The High‐Resolution X‐Ray Spectrum of SS 433 Using theChandraHETGS

We present observations of SS 433 using the Chandra High Energy TransmissionGrating Spectrometer. Many emission lines of highly ionized elements aredetected with the relativistic blue and red Doppler shifts. The lines aremeasurably broadened to 1700 km/s (FWHM) and the widths do not dependsignificantly on the characteristic emission temperature, suggesting that theemission occurs in a freely expanding region of constant collimation withopening angle of 1.23 +/- 0.06 deg. The blue shifts of lines from lowtemperature gas are the same as those of high temperature gas within ouruncertainties, again indicating that the hottest gas we observe to emitemission lines is already at terminal velocity. Fits to the emission linefluxes give a range of temperatures in the jet from 5e6 to 1e8 K. We derive theemission measure as a function of temperature for a four component model thatfits the line flux data. Using the density sensitive Si XIII triplet, thecharacteristic electron density is 1e14 cm^{-3}, where the gas temperature isabout 1.3e7 K. Based on an adiabatic expansion model of the jet, the electrondensities drop from ~2e15 to 4e13 cm^{-3} at distances of 2e10 to 2e11 cm fromthe apex of the jet cone. The jet mass outflow rate is 1.5e-7 Msun / yr. Thekinetic power is 3.2e38 erg/s, which is x1000 larger than the unabsorbed 2-10keV X-ray luminosity. The bremsstrahlung emission associated with the lines canaccount for the entire continuum; we see no direct evidence for an accretiondisk. The image from zeroth order shows extended emission at a scale of ~2",aligned in the general direction of the radio jets.Comment: 28 pages, 12 figures (1, 4, 5, and 6 are color), to appear in the Astrophysical Journa