Correlation analysis of photometric and spectroscopic data of symbiotic systems AG Dra and Z And...

Correlation analysis of photometric and spectroscopic data of symbiotic systems

AG Dra and Z AndJAROSLAV MERC1, RUDOLF GÁLIS1, LAURITS LEEDJÄRV2

1 Facu l ty o f Sc ience , P. J . Ša fá r i k Un ive rs i ty , Pa rk Ange l inum 9 , Koš i ce 040 01 , The S lovak Repub l i c

2 Tar tu Obse rva to ry , Obse rva toor ium i 1 , Tõ rave re , 61602 Tar tumaa , Es ton ia

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, 2015 KOLOS 2015

KOLOS 2015 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, 2015

KOLOS 2015 4

Correlation of photometric data of AG Dra


38000 40000 42000 44000 46000 48000 50000 52000 54000 56000JD - 2 400 000 [days]

1965 1970 1975 1980 1985 1990 1995 2000 2005 2010

10.0

9.5

9.0

8.5

V [m

ag]

12.0

11.5

11.0

10.5

10.0

9.5

9.0

B [

mag

]

12.0

11.5

11.0

10.5

10.0

9.5

9.0

8.5

8.0

7.5

U [m

ag

]

C Q4 D Q5 E+F Q6

C1C2

D1 D2

D3 D4 E0

E1E2

E3 E4 E5

E6

E7 E8

E9

E10

F1

F2

• 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

KOLOS 2015 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


KOLOS 2015 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


KOLOS 2015 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


KOLOS 2015 8

Consequences for principal component analysis


• 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

KOLOS 2015 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 l6825 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


KOLOS 2015 10

AG Dra vs. Z And• we performed a similar cross-correlation analysis of EWs of the O VI l6825 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


KOLOS 2015 11

AG Dra vs. Z And


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 l6825 of AG Dra and Z And. The 2s white level noise was about 0.1 and 0.16 for photometric and spectroscopic data, respectively.

Data setTime shift Cross-corr. function

median error median errorFilter U 2 108.7 8.2 0.76 0.05Filter B 2 108.7 5.7 0.84 0.03Filter V 2 116.3 3.2 0.82 0.04

EWs 2 289.8 24.7 0.59 0.052 102.7 4.2 0.49 0.082 972.3 6.4 0.31 0.03

51500 52000 52500 53000 53500 54000 54500 55000 55500JD - 2 400 000 [days]

0

10

20

Eq

. w

idth

s O

VI [

A]

0

10

20

Eq

. wid

ths O

VI [A

]

11

10

9

8

U [

mag

]

11

10

9

U [m

ag]

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010

AG Dra

Z And

AG Dra

Z And

°

°

KOLOS 2015 12

Thank you for your attention.


Correlation analysis of photometric and spectroscopic data of symbiotic systems AG Dra and Z And...

Documents

Transcript of Correlation analysis of photometric and spectroscopic data of symbiotic systems AG Dra and Z And...