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)

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) A0538-66 (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 J115113.3-623730 (ATel #2771) Summary

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

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

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

A0538-66 : the archetypal BeX Porb : 16.65 days Outbursts: during optical minima Psuper-orbital : ~ 421 days ( Be equatorial disk forms and disperses) MJD (+2448623.5) Alcock et al., 2001 McGowan & Charles, 2003

A0538-66 : the archetypal BeX

MACHO + OGLE projects ~ 18 years Data used - MACHO [ MAssive Compact Halo Objects] 1.27 m telescope Data available : from 1992 - 2000 ( Alcock et al., 1996) ‏ - OGLE [ Optical Gravitational Lensing Experiment] ( Udalsky et al,. 1997) 1.3 m Warsaw telescope Phase II : 1997 - 2000 Phase III : 2001 - 2009 Phase IV : First light on September 2009 MACHO + OGLE projects ~ 18 years

Results and findings

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

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

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

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) .

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

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

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

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

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

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 J115113.3-623730  V Sagittae stars 

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