observational overview of state transitions in x-ray binaries

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SOFT STATE The next state is called the soft state or the thermal dominant state. As the name already suggests, the spectrum is very soft and it is dominated by the thermal emission from the accretion disk - it is probably the best understood state. Weak non-thermal emission is also present in the form a weak tail. It’s origin is not well understood. Variability is very weak, with amplitudes of only a few percent of the total flux. QPO can be seen together if one combines data from many observations. Unlike the hard state, the soft state is only observed at high luminosities. There is no significant radio emission from the central source in the soft state.
INTERMEDIATE STATE Intermediate (transitional) states (TRANSITIONS) Moving on to the so-called intermediate states or transitional states. These correspond to the horizontal branches in the diagram. There is some debated as to whether these should be considered real states, or merely short lived unstable configurations. In the intermediate state the spectrum can be described by a combination of thermal and non-thermal emission, with the latter being stronger on the right hand side in the diagram. Not only the ratio of the two components changes, but also the slope of the non-thermal component, which steepens considerably. Both effects result in lower values of the hardness. Variability is interesting in this states. QPOs of different types are seen and I will describe their behavior shortly. Amplitudes decrease from tens of percent to a few percents. The intermediate state also gives radio to occasional radio flares. Radio emission usually starts to weaken when the source turns this corner, followed days later by a giant radio flare, associated with the ejection of matter in the form of an outflow. Intermediate states can be observed over a wide range of luminosities - typically the same as that of the soft state.
Page 1 and 2: !""#$%&'()*#'"$++$+)&(),-#!.+/ 4566
Page 3 and 4: MORE BACKGROUND • 1996>: Dedicate
Page 5 and 6: TRANSIENT SOURCES • Relation betw
Page 7 and 8: OUTBURST LIGHT CURVES 4U 1543-47 GR
Page 9 and 10: ENERGY DEPENDENCE This movie (Homan
Page 11 and 12: SPECTRAL EVOLUTION GX 339-4 First I
Page 13 and 14: COLOR EVOLUTION hardness-intensity
Page 15 and 16: Luminosity (erg/s) SPECTRAL EVOLUTI
Page 17 and 18: XTE J1752-223 XTE J1908+094 SPECTRA
Page 19 and 20: SPECTRAL EVOLUTION GRO J1655-40 I
Page 21 and 22: SPECTRAL EVOLUTION GRO J1655-40 We
Page 23 and 24: SPECTRAL EVOLUTION GX 339-4 Transit
Page 25 and 26: IMPLICATIONS FOR ACCRETION • outb
Page 27 and 28: STATE CLASSIFICATION • Various cl
Page 29 and 30: RAPID X-RAY VARIABILITY • power d
Page 31: • low-luminosity version of the h
Page 35 and 36: RAPID X-RAY VARIABILITY Okay, let
Page 37 and 38: Power type-B frequency up 1 10 100
Page 39 and 40: No Compact Jet (interaction with IS
Page 41 and 42: GRO J1655-40 weak abs. lines weak e
Page 43 and 44: Aql X-1 NEUTRON STARS hard - soft -
Page 45 and 46: Aql X-1 Back to the HID again. NEUT
Page 47 and 48: hard transitional Lin et al. 2009 H
Page 49 and 50: Lin et al. 2009 Homan et al. 2010 N

observational overview of state transitions in x-ray binaries

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