Browsing by Author "Fabian, A. C."

Now showing items 1-4 of 4

    • Accretion Disk Wind of Hercules X-1 during the Short High State 

      Kosec, P.; Kara, E.; Fabian, A. C.; Pinto, C.; Psaradaki, I.; Rogantini, D.; Staubert, R.; Walton, D. J. (2023-12-05)
      Hercules X-1 is a nearly edge-on X-ray binary with a warped, precessing accretion disk, which manifests through a 35-day cycle of alternating High and Low flux states. This disk precession introduces a changing line of ...

    • The Long Stare at Hercules X-1. I. Emission Lines from the Outer Disk, the Magnetosphere Boundary, and the Accretion Curtain 

      Kosec, P.; Kara, E.; Fabian, A. C.; Fürst, F.; Pinto, C.; Psaradaki, I.; Reynolds, C. S.; Rogantini, D.; Walton, D. J.; Ballhausen, R.; Canizares, C.; Dyda, S.; Staubert, R.; Wilms, J. (2022-09-14)
      Hercules X-1 is a nearly edge-on accreting X-ray pulsar with a warped accretion disk, precessing with a period of about 35 days. The disk precession allows for unique and changing sightlines toward the X-ray source. To ...

    • Long-term pulse period evolution of the ultra-luminous X-ray pulsar NGC 7793 P13 

      Fuerst, F.; Walton, D. J.; Heida, M.; Bachetti, M.; Pinto, C.; Middleton, M. J.; Brightman, M.; Earnshaw, H. P.; Barret, D.; Fabian, A. C.; Kretschmar, P.; Pottschmidt, K.; Ptak, A.; Roberts, T.; Stern, D.; Webb, N.; Wilms, J. (2021-07-16)
      Ultra-luminous X-ray pulsars (ULXPs) provide a unique opportunity to study super-Eddington accretion. We present the results of a monitoring campaign of ULXP NGC 7793 P13. Over our four-year monitoring campaign with Swift, ...

    • Unveiling the disc structure in ultraluminous X-ray source NGC 55 ULX-1 

      Barra, F.; Pinto, C.; Walton, D. J.; Kosec, P.; D'Aì, A.; Salvo, T. Di; Santo, M. Del; Earnshaw, H.; Fabian, A. C.; Fuerst, F.; Marino, A.; Pintore, F.; Robba, A.; Roberts, T. P. (2022-11-01)
      Despite two decades of studies, it is still not clear whether ULX spectral transitions are due to stochastic variability in the wind or variations in the accretion rate or in the source geometry. The compact object is also ...