3,445 research outputs found
Improved surface quality of anisotropically etched silicon {111} planes for mm-scale integrated optics
We have studied the surface quality of millimeter-scale optical mirrors
produced by etching CZ and FZ silicon wafers in potassium hydroxide to expose
the planes. We find that the FZ surfaces have four times lower noise
power at spatial frequencies up to . We conclude that mirrors
made using FZ wafers have higher optical quality
Hidden momentum of electrons, nuclei, atoms and molecules
We consider the positions and velocities of electrons and spinning nuclei and demonstrate that these particles harbour hidden momentum when located in an electromagnetic field. This hidden momentum is present in all atoms and molecules, however it is ultimately cancelled by the momentum of the electromagnetic field. We point out that an electron vortex in an electric field might harbour a comparatively large hidden momentum and recognise the phenomenon of 'hidden hidden momentum'
Deep spectroscopy of z~1 6C radio galaxies - II. Breaking the redshift-radio power degeneracy
The results of a spectroscopic analysis of 3CR and 6C radio galaxies at
redshift z~1 are contrasted with the properties of lower redshift radio
galaxies, chosen to be matched in radio luminosity to the 6C sources studied at
z~1, thus enabling the P-z degeneracy to be broken. Partial rank correlations
and principal component analysis have been used to determine which of z and P
are the critical parameters underlying the observed variation of the ionization
state andd kinematics of the emission line gas. [OII]/H-beta is shown to be a
useful ionization mechanism diagnostic. Statistical analysis of the data shows
that the ionization state of the emission line gas is strongly correlated with
radio power, once the effects of other parameters are removed. No dependence of
ionization state on z is observed, implying that the ionization state of the
emission line gas is solely a function of the AGN properties rather than the
hostt galaxy and/or environment. Statistical analysis of the kinematic
properties of the emission line gas shows that these are strongly correlated
independently withh both P and z. The correlation with redshift is the stronger
of the two, suggesting that host galaxy composition or environment may play a
role in producing the less extreme gas kinematics observed in the emission line
regions of low redshift galaxies. For both the ionization and kinematic
properties of thee galaxies, the independent correlations observed with radio
size are strongest. Radio source age is a determining factor for the extended
emission line regions.Comment: 10 pages, 5 figures, accepted for publication in MNRA
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