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X-RAY ANALYSIS of WX HYDRI with XMM-NEWTON Mukadder İĞDİ ŞEN, Füsun LİMBOZ, Gülnur İKİS GÜN 20/08/2009 1 İSTANBUL UNIVERSITY CANAKKALE ONSEKİZ MART UNIVERSTY.

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2 X-RAY ANALYSIS of WX HYDRI with XMM-NEWTON Mukadder İĞDİ ŞEN, Füsun LİMBOZ, Gülnur İKİS GÜN 20/08/ İSTANBUL UNIVERSITY CANAKKALE ONSEKİZ MART UNIVERSTY TURKEY

3 SUMMARY INTRODUCTION – Cataclysmic Variables (CVs) – Dwarf Novae – SU UMa – XMM-Newton OBSERVATIONS Data Reduction and Analysis CONCLUSIONS 2

4 X-ışınları, dalgaboyu 10 nm (100 A) ile 0.01 nm (0.1 A) olan elektromanyetik dalgalardır nm de  frekansı 3x10 19 hertz  Enerjisi 124 kev 10 nm de  frekansı 3x10 16 hertz  Enerjisi kev morötesi ışınlardan daha kısa dalgaboyuna, dolayısı ile daha yüksek frekans ve enerjiye sahiptir.dalgaboyunafrekans enerjiye X-ışınlarının bir başka adı Röntgen ışınlarıdır. ilk olarak Alman bilim adamı Wilhelm Conrad Roentgen tarafından 1895’te bulunmuştur.Röntgen c ışık hızıdır ve farklı enerjili fotonların birleşimidir. Fotonlar elektromanyetik ışınım paketleridir. Burada h Planck sabitidir. h=6.62x10-34 J s (kg m 2 /s 2 ) X-ışınları Elektromanyetik dalgaların dalgaboyu, enerji ve frekansları vardır. Bir dalganın iki tepe noktası arasındaki uzaklığına "Dalgaboyu" denir. Birimi metre (m) dir. = 0.01 nm Yumuşak Sert 12.4 keV Şekil 1.1. Elektromanyetik tayf diyagramı (λ) dalgaboyudalgaboyu 1 Angstrom = 0.1 nm = 1 x µm = 1 x cm = 1 x m 3

5 Variable Stars Variable starts İçten DeğişenlerGeometrically Variations Patlayan Değişen Yıldızlar Nova Benzeri Değişenler Novalar Cüce Nova Pulsasyon Yapan Değişen Yıldızlar U Gem (SS Cygni) Z Cam SU UMa Coşkun (Kataklizmik) Değişenler Tekrarlayan Novalar Parlaklıklarında zamanla düzenli ya da düzensiz değişim gösterirler. Variation, from occcultation Değişimin nedeni sıcaklık, yoğunluk ve basınçtır Parlaklıklarında düzenli değişim Çok az düzenli değişim gösterirler. Parlaklık ani bir şekilde artar veya azalır. İlk cüce nova olan U Geminorum 1855’te Hind tarafından keşfedilmiştir. kısa periyotludurlar. optik parlaklıkları kadir arasında değişen, küçük ve sık, tekrarlayan patlamalar gösterirler. Patlama sırasında kabuk atılımı yoktur. Patlamalar, birkaç günden birkaç haftaya kadar olan sürelerde devam eder ve düzenli şekilde tekrarlanır. Işınım gücü erg s -1 olan güçlü X-ışın kaynaklarıdır. Roche lobunu doldurmuş bir anakol yıldızı olan bir ikincil (eş) yıldızdan madde akımları ile kütle kazanan beyaz cüceli (birincil yıldız) yakın çift sistemlerdir. Yarı ayrıktırlar ve ortak bir kütle merkezi etrafında dolanmaktadırlar. Sistemlerin yörünge periyotları gnellikle 80 dakika ile birkaç saat arasındadır. Yörünge periyodu 0,1 günden kısadır. İkincil yıldızlarının kütleleri benzerdir ve yaklaşık 0,2 M  dir. iki tür patlama gösterirler: normal ve süper patlamalar. Süper patlamalar normal patlamalara göre ~0,7 kadir daha parlaktır (Vogt, 1980). Süper patlamaları sırasında ışık eğrisinde, "süper tümsek (superhump)" olarak adlandırılan periyodik parlaklık değişimi görülür. 4

6 The Cataclysmic Variables The schematic drawing of Cataclysmic variables Accretion disk Secondary star White Dwarf 5 CVs are close binary sistems with periods typically between 80 min and 8 hours. Primary component is a White Dwarf (WD). Generally, its mass is M .

7 Sistemle ilgili çeşitli hesaplamalar a1a1 a2a2 a Çift yıldızın ayrıklığı a = x 10 8 m a 1 = x 10 8 m a 2 = x 10 8 m R L1 = 3.14 x 10 8 m R L2 = ( ) x 10 8 m=1.535 x 10 8 m R L1 R2R2 ****

8 Hesaplamalar 1)G=6,67 x m 3 /kg.s 2 M1= 0.63 M  M2= 0.11 M  P yör = 107 dakika alınarak Çift yıldızın ayrıklığı a = x 10 8 m bulunmuştur. 2) a 1 = x 10 8 m 3) a = a 1 + a 2 den a 2 = x 10 8 m 4) q = M 2 / M 1 kütle oranı denkleminden q = 0.11 / 0.63 q = dir R L1 = 3.14 x 10 8 m 0.1 < q < 10 için: 5) Akışın açısal momentuma uygun olarak ulaştığı en düşük enerjili yörünge yarıçapı: Yukarıdan bulunan çiftin ayrıklığı (a) ve kütle oranı (q) yerlerine koyulduğunda R daire = x 10 8 m = x 10 8 cm dir 0.5 R daire > R 1 olmalıdır. R1 beyaz cücenin yarıçapıdır ve R 1 = 8.3 x 10 8 cm dir. Bu durumda 0.5 R daire = 55.6 x 10 8 cm olarak hesaplanmaktadır x 10 8 cm > 8.3 x 10 8 cm dir. Bu şartın sağlandığı ve böylece gaz akışının Beyaz cüceye çarpmadığı görülmektedir. R 2 =a (q / (1+q)) 1/3 R 2 =1.14 x 10 8 m

9 The Cataclysmic Variables The schematic drawing of Cataclysmic variables Accretion disk Secondary star White Dwarf 8 The second is a Late type star with the main sequence characteristics. Its mass is 0.12 M  and its radius is ~ 0.15 R  and it is fainter than WD. Surface temperature is 2900 o K and it’s cooler than Sun surface (5800 o K). Mass loss in a year is ~ – M  Secondary Star fills up its Roche lobe and as many other binaries, losses mass through the inner Lagrangian Point L 1, forming a stream flowing toward the primary. Due to the small dimension of WD and due to the specific angular momentum, this material cannot (at least not immediately) reach the surface of the WD. Instead it forms a gaseous disk (Accretion Disk), rotating around the primary component. As the stream collides with outer part of the disk, a part of its kinetic energy becomes dissipated. The place where this dissipation occurs is determinated by the size of the disk and the shape of the stream trajectory. It is called the Hot Spot.

10 The Cataclysmic Variables The schematic drawing of Cataclysmic variables Accretion disk Secondary star White Dwarf 9 The Boundary Layer connects the Accretion Disk to the WD surface. Roughly half of the available energy is emitted as the matter passes through the disk, and one half is in principle still available when the matter reaches the WD surface. Thus, half of the emited radiation may originate from the BL.

11 Dwarf Novae Cataclysmic Variables subgroups are ejected their shells except dwarf novae. Dwarf Novae have small and frequently outbursts. Thay have three subclasse as their lightcurves: U Geminorum Subclass (SS Cyg) Z Camelopardalis Subclass (Z Cam) SU Ursae Majoris Subclass (SU UMa).

12 SU UMa In this study, a spectral analysis of the dwarf novae WX Hyi and VW Hyi (which are SU UMa) are presented. SU UMa stars showed periodic peaks in the light curve during superoutburst so called “superhumps” by Voght (1974) and Warner (1975). SU UMa stars show many common properties: Ultra short orbital periods, Superhump periods, similar masses of the secondary stars, two very well seperated types of the outbursts and a similar behaviour in the periodicities for superoutbursts. Shape and amplitude of the superhump light curves (relatively sharp peaks and broad minima) are also typical, and common for all DNe with superoutburst (Voght, 1980). 11 The lightcurve of an SU UMa type (VW Hyi) (AAVSO). Superoutburst Normal outbursts

13 Coşkun Değişenlerin Çeşitli Dalgaboylarındaki Işımaları Diskli sistemlerde ışınıma katkısı olan beş bölge vardır Disk olmayan sistemlerde ise bu yapılar dört tanedir Aliş, 2002 Birincil ve ikincil yıldız, yığılma diski, gaz akışı ve sıcak leke. Birincil ve ikincil yıldız, gaz akımı ve yığılma sütunları. Aliş, 2002 Manyetik ve manyetik olmayan sistemler için Coşkun değişen çift yıldız sistemlerinin modelleri (Alis, 2002) White Dwarf It can observe in near and far UV and it can be dominated according to disk emission in several systems. (Mennickent ve diğ., 2004). Secondary Star It contributes in IR. The absorbtion lines of the Secondary star can be seen in the Cataclysmic Variables spectrum. Accretion Disk Especially it özellikle morötesi (ultraviolet, UV) bölgede ışınım yapmaktadır. Ayrıca yığılma diskinin katkısı optikte ve bir miktar da yakın- kızılötesinde kendini gösterir. (Mennickent ve diğ., 2004). Accretion Stream yakın morötesinde ışınım yapar (Gansicke ve Koester, 1999) Hot spot Optikbölgede ışınım yapar (Gansicke ve Koester, 1999) Boundary Layer Düşük yığılma oranlarında sınır tabakasından yayınlanan enerji frenleme mekanizması ile oluşmuş X-ışınları şeklindedir. Yüksek yığılma oranlarında, sınır tabakası optik olarak kalındır ve yayınlanan enerji uzak morötesi tayf bölgesinde gözlenir. (Mennickent ve diğ., 2004). 12

14 XMM-Newton The X-ray Multi-Mirror (XMM) Observatory

15 The X-ray Multi-Mirror (XMM) Observatory Launch timeDecember 10th, 1999 (ESA) Name originEnglish man-of-science “Sir Isaac NEWTON” Cost-price700 million dolar Mass4 ton Length10 m Duration time2-10 years Max. width16 m Focal lenght7.7 m Orbital altitude (apogee) km Orbital altitude (perigee)7 000 km Instruments EPIC MOS (keV) EPIC pn (keV) RGS (keV) OM (nm) Energy range – Field of view30' ~5'17' Angular resolution (FWHM) 6'' …~1'' All Scientific Instruments can work in the same time It can be observe the target for a long time Telescope Tube Focal Plane Assembly Service Module Mirror Support Platform XMM-Newton has four main Module XMM carries two distinct types of telescope: 1-three Wolter type-1 X-ray telescopes, with different X- ray detectors 2-a 30-cm optical/UV telescope Thus, XMM-Newton offers simultaneous access to two windows of the electromagnetic spectrum: X-ray and optical/UV.XMM-Newton 14

16 Chip Geometry MOS-CCD has 7 silicone chips. Every chip is 600x600 pixel PN-CCD has 12 silicone chips. Every chip is 64 x 200 pixel. 15

17 WX HYDRI and VW HYDRI Hydri – Small water snake 16

18 1Distance to the Earth265 parsec65 parsec 2TypeSU UMa Semidetached star SU UMa Semidetached star 3Equatorial coordinatesα = 2 h 09 m s δ = ' 39.9'' α = 4 h 09 m 08.3 s, δ = – ' 38'' dir 4Inclination angle Eclipse 40 ± 10◦ it does not show eclipse 60 o ±10 o it does not show eclipse 5orbital period days107 m=1.78 h= days 6The minimum brightness during the quiescent state14.2 mag13.8 mag 7The maximum brightness during normal outburst12.5 mag9.5 mag 8The maximum brightness during Superoutburst10.7 mag8.4 mag 9Normal outburst period14 days27.3 days 10Super outburst period140 days180 days 11 white dwarf mass 0.9±0.3 M ⊙ 0.63 M ⊙ 12Secondary star mass0.16 ± Mass rate q (M 2 /M 1 )0.177± The Some Properties WX Hyi VW Hyi gün gün

19 ACCRETION DISK VW HyiWX Hyi L disk =4x10 31 erg /sn M disk =12x M  /yr T disk = K T disk = o K V disk =3000 km /sn den büyük F disk =F opt =8,5x erg/cm 2 sn SECONDARY STAR VW HyiWX Hyi T II =2750 K M II =0,11 M  WHITE DWARF (WD) VW HyiWX Hyi T 1 = o K R 1 =8.3X10 8 cmR 1 =6.2X10 8 cm M 1 =0.63M  M 1 =0.86 (+0.18, -0.32)M  Accretion Rate onto WD= 5x M  /yr V 1 = km/s BOUNDARY LAYER VW HyiWX Hyi T sınır =6 keV=69,6x10 6 K (sürekli sıcaklık dağılımı) Optik olarak ince plazma V sınır =540 km/sn L sınır =8x10 30 erg /sn L sınır /L disk =0.2 BL deki x-ışın salan gazın dönme hızı: V sınır Sin i = 750 km/sn T HOT SPOT =12000 K 18

20 Optical images (NASA, Digital Sky Survey) X-ray images ( 0.1 – 2.4 keV) ROSAT X-ray ( keV) (Our study) VW Hyi WX Hyi 19

21 The XMM-Newton Observations of VW Hyi and WX Hyi Sky image obtained from EPIC PN with ds9 InstrumenttimeDurationAAVSO VW Hyi XMM :24: s (5 h 21 m) Checked for Quiescent time WX Hyi XMM :37: s (4 h 13 m) Checked for Quiescent time 20

22 Data Reduction DataInternet based data archieve of XMM-Newton Program(Science Analysis Subsystem, SAS) MethodsImaging of the source (from raw data) light curves (from raw data) (  Good time interval detection  Data filtering) Imaging of the source (from filtered data) In the different energy range: –soft(0,3-1,0 keV) –medium(1,0-1,6 keV) –hard(1,6-10,0 keV) –all(0,3-10,0 keV) Source detection Obtain the Spectrum The model fit to the spectrum Operating SystemLinux 21

23 MOS1 MOS2 PN The Light curve of MOS1, MOS2 and PN All raw data We don’t see occultation by the secondary star 22

24 Imaging of the source (from PN) 23

25 X-ray Images for EPIC Ximage Four energy range Filtered data 24

26 Source Detection The sources in the field of view for MOS1, MOS2 ve PN MOS1MOS2PN 25

27 Tayf Analysis Method MOS1MOS2PN We choose the fields for Source (green) and for background from MOS1, MOS2 ve PN images Net radiation= Source radiation – Background Radiation Background data:  (must be near to the source and far from the chip border and also it must be the same size) 26

28 THE SPECTRUMS From filtered data 27

29 Mekal Model An emission spectrum from hot diffuse gas based on the model calculations of Mewe and Kaastra with Fe L calculations by Liedahl. The model includes line emissions from several elements. EM(T) α (T/T maks ) α. Tmax is maximum plasma temperature (Singh et all., 1995). theMEKAL model describes an optically thin and collisionally ionized, isothermal plasma based on calculations by Mewe et al. (1985) and Liedahl et al. (1995) Cevmkl Model A multi-temperature plasma emission model built from the mekal code. It take the informations from the tables Mkcflow Model: A cooling flow model after Mushotzky & Szymkowiak (Cooling Flows in Clusters and Galaxies ed. A. C. Fabian, 1988). This one uses the mekal (or vmekal) model for the individual temperature components and differs from cflow in setting the emissivity function to be the inverse of the bolometric luminosity 28

30 29

31 The CEMEKL model fit to MOS1 and PN spectrums 30

32 The MKCFLOW model fit to MOS1 and PN spectrums 31

33 The CEVMKL model fit to MOS1 and PN spectrums. 32

34 CONCLUSIONS (1) 33 VW HyiWX Hyi F opt = F UV erg cm -2 s x x L disk (erg / s)4 x x kT max ( keV ) Flux from Cevmkl Model (F X ) (erg cm -2 s -1 )~ 6.8 x ~1.1 X Luminosity (L X ) ( erg / s ) ~6.8 x ~2 x Rate (L BL /L disk ) ~0.2 ~0.25 Mass accretion rate from the BL (M BL) 2.71 x gr / sn (4.3 x ( M  / yr)) 4 x gr / sn (7.3 x ( M  / yr)) Mass transfer rate of Accretion disk M disk ( M  / yr) 12 x x M BL /M disk ~ As the theoretical models: The Critical Accretion rate onto WD is 2 x g s -1 (3 x M  / yr). If this value is smaller than the Critical Accretion rate, The BL will optically thin and it wil radiate via Thermal bremssrahlung. It is correct for our study.

35 When we decide for X-ray emittig region these type systems: There is UV delay in VW Hyi and Meyer & Meyer accepts the UV delay. Meyer & Meyer-Hofmeister (1994) suggest that the inner disk in quiescent dwarf novae becomes unstable and is evaporated by a coronal siphon flow. The gas in the forming corona is partially accreted onto the white dwarf and partially lost in a wind. If the density in the corona is low, the X-ray spectrum would be dominated by emission from the cooling plasma piling up on the white dwarf. This scenario is also consistent with the results of our spectral analysis. In Addition, Gaseous plasmas with a normal astrophysical abundance of elements (abundances reduced with increasing atomic weight) are almost completely ionised at temperatures above 10 7 K. Therefore the mojor emission process which needs to be considered is bremsstrahlung. Obtained X-ray spectrum shows us: hot and optically thin plasma in the boundary layer that cools as it settles onto the WD. Our spectral analysis of XMM-Newton data indicates that the X-ray emission originates from a hot, optically thin multitemperature plasma. 34 mp the proton mass (m p = x g) the mean molecular weight (0.6) CONCLUSIONS (2)

36 CONCLUSIONS (3) Fe XXV and Fe XXVI lines come from a plasma having a temperature 0f K. In this study, The plasma temperature estimated as ~ 6.28 keV (7.3 x 10 7 K) and this value is corresponding to this structure. Rana et all. (2006) Residuals around the iron lines tend to be a sign of fluorescence from cold material (X-ray reflection) and/or an inadequate representation of the temperature structure of the spectrum. Baskill et all.(2005) keV In the X-ray spectrum: Fe XXV component of Fe Kα emission resonance line is a common feature in the hard X-ray spectra of Dne There is collision in the plasma. indicates that the temperature of the emitting plasma is above 3 × 10 7 K. We estimated Tmax ~ 7.3 x 10 7 K (for VW Hyi) and Rana et all. (2006) 6.42 keV Fe XXV component Flourescent line in the quiescent state indicates that the hard X-rays of the presence of significant reflection In non-magnetic CVs, the fluorescent iron line is believed to arise due to reflection of hard X-rays from the white dwarf surface or the inner edge of the accretion disk. at low accretion rates, the inner accretion disk is either absent or optically thin and hence contributes little to the observed reflection component. Therefore, a significant contribution to the fluorescent Fe line in DNe in the quiescent state comes from the reflection off the white dwarf surface. Rana et all. (2006) 6.9 keV Weak Fe XXVILy α lineshows the matter activity in the BL. In addition, clearly demonstrates that plasma at higher temperatures is either not present or not radiating efficiently in X-rays. It appears that the gas in the zoundary layer loses ∼ 2/3 of the available accretion energy before it begins to emit X-rays. Pandel,

37 REFERENCES 36 Bateson, 1956; Bateson, 1977 Belloni et all,1991 Fabian 1994 Godon and Sion, 2005 Liller, 1996; Mateo and Szkody, 1984 Mennickent et all.2004 Pandel et all Pandel, 2004 Pringle et all., 1987, Saygaç, 1993 Saygaç, 1994 Schoembs ve Vogt, 1981 Schreiber et all., 2004 Sion et all Sion et all Sion,1985 Smith et all., 2006 Van Amerongen et all., 1987 Vogt, 1974; Warner, 1987

38 X-RAY ANALYSIS of WX HYDRI with XMM-NEWTON

39 38

40 He, invited, encouraged in my hesitation, helped me before and now. Thanks a lot ALEXANDER ZHUK 39

41 X-RAY ANALYSIS of WX HYDRI with XMM-NEWTON


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