Current problems in the zodiacal light

Photometric observations of zodiacal ligh

A program of ground-based studies of the zodiacal light

Nonzodiacal light sources of polarization in nightglow, and polarization due to airglow line emission

Polarimetric observations of Comet Kohoutek (1973f)

Radio, optical, and visual observations were made of Comet Kohoutek (1973f) using facilities of the National Radio Astronomy Observatory (NRAO) and of the Hawaii Night Sky Observatory, State University of New York at Albany (SUNYA). Transit observations were made using the NRAO 300 ft radio telescope on six consecutive days beginning November 24, 1973. Observations were carried out in the continuum at 11 cm using the 4-feed system at different position angles. The data were recorded on magnetic tape and were computer reduced. Results were negative, with an rms error of 62 milli flux units, giving an upper limit of 180 mfu for the 11 cm continuum emission from the Comet. This relatively high detection limit resulted from a combination of interference and bad weather that affected these pre-perihelion observations. No observations could be scheduled near or after perihelion

Zodiacal light Summary report

Survey in form of tables and graphs of surface brightness and degree of polarization of zodiacal light as function of elongation in plane of elliptic - related bibliograph

Ultraviolet Divergences in Cosmological Correlations

A method is developed for dealing with ultraviolet divergences in calculations of cosmological correlations, which does not depend on dimensional regularization. An extended version of the WKB approximation is used to analyze the divergences in these calculations, and these divergences are controlled by the introduction of Pauli--Villars regulator fields. This approach is illustrated in the theory of a scalar field with arbitrary self-interactions in a fixed flat-space Robertson--Walker metric with arbitrary scale factor $a(t)$. Explicit formulas are given for the counterterms needed to cancel all dependence on the regulator properties, and an explicit prescription is given for calculating finite regulator-independent correlation functions. The possibility of infrared divergences in this theory is briefly considered.Comment: References added on various regularization methods. Improved discussion of further issues. 26 pages, 1 figur

The fate of cannibalized fundamental-plane ellipticals

Evolution and disruption of galaxies orbiting in the gravitational field of a larger cluster galaxy are driven by three coupled mechanisms: 1) the heating due to its time dependent motion in the primary; 2) mass loss due to the tidal strain field; and 3) orbital decay. Previous work demonstrated that tidal heating is effective well inside the impulse approximation limit. Not only does the overall energy increase over previous predictions, but the work is done deep inside the secondary galaxy, e.g. at or inside the half mass radius in most cases. Here, these ideas applied to cannibalization of elliptical galaxies with fundamental-plane parameters. In summary, satellites which can fall to the center of a cluster giant by dynamical friction are evaporated by internal heating by the time they reach the center. This suggests that true merger-produced multiple nuclei giants should be rare. Specifically, secondaries with mass ratios as small as 1\% on any initial orbit evaporate and those on eccentric orbits with mass ratios as small as 0.1\% evolve significantly and nearly evaporate in a galaxian age. Captured satellites with mass ratios smaller than roughly 1\% have insufficient time to decay to the center. After many accretion events, the model predicts that the merged system has a profile similar to that of the original primary with a weak increase in concentration.Comment: 19 pages, 10 Postscript figures, uses aaspp4.sty. Submitted to Astrophysical Journa

On the scaling behavior of the cosmological constant and the possible existence of new forces and new light degrees of freedom

A large value of the cosmological constant (CC) is induced in the Standard Model (SM) of Elementary Particle Physics because of Spontaneous Symmetry Breaking. To provide a small value of the observable CC one has to introduce the vacuum term which cancels the induced one at some point in the very far infrared cosmic scale. Starting from this point we investigate whether the cancellation is preserved at different energy scales. We find that the running of the Higgs mass, couplings and the vacuum term inevitably result in a scaling dependence of the observable CC value. As a consequence one meets a nonzero CC at an energy scale comparable to the typical electron neutrino mass suggested by some experiments, and the order of magnitude of this constant is roughly the one derived from recent supernovae observations. However the sign of it is negative -- opposite to what is suggested by these observations. This discrepancy may be a hint of the existence of an extra very light scalar, perhaps a Cosmon-like dilaton, which should essentially decouple from the SM Lagrangian, but that it nevertheless could mediate new macroscopic forces in the submillimeter range.Comment: LaTeX, 14 pages, no figures. Discussion of the new light scalar extended, some new references adde

Comparison of liquid-metal magnetohydrodynamic power conversion cycles

Comparison of liquid metal magnetohydrodynamic power conversion cycle

Further Evidence for a Gravitational Fixed Point

A theory of gravity with a generic action functional and minimally coupled to N matter fields has a nontrivial fixed point in the leading large N approximation. At this fixed point, the cosmological constant and Newton's constant are nonzero and UV relevant; the curvature squared terms are asymptotically free with marginal behaviour; all higher order terms are irrelevant and can be set to zero by a suitable choice of cutoff function.Comment: LaTEX, 4 pages. Relative to the published paper, a sign has been corrected in equations (17) and (18