Program: GN-2012A-Q-9

We propose to make late-time observations of gamma-ray burst (GRB) counterparts, complementary to our companion "Rapid ToO" program. High priority science goals for these "Standard ToO" observations include: (a) Afterglow and host galaxy characterization and redshift measurements for the short-duration class of GRBs, which are thought most likely to be compact binary mergers, but whose nature remains poorly understood due to their rarity and the faintness of their afterglows, (b) Late-time observations to help confirm and characterise high-redshift GRB candidates, which, led by our Gemini observations, are providing a unique new window on z>6 star formation and the reionization of the Universe, (c) Afterglow monitoring for "jet break" burst-collimation measurements, to constrain the total energy output for the highest energy bursts, (d) monitoring of low-redshift (z<~0.5) GRBs to search for photometric or spectroscopic evidence of (or place limits on) emission from accompanying supernovae, (e) Studies of serendipitous new GRB-like transients whose nature requires further observations to elucidate. We emphasise that our long-running Gemini campaign, which has allowed us to respond flexibly to rare GRB events, has been very successful and has contributed an essential legacy for Swift: late-time observations have been a key component of this.