Quantitative Three State Description for Active Accretion

In MR06, a new framework was used to define X-ray states (for an historical discussion of X-ray states, see MR06 and RM06). In Figure 2, we illustrate

GRO J1655-40

Fig. 2. Examples of the 3 states of active accretion for the black hole binary GRO J1655-40. Left panels show the energy spectra, with model components attributed to thermal-disk emission (red solid line), a power-law continuum (blue dashes) and a relativistically broadened Fe K-alpha line (black dotted). Power-law components for the SPL and hard states are distinguished by different values of the photon index (i.e. slope). The PDS (green solid lines) are shown in the right panels. A strong, band-limited continuum characterizes the hard state, while QPOs and the absence of the intense, broad continuum are usually seen in the SPL state. Reprinted with permission from Volume 44 of Annual Reviews of Astronomy & Astrophysics (RM06).

1 10 100 Energy (keV)

Fig. 2. Examples of the 3 states of active accretion for the black hole binary GRO J1655-40. Left panels show the energy spectra, with model components attributed to thermal-disk emission (red solid line), a power-law continuum (blue dashes) and a relativistically broadened Fe K-alpha line (black dotted). Power-law components for the SPL and hard states are distinguished by different values of the photon index (i.e. slope). The PDS (green solid lines) are shown in the right panels. A strong, band-limited continuum characterizes the hard state, while QPOs and the absence of the intense, broad continuum are usually seen in the SPL state. Reprinted with permission from Volume 44 of Annual Reviews of Astronomy & Astrophysics (RM06).

the character of each state by showing examples of PDSs and energy spectra for the black hole binary GRO J1655-40. The relevance of X-ray states fundamentally rests on the large differences in the energy spectra and PDSs that can be seen in a comparison of any two states.

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