Large-scale filaments--Newtonian vs. modified dynamics

Eisenstein Loeb and Turner (ELT) have recently proposed a method for estimating the dynamical masses of large-scale filaments, whereby the filament is modeled by an axisymmetric, isothermal cylinder, for which ELT derive a global relation between the (constant) velocity dispersion and the total line density. We first show that the model assumptions of ELT can be relaxed materially: an exact relation between the velocity and line density is derived for any cylinder (not necessarily axisymmetric), with an arbitrary constituent distribution function (so isothermality need not be assumed). We then consider the same problem in the context of the modified dynamics (MOND). After a brief comparison between scaling properties in the two theories, we study idealized MOND model filaments. A preliminary application to the segment of the Perseus-Pisces filament treated by ELT, gives MOND M/L estimates of order 10 s.u., compared with the Newtonian value of about 450, which ELT find. In spite of the large uncertainties still besetting the analysis, this instance of MOND application is of particular interest because: 1. Objects of this geometry have not been dealt with before. 2. It pertains to large-scale structure. 3. The typical accelerations involved are the lowest so far encountered in a semi-virialized system.Comment: 12 page

MOND mass-to-light ratios for galaxy groups

I estimate MOND M/L values for nine galaxy groups that were recently studied by Tully et al.. Instead of the large M/L values that they find with Newtonian dynamics (up to 1200 solar units) the MOND estimates cluster around 1 solar unit. Tully et al. find a systematic and significant difference between the M/L values of groups that do not contain luminous galaxies and those that do: Dwarfs-only groups have larger M/L values (by a factor of about 5). The MOND M/L values do not show this trend; the Newtonian disparity is traced back to the dwarfs-only groups having systematically smaller intrinsic accelerations (similar sizes, but rather smaller velocity dispersions).Comment: 7 pages, Astrophys. J. Lett., in pres

Distinguishing Between CDM and MOND: Predictions for the Microwave Background

Two hypothesized solutions of the mass discrepancy problem are cold dark matter (CDM) and modified Newtonian dynamics (MOND). The virtues and vices of these very different hypotheses are largely disjoint, making the process of distinguishing between them very dependent on how we weigh disparate lines of evidence. One clear difference is the nature of the principal mass constituent of the universe (CDM or baryons). This difference in the baryon fraction ($f_b \approx 0.1$ vs. 1) should leave a distinctive signature in the spectrum of fluctuations in the cosmic microwave background. Here I discuss some of the signatures which should be detectable in the near future. The most promising appears to be the ratio of the amplitudes of the first two peaks relative to the intervening trough.Comment: 8 pages, 1 figure, AASTeX. Accepted for publication in ApJ Letter

J. J. Thomson\u27s Theory of Matter

J. J. Thomson\u27s theory of matter is largely the outgrowth of his own experimental researches in the nature and structure of electricity. In reading the records of his work it is often hard to discriminate in just what sense he uses the term electricity. It is certainly not well defined whether the term stands for primordial energy or matter

Worksite Wellness: An Analysis of a Regional University Wellness Program

A Thesis Presented to the Faculty of the College of Science and Technology Morehead State University in Partial Fulfillment of the requirements for the Degree Master of Wellness Promotion by Kellen Begeman on November 24, 2014

Galaxy groups and the modified dynamics

I estimate Modified-Dynamics (MOND), median M/L values for recently published catalogues of galaxy groups. While the median, Newtonian M/L values quoted for these catalogues are 110-200 solar units, the corresponding values for MOND are less than 10 solar units.Comment: 5 pages, Latex, to appear in Astrophys. J. Let

Nucleations According to Barus

No doubt all students of science have read more or less about Barus\u27 work on condensation phenomena as produced in a specially constructed fog chamber. As is known, his work has been done under the direction of the Carnegie Institution of Washington, founded particularly for the solution of research problems, involving much time and considerable expense. The prime purpose of his work, so far as I can interpret it, is to determine the part played by various kinds of nuclei in the atmospheric condensation of vapor. This, of course, is a very interesting problem to the student of physiography, as well as to the physicist

Mutual Induction and the Internal Resistance of a Voltaic Cell

The usual method of making a rapid determination of the internal resistance of a voltiac cell, primary or secondary, is by means of the condenser in circuit with a ballistic galvanometer. The deflection of the galvanometer due to the discharge of the condenser is first taken on open circuit with the cell and again when the cell is on a closed circuit the known resistance. The working formula is r=d—d1 over d1xR, in which d and d1 are the different deflections of the galvanometer needle and R is the external resistance of the closed circuit. The explanation of this method can be found in Carhart and Patterson\u27s Electrical Measurements