The Mass of the Black Hole in LMC X-3

Understand

We analyze a large set of new and archival photometric and spectroscopic observations of LMC X-3 to arrive at a self-consistent dynamical model for the system.

• Using echelle spectra obtained with the MIKE instrument on the 6.5m Magellan Clay telescope and the UVES instrument on the second 8.2m Very Large Telescope we find a velocity semiamplitude for the secondary star of $K_2=241.1\pm 6.2$ km s$^{-1}$, where the uncertainty includes an estimate of the systematic error caused by X-ray heating.
• Using the spectra, we also find a projected rotational velocity of $V_{\rm rot}\sin i=118.5\pm 6.6$ km s$^{-1}$.
• From an analysis of archival $B$ and $V$ light curves as well as new $B$ and $V$ light curves from the SMARTS 1.3m telescope, we find an inclination of $i=69.84\pm 0.37^{\circ}$ for models that do not include X-ray heating and an inclination of $i=69.24\pm 0.72^{\circ}$ for models that incorporate X-ray heating.