Liu, JirenJirenLiuJi, LongLongJiJenke, Peter A.Peter A.JenkeDoroshenko, VictorVictorDoroshenkoLiao, ZhenxuanZhenxuanLiaoLi, XiaoboXiaoboLiZhang, ShuangnanShuangnanZhangORLANDINI, MAUROMAUROORLANDINIGe, MingyuMingyuGeZhang, ShuShuZhangSantangelo, AndreaAndreaSantangelo2022-06-082022-06-0820210035-8711http://hdl.handle.net/20.500.12386/32244GX 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 × 10<SUP>37</SUP> erg s<SUP>-1</SUP>, but the faint peak remains almost constant. The absorption column densities during the spin-up period are ~1.5 × 10<SUP>23</SUP> cm<SUP>-2</SUP>, much less than those of wind-fed state at similar luminosity (~9 × 10<SUP>23</SUP> cm<SUP>-2</SUP>), 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.STAMPAen10.1093/mnras/stab9382-s2.0-85107987519000659453800064https://academic.oup.com/mnras/article/504/2/2493/62110002021MNRAS.504.2493LFIS/05 - ASTRONOMIA E ASTROFISICAERC sectors::Physical Sciences and Engineering::PE9 Universe sciences: astro-physics/chemistry/biology; solar systems; stellar, galactic and extragalactic astronomy, planetary systems, cosmology, space science, instrumentation::PE9_10 High energy and particle astronomy – X-rays, cosmic rays, gamma rays, neutrinos