Disc versus wind accretion in X-ray pulsar GX 301-2
Date Issued
2021
Author(s)
Liu, Jiren
•
Ji, Long
•
Jenke, Peter A.
•
Doroshenko, Victor
•
Liao, Zhenxuan
•
Li, Xiaobo
•
Zhang, Shuangnan
•
•
Ge, Mingyu
•
Zhang, Shu
•
Santangelo, Andrea
Abstract
GX 301-2 provides a rare opportunity to study both disc and wind accretion in a same target. We report Insight-Hard X-ray Modulation Telescope observations of the spin-up event of GX 301-2 that happened in 2019 and compare with those of wind-fed state. The pulse profiles of the initial rapid spin-up period are dominated by one main peak, while those of the later slow spin-up period are composed of two similar peaks, as those of wind-fed state. These behaviours are confirmed by Fermi/Gamma-ray Burst Monitor data, which also show that during the rapid spin-up period, the main peak increases with luminosity up to 8 × 1037 erg s-1, but the faint peak remains almost constant. The absorption column densities during the spin-up period are ~1.5 × 1023 cm-2, much less than those of wind-fed state at similar luminosity (~9 × 1023 cm-2), supporting the scenario that most of material is condensed into a disc during the spin-up period. We discuss possible differences between disc and wind accretion that may explain the observed different trends of pulse profiles.
Volume
504
Issue
2
Start page
2493
Issn Identifier
0035-8711
Ads BibCode
2021MNRAS.504.2493L
Rights
open.access
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