NuSTAR ToO targets approved within the NuSTAR, Chandra, XMM-Newton, Swift, NICER, and INTEGRAL General Observer programs

    NuSTAR Target of Opportunity (ToO) observations may be proposed for in the NuSTAR, Chandra, XMM-Newton, Neil Gehrels Swift Observatory, NICER mission, and INTEGRAL General Observer (GO) programs.

    Last update: 2023-10-31

      Proposal title and abstracts are available here, or click on the Proposal number in the table below. Note that NuSTAR ToO and DDT observations may be requested at any time through the ToO/DDT observation request form which provides a list of currently active unanticipated ToO/DDT targets.

      Proposals will be marked with an orange background when they are triggered and a green background when they are completed. Targets that have yet to be identified have blank J2000 coordinates.

NuSTAR GO ToO programs
ObsIDTarget Name
J2000 RA (deg)
J2000 Dec (deg)
Exposure (ks)
08166Feng80802636B3 2247+381342.524 38.410 2x40Triggered 2022-09-24
Coordinated with Swift & VERITAS
08233Daniel Lawther80802652Mrk 59033.63992-0.7667520+20+60+50Triggered 2023-09-25
Multi-cycle ToO program

Coordinated with XMM-Newton or NICER
09029Kaya Mori80960302-15Polar WD in high accretion 14 x 20Multi-cycle ToO program
09029Kaya Mori80960301VV Pup123.778337-19.05493520Triggered 2023-06-08
09047Mariko Kimura80902330SS Cyg325.6783343.58608100 + 30Coordinated with XRISM
09050Sam Krucker80910201The Sun 2 x 25
09085Sibasish Laha809026321ES 1927+654291.83120865.5651034 x 40Triggered 2023-05-22
Coordinated with NICER
09094Joseph Neilsen80902333Swift J1727.8-1613261.930583 -16.205322 5 x 20Triggered 2023-08-27
Coordinated with NICER
09108Reshmi Mukherjee80902634Candidate neutrino blazar 2 x 40
09109Dheeraj Pasham80902635Relativistic TDE 2x20 + 40Coordinated with NICER
09124Amruta Jaodand80902336Binary neutron star merger 100 + 2x75
09138Marina Orio80902337New Symbotic Nova 3 x 20
09180Megumi Shidatsu80901338Disk-wind black hole binary 50Coordinated with XRISM
09191Svetlana Jorstad80901639BL Lac330.68038042.277772 20Coordinated with Gehrels-Swift and IXPE
80901640Flaring blazar 2 20
09198Kirill Sokolovsky80901341New Nova 60Coordinated with XMM-Newton
09235Aarran Shaw80902342GX 339-4255.70579-48.789752 x 20Coordinated with JWST
80902343Black hole LMXB 2 x 20
09251Koji Mukai80901344T CrB239.8756725.9201740Coordinated with XRISM
09257Sean Pike80911301Unknown MAXI source 1 2 x 20
80912301Unknown MAXI source 2 2 x 20
80913301Unknown MAXI source 3 2 x 20
09271Jennifer Sokoloski80902345T CrB239.8756725.920172 x 20Coordinated with NICER
09274Oluwashina Adegoke80902346Black hole binary 3 x 25Coordinated with NICER
09276Javier Garcia80901347Black hole transient 30Coordinated with NICER
09289James Steiner80902348SwiftJ1727.8-1613261.930583-16.2053224 x 20Coordinated with NICER
Triggered 2023-10-16
Joint NuSTAR/Chandra GO ToO programs
23400247Neilsen80802303Black Hole Transient 4 x 25
23500541Chornock80802504SN2012ap75.057167-3.3475602 x 50Triggered 2022-12-28
24400072Mori80902301GC transient 2x20
24400242Neilsen80902302Black Hole transient 4x25
24500203Brethauer80902503SN2022xxf172.524751 9.2826042x50Triggered 2023-04-24
24500280Matthews80902404AT2022tsd50.045282 8.748878 2x25,2x40Triggered 2022-10-07
25400276Kosec81002301LMC/SMC ULX 3x20Cycle-25 begins 2024-01-01
25400338Neilsen81002302Black Hole Transient 4x25Cycle-25 begins 2024-01-01
25500335Margutti81002403FBOT 2x25 + 2x40Cycle-25 begins 2024-01-01
Joint NuSTAR/XMM-Newton GO ToO programs
086127Allesandro Papitto80601304Terzan 5267.02083-24.780060Triggered 2023-03-01
088008Norbert Schartel80701608RX J0128.1-184822.0280-18.80862550
Triggered 2022-11-29
Coordinated with SALT or HET
088008Norbert Schartel80701609AGN outburst 250
Coordinated with SALT or HET
088054Pierre-Olivier Petrucci80702310Swift J1727.8-1613261.930583 -16.20532210x20Triggered 2023-08-29
088218Nanda Rea80702311SGR J1935+2154293.732021.89672050+40+80Triggered 2022-10-17
088470Alessandro Papitto80701312SAX J1808.4-3658272.114750-36.978970120Triggered 2022-08-20
Coordinated with IXPE
090022Norbert Schartel80801601AGN Minimum 180Coordinated with HST
80801602AGN Minimum 280
090023Norbert Schartel80801603PG 0043+03911.4467924.17315660Coordinated with HST and HET/SALT
Triggered 2022-06-16
090067Adam Ingram80802309GRS 1915+105288.79812510.9457783x30Coordinated with IXPE
090245Missagh Mehdipour80801604AGN obscuration30Coordinated with HST
090251Daniel Stern80860601eROSITA-fader120
090284Javier Garcia80801305BH transient40
090332David Matthews80802406FBOT2x25+2x40
090357Sergio Campana80801507GW counterpart160Coordinated with HST and NRAO
80801508GW counterpart260
092118Raffaella Margutti80902505SN2023ixf210.91066754.3116752x50Triggered 2023-06-04
092270Elias Kammoun80902606SMSS J114447.77-430859.3176.199-43.149842x80Triggered 2023-06-15
092317Alessandro Papitto80901307Accreting ms pulsar 120Coordinated with IXPE
092331Missagh Mehdipour 80901608NGC 3516 166.69776372.5686960Coordinated with HST

Triggered 2023-04-23
092346Arianna Miraval Zanon80901309Transitional ms pulsar 60Coordinated with VLA
092410Erin Kara80902610Mrk 817219.0920085858.794276360Coordinated with HST

Triggered 2023_04-24
Joint NuSTAR/INTEGRAL GO ToO programs
1840002Thomas Siegert80701501NS merger100
1840005Zhaosheng Li80701302ms pulsar30Also coordinated with XMM-Newton, NICER, and HXMT
1840021Ingo Kreykenbohm80701303Accreting X-ray pulsar40
1940020Ingo Kreykenbohm80801301Transient accreting pulsar40
1940025Thomas Siegert80801502GW Neutron star merger100
2040002Thomas Siegert80901324NS merger100
2040026Maria Teresa Fiocchi80901325Ultracompact XRB in outburst25
Joint NuSTAR/Swift GO ToO programs
1821098Kirill Sokolovsky80801310New Nova40
1821161Maria-Carla Nicotra80801311FRB120
1821161Maria-Carla Nicotra80801312FRB220
1922051Liliana Rivera Sandoval80902423Fast-evolving luminous transient3x20Swift cycle-19 begins on 2023-04-01
Joint NuSTAR/NICER GO ToO programs
05099Federico Garcia80802320GX 339-4255.705754-48.789753x20Triggered 2022-08-30
06039Teruaki Enoto80902311Magnetar Outburst20+30+50Coordinated with DSN
06057Fiamma Capitanio809023124U 1630-47248.50671-47.393003x20 + 20Triggered 2023-03-07
Coordinated with IXPE
06057Fiamma Capitanio80902313SwiftJ1727.8-1613261.930583-16.2053224x20Triggered 2023-09-04
Coordinated with IXPE
06078Yuhan Yao80901615Tidal Disruption Event50
06113Adam Ingram80902316GRS 1915+105288.79816710.9458063x20 Coordinated with IXPE
06141Jingyi Wang80902317Transient BH Binary3x20
06143James Steiner80902318Cygnus X-1299.59033335.2016113x20 Coordinated with IXPE
Triggered 2023-04-07
06197Joseph Neilsen80901320GRS 1915+105288.79816710.94580625
06203Paul Draghis80901321SwiftJ1727.8-1613261.930583-16.20532230Triggered 2023-08-28
80901321BH transient #230
07041Alice Borghese81001304Magnetar outburst #1 20Cycle-6 begins on 2024-03-01
07041Alice Borghese81001304Magnetar outburst #2 20Cycle-6 begins on 2024-03-01
07082Teruaki Enoto81002306Magnetar outburst 20+30+50Cycle-6 begins on 2024-03-01
07126Gugleilmo Mastroserio81001307Black hole transient 50Cycle-6 begins on 2024-03-01
07141Muryel Guolo81001608New TDE 50Cycle-6 begins on 2024-03-01
07164Keigo Fukumura81002309MAXI J1810-222273.17-22.313x20Cycle-6 begins on 2024-03-01
07170Edward Nathan81001310GRS1915+105288.79816710.94580630Cycle-6 begins on 2024-03-01

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