Discovery of SN 2009nz Associated with GRB 091127
  We report SMARTS, Gemini and Swift-UVOT observations of the optical transient
(OT) associated with gamma-ray burst (GRB) 091127, at redshift 0.49, taken
between 0.9 hr and 102 days following the Swift trigger. In our early-time
observations, the OT fades in a manner consistent with previously observed GRB
afterglows. However, after 9 days post-burst, the OT is observed to brighten
for a period of ~2 weeks, after which the source resumes fading. A comparison
of this late-time "bump" to SN 1998bw (the broad-lined Type Ic supernova
associated with GRB 980425), and several other GRB supernovae (SNe), indicates
that the most straightforward explanation is that GRB 091127 was accompanied by
a contemporaneous SN (SN 2009nz) that peaked at a magnitude of M_V=-19.0+/-0.2.
SN 2009nz is globally similar to other GRB supernovae, but evolves slightly
faster than SN 1998bw and reaches a slightly dimmer peak magnitude. We also
analyze the early-time UV-optical-IR spectral energy distribution of the
afterglow of GRB 091127 and find that there is little to no reddening in the
host galaxy along the line-of-slight to this burst.
