18 research outputs found

    Narrowband Searches for Continuous and Long-duration Transient Gravitational Waves from Known Pulsars in the LIGO-Virgo Third Observing Run

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    Isolated neutron stars that are asymmetric with respect to their spin axis are possible sources of detectable continuous gravitational waves. This paper presents a fully coherent search for such signals from eighteen pulsars in data from LIGO and Virgo's third observing run (O3). For known pulsars, efficient and sensitive matched-filter searches can be carried out if one assumes the gravitational radiation is phase-locked to the electromagnetic emission. In the search presented here, we relax this assumption and allow both the frequency and the time derivative of the frequency of the gravitational waves to vary in a small range around those inferred from electromagnetic observations. We find no evidence for continuous gravitational waves, and set upper limits on the strain amplitude for each target. These limits are more constraining for seven of the targets than the spin-down limit defined by ascribing all rotational energy loss to gravitational radiation. In an additional search, we look in O3 data for long-duration (hours-months) transient gravitational waves in the aftermath of pulsar glitches for six targets with a total of nine glitches. We report two marginal outliers from this search, but find no clear evidence for such emission either. The resulting duration-dependent strain upper limits do not surpass indirect energy constraints for any of these targets. © 2022. The Author(s). Published by the American Astronomical Society

    Constraints on the cosmic expansion history from GWTC–3

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    We use 47 gravitational wave sources from the Third LIGO–Virgo–Kamioka Gravitational Wave Detector Gravitational Wave Transient Catalog (GWTC–3) to estimate the Hubble parameter H(z), including its current value, the Hubble constant H0. Each gravitational wave (GW) signal provides the luminosity distance to the source, and we estimate the corresponding redshift using two methods: the redshifted masses and a galaxy catalog. Using the binary black hole (BBH) redshifted masses, we simultaneously infer the source mass distribution and H(z). The source mass distribution displays a peak around 34 M⊙, followed by a drop-off. Assuming this mass scale does not evolve with the redshift results in a H(z) measurement, yielding H0=688+12km  s1Mpc1{H}_{0}={68}_{-8}^{+12}\,\mathrm{km}\ \,\ {{\rm{s}}}^{-1}\,{\mathrm{Mpc}}^{-1} (68% credible interval) when combined with the H0 measurement from GW170817 and its electromagnetic counterpart. This represents an improvement of 17% with respect to the H0 estimate from GWTC–1. The second method associates each GW event with its probable host galaxy in the catalog GLADE+, statistically marginalizing over the redshifts of each event's potential hosts. Assuming a fixed BBH population, we estimate a value of H0=686+8km  s1Mpc1{H}_{0}={68}_{-6}^{+8}\,\mathrm{km}\ \,\ {{\rm{s}}}^{-1}\,{\mathrm{Mpc}}^{-1} with the galaxy catalog method, an improvement of 42% with respect to our GWTC–1 result and 20% with respect to recent H0 studies using GWTC–2 events. However, we show that this result is strongly impacted by assumptions about the BBH source mass distribution; the only event which is not strongly impacted by such assumptions (and is thus informative about H0) is the well-localized event GW190814

    Levantamento da flora apícola em Santa Luzia do Paruá, Sudoeste da Amazônia, Maranhão Survey of bee flora in Santa Luzia do Paruá, Southwest Amazonia, Maranhão

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    Foi realizado o levantamento das plantas visitadas por Apis mellifera L. através de análise polínica no município de Santa Luzia do Paruá, Maranhão, localizado a noroeste do Estado, em região amazônica. A temperatura média anual varia entre 26 °C e 27 °C, com umidade relativa do ar anual entre 79 a 82% e precipitação pluviométrica entre 2000 a 2400 mm anuais. O estudo foi conduzido entre agosto de 2005 e julho de 2006 em três apiários da região, com coletas mensais de mel, pólen e plantas, que foram submetidas ao método de acetólise. Os tipos polínicos das amostras de mel foram identificados e contados para a determinação da freqüência relativa média. Nas amostras de pólen foi realizada apenas a identificação dos tipos polínicos por meio da comparação com os polens das plantas (botões florais) depositados em coleção de referência. As principais famílias utilizadas por A. mellifera foram Amaranthaceae, Arecaceae, Asteraceae, Urticaceae, Euphorbiaceae, Lamiaceae, Fabaceae-Mimosoideae, Flacourtiaceae, Myrtaceae, Poaceae e Rubiaceae. Em amostras de mel, no período chuvoso destacaram-se os tipos polínicos de Mimosa pudica, Borreria e um tipo indeterminado da família Arecaceae. No período de safra foram representativos Hyptis e um tipo indeterminado de Asteraceae. Os tipos polínicos mais constantes nas amostras de pólen foram Euterpe oleracea, Asteraceae tipo 1, Mimosa pudica e Borreria.<br>The plant species visited by Apis mellifera L. were surveyed by pollen analysis in Santa Luzia do Paruá municipality, located in northwestern Maranhão state. Natural vegetation is Amazon rainforest, mean annual temperature varies between 26°C and 27°C, relative air humidity between 79 and 82%, and total rainfall between 2000 and 2400 mm. This study was conducted from August 2005 to July 2006 in three apiaries of the region, with monthly sampling of honey, pollen and plants. The samples were analyzed by the acetolysis method. The pollen types were identified and counted in honey samples to determine mean frequency of the three apiaries. In the pollen samples, pollen types were identified by comparison with the pollen of plants (flower buds) deposited in the reference collection. The main plant families used as floral resource by A. mellifera are Amaranthaceae, Arecaceae, Asteraceae, Urticaceae, Euphorbiaceae, Lamiaceae, Fabaceae-Mimosoideae, Flacourtiaceae, Myrtaceae, Poaceae and Rubiaceae. In the honey samples, the pollen types of Mimosa pudica, Borreria and members of the Arecaceae family were most important during the rainy season. At harvest time (transition between rainy and dry season), Hyptis, Borreria, and an undetermined pollen type of the Asteraceae family were most important. The pollen types that show major constancy in the sample pollen were Euterpe oleracea, Asteraceae type 1, Mimosa pudica and Borreria
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