The rms-flux relation In Black Hole Binaries Credit: ESA Lucy Heil - PowerPoint PPT Presentation

The rms-flux relation In Black Hole Binaries Credit: ESA Lucy Heil (Leicester) With: Simon Vaughan & Phil Uttley (Leicester) (Southampton)

The RMS-flux relation V4641  First identified in Uttley & McHardy (2001)  XRB Cyg X-1 and NS SAX J1808.4-3658  Seen in -  Selected observations in a few XRBs, NSs, AGN and a ULX  Optically in XRBs  Cyg X-1 studied in detail by Gleissner et.al. (2004)

Implications of rms-flux  Puts shot to shot noise models?

Measuring the RMS-flux relation √ RMS values are binned to at least 20 points per bin

Good Observations XTE J1550-564  Most RXTE archival data for  XTE J1118+480  GS 1354-64  4U 1543-475 k  XTE J1550-564  XTE J1650-500  GRO J1655-40  GX 339-4  XTE J1859+226 C x  H 1743-322 641 Good Observations

Ubiquity of the rms-flux relation GX 339-4  Apparently ubiquitous across all observations possible to process  Caveats:  Limited to observations above 3% fractional rms  Excludes many soft state observations  Observations with QPOs don't always behave themselves  Sudden changes in power spectral shape exclude some observations

Intercept vs. Gradient RMS frac Green- Red 10% RMS frac

Negative X-intercepts? RMS A A B Mean Flux

Outburst Behaviour GRO J1655-40 XTE J1650-500 Hardness Green -> Blue -> Pink

Long-term behaviour

Conclusion  RMS-flux relation appears to be ubiquitous for noise  For stationary observations only  Over both short and long terms  Large number of observations with negative intercepts  Extra components in light curve  Results are consistent with Cygnus X-1 (Gleissner et. al. 2004). But extended to new states Analysis is still ongoing...

Mini-outburst of V4641

Identifying Good Observations  Following criteria used:  Kendall's tau > 0.5  Tau test > 2.0 σ  X 2 test < 3.0 σ  RMS frac > 3% Data outside this range but with RMS frac > 3% then investigated  Good data needs:  Long observation > 1 ks  High count-rate > 100 ct/s/PCU  High RMS frac > 3% good observations

Non-zero intercepts  Suggest secondary component which does not obey the rms-flux relation  Doesn't produce true linear relation  Better to fit the variance – mean relation  Parabolic however, and much harder to constrain