High energy Millihertz quasi-periodic oscillations in 1A 0535+262 with Insight-HXMT challenge current models
arXiv:2209.10455 · doi:10.1093/mnras/stac2768
Abstract
We studied the millihertz quasi-periodic oscillation (mHz QPO) in the 2020 outburst of the Be/X-ray binary 1A 0535+262 using Insight-HXMT data over a broad energy band. The mHz QPO is detected in the 27-120 keV energy band. The QPO centroid frequency is correlated with the source flux, and evolves in the 35-95 mHz range during the outburst. The QPO is most significant in the 50-65 keV band, with a significance of ~ 8 sigma, but is hardly detectable (<2 sigma) in the lowest (1-27 keV) and highest (>120 keV) energy bands. Notably, the detection of mHz QPO above 80 keV is the highest energy at which mHz QPOs have been detected so far. The fractional rms of the mHz QPO first increases and then decreases with energy, reaching the maximum amplitude at 50-65 keV. In addition, at the peak of the outburst, the mHz QPO shows a double-peak structure, with the difference between the two peaks being constant at ~0.02 Hz, twice the spin frequency of the neutron star in this system. We discuss different scenarios explaining the generation of the mHz QPO, including the beat frequency model, the Keplerian frequency model, the model of two jets in opposite directions, and the precession of the neutron star, but find that none of them can explain the origin of the QPO well. We conclude that the variability of non-thermal radiation may account for the mHz QPO, but further theoretical studies are needed to reveal the physical mechanism.
arXiv comment13 pages, 7 figures. Accepted for publication in MNRAS
References in corpus (34)
- Estimating distances from parallaxes IV: Distances to 1.33 billion stars in Gaia Data Release 2
- Be/X-ray binaries
- A Unified Description of the Timing Features of Accreting X-ray Binaries
- Overview to the Hard X-ray Modulation Telescope (Insight-HXMT) Satellite
- Thermal and Bulk Comptonization in Accretion-Powered X-Ray Pulsars
- Are There Three Peaks in the Power Spectra of GX 339-4 and Cyg X-1?
- Discovery of Sub-Millisecond Quasi-Periodic Oscillations in the X-Ray Flux of Scorpius X-1
- A physical model for the continuum variability and QPO in accreting black holes
- A quasi-periodic modulation of the iron line centroid energy in the black hole binary H 1743-322
- Kilohertz QPO Peak Separation Is Not Constant in Scorpius X-1
- The Medium Energy (ME) X-ray telescope onboard the Insight-HXMT astronomy satellite
- Insight-HXMT observations of the New Black Hole Candidate MAXI J1535-571: timing analysis
- The Comptonising medium of the neutron star in 4U 1636-53 through its lower kilohertz Quasi-Periodic Oscillations
- Coupling between the accreting corona and the relativistic jet in the micro quasar GRS 1915+105
- vKompth: A variable Comptonisation model for low-frequency quasi-periodic oscillations in black-hole X-ray binaries
- A two-component Comptonisation model for the type-B QPO in MAXI J1348-630
- An evolving jet from a strongly-magnetised accreting X-ray pulsar
- Can disk-magnetosphere interaction models and beat frequency models for quasi-periodic oscillation in accreting X-ray pulsars be reconciled?
- X-Ray and Optical Observations of A 0535+26
- Discovery of a 0.02 Hz QPO feature in the Transient X-ray Pulsar KS 1947+300
- Timing and spectral studies of the transient X-ray pulsar GX 304-1 during an outburst
- A study of natural frequencies in a dynamic corona-disk system
- Quasiperiodic oscillations in Cen X-3 and the long term intensity variations
- Discovery of Soft Spectral Component and Transient 22.7s Quasi Periodic Oscillations of SAX J2103.5+4545
- Broadband aperiodic variability in X-ray pulsars: accretion rate fluctuations propagating under the influence of viscous diffusion
- A study of the long term evolution of quasi periodic oscillations in the accretion powered X-ray pulsar 4U 1626-67
- Discovery of new quasi-periodic oscillations in the X-ray transient source V~0332+53
- RXTE-PCA observations of 1A 1118--61: timing and spectral studies during an outburst
- Discovery of mHz UV Quasiperiodic Oscillations in Hercules X-1
- Timing analysis of the black hole candidate EXO 1846-031 with Insight-HXMT monitoring
- Detection of a variable QPO at ~41 mHz in the Be/X-ray transient pulsar 4U 0115+634
- Flares, Broadening of the Pulse frequency peak, and Quasi Periodic Oscillations in the Transient X-ray Pulsar 4U 1901+03
- Variable Quasi Periodic Oscillations during an outburst of the transient X-ray pulsar XTE J1858+034
- X-ray spectral-timing variability of 1A 0535+262 during the 2020 giant outburst