A New Galaxy in the Local Group: the Antlia Dwarf Galaxy

We report the discovery of new member of the Local Group in the constellation of Antlia. Optically the system appears to be a typical dwarf spheroidal galaxy of type dE3.5 with no apparent young blue stars or unusual features. A color-magnitude diagram in I, V-I shows the tip of the red giant branch, giving a distance modulus of 25.3 +/- 0.2 (1.15 Mpc +/- 0.1) and a metallicity of -1.6 +/- 0.3. Although Antlia is in a relatively isolated part of the Local Group it is only 1.2 degrees away on the sky from the Local Group dwarf NGC3109, and may be an associated system.Comment: AJ in press, 15 pages, 7 figures, figure 2 in b/w for space saving, full postscript version available at http://www.ast.cam.ac.uk/~gkth/antlia-pp.htm

An Observational Limit on the Dwarf Galaxy Population of the Local Group

We present the results of an all-sky, deep optical survey for faint Local Group dwarf galaxies. Candidate objects were selected from the second Palomar survey (POSS-II) and ESO/SRC survey plates and follow-up observations performed to determine whether they were indeed overlooked members of the Local Group. Only two galaxies (Antlia and Cetus) were discovered this way out of 206 candidates. Based on internal and external comparisons, we estimate that our visual survey is more than 77% complete for objects larger than one arc minute in size and with a surface brightness greater than an extremely faint limit over the 72% of the sky not obstructed by the Milky Way. Our limit of sensitivity cannot be calculated exactly, but is certainly fainter than 25 magnitudes per square arc second in R, probably 25.5 and possibly approaching 26. We conclude that there are at most one or two Local Group dwarf galaxies fitting our observational criteria still undiscovered in the clear part of the sky, and a roughly a dozen hidden behind the Milky Way. Our work places the "missing satellite problem" on a firm quantitative observational basis. We present detailed data on all our candidates, including surface brightness measurements.Comment: 58 pages in AJ manuscript format; some figures at slightly reduced quality; accepted by the Astronomical Journa

Derivations of Atomic Ionization Effects Induced by Neutrino Magnetic Moments

A recent paper [M.B. Voloshin, Phys. Rev. Lett. 105, 201801 (2010)] pointed out that our earlier derivations of atomic ionization cross-section due to neutrino magnetic moments (arXiv:1001.2074v2) involved unjustified assumptions. We confirm and elaborate on this comment with these notes. We caution that the results of the sum-rule approach in this paper contradict the expected behaviour in atomic transitions.Comment: V3 3 pages ; confirm and elaborate on unjustified assumptions in V1 & V

First quantized electron and photon model of QED and radiative processes

In this study we combine the classical models of the massive and massless spinning particles, derive the current-current interaction Lagrangian of the particles from the gauge transformations of the classical spinors, and discuss radiative processes in electrodynamics by using the solutions of the Dirac equation and the quantum wave equations of the photon. The longitudinal polarized photon states give a new idea about the vacuum concept in electrodynamics.Comment: LaTeX file, 20 pages, 7 figures. to appear in Canadian Journal of Physic

Increasing Power Density of LSGM-Based Solid Oxide Fuel Cells Using New Anode Materials

Chemical reactions between the superior perovskite oxide-ion conductor Sr- and Mg-doped LaGaO3 (LSGM), CeO2, and NiO have been studied by powder X-ray diffraction. The results showed that an extensive reactivity occurs as a result of La migration driven by a gradient of La chemical activity. La migration across the LSGM/electrode interfaces in a fuel cell leads to the formation of resistive phases at the interface, either LaSrGa3O7 or LaSrGaO4. Use of 40 mol % La2O3 -doped CeO2 as an interlayer between anode and electrolyte as well as in the NiO-containing anode prevents all reactions found. Consequently, the air-H2 cell maximum power density was increased to nearly 900 mW/cm2 at 800°C with a 600 μm thick LSGM electrolyte. No sign of degradation was observed at 800°C over 2 weeks for an interlayered cell under a loading current density of 250 mA/cm2

Immunoglobulin A in chickens. Comparison 0ft0ta1 and immune—specific lacrimal and serum IgA levels in two lines of chickens immunized with Newcastle Disease Virus

In the human lower than normal concentrations of IgA in saliva have been found to be associated with stress.In studies of animal welfare and prolonged stress there is a need for nominvasive methods and assays of secretory IgA would be simple to develop for many species. In the present study we studied IgA in the chicken and compared levels of IgA intears. serum and bile. Two strains of chickens were compared. The concentration of IgA in the lacrimal fluid of line C chickens was two-fold higher than that of line 151 chickens. Levels of IgA in their serum and bile where the same. Followingon from the replication of avirulent Newcastle disease virus (NDV)1n the Harderian gland of thc nietitating membiane line C chickens contained NDV — specific lacrimal IgA to a titre of 102 whereas line 151 chickens contained none at 10-1-5. Both lines conmined NDV ~specific IgA in their bile to a titre of 103. Line 151 chickens therefore have a selective deficiency in lacrimal IgA compared to biliary IgA