a 100 square degree patch of sky
centered at RA 23h30m and declination -55 degrees using the
polarization-sensitive SPTpol camera in two bands centered at 95 and 150 GHz.
These 6000 hours of observations provided continuous monitoring for day- to
month-scale millimeter-wave transient sources at the 10 mJy level. One
candidate object was observed with properties broadly consistent with a
gamma-ray burst afterglow, but at a statistical significance too low (p=0.01)
to confirm detection.
