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: 2021-07-16

      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)
06238Vestergaard80602604Mrk 59033.63992-0.7667550+40+30Joint with 3x25 ks XMM-Newton and 3x10 ks Swift observations
Multi-cycle program
07027Krucker80710201 to 209The Sun119.8876 20.5287 25Coordinated with STIX on 2021-07-20
07027Krucker80711201The Sun 25Coordinated with STIX
07037Brightman80701507NGC 4045 ULX180.67651.96903100Coordinated with XMM-Newton
07052Ballhausen80701320EXO 2030+375308.06364337.63745650Triggered 2021-08-23
07055Jiang80701321Black hole transient 30
07070Doroshenko80702322IXPE Transient X-Ray pulsar 10, 20, 30, 40, 50Coordinated with IXPE
07072Doroshenko80702323GK Persei52.843.904283 x 30
07106Margutti80702508SNINTERACTING 2 x 50Coordinated with XMM-Newton
07112Yao80701509TDE 1 40
07112Yao80701510TDE 2 40
07113Neilsen80702324V4641 Sgr274.8401428 -25.4071803 5 x 20Coordinated with NICER (5x10 ks)
Triggered 2021-10-14
07114Li80701325LAT-undetected Nova 60
07119Borghese807013261E 161348-5055244.40096-51.0401775Coordinated with XMM-Newton
07128Xu80701327Black hole Hard State 60
07137Ballhausen80701328Cep X4324.8778756.98622100Trigger on one of three possible targets
07137Ballhausen80701329MXB 0656-072104.57204-7.20978
07137Ballhausen80701330Low luminosity CRSF source
07164Krauss80701610ICECUBE1 40
07164Krauss80701611ICECUBE2 40
07167Tsuruta80701331SAX J1808.4-3658272.11475-36.9789750
07179Krumpe80701612AGN flux drop1 100
07179Krumpe80701613AGN flux drop2 100
07221Somalwar80702614ZTF TDE AGN 3 x 20Coordinated with Swift
07259Mehdipour80701615MRK 509311.04067-10.7234450Trigger on one of six possible targets
Coordinated with XMM-Newton
07259Mehdipour80701616MRK 841226.0048710.43789
07259Mehdipour80701617NGC 3783174.75733-37.73867
07259Mehdipour80701618NGC 4593189.91454-5.34419
07259Mehdipour80701619NGC 7469345.815298.87369
07259Mehdipour80701620NGC 98538.65738-8.78761
07266Coughenour80701332MAXI J1803-298270.76162-29.8304650Triggered 2021-05-12
07277Yao80702511FBOT 30 + 50
07286Feng80701621Candidate Neutrino blazar 40
07302Jaodand80702333Transitional ms pulsar 3 x 30Coordinated with NICER
Joint NuSTAR/Chandra GO ToO programs
21400516K Mori80602301Galactic Center transienttbdtbd2x20
22400400K Mori80702304Galactic Center VFXTtbdtbd2x20
22400529M Bachetti80701305M82 X-2148.96266769.67930380
22500172P Scholz80701506FRB 20200120E149.485068.818027Triggered 2020-12-02
Coordinated with Effelsberg 100m
22500192D Matthews80701407AT2020xnd
(Fast Blue Optical Transient)
335.008458-2.84036112x25, 2x40Triggered 2020-10-26
23400247Neilsen80802303Black Hole Transient 4 x 25Chandra cycle-23 begins on 2022-01-01
23500541Chornock80802504Intereacting SN 2 x 50Chandra cycle-23 begins on 2022-01-01
Joint NuSTAR/XMM-Newton GO ToO programs
078214Felix Fuerst80201011BH ToO 40Coordinated with 10 x 2 ks Swift observations. Program extended into cycle-17
078430Nanda Rea80202013XTE J1810-197272.46 -19.731 20+30+40+80Observations to be obtained over ~3 months. Triggered 2018-12-20
082145Alessandro Papitto80401306ms pulsar 60
082359Nanda Rea80402308Swift J1818.0-1607274.5009167 -16.1311944 20,30,40,80Triggered 2020-03-20
084079Fiona Harrison80501303BH hard state 40
084080Norbert Schartel80502606NGC 156665.00167-54.937805650Triggered 2019-05-30
084080Norbert Schartel80502607IRAS 23226-3843351.350833-38.44694450Triggered 2019-10-16
084355Raffaella Margutti80502405Fast blue optical transient 2x25 + 2x40
084377Norbert Schartel80501606AGN minimum 80
084434Jelle Kaastra80502609NGC 3227155.877519.86502x25Triggered 2019-11-11
084469Jian Li80501608muon track neutrino 40
084526Luigi Piro80501609GW event 150
084545James Court80502310GRO J1744-28266.137875-28.74083380
086127Allesandro Papitto80601304transitional ms pulsar60
086276Hannah Earnshaw8061305NGC 925 ULX-336.86458333.570278100Triggered 2020-08-11
086342Raffaella Margutti80602406SN2019yvr191.28389-0.459092x50Triggered 2020-06-18
086403Jennifer Sokoloski80602307T CrB239.87566725.92016750Triggered 2020-08-27
086460Nanda Rea80602315PSR J1846-0258281.60391667-2.9750277823,30,40,80Triggered 2020-08-02
088008Norbert Schartel80701608AGN outburst2x50
Coordinated with SALT or HET
088054Pierre-Olivier Petrucci80702310BH LMXB10x20
088218Nanda Rea80702311Magnetar outburst
088470Alessandro Papitto80701312accreting ms pulsar120
Coordinated with IXPE
Joint NuSTAR/INTEGRAL GO ToO programs
1740029Riccardo La Placa80601314Millisecond X-ray pulsar30Also coordinated with XMM-Newton
1740033Julia Alfonso-Garzon80501302H 1145-619177.000083-62.206916725Also coordinated with Swift
1840002Thomas Siegert80701501NS merger100
1840005Zhaosheng Li80701302Accreting ms pulsar30
Also coordinated with XMM-Newton, NICER, and HXMT
1840021Ingo Kreykenbohm80701303Accreting X-ray pulsar40
1940020Ingo Kreykenbohm80801301Transient accreting pulsar40Cycle-19 begins on 2022-01-01
1940025Thomas Siegert80801502GW Neutron star merger100Cycle-19 begins on 2022-01-01
Joint NuSTAR/Swift GO ToO programs
1619112Luigi Piro80601509FRB20112477.0125 26.060620Fast Radio burst
1619112Luigi Piro80601510Fast Radio burst 2tbd tbd 20
1619139Liliana Sandoval80602511Fast-Evolving Luminous Transienttbd tbd 3x20
Joint NuSTAR/NICER GO ToO programs
04060Teruaki Enoto 80702313Swift J1555.2-5402 238.78608-54.0614220+30+50Triggered 2021-06-07
04099Fiamma Capitanio80702314Transient black hole XRB 2x30 + 20
04118Jingyi Wang80702315Unknown BHB 3x20
04152Navin Sridhar80702316GX 339-4 255.70575-48.789783x20Triggered 2021-10-06
04155Riley Conners807023174U 1543-475 236.784486-47.6695234x20Triggered 2021-06-12
04163Jeroen Homan807023184U 1820-30 275.91904-30.3612783x20Triggered 2021-06-12
04181Gugleilmo Mastroserio80701319BH transient30

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