Hamiltonians of Spherically Symmetric, Scale-Free Galaxies in Action-Angle Coordinates

We present a simple formula for the Hamiltonian in terms of the actions for spherically symmetric, scale-free potentials. The Hamiltonian is a power-law or logarithmic function of a linear combination of the actions. Our expression reduces to the well-known results for the familiar cases of the harmonic oscillator and the Kepler potential. For other power-laws, as well as for the singular isothermal sphere, it is exact for the radial and circular orbits, and very accurate for general orbits. Numerical tests show that the errors are always small, with mean errors across a grid of actions always less than 1 % and maximum errors less than 2.5 %. Simple first-order corrections can reduce mean errors to less than 0.6 % and maximum errors to less than 1 %. We use our new result to show that :[1] the misalignment angle between debris in a stream and a progenitor is always very nearly zero in spherical scale-free potentials, demonstrating that streams can be sometimes well approximated by orbits, [2] the effects of an adiabatic change in the stellar density profile in the inner regions of a galaxy weaken any existing 1/r density cusp, which is reduced to $1/r^{1/3}$. More generally, we derive the full range of adiabatic cusp transformations and show how to relate the starting cusp index to the final cusp index. It follows that adiabatic transformations can never erase a dark matter cusp.Comment: 6 pages, MNRAS, in pres

Monitoring the Thermal Power of Nuclear Reactors with a Prototype Cubic Meter Antineutrino Detector

In this paper, we estimate how quickly and how precisely a reactor's operational status and thermal power can be monitored over hour to month time scales, using the antineutrino rate as measured by a cubic meter scale detector. Our results are obtained from a detector we have deployed and operated at 25 meter standoff from a reactor core. This prototype can detect a prompt reactor shutdown within five hours, and monitor relative thermal power to three percent within seven days. Monitoring of short-term power changes in this way may be useful in the context of International Atomic Energy Agency's (IAEA) Reactor Safeguards Regime, or other cooperative monitoring regimes.Comment: 10 pages, 9 figure

Evaluating the Baluti Formation at Sararu village, Ora Anticline, Iraqi Kurdistan : a stratigraphic and geochemical approach

Open access through Springer Compact Agreement Acknowledgements The authors would like to thank Colin Taylor and Walter Ritchie from University of Aberdeen for their technical support and assistance with laboratory work. We would also like to thank Mr. Omer Kamil Ali, the Head of the Qumri village, for providing accommodation during fieldwork.Peer reviewedPublisher PD

Application of remote sensing to selected problems within the state of California

There are no author-identified signficant results in this report

Application of remote sensing to selected problems within the state of California

There are no author-identified significant results in this report