NuSTAR SOC - ToO programs

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

NuSTAR Target of Opportunity (ToO) observations may be proposed for in the NuSTAR, Chandra, XMM-Newton, Neil Gehrels Swift Observatory, NICER, and IXPE General Observer (GO) programs.
A list of proposals selected for the joint NuSTAR/INTEGRAL General Observer (GO) program can be found here.
Last update: 2025-09-01
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
Proposal	PI	ObsID	Target Name	J2000 RA (deg)	J2000 Dec (deg)	Exposure (ks)	Comments
10216	Javier Garcia	81002343	4U 1630-472	248.506708	-47.3930	3x30 10x20 2x30 3x50	Coordinated with NICER Triggered 2025-04-07
10309	Oluwashina Adegoke	81002355	4U 1630-472	248.506708	-47.3930	3x25	Coordinated with NICER Triggered 2025-04-07
11016	Murray Brightman	81101525	TRANSIENT ULX	0	0	50	Coordinated with XMM-Newton
11046	Qi Feng	81102626	CANDIDATE NU BLAZAR	0	0	2x40	Coordinated with Swift & VERITAS
11086	Dheeraj Pasham	81102627	JETTED TDE	0	0	2x20 + 40	Coordinated with NICER
11118	Shifra Mandel	81102328	MAXI J1744-294	266.418542	-29.012944	2x20	Triggered 2025-06-15
11129	Dheeraj Pasham	81101629	ICECUBEGOLD	0	0	50
11131	Vittoria Gianolli	81101630	NGC4151	182.63575	39.40586	30	Coordinated with XMM-Newton and Swift
11133	Yuexin Zhang	81102331	GX 339m4	255.70579	-48.78975	3x20	Coordinated with NICER
11135	Jennifer Sokoloski	81102332	T CrB	239.87567	25.92017	2x20	Coordinated with NICER
11139	Ole Koenig	81101333	LMXB BH	0	0	100
11140	Marina Orio	81102334	NEW SYMBIOTIC NOVA	0	0	20+20	Coordinated with XMM-Newton
11149	Amruta Jaodand	81102735	X-BNS	0	0	100+75+75
11158	Mischa Breuhaus	81101636	KM3NET BLAZAR	0	0	35	Coordinated with XMM-Newton
11165	Yuexin Zhang	81102337	GRS 1915p105	288.79817	10.94581	2x20	Coordinated with NICER IXPE and VLA
11173	Dominic Walton	81102338	NGC5907 ULX1	228.99417	56.30278	2x100	Coordinated with XMM-Newton Triggered 2025-08-18
11181	Jon Miller	81101639	MARKARIAN 817	219.092	58.79428	100
11181	Jon Miller	81101640	PG 1211p143	183.57362	14.05367	80
11187	Alice Borghese	81102341	Magnetar outburst	0	0	30+60+80
11193	Xiurui Zhao	81102642	MRK 509	311.04063	-10.72353	20+20	Coordinated with Swift
11193	Xiurui Zhao	81102643	1H0419m577	66.503	-57.2005	40+20	Coordinated with Swift
11203	Kaya Mori	81101344	Long Period Radio Transient	0	0	80	Coordinated with XMM-Newton and Swift
11209	Alessio Marino	81101345	EP250623a	257.9974	-33.5482	50	Coordinated with NICER or EP-FXT Triggered 2025-06-26
11209	Alessio Marino	81101346	SAX J1808.4-3658	272.1148	-36.9790	50	Coordinated with NICER or EP-FXT Triggered 2025-08-08
11219	Federico Vincentelli	81160301	4U 1636-53	250.231250	-53.751390	20	Coordinated with NICER and VLT Triggered 2025-08-14
		81160302	GX 339-4	255.7058	-48.7897	3 x 20	Coordinated with NICER and VLT Triggered 2025-08-20
		81160303	LMXB 3	0	0	20	Coordinated with NICER and VLT
		81160304	LMXB 4	0	0	20	Coordinated with NICER and VLT
		81160305	LMXB 5	0	0	20	Coordinated with NICER and VLT
		81160306	LMXB 6	0	0	20	Coordinated with NICER and VLT
11258	Daniel Lawther	81101647	MRK590	33.63983	-0.76672	50	Coordinated with XMM-Newton Triggered 2025-07-29
11266	Lea Marcotulli	81101648	PKS 1725+123	262.0293	12.26096	180	Coordinated with XMM-Newton Triggered 2025-08-19
11282	Dheeraj Pasham	81102349	EP250702a	284.6897	-7.8748	2x20	Triggered 2025-07-03
11286	Mason Ng	81102350	HIGH B RPP	0	0	3x50
11287	Benjamin Coughenour	81101351	TRANSIENT BH XRB	0	0	50	Coordinated with NICER
11304	Christian Malacaria	81101352	New EP pulsar 1	0	0	50	Coordinated with NICER
11304	Christian Malacaria	81101353	New EP pulsar 2	0	0	50	Coordinated with NICER
11310	Edward Nathan	81101354	H1743m322	266.565	-32.23358	50	Coordinated with NICER
11310	Edward Nathan	81101355	A BRIGHT XRB	0	0	0	Coordinated with NICER

Joint NuSTAR/Chandra GO ToO programs
25400276	Kosec	81002301	LMC/SMC ULX			3x20
25400338	Neilsen	81002302	Black Hole Transient			4x25
25500335	Margutti	81002403	AT2024qfm	350.347753	11.942232	2x25 + 2x40	Triggered 2024-08-01
26400066	Peter Kosec	81102301	Magellanic Clouds ULX transient			3x20
26400115	Kaya Mori	81102302	MAXI J1744-294	266.424708	-29.009722	2x20	Triggered 2025-02-03
26400240	Joey Neilsen	81102303	4U 1630-472	248.506708	-47.3930	4x25	Triggered 2025-04-07
26500151	Raffaella Margutti	81102404	Interacting SN			2x50
27400158	Neilsen	81202301	Black Hole Transient			4x25	Cycle-27 begins 2026-01-01
27400226	Kosec	81202302	MLC/SMC ULX			3x20	Cycle-27 begins 2026-01-01
27500144	Margutti	81202403	InteractingSN			3x50	Cycle-27 begins 2026-01-01
27500150	Margutti	81202404	FBOT1			25,25,40,40	Cycle-27 begins 2026-01-01

Joint NuSTAR/XMM-Newton GO ToO programs
090022	Norbert Schartel	80801601	PG 1149-110	178.014789	-11.373359	80	Triggered 2024-12-09
090022	Norbert Schartel	80801602	RX J0134.7-0430	23.689583	-4.503597	80	Triggered 2024-12-05
090332	Rafaella Margutti	80802406	AT2024wpp	40.522853	-16.956397	2x25+2x40	Triggered 2024-11-14
094004	Norbert Schartel	81001611	RQ AGN outburst 1			50	Coordinated with SALT or HET
094004	Norbert Schartel	81001612	RQ AGN outburst 1			50	Coordinated with SALT or HET
094084	Rafaella Margutti	81002513	SNinteracting			2x50
094134	Erin Kara	81001614	Mrk 817	219.091958	58.794269	60	Coordinated with HST
094209	Michael Nowak	81001315	4U 1957+11	299.850042	11.708294	20
094218	Murray Brightman	81001516	NGC 4045 ULX	180.676208	1.96925	100	Coordinated with Swift monitoring Triggered 2024-12-19
094376	Samuel Barnier	81002317	GX 339-4			10x20	Triggered 2025-08-19
094484	Maxime Parra	81002318	BH LMXB outburst			10x20	Coordinated with Swift monitoring
096056	Raffaella Margutti	81102409	FBOT1			2x25, 2x40
096105	Arianna Miraval-Zanon	81101310	ms pulsar			60	Coordinated with NRAO/GBO
096132	Alessandro Papitto	81101311	SAX_J1808d4m3658	272.114750	-36.978970	110	Coordinated with IXPE Triggered 2025-08-09
096133	Sergio Campana	81101512	GW counterpart NS merger			60	Coordinated with HST and NRAO
096346	Nanda Rea	81102313	magnetar outburst			60, 100
096405	Eleonora Troja	81101514	GW afterglow			150

Joint NuSTAR/Swift GO ToO programs
1821098	Kirill Sokolovsky	80801310	New Nova			40
1821161	Maria-Carla Nicotra	80801311	FRB1			20
1821161	Maria-Carla Nicotra	80801312	FRB2			20
1922051	Liliana Rivera Sandoval	80902423	Fast-evolving luminous transient			3x20

Joint NuSTAR/NICER GO ToO programs
08005	Teruaki Enoto	81102315	MAGNETAR OUTBURST			20+30+50
08079	Joseph Neilsen	81101316	GRS 1915+105	288.798167	10.945806	25
08110	Alice Borghese	81101317	Magnetar outburst #1			20
08110	Alice Borghese	81101318	Magnetar outburst #2			20
08149	Paul Draghis	81101319	BH outburst #1			30
08149	Paul Draghis	81101320	BH outburst #2			30
08165	Riley Connors	81101321	Black Hole Binary			4x20
08172	Oluwashina Adegoke	81101322	Black Hole Binaries			6x20
08186	Edward Nathan	81101323	GRS 1915+105	288.798167	10.945806	30

Joint NuSTAR/IXPE GO ToO programs
02036	Svetlana Jorstad	81101605	LSP/ISP BLAZAR			20	Coordinated with Swift
02151	James Steiner	81102306	H1743-322	266.565	-32.23358	2x20	Coordinated with NICER
02156	Yash Bhargava	81102307	AQL X-1	287.81692	0.58497	2x20	Coordinated with NICER
02191	Maxime Parra	81101308	Wind Emitting BH-LMXB			20	Coordinated with NICER

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

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