Figure 7.35. The infrared spectrum of the HMXB Edd-1. Adapted from Mikles et al. (2006).

highly time-variable, as is the typical accretion flow in LMXBs in general. In addition, we can see rapid correlated line variability, such as the continuum/Bry correlation seen during jet-flaring events from the microquasar LMXB GRS 1915+105 (Eikenberry et al., 1998).

High-mass XRBs (HMXBs) can show similar accretion-disk features, but they can also be masked, obscured, or confused by similar features from the massive donor star itself! Figure 7.35 shows the IR spectrum of the Galactic Center HMXB Edd-1. In addition, the B[e] system shown above - CI Cam - is itself thought to be a HMXB system (though often in quiescence).

Finally, we conclude with a look at the power of emission lines for diagnosing some of these system - in this case SS433. As we can see in Figure 7.36, SS433 has the "standard" XRB emission lines - broadened H, He, etc. However, we can also see what appear to be red/blueshifted features. In fact, with sufficient sensitivity, we find that essentially every "rest-wavelength" emission feature has these counterparts. Furthermore, these line measurements reveal velocities as high as v ~ 0.26c (!!). In the radio, we see collimated outflows, and on combining the two we see that SS433 has emission lines emanating from two oppositely directed relativistic jets! A kinematic model of these jets shows that they are precessing with a period of P ~ 164d, and recent work shows that this period has been essentially stable for > 20 yr. Detailed models and observations of these jet emission lines are providing important probes into the formation of relativistic jets in this extremely interesting system.

Figure 7.35. The infrared spectrum of the HMXB Edd-1. Adapted from Mikles et al. (2006).

Wavelength (urn)

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