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تسجيل مستخدم جديدINTEGRAL observations of the Small Magellanic Cloud
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V.A. McBride
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The first INTEGRAL observations of the Small Magellanic Cloud (carried out in 2003) are reported in which two sources are clearly detected. The first source, SMC X-1, shows a hard X-ray eclipse and measurements of its pulse period indicate a continuation of the long-term spin-up now covering ~30 years. The second source is likely to be a high mass X-ray binary, and shows a potential periodicity of 6.8s in the IBIS lightcurve. An exact X-ray or optical counterpart cannot be designated, but a number of proposed counterparts are discussed. One of these possible counterparts shows a strong coherent optical modulation at ~2.7d, which, together with the measured hard X-ray pulse period, would lead to this INTEGRAL source being classified as the fourth known high mass Roche lobe overflow system.
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We present the preliminary results of the INTEGRAL survey of the Large Magellanic Cloud. The observations have been carried out in January 2003 (about 10^6 s) and January 2004 (about 4x10^5 s). Here we concentrate on the bright sources LMC X-1, LMC X
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A mosaic of four UIT far-UV (FUV; 1620A) images, which covers most of the SMC bar, is presented, with derived stellar and HII region photometry. The UV morphology of the Bar shows that recent star formation there has left striking features including:
a) four concentrations of UV-bright stars spread from northeast to southwest at nearly equal (~30 arcmin=0.5 kpc) spacings; b) a well-defined 8-arcmin ring of UV-bright stars surrounded by a larger H-alpha ring, suggesting sequential star formation. FUV PSF photometry is obtained for 11,306 stars, and a FUV luminosity function is derived. A (FUV-V,V) color-magnitude diagram for 195 identified supergiants, with derived extinctions; the bluest (least-reddened) stars of each spectral type have FUV-V colors consistent with models. FUV photometry is obtained for 42 H-alpha-selected HII regions, both for the stars and for the total emission within the apertures defined by Kennicutt & Hodge. The flux-weighted average ratio of total to stellar FUV flux is 2.15; the stellar FUV luminosity function indicates that most of the excess total flux is due to scattered FUV radiation, rather than faint stars. Both stellar and total emission are well correlated with H-alpha fluxes, and yield FUV/H-alpha ratios that are consistent with models of single-burst clusters with SMC metallicity, ages from 1-5 Myr, and moderate (E(B-V)=0.0-0.1 mag) internal SMC extinction.
We use new high-resolution HI data from the Australian Square Kilometre Array Pathfinder (ASKAP) to investigate the dynamics of the Small Magellanic Cloud (SMC). We model the HI gas component as a rotating disc of non-negligible angular size, moving
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