Program: GN-2016B-Q-12

The intermediate Palomar Transient Factory (iPTF) has been systematically exploring the optical transient sky. We focus on short timescales to optimize the survey discovery rate of very young supernovae and rare ephemeral transients. Building on the PTF legacy, our iPTF software pipeline is geared towards automated alerts for follow-up within hours of discovery. Rapid response spectroscopy of iPTF transients unveils (i) progenitors of supernovae: shock cooling, companion, circumstellar material properties, (ii) origin of recently discovered but poorly understood new classes of transients, and (iii) rapid classification of candidate counterparts to gravitational wave triggers. These unique physical insights into the nature of the explosion cannot be gained from late-time observations. Here, we request a continuation of our ongoing iPTF-Gemini program for rapid spectroscopy in the final semester of iPTF operations. We request a total of 12 target-of-opportunity triggers on the Gemini-North and 3 on Gemini-South telescopes (16.25 hours). The rapid Gemini data will be complemented with panchromatic observations: radio with JVLA, Ultraviolet/X-ray with the Swift satellite and long-term optical/near-IR studies with Palomar and Keck.