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

▶

Dec 13, 2023 373 likes •517 views

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

SLIDE 1

The rms-flux relation In Black Hole Binaries

Credit: ESA

Lucy Heil (Leicester) With: Simon Vaughan & Phil Uttley (Leicester) (Southampton)

SLIDE 2

The RMS-flux relation

 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)

V4641

SLIDE 3

Implications of rms-flux

 Puts shot to shot noise models?

SLIDE 4

Measuring the RMS-flux relation

RMS values are binned to at least 20 points per bin

√

SLIDE 5

Good Observations

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

XTE J1550-564

641 Good Observations

k Cx

SLIDE 6

Ubiquity of the rms-flux relation

 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

GX 339-4

SLIDE 7

Intercept vs. Gradient

10% RMSfrac

RMSfrac Green- Red

SLIDE 8

Negative X-intercepts?

Mean Flux RMS

A A

SLIDE 9

Outburst Behaviour

GRO J1655-40 XTE J1650-500

Hardness Green -> Blue -> Pink

SLIDE 10

Long-term behaviour

SLIDE 11

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...

SLIDE 12

Mini-outburst of V4641

SLIDE 13

Identifying Good Observations

 Following criteria used:  Kendall's tau > 0.5  Tau test > 2.0σ  X2 test < 3.0σ  RMSfrac > 3%

Data outside this range but with RMSfrac > 3% then investigated

 Good data needs:  Long observation > 1 ks  High count-rate > 100 ct/s/PCU  High RMSfrac > 3%

good observations

SLIDE 14

Non-zero intercepts

 Suggest secondary component which does not

bey the rms-flux relation

 Doesn't produce true linear relation  Better to fit the variance – mean relation  Parabolic however, and much harder to

constrain