Time-Domain Spectroscopic Observatory

  • Posted on: 27 April 2018
  • By: jgrindlay

A study for a "Probe"-class NASA mission concept, the Time-domain Spectroscopic Observatory (TSO), is being developed for the upcoming Astro2020 Decadal Survey. TSO would be a ~1.5m optical-IR (0.4um - 5um) imaging and spectroscopic telescope, radiatively cooled (110K) and in Geosynch orbit over LSST. This 1.5-hour Session will present the TSO concept and stimulate discussion of how the highest priority LSST variables and transients can be studied with a synergistic space telescope devoted to rapid imaging and spectroscopy extending to the mid-IR. The rapid-slew (<5min) capability to targets over 80% (!) of the sky (>30o from Earth, Sun and Moon) and cold mirror enable imaging and spectroscopy sensitivities not possible from the ground: for 30, 3000 sec exposures, imaging reaches 10sigma significance magnitudes of AB = 22.3, 26 and spectroscopy with resolution R = 200 reaches AB = 18.4, 23 over the full 0.4 - 5um band. Key science objectives include high-z Gamma-Ray Bursts, which will measure massive star formation and the Epoch of Reionization over redshifts z > 8 - 12, and Reverberation Mapping of AGN using Hbeta emission line spectroscopy combined with LSST continuum flaring to measure SMBH masses out to z = 8. A few TSO slides are uploaded here to encourage you to come and learn more about this exciting opportunity to extend LSST Time Domain Astronomy with both spectroscopy and extension(s) into the mid-IR.  Please contribute your own ideas for what such a unique spectroscopy and IR capability could do for your LSST science!

PLEASE let me (Josh Grindlay, jgrindlay@cfa.harvard.edu) know if you would like to show a few slides and/or contribute to any of the 4 Discussion sections listed below. NOW is the time to push for near real-time spectroscopy for LSST; please let us know your science interests!

TSO Session Agenda:

9:00am Session Introduction: Zeljko Ivezic (U. Washington) & Josh Grindlay (Harvard)

9:10  Overview of TSO:  Josh Grindlay

9:30 Discussion and short presentations on TSO science for LSST. What should be added?

9:45 Discussion and short presentations on TSO instrumentation. Is the current focal plane design optimized for your Science goals?

10:00 Discussion and short presentations on prioritization of LSST alerts. GRB alerts will come from Swift (and more advanced future missions, e.g. 4piXIO?). How are the MOST urgent LSST transient alerts to be extracted from near-real time LSST data? 

10:15 Discussion of how to implement TSO Key Science with a GI program. Variability studies and particular classes of Transient searches can be proposed as GI programs. What others are "natural" for the joint LSST-TSO capabilities? What about coordinated X-ray (Athena, Lynx) or gamma-ray (Fermi or CTA) observations with TSO/LSST ?

10:30  Session close