1. Long-term properties of Be/X-ray pulsars in the SMC
Andry RAJOELIMANANA 1 , 2 ‏
Supervisor : Prof Phil CHARLES 1 , 2
Co-supervisor : Prof Brian Warner 1
1 University of Cape Town (UCT), 2 South African Astronomical Observatory (SAAO)

2. Outline Introduction and Background Some results Summary
X-ray binary
High Mass X-ray Binaries (HMXBs)
Supergiant X-ray Binaries (SgrXBs)
Be/X-ray binary (BeX)
A (For Comparison)
Some results
Variation of outbursts amplitude.
Orbital and super-orbital period correlation.
Colour magnitude diagram of selected SMC BeX.
Misalignment effect
Optical spectroscopy of XMMU J (ATel #2771)
Summary

3. X-ray Binaries ??? Degenerate primary ( a NS, or a BH)
1035 erg s-1 < Lx < 1039 erg s-1
LMXBs or HMXBs.
Multi-wavelength objects:
Gamma-ray : Inverse-Compton scattering
X-ray : compact objects : NS or BH
Optical : Primary star, and accretion disc
Radio : Jets, synchrotron radiation

4. Supergiant X-ray binaries (SGXBs)
Early-type Supergiants
+ Compact object( NS or BH)
Period ~ 3-15 d ‏
Circular orbits
Persistent X-ray sources (Lx~1036 erg.s-1)
Accretion from strong radiative stellar wind

5. Be/X-ray binaries (BeX)
Be Star
+ X-ray pulsar
Transient X-ray sources (Lx~1037 erg.s-1)
Wide and eccentric orbit (0.1<e<0.9)
Accretion from the Be equatorial disc

6. A0538-66 : the archetypal BeX Porb : 16.65 days
Outbursts: during optical minima
Psuper-orbital : ~ 421 days ( Be equatorial disk forms and disperses)
MJD ( )
Alcock et al., 2001
McGowan & Charles, 2003

7. A : the archetypal BeX

8. MACHO + OGLE projects ~ 18 years
Data used
- MACHO [ MAssive Compact Halo Objects]
1.27 m telescope
Data available : from
( Alcock et al., 1996) ‏
- OGLE [ Optical Gravitational Lensing Experiment]
( Udalsky et al,. 1997)
1.3 m Warsaw telescope
Phase II :
Phase III :
Phase IV : First light on September 2009
MACHO + OGLE projects ~ 18 years

9. Results
and findings

10. Long-term variations i > 90o - α i < 90o - α
(where α is the opening angle of the disk)
i < 90o - α
SXP : SMC X-ray Pulsar

11. V vs. V-R diagram of selected SMC BeX sources
Rajoelimanana, Charles & Udalski ., 2010

12. 28 out of 31 sources show this behaviour.
V vs. V-R diagram
28 out of 31 sources show this behaviour.
WHY ???

13. Inclination probability
P ( i < 90o- α ) = 1 – cos (90o- α )
P (i < 80o ) = 0.83
Assuming α ~ 10o
31 sources  4-5 sources with i > 80o
Consistent with the number of source which get redder when fainter (3 sources) .

14. Outbursts amplitude vs. brightness
The strength of the outburst increases with the brightness of the source.

15. Variation of outbursts amplitude
Rajoelimanana, Charles & Udalski ., 2010

16. Outbursts profiles Double peaks Misalignment Supernova kick
Transient profile.
Double peaks Misalignment Supernova kick
(Brandt & Podsiadlowski, 1995)

17. Orbital and super-orbital period correlation
Linear correlation coefficient of 0.73
Shorter period : truncated at smaller radius
Rajoelimanana, Charles & Udalski ., 2010

18. Optical spectroscopy of XMMU J115113.3-623730
Exposure: 1200 s
SAAO 1.9m (Sutherland)
Interstellar absorption  distance of 1kpc
broad line widths and asymmetries
 outflow or jets
J. P. Hughes, P. Slane, B. Posselt, P. Charles, A. Rajoelimanana, R. Sefako, J. Halpern, and D. Steeghs, 2010, Atel #2771

19. Summary 19 super-orbital periods
compiled and updated their orbital periods (36 orbital periods) .
Brightness increases with Colour (MACHO ‘blue’ – ‘red’) for i < 90o - α
The outbursts amplitude vary with the brightness of the source.
outbursts profiles : - faster rise, slower decline
- double peaks (misalignment, from asymmetric
supernova kick)
Optical spectroscopy of XMMU J  V Sagittae stars 

20. Thank you