On the nature of the 35-day cycle in HZ Her/Her X-1

Abstract

Regular variations of the pulse period of Her X-1 with X-ray flux observed by Fermi-GBM are examined. We argue that these regular variations result from the free precession of the neutron star in Her X-1.

2 figures, to be published in Astronomy Reports

References in corpus (3)

• Swift/BAT and RXTE/ASM Observations of the 35-day X-ray Cycle of Hercules X-1
• Observations of Her X-1 in low states during SRG/eROSITA all-sky survey
• Modeling of 35-day superorbital cycle of $B$ and $V$ light curves of IMXB HZ Her/Her X-1