White Paper Study for the Proposed Time-domain Spectroscopic Observatory

December 2018

This accelerator workshop will review and prepare a series of white paper studies of the optical-Infra Red (IR) space telescope and instrumentation we proposed as a "Probe-class" mission concept to NASA, to be evaluated in 2019-2020 by the 2020 Astronomy and Astrophysics Decadal Survey (Astro 2020) conducted by the National Academy of Sciences. Our Time-domain Spectroscopic Observatory (TSO) is a novel concept for a 1.5m aperture space telescope in Geosynch orbit over the Large Synoptic Survey Telescope (LSST), the highest ranked ground-based telescope project of the 2010 Astronomy and Astrophysics Decadal Survey. LSST will transform the field of Time-domain Astrophysics (TDA) with vast numbers of new variables and transients each night but will not include the broader band imaging and spectroscopy needed for their physical understanding. TSO will provide this with exquisite sensitivity, that could extend from the near-UV to mid-IR that is impossible to achieve from the ground, and with rapid-response access to >80% of the sky. In combination with wide-field X-ray telescopes in space detecting Gamma-Ray Bursts (GRBs), TSO spectra of GRB afterglows will enable, at long last, GRBs to map cosmic structure back to the epoch of creation of the very first stars as well as the physics, from spectroscopy, of the creation of the heavy-metals (e.g. gold) in neutron star mergers by prompt response to LIGO/VIRGO gravitational wave events. Other key science priorities, including measuring masses of supermassive black holes powering quasars back to redshifts z = 8, will be prioritized. This workshop and series of white papers are needed to focus the TSO science, instrumentation and mission design in order to convince Astro 2020 to recommend Probe-class missions be instituted by NASA, with TSO as a leading candidate.