2004/09/30 by Nanda Rea, N. Rea, Luigi Stella +10
Earth and Planetary Sciences · Physics and Astronomy · #Accretion (finance) #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Binary number #Emission spectrum #Event (particle physics) #Flux (metallurgy) #High-pressure geophysics and materials #Line (geometry) #Neutron star #Physics #Pulsar #Pulsars and Gravitational Waves Research #Spectral line #Torus #X-ray binary #astro-ph
paper · pdf · doi:10.1016/j.asr.2005.04.086
accepted for publication in Advances in Space Research
arxiv created 2005/04/25 · openalex publication_date 2005/06/22 · arxiv updated 2015/06/24 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We report on a long X-ray observation of the slow-rotating binary pulsar GX 1+4. BeppoSAX observed, in the 0.1-200 keV energy range, an event in which the source flux dropped for almost a day, and then recovered. During this event only the high-energy emission was found to be pulsed and the pulsations were shifted in phase of ~0.2 . The spectrum during the event was well fitted by a Compton-reflection model. A broad iron line at ~6.55 keV was present outside of the event, where instead two narrow emission lines at ~6.47 keV and ~7.05 keV were detected. The pulse profile was highly variable as a function of both energy and time. We interpret this low-flux event as an occultation of the direct X-ray emission, due to the increase of a torus-like accretion disk; we then discuss similarities between this source and the recently discovered highly absorbed INTEGRAL sources.