A Deep Survey of HI-Selected Galaxies: The Sample and the Data

In a 21 cm neutral hydrogen survey of approximately 55 sq deg out to a redshift of cz=8340 km/s, we have identified 75 extragalactic HI sources. These objects comprise a well-defined sample of extragalactic sources chosen by means that are independent of optical surface brightness selection effects. In this paper we describe the Arecibo survey procedures and HI data, follow-up VLA HI observations made of several unusual sources, and Kitt Peak B-, R-, and I-band photometry for nearly all of the galaxies. We have also gathered information for some of the optically detected galaxies within the same search volume. We examine how samples generated by different types of search techniques overlap with selection by HI flux. Only the least massive HI object, which is among the lowest mass HI sources previously found, does not have a clear optical counterpart, but a nearby bright star may hide low surface brightness emission. However the newly-detected systems do have unusual optical properties. Most of the 40 galaxies that were not previously identified in magnitude-limited catalogs appear to be gas-dominated systems, and several of these systems have HI mass-to-light ratios among the largest values ever previously found. These gas-dominated objects also tend to have very blue colors, low surface brightnesses, and no central bulges, which correlate strongly with their relative star-to-gas content.Comment: 48 pages, 10 figures, Figure 3 included as 3 separate JPG images. To appear in Ap J Supplement

Massive low surface brightness galaxies

A multi-wavelength study of an extreme type of galaxy which will assist us in our attempts to understand the formation and evolution of galaxies was completed. In particular, a subset of low surface brightness (bar-mu(sub B) is approximately greater than 25 mag arcsec(sup -2)), giant galaxies (LSBG's) which contain large amounts of atomic gas (M(HI) is approximately greater than 10(exp 10) solar mass), have blue optical diameters similar to those of giant spiral galaxies, but which do not seem to have prodigious amounts of ongoing star formation were observed. Our sample was drawn from the first and second Palomar Sky Surveys. This population of galaxies has been largely ignored because of selection effects which make it difficult to detect optically. The question of how these massive systems differ from the higher surface brightness 'normal' spiral galaxies is addressed. Using B and R surface photometry, in conjunction with H-alpha, HI, CO-12, and far-infrared data, an attempt is made to determine if these galaxies had an early epoch of star formation that has since faded, have ongoing star formation with an unusual interplanetary magnetic field (IMF), or are perhaps galaxies which have never efficiently formed stars due to a lack of molecular clouds

Selection effects and binary galaxy velocity differences

Measurements of the velocity differences (delta v's) in pairs of galaxies from large statistical samples have often been used to estimate the average masses of binary galaxies. A basic prediction of these models is that the delta v distribution ought to decline monotonically. However, some peculiar aspects of the kinematics have been uncovered, with an anomalous preference for delta v approx. equal to 72 km s(sup-1) appearing to be present in the data. The authors examine a large sample of binary galaxies with accurate redshift measurements and confirm that the distribution of delta v's appears to be non-monotonic with peaks at 0 and approx. 72 km s (exp -1). The authors suggest that the non-zero peak results from the isolation criteria employed in defining samples of binaries and that it indicates there are two populations of binary orbits contributing to the observed delta v distribution

Tall Tales of Danger and Security: How a Critical Human Security Approach can Address Major Contradictions Revealed Through a Critical Narrative Analysis of Dominant U.S. Security Strategies

Over many generations, humans have developed many perspectives and practices regarding the best ways to recognize and address what they perceive to be dangerous. Stories are used to help shape and narrate perceptions about the world, and they serve to pass on vital information that impacts how a society responds to threats and vulnerabilities. These narratives of danger and security are subjective to the experiences and political intentions of society, and therefore in many ways are partial and biased in their assessments and policies. This results in flawed security practices that may actually exacerbate threats or create new insecurities. What this thesis examines is why the U.S. maintains harmful approaches to global security by contemplating how threats and insecurities are framed and discussed in the official narratives that guide their implementation. Using a critical narrative analysis to examine the words, phrases, value assumptions, and intentions of the 2015 and 2017 U.S. National Security Strategy (NSS), I illuminate how the shaping of perceptions in dominant security narratives limits the effective response to security problems by narrowing their assessments to militaristic and shallow analyses of the root causes of global insecurities. I then respond to the critical call for a broadening, deepening, and opening of security by expanding and applying Critical Human Security perspectives to the NSS in order to diagnostically engage each strategy in the spirit of humanizing their assessments and to reimagine new possibilities. Ultimately, I argue that perspectives and words matter because of their function in impacting political realities, that the strongly political nature of security narratives inhibits their effectiveness, and that the end-goals of protecting human rights and international law are better realized when more inclusive assessments and nuanced security practices allow people to comprehensively perceive and defend themselves from insecurity on all levels of society

Violence, organized crime, and illicit drug markets: a Canadian case study

This article tests two inter-related theories on the situational causes of violence in illicit drug markets: (i) drug markets that are unstable are more prone to violence and (ii) there is a higher risk of instability, and hence conflict and violence, in drug markets characterized by pure competition. These theories are applied to the violence that occurred between the Hell’s Angels and its rivals over dominance in Quebec’s lucrative cocaine market during the 1990s. The theory that violence stems from instability in an illicit market is applicable to this case study. However, Quebec’s cocaine market was characterized by oligopolistic conditions and the ensuing violence stemmed from the Hell’s Angels’ efforts to maintain hegemony in that market. This paper argues that oligopolistic and monopolistic conditions in illicit drug markets may heighten the risk of conflict and violence because such conditions inhibit competition.Este artigo testa duas teorias inter-relacionadas sobre as causas situacionais de violência nos mercados de drogas ilícitas: (i) os mercados de drogas que são instáveis são mais propensos à violência e (ii) existe um maior risco de instabilidade e, portanto, de conflito e violência, em mercados de drogas caracterizados por pura concorrência. Estas teorias aplicam-se à violência que ocorreu entre os Hell’s Angels e os seus rivais  pela posição dominante no mercado lucrativo de cocaína no Quebec durante a década de 1990. A teoria de que a violência decorre da instabilidade num mercado ilícito é aplicável a este estudo de caso. No entanto, o mercado de cocaína no Quebec foi caracterizado por condições oligopolísticas e a violência que se seguiu resultou dos esforços dos Hell’s Angels para manterem a hegemonia no mercado. Este artigo argumenta que as condições de oligopólio e monopólio em mercados de drogas ilícitas podem aumentar o risco de conflito e violência, porque inibem a concorrência.Cet article teste deux théories liées entre elles concernant les causes situationnelles de la violence sur les marchés des drogues illicites : (i) les marchés des drogues qui sont instables sont plus enclins à la violence, (ii) il y a un plus grand risque d’instabilité et, par conséquent, de conflit et de violence, sur les marchés des drogues caractérisés par la pure concurrence. Ces théories sont appliquées à la violence qui s’est produite entre les Hell’s Angels et leurs rivaux pour occuper une position dominante sur le marché lucratif de la cocaïne au Québec dans les années 1990. La théorie selon laquelle la violence découle de l’instabilité sur un marché illicite est applicable à cette étude de cas. Cependant, le marché de la cocaïne au Québec était caractérisé par des conditions oligopolistiques et la violence qui a suivi était le fruit des efforts des Hell’s Angels pour maintenir l’hégémonie sur le marché. Cet article soutient que les conditions oligopolistiques et monopolistiques sur les marchés des drogues illicites peuvent accroître le risque de conflit et de violence, car ces conditions freinent la concurrence.Este artículo prueba dos teorías inter-relacionadas sobre las causas situacionales de violencia en los mercados de drogas ilícitas: (i) los mercados de drogas que son inestables son más propensos a la violencia y (ii) existe un mayor riesgo de instabilidad, y, por lo tanto, de conflicto y violencia, en mercados de drogas caracterizados por pura competencia. Estas teorías se aplican a la violencia que ocurrió entre los Hell’s Angels y  sus rivales  por la posición dominante en el mercado lucrativo de cocaína en Quebec durante la década de 1990. La teoría de que la violencia resulta de la instabilidad en un mercado ilícito es aplicable a este estudio de caso. Sin embargo, el mercado de cocaína en Quebec fue caracterizado por condiciones oligopolistas y la violencia consecuente de los esfuerzos de los Hell’s Angels para mantener la hegemonía en el mercado. Este artículo argumenta que las condiciones oligopolistas y monopolistas en mercados de drogas ilícitas pueden aumentar el riesgo de conflicto y violencia, porque tales condiciones inhiben la competencia

Eratosthenes\u27 Proportion - Measure the diameter of the earth

Objective: To use a midday shadow on or close to the day of an Equinox to calculate Earth’s Polar Circumference

Planet Longitudes

Objectives: To apply the concept of Longitude to the location of planets in their orbits. To predict what planets can be seen in the night sky on any date