Systematic Assessment of Disk Truncation in the Black Hole X-Ray Binary Swift J1727.8–1613 Using NICER
König O, Steiner JF, Bollemeijer N, Connors RM, Dauser T, Dovčiak M, Fan N, García JA, Horn D, Ingram A, Lucchini M, Mastroserio G, Miller C, Nathan E, Nowak MA, Pottschmidt K, Remillard R, Song Y, Svoboda J, van der Klis M, Ubach S, Wilms J, Zhang Y (2026)
Publication Type: Journal article
Publication year: 2026
Journal
Book Volume: 1003
Article Number: 73
Journal Issue: 1
Abstract
The 2023/2024 NICER monitoring campaign of the 7 Crab bright black hole X-ray binary Swift J1727.8–1613 covered the outburst in almost all accretion states. High-quality data are available in the high-Eddington-fraction hard-intermediate state, the hard-to-soft transition, the soft state, and the poorly studied back transition to the dim hard state, making it an ideal dataset for comparing the accretion flow at vastly different accretion rates. We apply disk continuum fitting techniques to investigate the evolution of the inner-disk radius throughout the outburst. Taking a temperature-dependent color-correction factor into account, we see an evolution of the disk inner radius by a factor of a few comparing the hard states to the thermal/soft state. We tentatively detect an onset of disk truncation in the soft-to-hard transition, right after the source leaves the soft state. After accounting for model systematics, we find the disk to be more truncated in the high-luminosity bright hard state compared to the low-luminosity dim hard state.
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Involved external institutions
Academy of Sciences of the Czech Republic (ASCR) / Akademie věd České republiky (AVČR)
Czech Republic (CZ)
Stanford University
United States (USA) (US)
Smithsonian Institution
United States (USA) (US)
University of Amsterdam
Netherlands (NL)
Villanova University
United States (USA) (US)
National Aeronautics and Space Administration (NASA)
United States (USA) (US)
Newcastle University
United Kingdom (GB)
Scuola Superiore Studi Pavia IUSS
Italy (IT)
Washington University in St. Louis
United States (USA) (US)
Massachusetts Institute of Technology (MIT)
United States (USA) (US)
National Astronomical Observatories, Chinese Academy of Sciences / 中国科学院国家天文台 (NAOC)
China (CN)
Autonomous University of Barcelona (UAB) / Universitat Autònoma de Barcelona
Spain (ES)
Czech Republic (CZ)
Stanford University
United States (USA) (US)
Smithsonian Institution
United States (USA) (US)
University of Amsterdam
Netherlands (NL)
Villanova University
United States (USA) (US)
National Aeronautics and Space Administration (NASA)
United States (USA) (US)
Newcastle University
United Kingdom (GB)
Scuola Superiore Studi Pavia IUSS
Italy (IT)
Washington University in St. Louis
United States (USA) (US)
Massachusetts Institute of Technology (MIT)
United States (USA) (US)
National Astronomical Observatories, Chinese Academy of Sciences / 中国科学院国家天文台 (NAOC)
China (CN)
Autonomous University of Barcelona (UAB) / Universitat Autònoma de Barcelona
Spain (ES)
How to cite
APA:
König, O., Steiner, J.F., Bollemeijer, N., Connors, R.M., Dauser, T., Dovčiak, M.,... Zhang, Y. (2026). Systematic Assessment of Disk Truncation in the Black Hole X-Ray Binary Swift J1727.8–1613 Using NICER. Astrophysical Journal, 1003(1). https://doi.org/10.3847/1538-4357/ae60f5
MLA:
König, Ole, et al. "Systematic Assessment of Disk Truncation in the Black Hole X-Ray Binary Swift J1727.8–1613 Using NICER." Astrophysical Journal 1003.1 (2026).
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