SALT spectroscopy of the HMXB associated with the LMC supernova remnant MCSNR\,J0513$-$6724

Abstract

We report the results of optical échelle spectroscopy with the Southern African Large Telescope (SALT) of the mass donor star BSDL\,923 in the neutron star (NS) high-mass X-ray binary XMMU\,J051342.6$-$672412 associated with the LMC supernova remnant (SNR) MCSNR\,J0513$-$6724. We found that BSDL\,923 is a B0.7\,III star with double peaked emission lines originating in a circumbinary disk-like structure. This classification and the presence of double-peaked emission lines imply that BSDL\,923 is a Be star. Modelling with the stellar atmosphere code {\sc fastwind} was used to derive the effective temperature $T_{\mathrm{eff}}=27\pm 1$\,kK, surface gravity $\log g=3.22\pm 0.10$, projected rotational velocity $v\sin i\approx100\pm45 \, \kms$, colour excess $E(B-V)=0.53\pm 0.05$\,mag, and luminosity $\log(L_*/\lsun)=5.46\pm0.10$ of BSDL\,923, as well as to show that the surface of this star is polluted with $\alpha$-elements (O, Mg and Si) from the supernova ejecta. We found also that the NS is orbiting BSDL\,923 in an eccentric ($e=0.158\pm 0.061$) orbit with the orbital period of $1.280\pm 0.006$\,d and the semi-major axis of $17\pm3 \, \rsun$, and the radius of BSDL\,923 is $25\pm5 \,\rsun$. We speculate that the NS is embedded in the atmosphere of BSDL\,923 either because it was kicked at birth towards this star or because of inflation of BSDL\,923 caused by the energy input from the supernova blast wave. Using long-slit spectroscopy with SALT, we searched for possible signs of the SNR shell in the 2D spectrum, but did not find them. This lack of detection is consistent with the young age ($\approx 4_{-1}^{+2}$\,kyr) of MCSNR\,J0513$-$6724, implying that it is still in the adiabatic (non-radiative) phase.

13 pages, 11 figures and 6 tables. Accepted for publication by MNRAS

References in corpus (20)

• An Analysis of the Shapes of Interstellar Extinction Curves. V. The IR-Through-UV Curve Morphology
• An eclipsing binary distance to the Large Magellanic Cloud accurate to 2 per cent
• A Grid of NLTE Line-Blanketed Model Atmospheres of Early B-type Stars
• UBVJHK synthetic photometry of Galactic O stars
• First science with SALT: peering at the accreting polar caps of the eclipsing polar SDSS J015543.40+002807.2
• Spectral distribution of Be/X-ray binaries in the Small Magellanic Cloud
• The VLT-FLAMES Tarantula Survey XVIII. Classifications and radial velocities of the B-type stars
• A Luminous Gamma-ray Binary in the Large Magellanic Cloud
• Observability of inflated companion stars after supernovae in massive binaries
• The ASKAP-EMU Early Science Project: 888 MHz Radio Continuum Survey of the Large Magellanic Cloud
• Discovery of a very young high-mass X-ray binary associated with the supernova remnant MCSNRJ0513-6724 in the LMC
• Discovery of a putative supernova remnant around the long-period X-ray pulsar SXP 1323 in the Small Magellanic Cloud
• XMMU J050722.1-684758: Discovery of a new Be X-ray binary pulsar likely associated with the supernova remnant MCSNR J0507-6847
• The orbital parameters of the gamma-ray binary LMC P3
• Long-period eclipsing binaries: towards the true mass-luminosity relation. I. The test sample, observations and data analysis
• Understanding the coexistence of spin-up and spin-down behaviors in long period X-ray pulsars
• Long-period eclipsing binaries: towards the true mass-luminosity relation. II. Absolute parameters of the NN Del system
• SALT observations of the supernova remnant MCSNR J0127-7332 and its associated Be X-ray binary SXP 1062 in the SMC
• Early neutron star evolution in high-mass X-ray binaries
• Wray 15-906: a candidate luminous blue variable discovered with WISE, Herschel and SALT

Cited by in corpus (1)

• Long-period double-lined eclipsing binaries: the system V454 Aur with the secondary eclipse caused by the occultation of the hotter component