Doppler and modulation tomography of XTE J1118+480 in quiescence

Abstract

We present Doppler and modulation tomography of the X-ray nova XTE J1118+480 with data obtained during quiescence using the 10-m Keck II telescope. The hotspot where the gas stream hits the accretion disc is seen in H, H, He I 5876 and Ca II 8662, thus verifying the presence of continued mass transfer within the system. The disc is clearly seen in H and Ca II 8662. We image the mass-donor star in narrow absorption lines of Na I 5890, 5896, 8183, 8195 and Ca II 8662, implying an origin from the secondary itself rather than the interstellar medium. We also detect deviations in the centroid of the double peak of H akin to those found by Zurita et al. suggesting disc eccentricity.