Program: GN-2016A-LP-2

The intermediate Palomar Transient Factory (iPTF) is 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 new iPTF software pipeline is geared towards automated alerts for follow-up within hours of discovery. Rapid response spectroscopy of iPTF transients will unveil (i) progenitors of supernovae: shock cooling, companion, circumstellar material properties, (ii) origin of recently discovered but poorly understood new classes of gap transients, and (iii) redshifts of relativistic afterglows discovered in seventy square degree searches or even independent of a high energy trigger. These unique physical insights into the nature of the explosion cannot be gained from late-time observations. Here, we request a dedicated iPTF-Gemini program for rapid spectroscopy. We request a total of one hundred target-of-opportunity triggers on the Gemini-South and Gemini-North telescopes over the remaining two years of iPTF (108.3 hours). The rapid Gemini data will be complemented with panchromatic observations: radio with JVLA and CARMA, UV/X-ray with the Swift satellite and long-term optical/near-IR studies with Palomar/Magellan/Keck.