NuSTAR Target of Opportunity (ToO) or Directors Discretionary Time (DDT) observation request
NuSTAR ToO and DDT observation requests will in general not be considered for events or sources that could have been predicted and proposed for in General Observer (GO) programs. This restriction is being adopted as a result of guidance from NASA's 2019 Senior Review.
In particular, requests for observations of the following types of sources and events require special justification describing why the requested observation type could not have been proposed as a GO target:
Known or candidate black hole systems
Known or candidate pulsar or magnetar systems
Candidate counterparts of gravitational wave or astrophysical neutrino detections
Nova or Supernova events
Luminosity variations from known or candidate AGN (including blazars and Tidal Disruption Events)
Observations of the Sun or other Solar system objects
Observations of events with specific time constraints
Observations coordinated with other observatories that could have been proposed for to joint GO programs
As a specific example, binary systems where periastron intervals are known can be proposed to the GO program, with observations triggered from monitoring of activity by other observatories. Observations that are simultaneous with ground or space based activities can also be proposed to the GO program, even if the exact dates for the coordinated observations are not known at the time of the proposal.
40 ks coordinated with NICER for NuSTAR GO cycle-9 proposal 9029
PI Mori
PKS 1217+02
2 x 40 ks for NuSTAR cycle-10 proposal 10112
PI Feng, Filbert
MAXI J1744-294
4 x 20 ks for NuSTAR GO cycle-10 proposal 10090 and joint NuSTAR / Chandra cycle-26 proposal 26400115 coordinated with XMM and XRISM
PI Mori
AT2024kmq
2x20 + 40 ks coordinated with NICER for joint NICER / NuSTAR proposal 10182
PI Pasham
PKS 0446+11
2 x 40 ks for the NuSTAR GO cycle-9 proposal 9108 coordinated with Swift and VERITAS
PI Mukherjee
Last updated: 2025-02-23 1600 UTC
Please review the NuSTAR schedules for details of upcoming observations and the table of approved ToO programs from the NuSTAR GO program and joint GO programs with Chandra, XMM-Newton, INTEGRAL, NICER, IXPE, and the Neil Gehrels Swift Observatory.