15,225 research outputs found
ROSAT observations of two 'cooling flow' EMSS Galaxies
We present ROSAT observations of two luminous L~10^44 erg/s EMSS galaxies,
MS1019+5139 and MS1209+3917, previously classified as 'cooling flow' galaxies.
MS1019+5139 does not appear to be spatially extended (<13 kpc) while its
spectrum is well fit by a power law with Gamma = 1.73 +0.19-0.18; X-ray
variability on a timescale of ~ years is also clearly detected. MS1209+3917
shows no evidence of spatial extension (<50 kpc) but it shows variability,
while its spectrum can be fit with thermal bremsstrahlung emission (kT=1.8
+0.9-0.4 keV) or a power law model (Gamma = 2.50 +0.44-0.42, but with excess
photoelectric absorption above the Galactic value). All the above argue against
thermal emission from a group of galaxies or a galaxy but in favour of an AGN
(possibly BL Lac) interpretation. We conclude that no 'normal' galaxies with
high X-ray luminosities have yet been detected in the EMSS survey that could be
significant contributors to the X-ray background.Comment: 6 pages, LaTeX, 6 postscript figures included, to appear in MNRA
Integral Field Spectroscopy of a peculiar Supernova Remnant MF16 in NGC6946
We present a study of a peculiar Supernova Remnant MF16, associated with the
Ultraluminous X-ray Source (ULX) NGC6946 ULX-1. Observations were taken with
the MultiPupil Fiber Spectrograph (MPFS) with 6-m telescope on January 2005.
The nebula is found to be highly asymmetric, one of the parts being much denser
and colder. The two-component structure of the emission lines and radial
velocity gradient argue for a non-spherical nebula, expanding with a velocity
of about 100 km/s. Neither shock models nor the X-ray emission can adequately
explain the actual emission line spectrum of MF16, so we suggest an additional
ultraviolet source with a luminosity of about 10E40 erg/s. We confirm
coincidence of the ULX with the central star, and identify radio emission
observed by VLA with the most dense part of the nebula.Comment: Proceedings of the ESO and Euro3D Workshop "Science Perspectives for
3D Spectroscopy", Garching (Germany), October 10-14, 2005. M. Kissler-Patig,
M.M. Roth and J.R. Walsh (eds.
Cyclic and ruled Lagrangian surfaces in complex Euclidean space
We study those Lagrangian surfaces in complex Euclidean space which are
foliated by circles or by straight lines. The former, which we call cyclic,
come in three types, each one being described by means of, respectively, a
planar curve, a Legendrian curve of the 3-sphere or a Legendrian curve of the
anti de Sitter 3-space. We also describe ruled Lagrangian surfaces. Finally we
characterize those cyclic and ruled Lagrangian surfaces which are solutions to
the self-similar equation of the Mean Curvature Flow. Finally, we give a
partial result in the case of Hamiltonian stationary cyclic surfaces
Causes and explanation of ''breakthrough phenomenon'' when LEM cooling system sublimator is fed with chlorinated feedwater
Comparison of chlorine or iodine use as feedwater bactericides in lunar excursion module cooling system sublimato
Multiple scattering of matter waves: an analytic model of the refractive index for atomic and molecular gases
We present an analytic model of the refractive index for matter waves
propagating through atomic or molecular gases. The model, which combines a WKB
treatment of the long range attraction with the Fraunhofer model treatment of
the short range repulsion, furnishes a refractive index in compelling agreement
with recent experiments of Jacquey et al. [Phys. Rev. Lett. 98, 240405 (2007)]
on Li atom matter waves passing through dilute noble gases. We show that the
diffractive contribution, which arises from scattering by a two dimensional
"hard core" of the potential, is essential for obtaining a correct imaginary
part of the refractive index.Comment: 5 pages, 1 figure, 2 table
On transversally elliptic operators and the quantization of manifolds with -structure
An -structure on a manifold is an endomorphism field
\phi\in\Gamma(M,\End(TM)) such that . Any -structure
determines an almost CR structure E_{1,0}\subset T_\C M given by the
-eigenbundle of . Using a compatible metric and connection
on , we construct an odd first-order differential operator ,
acting on sections of , whose principal symbol is of the
type considered in arXiv:0810.0338. In the special case of a CR-integrable
almost -structure, we show that when is the generalized
Tanaka-Webster connection of Lotta and Pastore, the operator is given by D
= \sqrt{2}(\dbbar+\dbbar^*), where \dbbar is the tangential Cauchy-Riemann
operator.
We then describe two "quantizations" of manifolds with -structure that
reduce to familiar methods in symplectic geometry in the case that is a
compatible almost complex structure, and to the contact quantization defined in
\cite{F4} when comes from a contact metric structure. The first is an
index-theoretic approach involving the operator ; for certain group actions
will be transversally elliptic, and using the results in arXiv:0810.0338,
we can give a Riemann-Roch type formula for its index. The second approach uses
an analogue of the polarized sections of a prequantum line bundle, with a CR
structure playing the role of a complex polarization.Comment: 31 page
The BDSIM Toolkit
This report is a description of the BDSIM toolkit based on the User's Manual for the v0.1 version
Electron Spin Relaxation of Cu_A and Cytochrome a in Cytochrome c Oxidase. Comparison to heme, copper, and sulfur radical complexes
The method of continuous saturation has been used to measure the electron spin relaxation parameter T_(1)T_(2) at temperatures between 10 and 50 K for a variety of S = 1/2 species including: Cu_A and cytochrome a of cytochrome c oxidase, the type 1 copper in several blue copper proteins, the type 2 copper in laccase, inorganic Cu(II) complexes, sulfur radicals, and low spin heme proteins. The temperature dependence and the magnitude of T_(1)T_(2) for all of the species examined are accounted for by assuming that the Van Vleck Raman process dominates the electron spin-lattice relaxation. Over the entire temperature range examined, the relaxation of the type 1 coppers in six to seven times faster than that of type 2 copper, inorganic copper, and sulfur radicals, in spite of the similar g-anisotropies of these species. This result may indicate that the coupling of the phonon bath to the spin center is more effective in type 1 coppers than in the other complexes studied. The relaxation of Cu_A of cytochrome oxidase exhibits an unusual temperature dependence relative to the other copper complexes studied, suggesting that the protein environment of this center is different from that of the other copper centers studied and/or that Cu_A is influenced by a magnetic dipolar interaction with another, faster-relaxing paramagnetic site in the enzyme. A comparison of the saturation characteristics of the Cu_A EPR signal in native and partially reduced CO complexes of the enzyme also suggests the existence of such an interaction. The implications of these results with respect to the disposition of the metal centers in cytochrome oxidase are discusse
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