English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Here we report the spectral-timing results of the black hole X-ray binary 4U1630-47 during its 2021 outburst using observations from the Hard X-rayModulation Telescope. Type-C quasi-periodic oscillations (QPOs) in 1.6--4.2 Hzand quasi-regular modulation (QRM) near 60 mHz are detected during theoutburst. The mHz QRM has a fractional rms of 10%--16% in the 8--35 keV energyband with a Q factor (frequency/width) of 2--4. Benefiting from the broadenergy band of hxmt, we study the energy dependence of the 60 mHz QRM in 1--100keV for the first time. We find that the fractional rms of the mHz QRMincreases with photon energy, while the time lags of the mHz QRM are soft anddecrease with photon energy. Fast recurrence of the mHz QRM, in a timescale ofless than one hour, has been observed during the outburst. During this period,the corresponding energy spectra moderately change when the source transitionsfrom the QRM state to the non-QRM state. The QRM phenomena also shows adependence with the accretion rate. We suggest that the QRM could be caused byan unknown accretion instability aroused from the corona.

An Insight-HXMT view of the mHz quasi-regular modulation phenomenon in the black hole X-ray binary 4U 1630-47