broadband variability properties of cvs compared to xrbs/agn fileobjects white dwarfs neutron stars...
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Broadband variability properties of CVs compared to XRBs/AGN
Simone Scaringi
Ierapetra16 Jun 2014
Universal accretion
Why study broadband variability?To probe accretion!
Accretion regulates the growth and evolution of all objects in the Universe
Young stellar objects White dwarfs
Neutron stars & Black holes
Active Galactic Nuclei
~1M☉
1<M☉<20 106<M
☉<109<1.4 M
☉
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Ierapetra16 Jun 2014
Universal accretion
Why accretion?Up until now the physical models seeking to explain the observed accretiondriven phenomena have been developed for individual
classes...
...but there is one underlying ansatz to accretion!
???
Young stellar objects White dwarfs
Neutron stars & Black holes
Active Galactic Nuclei
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Ierapetra16 Jun 2014
Universal accretion
Compact interacting binaries● Observationally all exhibit large
amplitude outbursts ● Theoretically explained through
thermal/viscous disk instabilities● Accretion disk dynamics governed
by the embedded gravitational potential:
> for the same mass...
XRBs
few km
Xrays
~ 103 – 104 Hz
CVs
few thousand km
Optical/UV
~ 0.1 Hz
Surface
Emission
fdyn
at surface
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Ierapetra16 Jun 2014
Universal accretion
State changes + jets in CVs
Koerding et al. (2008)
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Universal accretion
Accretiondriven flickering
XraysCyg X1
OpticalMV Lyr
20 seconds
Xrays3C 279
5 days
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15 years
Ierapetra16 Jun 2014
Universal accretion
10 degrees
● Launched March 2009
● 32 CCDs: 95 Megapix!
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Ierapetra16 Jun 2014
Universal accretion
Power spectral densities
Black hole XRB Neutron star
White dwarfBlack hole AGN
Scaringi et al. (2012b)
Belloni et al. (2002)McHardy et al. (2007)
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Universal accretion
The rmsflux relation
MV Lyr
● Observed flux distribution is lognormal
→ Additive processes are immediately ruled out!
● Observed lightcurves must be the result of multiplicative processes
Scaringi et al. (2012a)Uttley & McHardy 2001
Uttley et al. 2005
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Ierapetra16 Jun 2014
Universal accretion
Fourierdependent time lags
Emmanoulopoulos et al. (2011)Soft lags
Hard lags
AGN
XRBs
0.1Frequency (Hz)
0.01 1 10
Uttley et al. (2011)
Nowak & Vaughan 1997Nowak et al. 1999
Cyg X-1
GX 339-4
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Universal accretion
Fluctuating accretion disksLyubarskii 1997Arevalo & Uttley 2006 (AGN)Ingram & van der Klis 2013 (XRBs)Scaringi 2014 (CVs)etc...
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Universal accretion
Fluctuating accretion disksEmmanoulopoulos et al. 2014Gardner & Done 2014etc...
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Universal accretion
Fourier time lags in CVs
● Need to “translate” energies and frequencies
● ULTRACAM & MAIA are best suited
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Universal accretion
Fourier time lags in CVs and AGN
LU CamMV Lyr
AGNCVs
Scaringi et al. (2013b) De Marco et al. (2013)
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Universal accretion
Fourier time lags in CVs and AGN
(Scaringi et al. 2013b)
LU CamMV LyrSS Cyg (prelim.)
AGNCVs
U Gem (prelim.)
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Scaringi et al. (2013b) De Marco et al. (2013)
Ierapetra16 Jun 2014
Universal accretion
Future work...● The ansatz still holds for now:
→ the physics of accretion is universal! ● Data on only 4 CVs:
→ look at more with MAIA and ULTRACAM and for longer!● YSO also display flickerlike variability:
→ is this also similar to XRBs/AGN/CVs?● PSD modelling of Kepler CVs:
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MV Lyr (done!) KIC8751494V1506 Cyg
Ierapetra16 Jun 2014
Universal accretion
The K2 mission
● Field 0 8 CVs→
● Field 1 9 CVs (1 IP) →
● Field 2 might include Sco X1
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Universal accretion
PLATO – ESA M3 mission
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