منابع مشابه
5 v 1 2 J un 1 99 9 Cygnus X - 2 : the Descendant of an Intermediate - Mass X - Ray
Technology Received ; accepted – 2 – ABSTRACT The X-ray binary Cygnus X-2 (Cyg X-2) has recently been shown to contain a secondary that is much more luminous and hotter than is appropriate for a low-mass subgiant. We present detailed binary-evolution calculations which demonstrate that the present evolutionary state of Cyg X-2 can be understood if the secondary had an initial mass of around 3.5...
متن کاملThe 1996 Soft State Transition of Cygnus X-1
We report continuous monitoring of Cygnus X-1 in the 1.3–200 keV band using All-Sky MonitoryRossi X-Ray Timing Explorer and BATSEyCompton Gamma Ray Observatory for about 200 days from 1996 February 21 to early September. During this period, Cygnus X-1 experienced a hard-to-soft and then a soft-to-hard state transition. The low-energy X-ray (1.3–12 keV) and high-energy X-ray (20–200 keV) fluxes ...
متن کاملRossi X-ray Timing Explorer Observation of Cygnus X-1 in Its High State
We present the results from the Rossi X-Ray Timing Explorer observations of Cygnus X-1 in its high state. In the energy range of 2–200 keV, the observed X-ray spectrum can be described by a model consisting of a soft blackbody component and a broken power law with a high-energy cutoff. The low-energy spectrum (below 111 keV) varies significantly from observation to observation while the high-en...
متن کاملX-ray Variability of Cygnus X-1 in Its Soft State
We reported previously that for Cyg X-1 there is a settling period following the transition from hard to soft state (Cui et al. 1996). During the transiton, The low energy spectrum (below ∼ 10 keV) varies significantly from observation to observation while the high energy portion changes little. The source reaches nominal soft-state brightness during the settling period. It can be characterized...
متن کاملUltraviolet observations of the X - ray photoionized wind of Cygnus X - 1 during X - ray soft / high state 1
High-resolution ultraviolet observations of the black hole X-ray binary Cygnus X-1 were obtained using the Space Telescope Imaging Spectrograph on the Hubble Space Telescope. Observations were taken at two epochs roughly one year apart; orbital phase ranges around φorb = 0 and 0.5 were covered at each epoch. We detect P Cygni line features from high (N V, C IV, Si IV) and absorption lines from ...
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ژورنال
عنوان ژورنال: The Astrophysical Journal
سال: 1996
ISSN: 0004-637X
DOI: 10.1086/310369