Description:

The dynamic infrared sky is hitherto largely unexplored. The infrared is key to understand elusive stellar fates that are opaque (cf neutron star mergers), cold or dusty. I will present the SPitzer InfraRed Intensive Transients Survey (SPIRITS) −−− a systematic search of 194 nearby galaxies within 30 Mpc, on timescales ranging between a week to a year, to a depth of 20 mag with Spitzer's IRAC camera. SPIRITS has already uncovered over 131 explosive transients and over 2536 strong variables. Of these, 64 infrared transients are especially interesting as they have no optical counterparts whatsoever even with deep limits from Keck and HST. Interpretation of these new discoveries may include (i) deeply enshrouded supernovae, (ii) stellar mergers with dusty winds, (iii) 8--10 solar mass stars experiencing e-capture induced collapse in their cores, (iv) the birth of massive binaries that drive shocks in their molecular cloud, or (v) formation of stellar mass black holes. Motivated by the treasure trove of SPIRITS discoveries, we just commissioned Palomar Gattini-IR - a new 25 sq deg J-band camera to robotically chart the dynamic infrared sky.

Speaker: Mansi Kasliwal, Caltech

Host: Raffaella Margutti

Keywords: Physics, Astronomy, Astrophysics