34 research outputs found

    The status of GEO 600

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    The GEO 600 laser interferometer with 600m armlength is part of a worldwide network of gravitational wave detectors. GEO 600 is unique in having advanced multiple pendulum suspensions with a monolithic last stage and in employing a signal recycled optical design. This paper describes the recent commissioning of the interferometer and its operation in signal recycled mode

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

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    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

    The Earth: Plasma Sources, Losses, and Transport Processes

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    This paper reviews the state of knowledge concerning the source of magnetospheric plasma at Earth. Source of plasma, its acceleration and transport throughout the system, its consequences on system dynamics, and its loss are all discussed. Both observational and modeling advances since the last time this subject was covered in detail (Hultqvist et al., Magnetospheric Plasma Sources and Losses, 1999) are addressed

    Dwelling on de Sitter

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    A careful reduction of the three-dimensional gravity to the Liouville description is performed, where all gauge fixing and on-shell conditions come from the definition of asymptotic de Sitter spaces. The roles of both past and future infinities are discussed and the conditions space-time evolution imposes on both Liouville fields are explicited. Space-times which correspond to non-equivalent profiles of the Liouville field at past and future infinities are shown to exist. The qualitative implications of this for any tentative dual theory are presented.Comment: RevTeX 4, 8 pages, v3: Small clarifications on sections III and IV and references added/corrected, v4: typo

    Specification of the near-Earth space environment with SHIELDS

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    Predicting variations in the near-Earth space environment that can lead to spacecraft damage and failure is one example of “space weather” and a big space physics challenge. A project recently funded through the Los Alamos National Laboratory (LANL) Directed Research and Development (LDRD) program aims at developing a new capability to understand, model, and predict Space Hazards Induced near Earth by Large Dynamic Storms, the SHIELDS framework. The project goals are to understand the dynamics of the surface charging environment (SCE), the hot (keV) electrons representing the source and seed populations for the radiation belts, on both macro- and micro-scale. Important physics questions related to particle injection and acceleration associated with magnetospheric storms and substorms, as well as plasma waves, are investigated. These challenging problems are addressed using a team of world-class experts in the fields of space science and computational plasma physics, and state-of-the-art models and computational facilities. A full two-way coupling of physics-based models across multiple scales, including a global MHD (BATS-R-US) embedding a particle-in-cell (iPIC3D) and an inner magnetosphere (RAM-SCB) codes, is achieved. New data assimilation techniques employing in situ satellite data are developed; these provide an order of magnitude improvement in the accuracy in the simulation of the SCE. SHIELDS also includes a post-processing tool designed to calculate the surface charging for specific spacecraft geometry using the Curvilinear Particle-In-Cell (CPIC) code that can be used for reanalysis of satellite failures or for satellite design

    Search for gravitational waves associated with the gamma ray burst GRB030329 using the LIGO detectors

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    We have performed a search for bursts of gravitational waves associated with the very bright gamma ray burst GRB030329, using the two detectors at the LIGO Hanford Observatory. Our search covered the most sensitive frequency range of the LIGO detectors (approximately 80 - 2048 Hz), and we specifically targeted signals shorter than 150ms. Our search algorithm looks for excess correlated power between the two interferometers and thus makes minimal assumptions about the gravitational waveform. We observed no candidates with gravitational-wave signal strength larger than a predetermined threshold. We report frequency-dependent upper limits on the strength of the gravitational waves associated with GRB030329. Near the most sensitive frequency region, around 250Hz, our root-sum-square (RSS) gravitational-wave strain sensitivity for optimally polarized bursts was better than hRSS 6×10-21Hz-1/2. Our result is comparable to the best published results searching for association between gravitational waves and gamma ray bursts. © 2005 The American Physical Society

    Limits on gravitational-wave emission from selected pulsars using LIGO data

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    We place direct upper limits on the amplitude of gravitational waves from 28 isolated radio pulsars by a coherent multidetector analysis of the data collected during the second science run of the LIGO interferometric detectors. These are the first direct upper limits for 26 of the 28 pulsars. We use coordinated radio observations for the first time to build radio-guided phase templates for the expected gravitational-wave signals. The unprecedented sensitivity of the detectors allows us to set strain upper limits as low as a few times 10-24. These strain limits translate into limits on the equatorial ellipticities of the pulsars, which are smaller than 10-5 for the four closest pulsars. © 2005 The American Physical Society

    Exposure to sexually attractive men decreases women's preferences for feminine faces

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    Here we show that women's preferences for femininity (vs. masculinity) in men's faces are decreased after viewing a slideshow of images of highly attractive men, but not after viewing a slideshow of relatively unattractive men. As masculinity is thought to be a cue of men's heritable fitness and viewing images of highly attractive opposite-sex individuals increases sexual motivation, this may indicate that women increase their preferences for male cues of heritable fitness in circumstances where mating is likely to occur. This context-sensitivity in women's face preferences may, therefore, be adaptive, since decreased preferences for feminine men (i.e. increased preferences for masculine men) when sexual motivation is enhanced may increase offspring viability. Interestingly, we found that viewing images of highly attractive men also decreased women's preferences for femininity in female faces. This latter finding could either reflect increased derogation of attractive (i.e. feminine) same-sex competitors when sexual motivation is enhanced or be a low-cost functionless by-product of a mechanism for increasing preferences for cues of men's heritable fitness when sexual motivation is high. Collectively, our findings demonstrate that recent visual experience with highly attractive opposite-sex individuals influences attractiveness judgments, and present novel evidence for potentially adaptive context-sensitivity in attractiveness judgments
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