1. Correlation analysis of photometric and spectroscopic data of symbiotic systems AG Dra and Z And JAROSLAV MERC 1, RUDOLF GÁLIS 1, LAURITS LEEDJÄRV 2 1 Faculty of Science, P. J. Šafárik University, Park Angelinum 9, Košice 040 01, The Slovak Republic 2 Tartu Observatory, Observatooriumi 1, Tõravere, 61602 Tartumaa, Estonia

2. Outline Symbiotic systems AG Dra and Z And Correlation of photometric data of AG Dra Correlation of spectroscopic data of AG Dra Consequences for principal component analysis AG Dra vs. Z And Thursday, December 2, 2015KOLOS 2015 2

3. Symbiotic systems AG Dra and Z And AG Draconis one of the best studied symbiotic systems cool component is a red giant of early spectral type (K0 – K4) hot component is a high luminosity white dwarf system is in circumbinary nebula Z Andromedae the class prototype of the symbiotic stars cool component is of spectral type M4 – M5 Thursday, December 2, 2015KOLOS 2015 3

4. Correlation of photometric data of AG Dra Thursday, December 2, 2015KOLOS 2015 4 photometric data are very well correlated with each other (corr. coeff. > 0.9) changes due to orbital period are not so obvious in B and V as in U

5. Correlation of spectroscopic data of AG Dra radial velocities curves are not well correlated errors on data (2 – 7 km/s) are similar to amplitude of changes correlation analysis cannot bring any new information about system in such case Thursday, December 2, 2015KOLOS 2015 5

6. Correlation of spectroscopic data of AG Dra the equivalent widths these are well correlated in active stages E4+E5, E6-F2 and in quiescent stage Q6 interesting stage Q* - very short quiescent stage (in photometric) but there is some activity seen in spectroscopic data Thursday, December 2, 2015KOLOS 2015 6

7. Correlation of spectroscopic data of AG Dra absolute fluxes curves are well correlated in stages E4+E5, E6-E10 and Q6 Q* shows similar features as in EWs in stage F O VI line is in anticorrelation – possibly there are present several mechanisms controlling outbursts of the system Thursday, December 2, 2015KOLOS 2015 7

8. Consequences for principal component analysis Thursday, December 2, 2015KOLOS 2015 8 Principal Component Analysis (PCA) statistical method of processing of data obtained in different filters or spectral lines most significant variations will be contained in PCA1, least significant in the last one first few principal components can be used for period analysis without any loosing significant signal Consequences of level of correlation of data badly correlated data sets cannot be processed by PCA method every component will contain „significant“ variations

9. AG Dra vs. Z And during cool outburst of AG Dra started after JD2 453 900 (July 2006, peak of the active stage F1) weakening of the Raman scattered O VI line is very well seen similar weakening of the O VI 6825 was detected line in the spectrum of the prototypical symbiotic star Z And we selected about 3270 days time intervals from the UBV light curves of both AG Dra and Z And we performed their cross-correlation analysis (more runs with different lengths, beginnings and ends of the interval) rather strong correlation was found when the light curves were shifted by about 2100 days Thursday, December 2, 2015KOLOS 2015 9

10. AG Dra vs. Z And we performed a similar cross-correlation analysis of EWs of the O VI 6825 line in AG Dra and Z And the maximum value of the cross-correlation function appeared for the time shift around 2 290 days in many runs this maximum has double-peaked structure with the second maximum around 2 100 days these results showed the strong similarity of photometric and spectroscopic behavior of AG Dra and Z And those reasonable correlations would imply some similarity of the nature of hot components and mechanisms of the outbursts in AG Dra and Z And Thursday, December 2, 2015KOLOS 2015 10

11. AG Dra vs. Z And Thursday, December 2, 2015KOLOS 2015 11 Tab. 1 - The results of the cross-correlation analysis of the U, B and V light curves as well as EW curves of O VI line at 6825 of AG Dra and Z And. The 2  white level noise was about 0.1 and 0.16 for photometric and spectroscopic data, respectively. Data set Time shift Cross-corr. function medianerrormedianerror Filter U2 108.78.20.760.05 Filter B2 108.75.70.840.03 Filter V2 116.33.20.820.04 EWs 2 289.824.70.590.05 2 102.74.20.490.08 2 972.36.40.310.03

12. Thank you for your attention. Thursday, December 2, 2015KOLOS 2015 12