We report on the X-ray spectral behavior within the steady states of GRS1915+105. Our work is based on the full data set of the source obtained using the Proportional Counter Array (PCA) on the Rossi X-ray Timing Explorer (RXTE) and 15 GHz radio data obtained using the Ryle Telescope. The steady observations within the X-ray data set naturally separated into two regions in the color-color diagram and we refer to these regions as steady-soft and steady-hard. GRS1915+105 displays significant curvature in the coronal component in both the soft and hard data within the RXTE/PCA bandpass. A majority of the steady-soft observations displays a roughly constant inner disk radius (R in ), while the steady-hard observations display an evolving disk truncation which is correlated to the mass accretion rate through the disk. The disk flux and coronal flux are strongly correlated in steady-hard observations and very weakly correlated in the steady-soft observations. Within the steady-hard observations, we observe two particular circumstances when there are correlations between the coronal X-ray flux and the radio flux with log slopes h~ 0.68 0.35and h~ 1.12 0.13. They are consistent with the upper and lower tracks of Gallo et al. (2012), respectively. A comparison of the model parameters to the state definitions shows that almost all of the steady-soft observations match the criteria of either a thermal or steep power-law state, while a large portion of the steady-hard observations match the hard-state criteria when the disk fraction constraint is neglected.
We present Doppler and modulation tomography of the low‐mass X‐ray binary V691 CrA with data obtained using the 6.5‐m Magellan Baade telescope at the Las Campanas Observatory in 2010 and 2011. The disc and hotspot are observed in Hα and He ii (λ4686) in both years. A clear image of the disc is seen in He ii (λ5411) using the 2010 data. We present the first tomography of the absorption line He i (λ5876) and detect absorption near the L1 point of the donor star. We also present the first modulation tomography of the emission line Hα and detect emission from the secondary. The Hα double peaks are imbedded in a deep absorption trough confirming the presence of Balmer line absorbing material in the system. Our observations of Hα show absorption in a larger phase range than in Hβ which could be due to heating up of sprayed matter from the hotspot as it travels downstream. We also suggest possible occultation of the Hα absorbing spray by the disc bulge at certain phases.
We present a spectroscopic analysis of the black hole binary Nova Muscae 1991 in quiescence using data obtained in 2009 with MagE on the Magellan Clay telescope and in 2010 with IMACS on the Magellan Baade telescope at the Las Campanas Observatory. Emission from the disc is observed in H α, H β and Ca II (λ8662). A prominent hotspot is observed in the Doppler maps of all three emission lines. The existence of this spot establishes ongoing mass transfer from the donor star in 2009-2010 and, given its absence in the 1993-1995 observations, demonstrates the presence of a variable hotspot in the system. We find the radial distance to the hotspot from the black hole to be consistent with the circularization radius. Our tomograms are suggestive of stream-disc overflow in the system. We also detect possible Ca II (λ8662) absorption from the donor star.
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