13,045 research outputs found
On cyclic numbers and an extension of Midy's theorem
In this note we consider fractions of the form 1/m and their floating-point
representation in various arithmetic bases. For instance, what is 1/7 in base
2005? And, what about 1/4? We give a simple algorithm to answer these
questions. In addition, we discuss an extension of Midy's theorem whose proof
relies on elementary modular arithmetic.Comment: 6 pages, aimed at undergraduate student
Detection of H-alpha emission from the Magellanic Stream: evidence for an extended gaseous Galactic halo
We have detected faint, diffuse H\alpha emission of surface brightness Rayleighs, R, and R respectively,
corresponding to emission measures of 1.0 to 0.5 \cmsixpc. We have observed
several positions near the MS IV concentration, and find that the strongest
emission is on the sharp leading-edge density gradient. There is less emission
at points away from the gradient, and halfway between MS III and MS IV the
H< 0.04\alpha emission at cloud leading edges to heating of the
Stream clouds by ram pressure from ionized gas in the halo of the Galaxy. These
observations suggest that ram pressure from halo gas plays a large role in
stripping the Stream out of the Magellanic Clouds. They also suggest the
presence of a relatively large density of gas, , in the Galactic halo at kpc radius, and far above the
Galactic plane, . This implies that the Galaxy has a very large
baryonic, gaseous extent, and supports models of Lyman-$\alpha and metal-line
QSO absorption lines in which the absorption systems reside in extended
galactic halos.Comment: 15 pages, aaspp latex, + 1 table & 3 figures. Accepted in A.J. Also
available from http://www.physics.rutgers.edu/~bweiner/astro/papers
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