Paper: astro-ph/0507271
Date: Tue, 12 Jul 2005 03:45:50 GMT (104kb)

Title: Observational studies of stellar black hole binaries and ULXs

Authors: Aya Kubota (RIKEN), Kazuo Makishima (University of Tokyo, RIKEN)
Comments: 11 pages 14 figures, accepted for publication on Advances in Space
Research, Special Issue Proceedings of 35th COSPAR (Paris, France, 18-25 July
2004)
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We outline a framework for understanding the X-ray spectra of high mass
accretion rate stellar black holes based on X-ray data from RXTE and ASCA.
Three spectral regimes can be separated out by the behaviour of the observed
disk luminosity and temperature. The well established "standard regime" is seen
when the disk dominates the spectrum, where only a small fraction of the
luminosity is emitted in the power law tail. These spectra generally satisfy
the standard relation expected for thermal emission from a constant area,
namely that the disk bolometric luminosity, Ldisk, is proportional to its
maximum temperature, Tin^4. However, at higher luminosities this starts to
change to Tin^2. This "apparently standard regime" is still dominated by the
disk emission, but this difference luminosity-temperature relation and subtle
changes in spectral shape may show that another cooling process is required in
addition to radiative cooling. At intermediate luminosities there is an
anomalous regime (or weak very high state) where the disk temperature and
luminosity are less clearly related. These spectra are characterized by the
presence of a much stronger comptonized tail indicating high energy electrons.
When observed disk emission is corrected for the the effects of comptonisation
then these points lie back on the standard relation. The growth of this
comptonising corona is also clearly linked to the quasi-periodic oscillations,
as these are observed preferentially in the anomalous regime. This presented
picture was found to explain the spectral behavior of both black hole binaries
in our Galaxy and LMC. Spectral evolution of several bright ULXs observed with
ASCA were also successfully explained in the same picture.

\\ ( http://arXiv.org/abs/astro-ph/0507271 , 104kb)

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Paper: astro-ph/0507272
Date: Tue, 12 Jul 2005 07:18:47 GMT (684kb)

Title: Disentangling the composite continuum of symbiotic binaries I. S-type
systems

Authors: A. Skopal
Comments: 37 pages in printed format, 27 figures, 4 tables, accepted for
publication in Astronomy and Astrophysics
\\
We describe a method of disentangling the composite,0.12-5 microns continuum
of symbiotic binaries.The observed SED is determined by the IUE/HST archival
spectra and flux-points corresponding to the optical UBVRI and infrared JHKLM
photometric measurements. The modeled SED is given by superposition of fluxes
from the cool giant, hot stellar source and nebula including the effect of the
Rayleigh scattering process and considering influence of the iron curtain
absorptions.We applied this method to 21 S-type symbiotic stars during
quiescence, activity and eclipses.

\\ ( http://arXiv.org/abs/astro-ph/0507272 , 684kb)