Geochemical-geophysical investigations, Fairbanks district

Trace element distribution in a subarctic valley in the Cleary Hill area of the Fairbanks gold district has been studied. Zinc and arsenic have been found excellent pathfinder elements for auriferous deposits. Methods of analysis for copper, lead, zinc, molybdenum, silver and arsenic as well as heavy metals are discussed. The University of Alaska method #2 has been improved, Terrain, slope, and frozen ground have little effect upon the distribution of trace elements associated with the Cleary H i l l vein. A new method for the determination of zinc using dilute acid is proposed. Analysis of geochemical data by trend surface procedures proved effective for localization of anomalies

I^+ states of ^<26>Mg through the (α, ^3He) reaction at 81MeV

The ^Mg (α, ^3He) ^Mg reaction leading to seven 1^+ states, proposed previously by proton scattering at 201 MeV and by the (α, ^3He) reaction at 50MeV, was measured at E_α=80.9MeV. The cross sections obtained were analyzed within the framework of the exact-finite-range distorted wave Born approximation. The spectroscopic factors for a d_ transfer to 1^+ states were compared with those predicted by sd shell model calculations. Two of the 1^+ states were found to have a simple (d_d_) structure consistent with the shell model picture. Others with too large d_ transfer strength were ascribed owing to a mixture of other nearby states with J^π values other than 1^+ in referring to a recent compilation

Spectroscopy of A=12 at High Excitation

Supported by the National Science Foundation and Indiana Universit

Proton Stripping to Stretched States in 26-Al, 52-Cr, and 60-Si

This research was sponsored by the National Science Foundation Grant NSF PHy 87-1440

Cold Feedback in Cooling-Flow Galaxy Clusters

We put forward an alternative view to the Bondi-driven feedback between heating and cooling of the intra-cluster medium (ICM) in cooling flow galaxies and clusters. We adopt the popular view that the heating is due to an active galactic nucleus (AGN), i.e. a central black hole accreting mass and launching jets and/or winds. We propose that the feedback occurs with the entire cool inner region (5-30 kpc). A moderate cooling flow does exist here, and non-linear over-dense blobs of gas cool fast and are removed from the ICM before experiencing the next major AGN heating event. Some of these blobs may not accrete on the central black hole, but may form stars and cold molecular clouds. We discuss the conditions under which the dense blobs may cool to low temperatures and feed the black hole.Comment: 6 pages, no figures, to appear in the Proceedings of "Heating vs. Cooling in Galaxies and Clusters of Galaxies", August 2006, Garching (Germany

Angular 21 cm Power Spectrum of a Scaling Distribution of Cosmic String Wakes

Cosmic string wakes lead to a large signal in 21 cm redshift maps at redshifts larger than that corresponding to reionization. Here, we compute the angular power spectrum of 21 cm radiation as predicted by a scaling distribution of cosmic strings whose wakes have undergone shock heating.Comment: 13 pages, 6 figures; v2: minor modifications, journal versio

Active Galaxies in the UV

In this article we present different aspects of AGN studies demonstrating the importance of the UV spectral range. Most important diagnostic lines for studying the general physical conditions as well as the metalicities in the central broad line region in AGN are emitted in the UV. The UV/FUV continuum in AGN excites not only the emission lines in the immediate surrounding but it is responsible for the ionization of the intergalactic medium in the early stages of the universe. Variability studies of the emission line profiles of AGN in the UV give us information on the structure and kinematics of the immediate surrounding of the central supermassive black hole as well as on its mass itself.Comment: 29 pages, 13 figures, Ap&SS in pres