In astrophysics, the lower mass gap is a mass range between the maximum mass for a typical neutron star and the minimum mass for a typical black hole, often defined as roughly 2.5–5 solar masses (M☉).[1][2][3] A compact object in this mass range often cannot be confidently determined to be a neutron star or a black hole due to uncertainties in measurement[4] and in the maximum mass of a neutron star (the Tolman-Oppenheimer-Volkoff limit).[5]
This list considers a "lower mass gap object" to be any compact object whose estimated mass or mass range overlaps with the range of 2.5–5 M☉.
List
edit| Object | Mass (M☉) | Classification (if known) | References |
|---|---|---|---|
| PSR J1641+3627F | 1.4–3.7 | Neutron star | [6] |
| Primary object in GW190425 | 1.60−2.52 | [7] | |
| Primary object in V1408 Aquilae | 2.0–6.2 | Likely black hole | [8] |
| Secondary object in GW190917_114630 | 2.1+1.1 −0.4 |
[9] | |
| XMMU J013236.7+303228 | 2.2+0.8 −0.6 |
Neutron star | [10] |
| PSR J0952−0607 | 2.35±0.17 | Neutron star | [11] |
| Cygnus X-3 | 2.4+2.1 −1.1 |
Likely black hole | [12] |
| PSR J2017−1614 | 2.4±0.6 | Neutron star | [13] |
| PSR J1600−3053 | 2.5+0.9 −0.7 |
Neutron star | [14] |
| Secondary object in GW190814 | 2.59+0.08 −0.09 |
Likely black hole | [15] |
| GRO J0422+32 | 2.7+0.7 −0.5 |
Black hole | [16] |
| 4U 1543-475 | 2.7–7.5 | Likely black hole | [17] |
| Secondary object in GW200210 | 2.83+0.47 −0.42 |
[18] | |
| 2MASS J05215658+4359220 | 3.3+2.8 −0.7 |
Likely black hole | [19] |
| Primary object in Gaia DR3 3425577610762832384 | 3.6+0.8 −0.5 |
Likely black hole | [20] |
| Primary object in GW230529 | 3.66+0.82 −1.21 |
Likely black hole | [21] |
| GRO J1655−40 | 4.1−7.9 | Likely black hole | [22] |
| GW230529 remnant | 4.92+0.62 −0.63 |
[21] | |
| Secondary object in GW190924_021846 | 5.0+1.4 −1.9 |
[23] | |
| Primary object in GW200115_042309 | 5.7+1.8 −2.1 |
Black hole | [24] |
| Primary object in GW190426_152155 | 5.7+3.9 −2.3 |
[23] | |
| Secondary object in GW230627 | 5.79+0.95 −0.92 |
Black hole | [21] |
| Secondary object in GW191113 | 5.9+4.4 −1.3 |
Black hole | [18] |
| Secondary object in GW190725_174728 | 6.3+2.1 −2.5 |
Likely black hole | [9] |
| Secondary object in GW191129 | 6.7+1.5 −1.7 |
Black hole | [18] |
| Secondary object in GW231223_075055 | 6.80+2.00 −2.13 |
Black hole | [21] |
| Secondary object in GW231118_090602 | 7.29+2.13 −3.27 |
Black hole | [21] |
| Secondary object in GW231020 | 7.30+2.06 −2.85 |
Black hole | [21] |
| Secondary object in GW230729 | 7.62+2.12 −2.63 |
Black hole | [21] |
| Secondary object in GW190930_133541 | 7.8+1.7 −3.3 |
Black hole | [23] |
| Secondary object in GW200316 | 7.8+2.0 −2.9 |
Black hole | [18] |
See also
editReferences
edit- ↑ Yang, Y.; Gayathri, V.; Bartos, I.; Haiman, Z.; Safarzadeh, M.; Tagawa, H. (2020). "Black Hole Formation in the Lower Mass Gap through Mergers and Accretion in AGN Disks". The Astrophysical Journal Letters. 901 (2): L34. doi:10.3847/2041-8213/abb940.
- ↑ Gao, Shi-Jie; Li, Xiang-Dong (2023). "Can Cosmologically Coupled Mass Growth of Black Holes Solve the Mass Gap Problem?". The Astrophysical Journal. 956 (2): 128. doi:10.3847/1538-4357/ace890.
- ↑ Wang, Song; et al. (2024). "A potential mass-gap black hole in a wide binary with a circular orbit". Nature Astronomy. 8 (12): 1583–1591. arXiv:2409.06352. doi:10.1038/s41550-024-02359-9.
- ↑ Tsokaros, Antonios; Ruiz, Milton; Shapiro, Stuart L.; Sun, Lunan; Uryū, Kōji (2020). "Great Impostors: Extremely Compact, Merging Binary Neutron Stars in the Mass Gap Posing as Binary Black Holes". Physical Review Letters. 124 (7) 071101. arXiv:1911.06865. doi:10.1103/PhysRevLett.124.071101. PMID 32142310.
- ↑ Hebeler, K.; Lattimer, J. M.; Pethick, C. J.; Schwenk, A. (2013). "Equation of State and Neutron Star Properties Constrained by Nuclear Physics and Observation". The Astrophysical Journal. 773: 11. doi:10.1088/0004-637X/773/1/11.
- ↑ Cadelano, Mario; Chen, Jianxing; Pallanca, Cristina; Istrate, Alina G.; Ferraro, Francesco R.; Lanzoni, Barbara; Freire, Paulo C. C.; Salaris, Maurizio (2020). "PSR J1641+3627F: A Low-mass He White Dwarf Orbiting a Possible High-mass Neutron Star in the Globular Cluster M13". The Astrophysical Journal. 905: 63. doi:10.3847/1538-4357/abc345.
- ↑ Abbott, B. P.; et al. (2020). "GW190425: Observation of a Compact Binary Coalescence with Total Mass ∼ 3.4 M⊙". The Astrophysical Journal Letters. 892: L3. doi:10.3847/2041-8213/ab75f5.
- ↑ Gomez, Sebastian; Mason, Paul A.; Robinson, Edward L. (2015). "The Case for a Low Mass Black Hole in the Low Mass X-Ray Binary V1408 Aquilae (= 4U 1957+115)". The Astrophysical Journal. 809: 9. arXiv:1506.00181. doi:10.1088/0004-637X/809/1/9.
- 1 2 Abbott, R.; et al. (2024). "GWTC-2.1: Deep extended catalog of compact binary coalescences observed by LIGO and Virgo during the first half of the third observing run". Physical Review D. 109 (2) 022001. doi:10.1103/PhysRevD.109.022001.
- ↑ Bhalerao, Varun B.; Van Kerkwijk, Marten H.; Harrison, Fiona A. (2012). "Constraints on the Compact Object Mass in the Eclipsing High-Mass X-Ray Binary Xmmu J013236.7+303228 in M 33". The Astrophysical Journal. 757: 10. doi:10.1088/0004-637X/757/1/10.
- ↑ Romani, Roger W.; Kandel, D.; Filippenko, Alexei V.; Brink, Thomas G.; Zheng, Weikang (2022). "PSR J0952−0607: The Fastest and Heaviest Known Galactic Neutron Star". The Astrophysical Journal Letters. 934 (2): L17. doi:10.3847/2041-8213/ac8007.
- ↑ Zdziarski, Andrzej A.; Mikołajewska, Joanna; Belczyński, Krzysztof (2013). "Cyg X-3: A low-mass black hole or a neutron star". Monthly Notices of the Royal Astronomical Society: Letters. 429: L104–L108. doi:10.1093/mnrasl/sls035.
- ↑ Bobakov, A. V.; Kirichenko, A. Yu.; Zharikov, S. V.; Karpova, A. V.; Zyuzin, D. A.; Shibanov, Yu. A.; Mennickent, R. E.; Garcia-Álvarez, D. (2024). "Two black widow pulsars in the optical and X-rays". Astronomy & Astrophysics. 690: A173. doi:10.1051/0004-6361/202450205.
- ↑ Arzoumanian, Zaven; et al. (2018). "The NANOGrav 11-year Data Set: High-precision Timing of 45 Millisecond Pulsars". The Astrophysical Journal Supplement Series. 235 (2): 37. doi:10.3847/1538-4365/aab5b0.
- ↑ Abbott, R.; et al. (2020). "GW190814: Gravitational Waves from the Coalescence of a 23 Solar Mass Black Hole with a 2.6 Solar Mass Compact Object". The Astrophysical Journal Letters. 896 (2): L44. doi:10.3847/2041-8213/ab960f.
- ↑ Casares, J.; Muñoz-Darias, T.; Torres, M A P.; Mata Sánchez, D.; Britt, C. T.; Armas Padilla, M.; Álvarez-Hernández, A.; Cúneo, V. A.; González Hernández, J. I.; Jiménez-Ibarra, F.; Jonker, P. G.; Panizo-Espinar, G.; Sánchez-Sierras, J.; Yanes-Rizo, I. V. (2022). "A correlation between H α trough depth and inclination in quiescent X-ray transients: Evidence for a low-mass black hole in GRO J0422+32". Monthly Notices of the Royal Astronomical Society. 516 (2): 2023–2037. doi:10.1093/mnras/stac1881.
- ↑ Orosz, Jerome A.; Jain, Raj K.; Bailyn, Charles D.; McClintock, Jeffrey E.; Remillard, Ronald A. (1998). "Orbital Parameters for the Soft X-Ray Transient 4U 1543−47: Evidence for a Black Hole". The Astrophysical Journal. 499: 375–384. arXiv:astro-ph/9712018. doi:10.1086/305620.
- 1 2 3 4 Abbott, R.; et al. (2023). "GWTC-3: Compact Binary Coalescences Observed by LIGO and Virgo during the Second Part of the Third Observing Run". Physical Review X. 13 (4) 041039. doi:10.1103/PhysRevX.13.041039.
- ↑ Thompson, Todd A.; Kochanek, Christopher S.; Stanek, Krzysztof Z.; Badenes, Carles; Post, Richard S.; Jayasinghe, Tharindu; Latham, David W.; Bieryla, Allyson; Esquerdo, Gilbert A.; Berlind, Perry; Calkins, Michael L.; Tayar, Jamie; Lindegren, Lennart; Johnson, Jennifer A.; Holoien, Thomas W.-S.; Auchettl, Katie; Covey, Kevin (2019). "A noninteracting low-mass black hole–giant star binary system". Science. 366 (6465): 637–640. arXiv:1806.02751. doi:10.1126/science.aau4005. PMID 31672898.
- ↑ Wang, Song; et al. (2024). "A potential mass-gap black hole in a wide binary with a circular orbit". Nature Astronomy. 8 (12): 1583–1591. arXiv:2409.06352. doi:10.1038/s41550-024-02359-9.
- 1 2 3 4 5 6 7 The LIGO Scientific Collaboration; et al. (2025). "GWTC-4.0: Updating the Gravitational-Wave Transient Catalog with Observations from the First Part of the Fourth LIGO-Virgo-KAGRA Observing Run". arXiv:2508.18082.
{{cite journal}}: Cite journal requires|journal=(help) - ↑ Chaty, S.; Mirabel, I. F.; Goldoni, P.; Mereghetti, S.; Duc, P.- A.; Marti, J.; Mignani, R. P. (2002). "Near-infrared observations of Galactic black hole candidates". Monthly Notices of the Royal Astronomical Society. 331 (4): 1065–1071. doi:10.1046/j.1365-8711.2002.05267.x.
- 1 2 3 Abbott, R.; et al. (2021). "GWTC-2: Compact Binary Coalescences Observed by LIGO and Virgo during the First Half of the Third Observing Run". Physical Review X. 11 (2) 021053. doi:10.1103/PhysRevX.11.021053.
- ↑ Abbott, R.; et al. (2021). "Observation of Gravitational Waves from Two Neutron Star–Black Hole Coalescences". The Astrophysical Journal Letters. 915: L5. doi:10.3847/2041-8213/ac082e.