Iron Kα line profiles and the inner boundary condition of accretion flows

Recent X-ray observations have shown evidence for exceptionally broad and skewed iron Kα emission lines from several accreting black hole systems. The lines are assumed to be due to fluorescence of the accretion disc illuminated by a surrounding corona and require a steep emissivity profile increasing into the innermost radius. This appears to question both standard accretion disc theory and the zero-torque assumption for the inner boundary condition, both of which predict a much less extreme profile. Instead it argues that a torque may be present due to magnetic coupling with matter in the plunging region or even to the spinning black hole itself. Discussion so far has centred on the torque acting on the disc. However, the crucial determinant of the iron line profile is the radial variation of the power radiated in the corona. Here we study the effects of different inner boundary conditions on the coronal emissivity and on the profiles of the observable Fe Kα lines. We argue that in the extreme case where a prominent highly redshifted component of the iron line is detected, requiring a steep emissivity profile in the innermost part and a flatter one outside, energy from the gas plunging into the black hole is being fed directly to the corona.     

Studies on the phosphorus requirement and proper calcium/phosphorus ratio in the diet of the black sea bream (Sparus macrocephalus)

An expriment on the phosphorus requirement and the proper Ca/P ratio in the diet of the black sea bream using the phosphorus gradient method (with casein as basic diet, sodium dihydrogen phosphate as source of phosphorus, and calcium lactate as source of calcium) showed that growth was greatly affected by the diet's phosphorus content and Ca/P ratio. Inadequate phosphorus in the diet resulted in slow growth and poor food conversion ratio (FCR). Analyses of the fish body showed it contained a high level of lipid but a low level of moisture, ash, calcium and phosphorus. The optimal values of phosphorus and Ca/P ratio in the black sea bream diet are 0.68% and 1∶2 respectively. Phosphorus in excess of this optimum value resulted in slow growth or even death. The results of this experiment clearly indicated that phosphorus is the principal mineral additive affecting black sea bream growth. Contribution No. 1972 from the Institute of Oceanology, Academia Sinica.     

Discovery of Five Narrow-Line Seyfert 1 Galaxies and Im- plications on the NLS1 Model

We report the discovery of five Narrow-Line Seyfert 1 galaxies (NLSls) identified from the ROSAT All-Sky Survey bright sources. One of them has a quasar-like luminosity and two, including the quasar-like one, have close companions and/or show interacting features. We calculate the central black hole masses and Eddington ratios for the five NLSls. In combination with the objects of Kaspi et al., we find that NLSls have smaller central black hole masses and higher accretion rate than normal Seyfert 1s.     

Preliminary Study on the Water Drag of Schlegel's Black Rockfish Sebastes schlegeli

1　Introduction　FishcageculturesystemhasbeenwidelyusedinmaricultureindustryinChina .Indesigningthecagesystem ,thewaterdragactingonit,includingthatonculturedfish ,shouldbetakenintoaccount.Avarietyofmethodshavebeenusedtodeterminethewaterdragofanimalsrangin…     

RXTE observations of 4U 1630−47 during the peak of its 1998 outburst

We present an analysis of the RXTE observations of 4U 1630−47 during its 1998 outburst. The light curve and the spectral evolution of the outburst were significantly different from the outbursts of the same source in 1996 and 1999. Special emphasis was placed on observations taken during the initial rise and during the maximum of the outburst. The maximum of the outburst was divided into three plateaux, with almost constant flux within each plateau, and fast jumps between them. The spectral and timing parameters are stable for each individual plateau, but significantly different between the plateaux. The variability detected on the first plateau is of special interest. During these observations the source exhibits quasi-regular oscillations with a period of ∼ 10–20 s. Our analysis revealed a difference in temporal behaviour of the source at high and low fluxes during this period of time. The source behaviour can be generally explained in the framework of the two-phase model of accretion flow, involving a hot inner Comptonization region and surrounding optically thick disc.
The variability and spectral evolution of the source were similar to what was observed earlier for other X-ray novae. We show that 4U 1630−47 resembles, in several aspects, other transient and persistent black hole binaries.