Properties of Galaxies in and around Voids

Two surveys for intrinsically faint galaxies towards nearby voids have been conducted at the MPI f\"ur Astronomie, Heidelberg. One selected targets from a new diameter limited ($\Phi \ge 5''$) catalog with morphological criteria while the other used digitized objective prism Schmidt plates to select mainly HII dwarf galaxies. For some 450 galaxies, redshifts and other optical data were obtained. We studied the spatial distribution of the sample objects, their luminosity function, and their intrinsic properties. Most of the galaxies belong to already well known sheets and filaments. But we found about a dozen highly isolated galaxies in each sample (nearest neighborhood distance $\ge 3 h_{75}^{-1} Mpc$). These tend to populate additional structures and are not distributed homogeneously throughout the voids. As our results on 'void galaxies' still suffer from small sample statistics, I also tried to combine similar existing surveys of nearby voids to get further hints on the larger structure and on the luminosity function of the isolated galaxies. No differences in the luminosity function of sheet and void galaxies could be found. The optical and infrared properties of both samples are in the normal range for samples dominated by late-type dwarfs. Follow-up HI studies show that the isolated dwarfs in both samples have unusual high amount of neutral gas for a given luminosity.Comment: 10 pages, 4 figures, latex, to appear in the proceedings of the 'Ringberg workshop on Large Scale Structure', hold Sep. 23-28, 199

Strong Ultraviolet Pulse From a Newborn Type Ia Supernova

Type Ia supernovae are destructive explosions of carbon oxygen white dwarfs. Although they are used empirically to measure cosmological distances, the nature of their progenitors remains mysterious, One of the leading progenitor models, called the single degenerate channel, hypothesizes that a white dwarf accretes matter from a companion star and the resulting increase in its central pressure and temperature ignites thermonuclear explosion. Here we report observations of strong but declining ultraviolet emission from a Type Ia supernova within four days of its explosion. This emission is consistent with theoretical expectations of collision between material ejected by the supernova and a companion star, and therefore provides evidence that some Type Ia supernovae arise from the single degenerate channel.Comment: Accepted for publication on the 21 May 2015 issue of Natur

Avaliação da Usabilidade de Relatórios Gerenciais em Sistema Jurídico

TCC (graduação) - Universidade Federal de Santa Catarina. Centro Tecnológico. Curso de Sistemas de Informação.Este trabalho tem como objetivo analisar as características da interface dos gráficos estatístico do sistema PGnet, verificando se é adequada e atende às necessidades de seus usuários. Avaliando as necessidades e as dificuldades encontradas nas relações entre os usuários e o sistema. PGnet é um sistema de informações desenvolvido para administração dos processos de Procuradorias de Estados e Municípios. Seu objetivo é simplificar as tarefas diárias, agilizando todos os procedimentos de forma completa e totalmente segura. Para isso faz-se necessário caracterizar o perfil do usuário (graus de escolaridade, nível de conhecimento em informática, entre outros), a fim de melhor atender suas necessidades específicas; realizar análises de usabilidade (voltado para os gráficos estatísticos), qualidade das informações visualizadas e proposta de melhorias