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An intense soft excess and evidence for light bending in the luminous narrow-line quasar PHL 1092
The narrow-line quasar PHL 1092 was observed by XMM-Newton at two epochsseparated by nearly 30 months. Timing analyses confirm the extremevariability observed during previous X-ray missions. A measurement ofthe radiative efficiency is in excess of what is expected from aSchwarzschild black hole. In addition to the rapid X-ray variability,the short ultraviolet (UV) light curves (<4 h) obtained with theOptical Monitor (OM) may also show fluctuations, albeit at much loweramplitude than the X-rays. In general, the extreme variability isimpressive considering that the broad-band (0.4-10 keV rest frame)luminosity of the source is ~1045 erg s-1. Duringat least one of the observations, the X-ray and UV light curves showcommon trends, although given the short duration of the OM observations,and low significance of the UV light curves, it is difficult to commenton the importance of this possible correlation. Interestingly, thehigh-energy photons (>2 keV) do not appear highly variable. The X-rayspectrum resembles that of many narrow-line Seyfert 1 type galaxies: anintense soft excess modelled with a multicolour disc blackbody, apower-law component, and an absorption line at ~1.4 keV. The ~1.4-keVfeature is curious given that it was not detected in previousobservations, and its presence could be related to the strength of thesoft excess. Of further interest is curvature in the spectrum above ~2keV which can be described by a strong reflection component. The strongreflection component, lack of high-energy temporal variability, andextreme radiative efficiency measurements can be understood if weconsider gravitational light-bending effects close to a maximallyrotating black hole.
| The Tokyo PMC catalog 90-93: Catalog of positions of 6649 stars observed in 1990 through 1993 with Tokyo photoelectric meridian circle
The sixth annual catalog of the Tokyo Photoelectric Meridian Circle(PMC) is presented for 6649 stars which were observed at least two timesin January 1990 through March 1993. The mean positions of the starsobserved are given in the catalog at the corresponding mean epochs ofobservations of individual stars. The coordinates of the catalog arebased on the FK5 system, and referred to the equinox and equator ofJ2000.0. The mean local deviations of the observed positions from theFK5 catalog positions are constructed for the basic FK5 stars to comparewith those of the Tokyo PMC Catalog 89 and preliminary Hipparcos resultsof H30.
| Photoelectric observations of lunar occultations. XV
The last (or possibly penultimate) paper in a series on lunaroccultations presents observations of 404 phenomena, preceded by somegeneral remarks of a retrospective nature. The series of observationsbegan in 1968. Data for 20 doubles or suspected doubles are presented,ranked in order of certainty, with designation 3 representing thesurest. Thirteen of the cases refer to stars not previously noted asdoubles. Seven determinations of angular diameters are presented, ofwhich three have been previously observed.
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Gözlemler ve gökölçümü verileri
| Takýmyýldýz: | Baliklar |
| Sað Açýklýk: | 01h40m03.86s |
| Yükselim: | +06°23'09.9" |
| Görünürdeki Parlaklýk: | 8.946 |
| Uzaklýk: | 158.228 parsek |
| özdevim Sað Açýklýk: | 18.6 |
| özdevim Yükselim: | -22.4 |
| B-T magnitude: | 9.331 |
| V-T magnitude: | 8.978 |
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