1. Space Research and Technology Institute, Sofia, Bulgaria
X Serbian-Bulgarian Astronomical Conference (X SBAC): 30 May – 03 June 2016, Belgrade, Serbia
Emission Properties of White Dwarf’s Accreting Binaries By The Polarization Methods
Daniela Boneva
Space Research and Technology Institute, Sofia, Bulgaria

2. Model of the flare activity Indications of active states
Outline
Aim:
Investigation of the relationship between the flare-ups activity in white dwarf binaries and the polarization state.
Objects
Model of the flare activity
Indications of active states
Polarization methods and model
Analysis of the preliminary results
What’s next…
X Serbian-Bulgarian Astronomical Conference (X SBAC): 30. May – 03. June 2016, Belgrade, Serbia

3. Objects L1 M1 M2 CVs stars: SS Cyg and V592 Cas
StarLightPro-2 simulation
CVs stars: SS Cyg and
V592 Cas
X Serbian-Bulgarian Astronomical Conference (X SBAC): 30. May – 03. June 2016, Belgrade, Serbia

4. Model of bursts and flare-ups activities
(Kononov et al. 2008, Boneva et al. 2009)
Mass transfer and disturbances in the disc’s flow
stronger emission during the development of the outburst
Flow transformations, wave pattern formation
Gas is leaving the toroidal shell; it forms an expanding spherical shell around the accretor
angular momentum transportation efficiency raise; accretion rate onto the binary increases
strong heating of the gas between the toroidal shell and the accretor
growing intensity of the white dwarf radiation
a toroidal shell (C) forms around the accretor (A)
heating of the nearest parts of accretion disc
growth of the inner parts thickness

5. Indications of Flare-ups; bursts
SS Cyg:
Semidetached binary: red dwarf ~ 0.56 Mo and white dwarf ~ 0.97 Mo
SS Cyg light curve AAVSO light curve indicates activity
Hγ Doppler tomograms for SS Cyg in its active state from spectral observations of this star (Boneva et al. 2009).
X Serbian-Bulgarian Astronomical Conference (X SBAC): 30. May – 03. June 2016, Belgrade, Serbia

6. Swift-XRT Energy spectrum, PC mode
Indications of Flare-ups; bursts
Swift-XRT Energy spectrum, PC mode
Swift-XRT light curve of SS Cyg (Swift-XRT generator)
X Serbian-Bulgarian Astronomical Conference (X SBAC): 30. May – 03. June 2016, Belgrade, Serbia

7. Indications of Flare-ups; bursts
V592 Cas:
Cataclysmic variable; white dwarf ~ 0.75 Mo
Mac.r. ~ 1×10^−8 M⊙ yr ^−1
Swift-XRT Energy spectrum, PC mode
AAVSO light curve of V592 Cas
X Serbian-Bulgarian Astronomical Conference (X SBAC): 30. May – 03. June 2016, Belgrade, Serbia

8. A Schematic view of the polarization modeling: flares to polarization
Algorithm of the processes
Stages of calculation
Bursts; Flare-ups
Flare-ups
dramatic flux and polarization variations in the optical, near-infrared and X-Ray bands
Measurement of the emission intensity
Stokes parameters measurement
Variations in the flow density level
the polarization degree increasing significantly
Degree of polarization
Type of polarization

9. Four Stokes parameters
Degree of polarization P
Degree of circular polarization PC
The Poincare vector of polarization
…and on the base of models: (Churazov et al. 2002), (Marin et al. 2014) and (Molinary et al. 2011) ….
X Serbian-Bulgarian Astronomical Conference (X SBAC): 30. May – 03. June 2016, Belgrade, Serbia

10. Polarization degree (P) during the bursts activity of SS Cyg.
P=1 – fully polarized
X Serbian-Bulgarian Astronomical Conference (X SBAC): 30. May – 03. June 2016, Belgrade, Serbia

11. Polarization degree (P) during the bursts activity of V592 Cas.
P=1 – fully polarized
X Serbian-Bulgarian Astronomical Conference (X SBAC): 30. May – 03. June 2016, Belgrade, Serbia

12. Under Discussion; remarks
Pmax depends on the number of dust grains along the line of sight to the star
the state of polarization of the emitted light in general provides information on various spatial anisotropies of the excited system
polarization parameters could give us information about the basic properties and structures of the flares material
degree of polarization depends on the inclination of the disc, and the wavelength dependence of polarization gives information on the size of the scatterers
X Serbian-Bulgarian Astronomical Conference (X SBAC): 30. May – 03. June 2016, Belgrade, Serbia

13. To develop and improve the model;
…to be continued
Future work:
To develop and improve the model;
To define the properties and structures of flares;
Is it possible to detect the mechanisms that could trigger bursts by the methods of polarimetry?
To receive more real data;
X Serbian-Bulgarian Astronomical Conference (X SBAC): 30. May – 03. June 2016, Belgrade, Serbia

14. THANK YOU!  Acknowledgments: X SBAC Organizing committee
This work made use of data supplied by the UK Swift Science Data Centre at the University of Leicester.
Thank the AAVSO (American Association of Variable Star Observers) to provide the data of Light Curve Generator.
X Serbian-Bulgarian Astronomical Conference (X SBAC): 30. May – 03. June 2016, Belgrade, Serbia