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Register a new userIonization Cone in the X-ray Binary LMC X-1
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R. Cooke
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In an earlier paper, we presented the first evidence for a bow-shock nebula surrounding the X-ray binary LMC X-1 on a scale of ~15 pc, which we argued was powered by a jet associated with an accretion disk. We now present the first evidence for an ionization cone extending from an X-ray binary, a phenomenon only seen to date in active galactic nuclei (AGN). The ionization cone, detected in the HeII4686/Hbeta and [OIII]5007/Hbeta line ratio maps, aligns with the direction of the jet inferred from the bow-shock nebula. The cone has an opening angle ~45 deg and radial extent ~3.8 pc. Since the HeII emission cannot be explained by the companion O star, the gas in the ionization cone must be exposed to the `naked accretion disk, thereby allowing us to place constraints on the unobservable ionizing spectrum. The energetics of the ionization cone give unambiguous evidence for an ultraviolet - soft X-ray (XUV) excess in LMC X-1. Any attempt to match the hard X-ray spectrum (>1keV) with a conventional model of the accretion disk fails to account for this XUV component. We propose two likely sources for the observed anisotropy: (1) obscuration by a dusty torus, or (2) a jet-blown hole in a surrounding envelope of circumstellar absorbing material. We discuss the implications of our discovery in the context of the mass-scaling hypothesis for accretion onto black holes and suggest avenues for future research.
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In this work, at first we present a model of studying astrophysical flows of binary systems and microquasars based on the laws of relativistic magnetohydrodynamics. Then, by solving the time independent transfer equation, we estimate the primary and secondary particle distributions within the hadronic astrophysical jets as well as the emissivities of high energy neutrinos and $gamma$-rays. One of our main goals is, by taking into consideration the various energy-losses of particles into the hadronic jets, to determine through the transport equation the respective particle distributions focusing on relativistic hadronic jets of binary systems. As a concrete example we examine the extragalactic binary system LMC X-1 located in the Large Magellanic Cloud, a satellite galaxy of our Milky Way Galaxy.
This paper reports the results of Suzaku observation of the spectral variation of the black hole binary LMCX-1 in the soft state. The observationwas carried out in 2009 from July 21 to 24. the obtained net count rate was $sim$30 counts s$^{-1}$ in the 0.5--50 keV band with $sim$10% peak-to-peak flux variation. The time-averaged X-ray spectrum cannot be described by a multi-color disk and single Compton component with its reflection, but requires additional Comptonized emissions. This double Compton component model allows a slightly larger inner radius of the multi-color disk, implying a lower spin parameter. Significant spectral evolution was observed above 8 keV along with a flux decrease on a timescale of $sim$10$^4$--10$^5$ s. By spectral fitting, we show that this behavior is well explained by changes in the hard Comptonized emission component in contrast to the maintained disk and soft Comptonized emission.
Of all known persistent stellar-mass black hole candidates, only LMC X-1 and LMC X-3 consistently show spectra that are dominated by a soft, thermal component. We present results from long (170ksec) Rossi X-ray Timing Explorer (RXTE) observations of LMC X-1 and LMC X-3 made in 1996 December. The spectra can be described by a multicolor disk blackbody plus an additional high-energy power-law. Even though the spectra are very soft (Gamma is about 2.5), RXTE detected a significant signal from LMC X-3 up to energies of 50keV, the hardest energy at which the object was ever detected. Focusing on LMC X-3, we present results from the first year of an ongoing monitoring campaign with RXTE which started in 1997 January. We show that the appearance of the object changes considerably over its ~200d long cycle. This variability can either be explained by periodic changes in the mass transfer rate or by a precessing accretion disk analogous to Her X-1.
Two nights of phase-resolved medium resolution VLT spectroscopy of the extra-galactic low mass X-ray binary LMC X-2 have revealed a 0.32+/-0.02 day spectroscopic period in the radial velocity curve of the HeII lambda4686 emission line that we interpret as the orbital period. However, similar to previous findings, this radial velocity curve shows a longer term variation that is most likely due to the presence of a precessing accretion disk in LMC X-2. This is strengthened by HeII lambda4686 Doppler maps that show a bright spot that is moving from night to night. Furthermore, we detect narrow emission lines in the Bowen region of LMC X-2,with a velocity of K_em=351+/-28 km/s, that we tentatively interpret as coming from the irradiated side of the donor star. Since K_em must be smaller than K_2, this leads to the first upper-limit on the mass function of LMC X-2 of f(M_1)>=0.86Msun (95% confidence), and the first constraints on its system parameters.
We modelled optical light curves of Sco~X-1 obtained by the Kepler space telescope during K2 mission. Modelling was performed for the case of the strong heating of the optical star and accretion disc by X-rays. In the considered model the optical star fully filled its Roche lobe. We investigated the inverse problem in wide ranges of values of model parameters and estimated following parameters of Sco X-1: the mass ratio of components $q=M_x/M_v=3.6$ ($3.5-3.8$), where $M_x$ and $M_v$ were masses of the neutron and optical stars correspondingly, the orbital inclination was $i=30^{circ}$ ($25^{circ}-34^{circ}$). In the brackets uncertainties of parameters $q$ and $i$ were shown, they originated due to uncertainties of characteristics of the physical model of Sco X-1. The temperature of non-heated optical star was $T_2 = 2500-3050$ K, its radius was $R_2=1.25R_{odot}=8.7times 10^{10}$ cm, and its bolometric luminosity was $L_{bol}=(2.1-4.6)times 10^{32}$ erg s$^{-1}$. The mass of the star was $M_vsimeq 0.4M_{odot}$. The contribution of the X-ray heated accretion disc dominated in the total optical emission of Sco~X-1. The transition between low and high states occurred due to the increase of X-ray luminosity by a factor $2-3$.
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