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Post Info TOPIC: SS433 Binary System
Blobrana


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RE: SS433 Binary System
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Title: SS433: Observation of the circumbinary disc and extraction of the system mass
Authors: Katherine Blundell, Michael Bowler, Linda Schmidtobreick

The so-called "stationary" H-alpha line of SS433 is shown to consist of three components. A broad component is identified as emitted in that wind from the accretion disc which grows in speed with elevation above the plane of the disc. There are two narrow components, one permanently redshifted and the other permanently to the blue. These are remarkably steady in wavelength and must be emitted from a circumbinary ring, orbiting the centre of mass of the system rather than orbiting either the compact object or its companion: perhaps the inner rim of an excretion disc. The orbiting speed (approximately 200 km/s) of this ring material strongly favours a large mass for the enclosed system (around 40 solar masses), a large mass ratio for SS433, a mass for the compact object plus accretion disc of ~16 solar masses and hence the identity of the compact object as a rather massive stellar black hole.

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Blobrana


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Posts: 131433
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Microquasar SS 433
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Title: Spectroscopic Observations of the Mass Donor Star in SS 433
Authors: Todd C. Hillwig, Douglas R. Gies

The microquasar SS 433 is an interacting massive binary consisting of an evolved mass donor and a compact companion that ejects relativistic jets. The mass donor was previously identified through spectroscopic observations of absorption lines in the blue part of the spectrum that showed Doppler shifts associated with orbital motion and strength variations related to the orbital modulation of the star-to-disk flux ratio and to disk obscuration. However, subsequent observations revealed other absorption features that lacked these properties and that were probably formed in the disk gas outflow. We present here follow-up observations of SS 433 at orbital and precession phases identical to those from several previous studies with the goals of confirming the detection of the mass donor spectrum and providing more reliable masses for the two system components. We show that the absorption features present as well as those previously observed almost certainly belong to the mass donor star, and we find revised masses of 12.3 ±3.3 and 4.3 ±0.8 M(sun) for the mass donor and compact object, respectively.

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Blobrana


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Posts: 131433
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The Distance to SS433/W50
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Title: The Distance to SS433/W50 and its Interaction with the ISM
Authors: Felix J. Lockman, Katherine M. Blundell, W. M. Goss

The distance to the relativistic jet source SS433 and the related supernova remnant W50 is re-examined using new observations of HI in absorption from the VLA, HI in emission from the GBT, and 12CO emission from the FCRAO. The new measurements show HI in absorption against SS433 to a velocity of 75 km/s but not to the velocity of the tangent point, which bounds the kinematic distance at 5.5 < d_k < 6.5 kpc. This is entirely consistent with a 5.5 ± 0.2 kpc distance determined from light travel-time arguments (Blundell & Bowler 2004). The HI emission map shows evidence of interaction of the lobes of W50 with the interstellar medium near the adopted systemic velocity of V_LSR = 75 km/s. The western lobe sits in a cavity in the HI emission near the Galactic plane, while the eastern lobe terminates at an expanding HI shell. The expanding shell has a radius of 40 pc, contains 8 ± 3 x 10³ M_sun of HI and has a measured kinetic energy of 3 ± 1.5 x 10^{49} ergs. There may also be a static HI ring or shell around the main part of W50 itself at an LSR velocity of 75 km/s, with a radius of 70 pc and a mass in HI of 3.5 - 10 x 10^4 M_sun. We do not find convincing evidence for the interaction of the system with any molecular cloud or with HI at other velocities. The HI emission data suggest that SS433 lies in an interstellar environment substantially denser than average for its distance from the Galactic plane. This Population I system, now about 200 pc below the Galactic plane, most likely originated as a runaway O-star binary ejected from a young cluster in the plane. New astrometric data on SS433 show that the system now has a peculiar velocity of a few tens of km/s in the direction of the Galactic plane. From this peculiar velocity and the symmetry of the W50 remnant we derive a time since the SN of < 10^5 yr.

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Blobrana


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Posts: 131433
Date:
RE: SS433 Binary System
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Title: NTEGRAL Observations of SS433: Analysis of Precessional and Orbital X-ray Periodicities
Authors: A.M. Cherepashchuk, R.A. Sunyaev, E.V. Seifina, E.A. Antokhina, D.I. Kosenko, S.V. Molkov, N.I. Shakura, K.A. Postnov, A.N. Timokhin, I.E. Panchenko

Hard X-ray INT observations of SS 433 carried out during 2003-2005 years with an analysis of precessional and orbital variability is presented. The width of X-ray eclipse in the 25-50 keV range at the precessional phase psi=0.1 (accretion disk is open to observer) is higher than that in the Ginga 18.4-27.6 keV range. This fact suggests existance the presence of hot extended corona around the supercritical accretion disk. Spectrum of hard X-rays in the range 10-200 keV does not change with the precessional phase which also suggests that hard X-ray flux is generated in the hot extended corona around the accretion disk. The parameters of this hot corona are: kT=23-25 keV, tau = 1.8-2.8. Mass ratio estimated from the analysis of the ingress part of the eclipse light curve is in the range q=m_x/m_v=0.3-0.5.

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Blobrana


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Posts: 131433
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Title: Determining the Nature of the SS 433 Binary Using an X-ray Spectrum During Eclipse
Authors: Laura A. Lopez (1, 2, 3), Herman L. Marshall (4), Claude R. Canizares (4), Norbert S. Schulz (4), Julie F. Kane (5) ((1) UCSC (2) IAS (3) NSF Graduate Research Fellow (4) MIT Kavli Institute for Astrophysics and Space Research (5) MIT Dept of Earth, Atmospheric, and Planetary Science)

Researchers test the physical model of the relativistic jets in the galactic X-ray binary SS 433 proposed in their previous paper using additional observations from the Chandra High Energy Transmission Grating Spectrometer.
These observations sample two new orbital/precessional phase combinations. In the observation near orbital phase zero, the H- and He-like Fe lines from both receding and approaching jets are comparably strong and unocculted while the He-like Si line of the receding jet is significantly weaker than that of the approaching jet.
This condition may imply the cooler parts of the receding jet are eclipsed by the companion. The X-ray spectrum from this observation has broader emission lines than obtained in Paper I that may arise from the divergence of a conical outflow or from Doppler shift variations during the observation. Using recent optical results, along with the length of the unobscured portion of the receding jet assuming adiabatic cooling, they calculate the radius of the companion to be 9.6±1.0 solar masses radaii, about one third of the Roche lobe radius.
For a main sequence star, this corresponds to a companion mass of 35±7 solar masses, giving a primary source mass of 20±5 solar masses. If their model is correct, this calculation indicates the compact object is a black hole, and accretion occurs through a wind process.
In a subsequent paper, they will examine the validity of the adiabatic cooling model of the jets and test the mode of line broadening.

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Coordinates (2000): RA 19h 11m 49.5s | Dec +04º 58' 58"
Constellation Aquila

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