NICER Science Team Investigations

Targets & Exposures by Working Group

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By agreement with NASA's Astrophysics Explorers Program, the NICER project is required to fulfill certain science objectives during its 18-month baseline mission, July 2017-January 2019. In pursuit of these objectives, the NICER Science Team is conducting investigations with specific astrophysical targets. As part of a legacy-science effort, some of these investigations will continue into the "bridge" mission phase, January-September 2019, concurrent with Cycle 1 of NICER's Guest Observer program.

Tabulated here — and organized by the Team's topical Working Groups (WGs) — are the NICER Science Team's targets and observation plans in support of its science investigations, including planned and accumulated exposure times "to date" (i.e., as of the end of September 2018). Targets with measurement objectives spanning multiple WGs may appear in more than one table.

Please note: The content of these tables is subject to change. The most recent edit was made on October 8, 2018.

Lightcurve Modeling Working Group (Chair: S. Bogdanov)

One of NICER's primary goals is to obtain tight constraints on the long sought-after neutron star mass-radius relation. Sophisticated modeling of the rotation-induced modulation of thermal X-ray emission from millisecond pulsars, including relativistic and atmospheric effects, offers a particularly promising approach for inferring neutron star radii. Determining these radii will constrain the equation of state of neutron-star matter, thereby providing information about the properties of cold matter at supra-nuclear densities. The table below lists the targets that NICER is observing for this purpose.

Target Name	Contact	Exposure (ksec)		Monitoring?	Legacy?	Purpose
		Plan	To date (approx)
PSR J0030+0451	S. Bogdanov	1,600	1,225	—	Y	Radius, mass constraints from energy-dependent lightcurve modeling
PSR J0437-4715	S. Bogdanov	1,000	900	—	Y	Same
PSR J0740+6220	Z. Arzoumanian	1,600	75	—	Y	Same
PSR J1231-1411	P. Ray	1,600	825	—	Y	Same
PSR J2124-3358	S. Bogdanov	1,600	480	—	Y	Same
PSR J1614-2230	M. Wolff	500	400	—	Y	Radius lower limit from lightcurve modeling

High-Precision Timing (Chair: A. Lommen)

NICER enables high-precision timing of millisecond pulsars without the time- dependent pulse delays and broadening — due to dispersion and scattering by the interstellar medium — that plague timing at radio wavelengths. Three targets make up this investigation.

Target Name	Contact	Exposure (ksec)		Monitoring?	Legacy?	Purpose
		Plan	To date (approx)
PSR J0218+4232	A. Lommen	1,000	910	10-15 ks/week	Y	Long-term rotational stability, radio giant pulse correlation
PSR B1821-24	A. Lommen	1,000	495	Same	Y	Same
PSR B1937+21	A. Lommen	1,500	875	Same	Y	Same

Bursts & Accretion Physics (co-Chairs: D. Chakrabarty & F. Ozel)

Type I X-ray bursts, together with their more-energetic (but much rarer) intermediate-duration and "superburst" counterparts, deliver unique diagnostic information about neutron stars. NICER seeks to:

• reveal neutron star spins by detecting burst oscillations,
• probe the character and composition of thermonuclear fuels, accretion flows, and the star's crustal layers through measurement of burst durations, fluences, and recurrence times, and
• constrain the radii of the neutron stars in accreting systems through burst spectroscopy, including searches for absorption edges and other spectral features in regular and super-expansion (should any occur during the mission) bursts.

Spectroscopy of disk "reflection" and quasi-periodic oscillations (QPOs) probe the inner edge of the accretion disk, providing an independent handle on neutron star properties.

These objectives are being pursued with the following targets.

Target Name	Contact	Exposure (ksec)		Monitoring?	Legacy?	Purpose
		Plan	To date (approx)
4U 1636-536	P. Bult	450	195	Various states	Y	Photospheric radius expansion, superburst, edges, burst oscillations
4U 1820-30	T. Strohmayer	450	100	Various states	Y	Same
4U 1608-522	T. Guver	300	100	—	—	Same
Aquila X-1	P. Bult	300	57	In outburst	—	Same
4U 1722-30	T. Strohmayer	50	29	—	—	Same
4U 1702-429	J. Chenevez	150	16	—	—	Burst oscillations
4U 1728-34	D. Chakrabarty	300	110	—	—	Burst spectroscopy
Rapid Burster	D. Altamirano	10	12	—	—	Burst analysis, pulsation search
Serpens X-1	R. Ludlam	30	70	—	—	Disk reflection
4U 1735-44	R. Ludlam	20	25	—	—	Disk reflection
GX 9+9	R. Ludlam	10	8	—	—	Disk reflection
4U 1543-624	R. Ludlam	ToO	90	In outburst	—	Spectral evolution
4U 0614+091	P. Bult	40	415	—	—	QPOs
GS 1826-24	T. Strohmayer	50	78	—	—	QPOs, burst oscillations
4U 1705-44	T. Strohmayer	50	7	—	—	Burst oscillation search
4U 1323-62	J. Homan	50	125	—	—	QPO, burst oscillation search
GX 340+0	J. Homan	50	41	—	—	Winds, Z-tracks, QPOs
GX 13+1	J. Homan	50	14	—	—	Same
Scorpius X-1	P. Bult	50	5	—	—	Same
Cygnus X-2	D. Chakrabarty	40	250	—	—	Oscillation, pulse search
Swift J0243.6+6124	C. Wilson-Hodge	ToO	283	In outburst	—	Period, pulse-profile, and spectral evolution
2S 1417-624	M. Wolff	ToO	91	In outburst	—	Same

Magnetars & Magnetospheres (Chair: T. Enoto)

NICER is a powerful tool for studying surface and magnetospheric radiation from a variety of neutron star classes, such as magnetars, highly magnetized radio pulsars, isolated thermally emitting objects, and rotation-powered pulsars. Investigations include long-term timing of faint magnetars and high-field pulsars (to measure spin-down and detect glitches), spectral diagnostics of absorption features in surface radiation, and phase-resolved spectroscopy of all varieties that exhibit pulsations, correlated with radio and gamma-ray properties.

The following targets enable these investigations.

Target Name	Contact	Exposure (ksec)		Monitoring?	Legacy?	Purpose
		Plan	To date (approx)
PSR J0537-6910	Z. Arzoumanian	200	312	2-3 ks/week	Y	Glitch monitoring
PSR B0833-45	N. Lewandowska	200	177	2-3 ks/week	Y	Same
CXO J164710.2-455216	V. Kaspi	300	67	30 ks bi-monthly	—	Spin-down measurement
SGR 0501+4516	T. Enoto	90	121	5 ks/month	—	Same
1E 1048.1-5937	T. Guver	60	35	—	—	Phase-resolved spectroscopy
1E 2259+586	T. Guver	25	24	—	—	Same
PSR B0656+14	A. Harding	100	198	—	—	Same
PSR B0633+17	W. Ho	50	146	—	—	Same
PSR B1509-58	K. Wood	20	8	—	—	Same
PSR B1055-52	K. Wood	50	66	—	—	Same
RX J1605.3+3249	C. Malacaria	150	165	—	—	Absorption features, pulsation search
1E 1207.4-5209	W. Ho	100	109	30 ks bi-monthly	—	Absorption features, glitch monitoring
PSR J2252-37	T. Enoto	50	62	—	—	Pulsation search
PSR J1813-1749	W. Ho	50	0	—	—	Same
PSR J1622-4950	W. Majid	20	15	—	—	Pulsation search, radio correlation
PSR J1119-6127	W. Majid	90	100	—	—	Same
PSR B0531+21	T. Enoto	100	120	—	—	Giant radio pulse correlation
PSR J0726-2612	T. Enoto	50	60	—	—	Absorption features
RX J0720.4-3125	W. Ho	100	110	—	—	Same
PSR J1740+1000	Z. Arzoumanian	40	25	—	—	Same
PSR J0205+6449	W. Ho	60	160	5 ks/month	—	Long-term spin ephemeris
PSR J1412+7922	S. Bogdanov	120	310	10 ks/month	Y	Same
PSR J1849-0001	W. Ho	60	62	5 ks/month	Y	Same
PSR J1819-1458	W. Ho	60	12	5 ks/month	—	Same
PSR J1838-0655	A. Harding	60	40	5 ks/month	—	Same
PSR J1846-0258	A. Harding	60	10	5 ks/month	—	Same
PSR J2022+3842	Z. Arzoumanian	120	116	10 ks/month	Y	Same
PSR J2229+6114	W. Ho	120	290	10 ks/month	Y	Same
PSR B1757-24	W. Ho	50	45	—	—	Surface emission
RX J1308.8+2127	W. Ho	60	120	—	—	Same
PSR B0943+10	W. Ho	50	80	—	—	Radio correlation
PSR B0540-59	N. Lewandowska	50	51	—	—	Optical correlation
4U 0142+61	M. Nynka	ToO	90	In outburst	—	Glitch recovery

Pulsation Searches (Chair: P. Ray)

Periodic and quasi-periodic fluctuations in X-ray emissions arise from stellar spins and orbital motion, revealing one of the most fundamental properties of neutron stars of all types. Periodicity searches are planned for the targets tabulated below.

Target Name	Contact	Exposure (ksec)		Monitoring?	Legacy?	Purpose (pulsation candidate type)
		Plan	To date (approx)
PSR J0614-3329	S. Ransom	100	120	—	—	MSP
PSR J0636+5129	P. Ray	100	167	—	—	MSP
PSR J0751+1807	P. Ray	100	290	—	—	MSP
PSR J1012+5307	J. Deneva	80	176	—	—	MSP
PSR J1552+5437	S. Guillot	50	75	—	—	MSP
PSR J1744-1134	S. Guillot	50	58	—	—	MSP
PSR J2241-5236	M. Kerr	100	65	—	—	MSP
PSR B1957+20	Z. Arzoumanian	50	130	—	—	MSP
PSR J1723-2837	S. Bogdanov	60	0	—	—	MSP
2FGL J0846.0+2820	S. Bogdanov	50	164	—	—	MSP
3FGL J0212.1+5320	S. Bogdanov	50	211	—	—	MSP
1RXS J044048.0+292440	S. Bogdanov	50	4	—	—	Transitional MSP
2XMM J104608.7-5943	S. Bogdanov	100	99	—	—	Transitional MSP
1RXS J154439.4-112820	S. Bogdanov	60	231	—	—	Transitional MSP
MAXI J0911-655	P. Bult	25	40	—	—	AMXP
MAXI J1621-501	P. Bult	ToO	30	—	—	AMXP
IGR J17062-6143	T. Strohmayer	10	60	—	—	AMXP
Cen X-4	D. Chakrabarty	50	104	—	—	LMXB persistent
GX 349+2	D. Chakrabarty	20	43	—	—	LMXB persistent
SAX J1748.9-2021	D. Chakrabarty	30	9	—	—	LMXB persistent
M15	T. Strohmayer	60	32	—	—	LMXB persistent
Omega Centauri	S. Guillot	250	58	—	—	LMXB persistent
HESS J1713-381	S. Guillot	200	52	—	—	Young pulsar
PSR J1833-1034	M. Wolff	100	0	—	—	Young pulsar
AX J184440-030501	A. Harding	30	0	—	—	Young pulsar
3XMM J201744.7+365045	A. Harding	30	45	—	—	Young pulsar
DA 495	A. Harding	30	90	—	—	Young pulsar
PSR B1259-63	K. Wood	30	14	—	—	Main sequence binary
LSI +61 303	M. Kerr	50	95	—	—	Main sequence binary
LS 5039	T. Enoto	90	0	—	—	Main sequence binary
1C 10 ULX	D. Pasham	50	0	—	—	ULX
Holmberg II X-1 ULX	T. Strohmayer	80	120	—	—	ULX
Holmberg IX X-1 ULX	S. Guillot	20	37	—	—	ULX
M51 ULX-8	S. Guillot	50	59	—	—	ULX
M82 X-1	D. Pasham	100	126	—	—	ULX
M83 ULX	S. Guillot	50	88	—	—	ULX
NGC 1313 ULX	T. Strohmayer	80	7	—	—	ULX
NGC 300 ULX1	P. Ray	10	138	—	—	ULX
NGC 5907 ULX	S. Guillot	50	49	—	—	ULX
NGC 7793 P13 ULX	S. Guillot	15	15	—	—	ULX

Observatory Science (Chair: R. Remillard)

NICER's utility as a general-purpose X-ray observatory are demonstrated by applying its unique capabilities to a broad class of targets and investigations beyond neutron stars, as shown below.

Target Name	Contact	Exposure (ksec)		Monitoring?	Legacy?	Purpose
		Plan	To date (approx)
MAXI J1535-571	P. Uttley	—	355	2-3 ks/week	—	Spectral-timing, reflection, long-term accretion evolution study
MAXI J1820+070	E. Kara	—	414	2-3 ks/week	—	Spectral-timing, reflection study
GX 339-4	J. Steiner	90	73	—	—	Same
Cygnus X-1	R. Remillard	60	142	—	—	Same
GRS 1915+105	J. Steiner	75	183	—	—	Same
Swift J1658.2+4242	D. Altamirano	—	67	—	—	Same
MAXI J1727-203	D. Altamirano	—	113	—	—	Same
LMC X-3	J. Steiner	60	65	—	—	Same
GX 349+2	D. Altamirano	—	61	—	—	Same
Gamma Cas	K. Hamaguchi	40	101	—	—	Origin of X-ray emission
GT Mus	K. Hamaguchi	—	8	—	—	Stellar flare
UX Ari	S. Drake	—	6	—	—	Same
HR 1099	S. Drake	—	120	—	—	Same
Proxima Centauri	T. Enoto	80	100	2-3 ks/week	—	Optical/X-ray correlation, long-term monitoring
Eta Car	M. Corcoran	52	65	2-3 ks/week	—	Colliding winds
WR 140	M. Corcoran	104	111	2-3 ks/week	—	Same
HD 93129a	M. Corcoran	—	35	2-3 ks/week	—	Same
LM Vel	M. Corcoran	100	—	—	—	Wind accretion
Cygnus X-3	M. Corcoran	—	144	—	—	Quenched/hypersoft state flares, spectra
MCG-6-30-15	J. Miller	45	120	—	—	Warm absorber
3C 120	E. Kara	50	150	—	—	Disk-jet connection
NGC 4051	J. Steiner	100	150	10 ks/month	—	Variability, soft excess
NGC 4388	J. Miller	45	109	30 days	—	Same
1H 0707-495	E. Kara	100	79	30 days	—	Same
RX J0019.8+2156	R. Remillard	20	71	—	—	Origin of X-ray emission
GW170817	R. Remillard	12	26	—	—	Same
Holmberg II X-1	T. Strohmayer	80	125	—	—	QPO search
NCG 1313 X-1	T. Strohmayer	80	7	—	—	Same
M82 X-1	D. Pasham	100	127	—	—	Same
NGC 5408 X-1	D. Pasham	100	38	—	—	Same
Holmberg IX X-1	J. Steiner	20	37	—	—	Oxygen lines
2XMM J034615.6+681112	J. Steiner	20	42	—	—	Same
2XMM J034555.6+680455	J. Steiner	20	39	—	—	Same
2XMM J132938.6+582506	J. Steiner	30	61	—	—	Same
V407 Vul	T. Strohmayer	40	57	—	—	Long-term orbital period evolution
HM CnC	T. Strohmayer	40	41	—	—	Same
ASASSN-18el	E. Kara	—	173	—	—	Origin of X-ray emission
AT2018cow	D. Pasham	—	46	—	—	Same
ASASSN-18pg	J. Miller	—	10	—	—	Candidate TDE
A1750	E. Bulbul	100	84	—	—	WHIM search

Last Updated: October 8, 2018