Optimal generalization of power filters for gravitational wave bursts, from single to multiple detectors

Searches for gravitational wave signals which do not have a precise model describing the shape of their waveforms are often performed using power detectors based on a quadratic form of the data. A new, optimal method of generalizing these power detectors so that they operate coherently over a network of interferometers is presented. Such a mode of operation is useful in obtaining better detection efficiencies, and better estimates of the position of the source of the gravitational wave signal. Numerical simulations based on a realistic, computationally efficient hierarchical implementation of the method are used to characterize its efficiency, for detection and for position estimation. The method is shown to be more efficient at detecting signals than an incoherent approach based on coincidences between lists of events. It is also shown to be capable of locating the position of the source.Comment: 16 pages, 5 figure

Detector Description and Performance for the First Coincidence Observations between LIGO and GEO

For 17 days in August and September 2002, the LIGO and GEO interferometer gravitational wave detectors were operated in coincidence to produce their first data for scientific analysis. Although the detectors were still far from their design sensitivity levels, the data can be used to place better upper limits on the flux of gravitational waves incident on the earth than previous direct measurements. This paper describes the instruments and the data in some detail, as a companion to analysis papers based on the first data.Comment: 41 pages, 9 figures 17 Sept 03: author list amended, minor editorial change

Analysis of LIGO data for gravitational waves from binary neutron stars

We report on a search for gravitational waves from coalescing compact binary systems in the Milky Way and the Magellanic Clouds. The analysis uses data taken by two of the three LIGO interferometers during the first LIGO science run and illustrates a method of setting upper limits on inspiral event rates using interferometer data. The analysis pipeline is described with particular attention to data selection and coincidence between the two interferometers. We establish an observational upper limit of $\mathcal{R}<$1.7 \times 10^{2}$per year per Milky Way Equivalent Galaxy (MWEG), with 90coalescence rate of binary systems in which each component has a mass in the range 1--3$M_\odot$.Comment: 17 pages, 9 figure

Pteridófitas da Serra Negra, Minas Gerais, Brasil

Este trabalho apresenta uma lista de espécies de pteridófitas que ocorrem na Serra Negra, Minas Gerais. A serra está inserida no complexo da Serra da Mantiqueira situada entre Rio Preto, Lima Duarte, Santa Bárbara do Monte Verde e Olaria, tendo seus limites nos pontos 21º58'11"S 43º53'21" W, 22º01'46,4" S 43º52'31,5" W, 21º58'21,4" S 43º50'06,5" W e 21º58'53" S 43º56'08" W. A vegetação da serra é formada por um mosaico de fitofisionomias, sendo encontradas formações florestais (florestas ombrófilas e semidecíduas) e campestres (campos rupestres). O inventário florístico foi realizado entre os anos de 2003 e 2008, em excursões mensais para coleta de amostras e registro de dados. Na serra foram registradas 209 táxons infragenéricos distribuídas em 24 famílias e 75 gêneros. As famílias com maior número de espécies foram Polypodiaceae (40), Dryopteridaceae (33) e Pteridaceae (25). A maioria das espécies (109) foi encontrada ocorrendo exclusivamente no interior de floresta. Em relação ao hábito, 69 espécies foram encontradas exclusivamente como terrestres, 37 como rupícolas ou terrestres e 32 exclusivamente epífitas. Este trabalho revela uma elevada riqueza de pteridófitas na região e indica a importância de estudos desta natureza na conservação e manejo das pteridófitas em Minas Gerais.This work presents an inventory of pteridophyte species that occur in the Serra Negra, of Minas Gerais. The area is part of the Mantiqueira Range, and is situated between the coordinates 21º58'11"S 43º53'21" W, 22º01'4.4" S, 43º52'31.5" W, 21º58'21.4" S, 43º50'06.5" W and 21º58'53" S, 43º56'08" W. The vegetation in the Serra Negra is characterized by a mosaic of different phytophysiognomies, divided into forests (evergreen and seasonal semideciduous forests) and open formations (rocky grasslands). The inventory was carried out from 2003 to 2008, during monthly excursions to collect botanical material and data in the study area. A total of 209 species, distributed in 24 families and 75 genera, were recorded. The families with the highest number of species were Polypodiaceae (40), Dryopteridaceae (33) and Pteridaceae (25). More than the half (110) of the inventoried species were recorded exclusively in the forests formations. Sixty-nine species were terrestrial, 37 were saxicolous or terrestrial and 32 were epiphytes. This work shows that this region is rich in ferns and reveals the importance of this kind of study for conservation and management of pteridophytes in the state of Minas Gerais