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

We analyze the energy dependence of the X-ray pulse profile and thephase-resolved spectra (PRS) of the Crab pulsar using observations from theNeutron star Interior Composition Explorer (NICER) and the Hard X-rayModulation Telescope (Insight-HXMT). We parameterize the pulse profiles andquantify the evolution of these parameters in the broad energy band of 0.4-250keV. A log-parabola function is used to fit the PRS in 2-250 keV, and thecurvature of the spectrum, i.e., the evolution of the photon index with energy,as represented by the parameter \{beta} of the log-parabola model, also changeswith phase. The relation of \{beta} and phase has two turning points slightlylater than those of the pulse intensity profile, where the values of \{beta}are the lowest, suggesting that the energy-loss rate of the particles is thelowest in the corresponding regions. A three-segment broken-power-law model isalso used to fit those PRS. The differences between the hard spectral index andthe soft ones have a distribution similar to that of \{beta}, confirming thefitting results of the log-parabola model, while the broken energies aregenerally higher in the region bridging the two pulses. We findanticorrelations between the spectral indices and the curvature of thelog-parabola model fitting and a similar anticorrelation between the spectralindices and broken energies of the broken-power-law model fitting, suggesting ascenario where the highest-energy particles are produced in regions whereradiation energy loss is strongest.

A Study on the X-Ray Pulse Profile and Spectrum of the Crab Pulsar Using NICER and Insight-HXMT's Observations