SIMBAD references

We have analysed the new Rossi X-ray Timing Explorer Proportional Counter Array data of the atoll neutron star (NS) low-mass X-ray binary (LMXB) system XB 1254-690. The colour-colour diagram shows that the source was in the high-intensity banana state. We have found two low-frequency candidate peaks with single trial significances of ≈2.65 {x} 10^–8 and ≈7.39 {x} 10^–8 in the power spectra. After taking into account the number of trials, the joint probability of appearance of these two peaks in the data set only by chance is ∼ 4.5 {x} 10^–4, and hence a low-frequency quasi-periodic oscillation can be considered to be detected with a significance of ∼ 4.5 {x} 10^–4, or ∼ 3.5σ for the first time from this source. We have also done the first systematic X-ray spectral study of XB 1254-690, and found that, while one-component models are inadequate, three-component models are not required by the data. We have concluded that a combined broken-power-law and Comptonization model best describes the source continuum spectrum among 19 two-component models. The plasma temperature (∼3 keV) and the optical depth (∼7) of the Comptonization component are consistent with the previously reported values for other sources. However, the use of a broken-power-law component to describe the NS LMXB spectra has recently been started, and we have used this component for XB 1254-690 for the first time. We have attempted to determine the relative energy budgets of the accretion disc and the boundary layer using the best-fitting spectral model, and concluded that a reliable estimation of these budgets requires correlations among time variations of spectral properties in different wavelengths. The Type Ib SN 1999dn: one year of photometric and spectroscopic monitoring