Low Frequency Gravitational Waves from Black Hole MACHO Binaries

Nakamura, Sasaki, Tanaka, and Thorne have recently estimated the initial distribution of binary MACHOs in the galactic halo assuming that the MACHOs are primordial half solar mass black holes, and considered their coalescence as a possible source for ground-based interferometer gravitational wave detectors such as LIGO. Evolving their binary distribution forward in time to the present, the low-frequency (10^{-5} < f < 10^{-1} Hz) spectrum of gravitational waves associated with such a population of compact binaries is calculated. The resulting gravitational waves would form a strong stochastic background in proposed space interferometers such as LISA and OMEGA. Low frequency gravitational waves are likely to become a key tool for determining the properties of binaries within the dark MACHO population.Comment: 8 pages + 2 ps figures; AASTe

Plans, estimates and specifications for a sewer system for the city of Plattsburg

Plattsburg, Missouri is a thriving city of about two thousand population. It is situated in the heart of the most fertile Missouri land. Three railroads - Atchison, Topeka and Santa Fe.; Chicago, Rock Island and Pacific; Quincy, Omaha and Kansas City - give easy access to St. Joseph, thirty miles distant, Leavenworth forty miles, or Kansas City, forty-one miles; respectively. The city is growing steadily and will in a few years be of such size that a sewage system will be necessary. We therefore submit the following plans, specifications and estimates. Since the city could not afford both Stone Sewers and Domestic Sewers or a combined Sewer System these plans will treat only of a Domestic Sewer System --Introductory, pages i-ii

Pulsed Triple Frequency Modulation for Frequency Stabilization and Control of Two Lasers to an Optical Cavity

We present a method to stabilize two lasers to an optical cavity using pulsed triple frequency modulation. The setup allows simultaneous Pound–Drever–Hall stabilization, as well as independent frequency control, while removing interference terms that limit the frequency scan range and allowing for smaller modulation depths. A review of single, dual, and triple frequency modulation is also presented in addition to a discussion of how to effectively turn pulsed triple frequency modulation into independent dual frequency modulation for each laser. This method would increase the scan range to half the free spectral range

Absolute Frequency Measurement of the lLevel of Neutral Using Two-Photon Spectroscopy

We report absolute frequency measurements on the level of neutral using sub-Doppler two-photon spectroscopy. The absolute center-of-gravity energy for the level is determined to be , a factor of 170 times improvement over the previous measurement from 1964 of . This measurement also corrects a discrepancy with the previously measured value. The hyperfine coefficients were found to be and , which are consistent with previous results

Testing Quantum Electrodynamics in the Lowest Singlet State of Neutral Beryllium-9

We report spectroscopic results on the 2s2p1P1 state in neutral atomic beryllium-9. The absolute frequency for the center of gravity is determined to be 42 565.4501(13)  cm−1, a factor of 130 more precise than the previous experimental measurement. The result is in agreement with and a factor of 8 more precise than the current best theoretical estimate of 42 565.441(11)  cm−1, which was calculated including the effects of quantum electrodynamics. Because of the large natural linewidth of the transition, the hyperfine constants were not able to be extracted to high precision

Book Reviews

This is a book that every lawyer should read and every law student should be required to read. It is the culminating work of a masterly mind that for over fifty years has been studying governments, ancient and modern,\u27 and meantime the writer has had the practical advantage of holding high and responsible offices, including that of British Ambassador to the United States. Viscount Bryce speaks plainly of American national, state and municipal shortcomings in government, especially the last, but it is done in a kindly vein. He is a friend of America and gives us credit for much

Gamma-Ray Imaging Observations of Point Source Emission From the Galactic Center Region

The first coded-aperture images of the galactic center region at energies above 30 keV reveal two strong 7-ray sources. One source is tentatively identified as the X-ray source 1El740.7-2942. If this source is at the distance of the galactic center, it is one of the most luminous objects in the galaxy at energies from 35 to 200 keV. The second source is consistent in location with the X-ray source GX354-0. No significant flux was detected from the direction of the galactic nucleus (Sgr A*)