ItemArticle

Spectrotemporal Evolution in XTE J1701-462 during Its 2022 Outburst as Revealed by NICER

Title
Spectrotemporal Evolution in XTE J1701-462 during Its 2022 Outburst as Revealed by NICER
Creator
Thomas, Neal Titus; Jirawala, Khushi; Gudennavar, S.B.; Bubbly, S.G.
Description
We present a comprehensive spectrotemporal study of the 2022 outburst of the transient neutron star low-mass X-ray binary (NS-LMXBs) XTE J1701?462 using 57 NICER observational epochs (E1?E57). The 0.8?10 keV lightcurve exhibits a FRED-like profile with multiple rebrightenings and intensity dips, indicating a nonmonotonic evolution of the accretion flow. Broadband spectral modeling with an absorbed Comptonized disk-blackbody model reveals a coherent evolution of spectral parameters consistent with changes in the disk?corona geometry driven by a varying mass accretion rate. The ??Fbol diagram shows distinct clustering, enabling the identification of six accretion states: LHS-1, IMS-1, HSS, IMS-2, LHS-2, and QS. These states trace the expected cycle of disk truncation, inward propagation, and recession, with notable deviations such as sustained coronal heating in IMS-1 and the HSS, likely caused by changes in coronal geometry or the limited bandpass of NICER. State-resolved hardnessintensity diagrams reveal that XTE J1701?462 exhibits a hybrid phenomenology: island and banana branches characteristic of atoll-state early in the outburst, followed by well-defined horizontal and normal branches during IMS-1 and the HSS. As the source decays through IMS-2 and LHS-2, the HID returns to isolated clumps with increasing hardness before entering quiescence. We detected a quasiperiodic oscillation (QPO) at ?27 Hz with a quality factor Q ? 3.4 during epochs E30 and E31. A Crab-based cross-calibration between NICER and NuSTAR shows that XTE J1701?462 reached a peak accretion rate of ?1.21 (Formula presented) ?Edd, suggesting near- or super-Eddington luminosities consistent with its 2006 outburst. 2026. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the https://creativecommons.org/licenses/by/4.0/. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
Source
Astrophysical Journal;Volume;1002;Issue;1;
Date
01-01-2026
Publisher
American Astronomical Society
Subject
High energy astrophysics (739); Low-mass x-ray binary stars (939); Neutron stars (1108); Stellar accretion disks (1579); X-ray binary stars (1811)
Coverage
Thomas N.T., Department of Physics and Electronics, CHRIST University, Karnataka, Bengaluru, 560029, India; Jirawala K., Department of Physics and Electronics, CHRIST University, Karnataka, Bengaluru, 560029, India; Gudennavar S.B., Department of Physics and Electronics, CHRIST University, Karnataka, Bengaluru, 560029, India; Bubbly S.G., Department of Physics and Electronics, CHRIST University, Karnataka, Bengaluru, 560029, India
Rights
All Open Access; Gold Open Access; Green Open Access
Relation
ISSN: 0004637X;
Format
online
Language
English
Type
Article

Citation

Thomas, Neal Titus; Jirawala, Khushi; Gudennavar, S.B.; Bubbly, S.G., “Spectrotemporal Evolution in XTE J1701-462 during Its 2022 Outburst as Revealed by NICER,” CHRIST (Deemed To Be University) Institutional Repository, accessed June 21, 2026, https://archives.christuniversity.in/items/show/23591.

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