NICER Science Team Investigations

Targets & Exposures by Working Group

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
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
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
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
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
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
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