Transient Astrophysics Observatory (TAO) (Formerly Known As ETA, ISS

Transient Astrophysics Observatory (TAO)

(formerly known as ETA, ISS-Lobster, Lobster)

Judy Racusin (NASA/GSFC) on behalf of the TAO team

PI: Jordan Camp (NASA/GSFC) TAO Mission

• ISS payload on the Express Logistics Carrier • ISS provides • “free” launch • “free” power • continuous uplink/downlink 80% of the time, with sufﬁcient data rates • Instruments • Gamma-ray Transient Monitor (GTM) • Wide-ﬁeld Imager (WFI) • Operations: • Sky survey/ToOs • Rapid autonomous repointing to new transients • 3 year mission (5 year goal) • launch in 2021 2 Gamma-ray Transient Monitor (GTM) • 2x Fermi-GBM built-to-print NaI detectors (scintillators + PMTs) • FoV ~2π • Energy range 10 keV - 1 MeV • Onboard triggering in 3 timescales and 3 energy ranges • Localization not possible, but higher probability towards zenith direction • Continuous data and triggered datasets (much like GBM)

3 Wide Field Imager (WFI)

• Multi-channel (lobster) optics with CCD focal plane (Angel 1979) • 45 cm focal length • FoV: 20° x 20° • Sensitivity: 10-10 erg cm-2 s-1 (20 s), 10-12 erg cm-2 s-1 (10 ks) • Energy Range: 0.3-5 keV • Centroid: ~1 arcmin

4 WFI Properties

5 TAO Science

• X-ray Counterparts to Gravitational Wave Sources

• Highest Sensitivity Survey of the Transient X-ray Sky

6 TAO Transient Response

WFI Candidate Pointing/ GTM sGRB autonomous - minutes X-ray Source Ground- Tiling Detection based variability Follow-up timescale, ﬂux upload in minutes no X-ray Candidate WFI GW Ground- Opt/NIR/ Follow-up Detection based Radio peaks on Follow-up Source days timescales of hours-days days color, variability timescale, ﬂux

WFI Candidate Ground- Pointing/ GTM sGRB X-ray Source Based Tiling Detection minutes Redshift & fading, ﬂux Follow-up prompt WFI WFI GRB Follow-up seconds Ground- Detection Candidate based NIR Source (in FoV) Follow-up hours prompt or afterglow 7 fading, ﬂux Astrophysical Context of Gravitational Wave Sources

• 3 ways to detect GW counterpart sources • GTM short GRB • X-ray transient in LIGO localization • X-ray transient in WFI • WFI will automatically Metzger & Berger (2012) start following up all GTM triggers • As soon as GW localization available (minutes), follow-up program will be uploaded

8 High-redshift GRBs

• TAO-ISS is more sensitive than Swift or Fermi-GBM to high-z GRBs due to soft X-ray bandpass of the WFI • Rapid GRB detection and dissemination to ground- based facilities for optical searches and redshifts

Simulations of GRB rate and detectability using instrinsic model from Lien et al. (2014) and preliminary WFI trigger algorithm

9 Other Transient Sources

• GRBs • Core Collapse SNe shock breakouts • Tidal Disruption Events • AGN/Blazar Monitoring • Stellar Super Flares • Novae • Thermonuclear Bursts • Soderberg Binaries et al. 2008 • Counterparts to FRBs? • Counterparts to neutrinos?

Burrows et al. 2011 10 TAO Source Rates (yr-1) Source Type WFI NS-NS GW counterparts 1-3 NS-BH GW counterparts 8-14 ccSN shock breakout 1 TDEs 24 (15 non-jetted, 9 jetted) 600 (weekly) AGN (monitored) 100 (daily) 300 (weekly) Blazars (monitored) 80 (daily) Stellar Super Flares 10-100 Novae 0.3 Thermonuclear Bursts 110 Long GRBs 80 High-z GRBs (z≥5) 2 Short GRBs 10

11 TAO-ISS Outlook

• Versatile rapid-response multi-wavelength observatory • Follow-on to the legacy of Swift • Optimized for gravitational wave follow-up • To be submitted to the NASA Astrophysics Mission of Opportunity (MoO) Explorer AO on Dec 15, 2016 for launch in 2021 • Transient Astrophysics Probe (TAP) also being submitted to Probe Concept Study (TAO+NIR telescope+sensitivity X-ray telescope)