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131.
Paul D. Allen Simon P. Driver Alister W. Graham Ewan Cameron Jochen Liske Roberto De Propris 《Monthly notices of the Royal Astronomical Society》2006,371(1):2-18
We present near-infrared (NIR) adaptive optics-assisted spectroscopic observations of the CO (Δμ= 2) absorption bands towards the centre of the giant elliptical galaxy NGC 1399. The observations were made with NAOS-CONICA (on the European Southern Observatory's Very Large Telescope) and have a full width at half-maximum resolution of 0.15 arcsec (14 pc). Kinematic analysis of the observations reveals a decoupled core and strongly non-Gaussian line-of-sight velocity profiles in the central 0.2 arcsec (19 pc). NIR imaging also indicates an asymmetric elongation of the central isophotes in the same region.
We use spherical orbit-superposition models to interpret the kinematics, using a set of orthogonal 'eigen-velocity profiles' that allow us to fit models directly to spectra. The models require a central black hole of mass 1.2+0.5 −0.6 × 109 M⊙ , with a strongly tangentially biased orbit distribution in the inner 40 pc. 相似文献
We use spherical orbit-superposition models to interpret the kinematics, using a set of orthogonal 'eigen-velocity profiles' that allow us to fit models directly to spectra. The models require a central black hole of mass 1.2
132.
The intermediate polar (IP) HT Cam is unusual in that it shows no evidence for dense absorption in its spectrum. We analyse an XMM–Newton observation of this star, which confirms the absence of absorption and shows that the X-ray spin pulse is energy independent. The modulation arises solely from occultation effects and can be reproduced by a simple geometrical model in which the lower accretion footprint is fainter than the upper one.
We suggest that the lack of opacity in the accretion columns of HT Cam, and also of EX Hya and V1025 Cen, results from a low accretion rate owing to their being below the cataclysmic variable period gap. 相似文献
We suggest that the lack of opacity in the accretion columns of HT Cam, and also of EX Hya and V1025 Cen, results from a low accretion rate owing to their being below the cataclysmic variable period gap. 相似文献
133.
Hiromoto Shibahashi 《Journal of Astrophysics and Astronomy》2005,26(2-3):139-160
The increasing number of pulsating modes in a star leads to the increase of the amount of information derived from the pulsation.
Probing the invisible interior of stars is a dream come true. In this review, I summarize the fundamental properties of stellar
pulsations and the excitation mechanisms, emphasizing several cases of recent progress. 相似文献
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Our spectroscopic monitoring of the hypergiants HD 168607 (B9.5 Ia-0) and HD 168625 (B5.5 Ia-0) with resolutions from 15000 to 70000 confirms that both stars belong to the Ser OB1 association, proves their spatial closeness, and increases the probability that they constitute a physical pair. 相似文献
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Y.-F. Yuan Jeremy S. Heyl † 《Monthly notices of the Royal Astronomical Society》2005,360(4):1493-1505
We study the evolution of a rigidly rotating protoneutron star (PNS) with hyperons and nucleons or solely nucleons in its core due to the escape of trapped neutrinos. As the neutrinos escape, the core nucleonic neutron star (NS) expands and the stellar rotation slows. After the neutrinos escape, the range of the spin periods is narrower than the initial one, but the distribution is still nearly uniform. A PNS with hyperons, at the late stage of its evolution, keeps shrinking and spinning up until all the trapped neutrinos escape. Consequently, the distribution of the stellar initial spin periods is skewed towards shorter periods. If the hyperonic star is metastable, its rotational frequency accelerates distinguishedly before it collapses to a black hole. 相似文献
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