Year: 2024
Type: article
Abstract: We report results from a detailed study of the neutron star X-ray binary, 4U 1608-52, using observations with AstroSat (Large Area X-ray Proportional Counter/Soft X-ray Telescope) and the Neutron Star Interior Composition Explorer during its 2016 and 2020 outbursts. The 0.7–20.0 keV spectra could be well described with the disk blackbody and thermal Comptonization model. The best-fitting inner disk temperature is ∼1 keV and radius ∼ 22.17 − 2.38 + 2.57 –27.19 − 1.85 + 2.03 km and no significant evolution was observed in the disk radius after performing flux and time-resolved spectroscopy. We used a multi-Lorentzian approach to fit the power density spectra and obtained broadband noise variability. We estimated the energy-dependent fractional rms and time lag of the broadband noise, and these variations are quantitatively modeled as being due to the coherent variation of the disk emission and the coronal heating rate. Thus, the rapid temporal modeling is consistent with the longer-term spectral evolution where the inner disk radius does not vary, and instead, the variations can be attributed to accretion rate variations that change the inner disk temperature and the coronal heating rate.
Source: The Astrophysical Journal
Authors: Sree Bhattacherjee, Ankur Nath, Biplob Sarkar, Aru Beri, Suchismito Chattopadhyay, Yashpal Bhulla, Ranjeev Misra
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $4,499
Awards: G1903882006, G6090609995, G7429695201
OpenAlex ID: W4401587209