2025/06/06 by Yang, Wen, Wang, Wei · 1 citation
#FOS: Physical sciences #High Energy Astrophysical Phenomena (astro-ph.HE) #High Energy Physics - Phenomenology (hep-ph) #Solar and Stellar Astrophysics (astro-ph.SR)
paper · doi:10.48550/arxiv.2506.05771
We report the timing results with Insight-HXMT observations of X-ray binary IGR J19294+1816 during its 2019 Type I outburst at the decline phase shortly following its peak. We analyze the light curves and power density spectrum (PDS) of the 2019 observations and reveal a peak at approximately νNS ∼ 80.2 mHz, corresponding to X-ray pulsations from the neutron star. In addition, a significant quasi-periodic oscillation (QPO) feature is observed at around νQPO ∼ 30.2 mHz from 10-50 keV, with the rms amplitude increasing with energy. Furthermore, we detect two QPOs at the frequency of ∼ 51.1 mHz and 113.7 mHz (corresponding to sidebands near νNS ± νQPO) in 25-50 keV, exhibiting an rms amplitude of around 12%. Wavelet analysis also shows multiple QPOs at the frequency of ∼ 30 mHz, 50 mHz and 110 mHz and these QPO features show transient behaviors, the centroid frequencies of ∼ 30 mHz remain nearly constant for different luminosities. Our research identifies IGR J19294+1816 as the second strong magnetic-field pulsar with significant sideband signals around the spin frequency. We explore various physical origins that could explain the presence of multiple QPOs.