Wind Accretion and State Transitions in the Black Hole Binary Cyg X-1

Details Wind Accretion and State Transitions in the Black Hole Binary Cyg X-1 Wind Accretion and State Transitions in the Black Hole Binary Cyg X-1

Jul 2004

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2004hst..prop10243g&link_type=abstract

HST Proposal ID #10243

Other

Hst Proposal Id #10243 Hot Stars

Scientific paper

The black hole binary, Cyg X-1, is generally observed in one of two long duration X-ray states: a low flux, hard spectrum state {most common} and a high flux, soft spectrum state. Models predict that the high/soft state corresponds to a high mass transfer phase in the binary, and since the X-ray source is fueled by accretion from the stellar wind of the supergiant companion, the simple expectation is that the high/soft state results from an increased wind mass loss rate. Alternatively, a decrease in the wind mass loss rate could result in a more ionized and slower wind in the vicinity of the black hole, which would then be more easily accreted by the black hole. The best test of these hypotheses is to observe the UV P Cygni lines of the supergiant that are formed in its wind outflow. We recently used HST/STIS to obtain the first ever high resolution UV spectra of the system while it resided in the high/soft state. These spectra show that the wind is extensively ionized in the high/soft state, making the wind slower and easier to accrete. Here we propose to revisit Cyg X-1 in the low/hard state and to complete our investigation of the connection between the wind and the X-ray state. The study will determine {1} the mass loss rate and the dynamical {density and velocity} structure of the wind of the supergiant star in both X-ray states, and {2} how the X-ray source ionizes the wind. These spectra will be useful for other investigations and will form an important resource for the entire research community.

Affiliated with

Also associated with

No associations

Rating

Wind Accretion and State Transitions in the Black Hole Binary Cyg X-1 does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Wind Accretion and State Transitions in the Black Hole Binary Cyg X-1, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Wind Accretion and State Transitions in the Black Hole Binary Cyg X-1 will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1011166