ItemArticle

Spin Frequency of Neutron Star in the Bright Atoll Source 4U 1705-44 Using NICER Observation

Title
Spin Frequency of Neutron Star in the Bright Atoll Source 4U 1705-44 Using NICER Observation
Creator
Giridharan, L.; Thomas, Neal Titus; Gudennavar, S.B.; Bubbly, S.G.
Description
We conducted a systematic study of two thermonuclear type I X-ray bursts (B1 and B2) and the spectral properties of the bright atoll type neutron star low-mass X-ray binary 4U 1705?44 using NICER observation. In our analysis, a burst oscillation at ?702 Hz was detected during the double-peaked profile of burst B1. This provides the first strong evidence for the spin frequency of the neutron star, which establishes 4U 1705?44 as a rapid rotator. The measured convexity parameters of the bursts indicate that both bursts likely ignited at off-equatorial latitudes. The ignition depth of burst B1 was nearly twice that of B2, indicating substantial fuel consumption between the two events. The recurrence time of B2 (?1 hr) categorizes it as a short waiting time burst. The complementary spectral analysis of persistent emission, modeled with tbabsnthcomp+ diskbb), showed a hard state with a photon index ? < 1.12. The hardnessintensity diagram was consistent with the source being in the island state. Notably, the accretion disk appeared to extend close to the neutron star surface. 2026. The Author(s). Published by the American Astronomical Society.
Source
Astrophysical Journal;Volume;998;Issue;2;Article No.;338;
Date
01-01-2026
Publisher
American Astronomical Society
Coverage
Giridharan L., Department of Physics and Electronics, CHRIST University, Karnataka, Bangalore, 560029, India; Thomas N.T., Department of Physics and Electronics, CHRIST University, Karnataka, Bangalore, 560029, India; Gudennavar S.B., Department of Physics and Electronics, CHRIST University, Karnataka, Bangalore, 560029, India; Bubbly S.G., Department of Physics and Electronics, CHRIST University, Karnataka, Bangalore, 560029, India
Rights
All Open Access; Gold Open Access
Relation
ISSN: 0004637X;
Format
online
Language
English
Type
Article

Citation

Giridharan, L.; Thomas, Neal Titus; Gudennavar, S.B.; Bubbly, S.G., “Spin Frequency of Neutron Star in the Bright Atoll Source 4U 1705-44 Using NICER Observation,” CHRIST (Deemed To Be University) Institutional Repository, accessed June 20, 2026, https://archives.christuniversity.in/items/show/23589.

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