Stochastic Background Search Correlating ALLEGRO with LIGO Engineering Data

We describe the role of correlation measurements between the LIGO interferometer in Livingston, LA, and the ALLEGRO resonant bar detector in Baton Rouge, LA, in searches for a stochastic background of gravitational waves. Such measurements provide a valuable complement to correlations between interferometers at the two LIGO sites, since they are sensitive in a different, higher, frequency band. Additionally, the variable orientation of the ALLEGRO detector provides a means to distinguish gravitational wave correlations from correlated environmental noise. We describe the analysis underway to set a limit on the strength of a stochastic background at frequencies near 900 Hz using ALLEGRO data and data from LIGO's E7 Engineering Run.Comment: 8 pages, 2 encapsulated PostScript figures, uses IOP class files, submitted to the proceedings of the 7th Gravitational Wave Data Analysis Workshop (which will be published in Classical and Quantum Gravity

Crescimento da batateira em sistema de preparo profundo de solo e sucessão de poáceas.

O presente estudo, realizado com a cultivar Atlantic, teve como objetivo comparar o sistema de preparo convencional (PC) de solo adotado para a cultura da batata, em sucessão à cultura do milho, a um sistema de preparo profundo (PP), em sucessão a três diferentes poáceas (milho, capim Marandu capim Tanzânia) quanto à dinâmica do crescimento da batateira. A produção em matéria seca (MS, t/ha) da parte aérea das poáceas variou conforme: Tanzânia PP (26,56) > Marandu PP (19,94) > Milho PP (5,57) = Milho PC (5,720)

Searching for Gravitational Waves from Binary Inspirals with LIGO

We describe the current status of the search for gravitational waves from inspiralling compact binary systems in LIGO data. We review the result from the first scientific run of LIGO (S1). We present the goals of the search of data taken in the second scientific run (S2) and describe the differences between the methods used in S1 and S2.Comment: 9 pages, 2 figures. Published in proceedings of the 8th Gravitational Wave Data Analysis Workshop, Milwaukee, WI, USA, 17-20 December 200

Normal Utilization as the Adjusting Variable in Neo-Kaleckian Growth Models: A Critique

As well-known, the canonical Neo-Kaleckian growth model fails to reconcile actual and normal rates of utilization in equilibrium. Some recent contributions revive an old proposal for solving this problem – making the normal rate of utilization an endogenous variable that converges to the actual utilization rate – justifying it with new, micro-founded premises. We argue that these new justifications for the convergence of normal to actual utilization do not stand closer scrutiny. First, the proposed microeconomic model relies on various restrictive assumptions, some of which are mutually inconsistent. Second, the derivation of the macroeconomic adjustment mechanism from the microeconomic analysis involves a logical leap, that can be justified only by a very arbitrary assumption with little economic justification. Finally, we discuss the way in which this mechanism has been incorporated into the Neo-Kaleckian growth model by proposers of this approach. We show that, even if one puts aside, for the sake of argument, the first two points, the existence of autonomous components of demand is sufficient to invalidate the resulting macroeconomic model

A First Comparison Between LIGO and Virgo Inspiral Search Pipelines

This article reports on a project that is the first step the LIGO Scientific Collaboration and the Virgo Collaboration have taken to prepare for the mutual search for inspiral signals. The project involved comparing the analysis pipelines of the two collaborations on data sets prepared by both sides, containing simulated noise and injected events. The ability of the pipelines to detect the injected events was checked, and a first comparison of how the parameters of the events were recovered has been completed.Comment: GWDAW-9 proceeding

A comparison of methods for gravitational wave burst searches from LIGO and Virgo

The search procedure for burst gravitational waves has been studied using 24 hours of simulated data in a network of three interferometers (Hanford 4-km, Livingston 4-km and Virgo 3-km are the example interferometers). Several methods to detect burst events developed in the LIGO Scientific Collaboration (LSC) and Virgo collaboration have been studied and compared. We have performed coincidence analysis of the triggers obtained in the different interferometers with and without simulated signals added to the data. The benefits of having multiple interferometers of similar sensitivity are demonstrated by comparing the detection performance of the joint coincidence analysis with LSC and Virgo only burst searches. Adding Virgo to the LIGO detector network can increase by 50% the detection efficiency for this search. Another advantage of a joint LIGO-Virgo network is the ability to reconstruct the source sky position. The reconstruction accuracy depends on the timing measurement accuracy of the events in each interferometer, and is displayed in this paper with a fixed source position example.Comment: LIGO-Virgo working group submitted to PR

A first comparison of search methods for gravitational wave bursts using LIGO and Virgo simulated data

We present a comparative study of 6 search methods for gravitational wave bursts using simulated LIGO and Virgo noise data. The data's spectra were chosen to follow the design sensitivity of the two 4km LIGO interferometers and the 3km Virgo interferometer. The searches were applied on replicas of the data sets to which 8 different signals were injected. Three figures of merit were employed in this analysis: (a) Receiver Operator Characteristic curves, (b) necessary signal to noise ratios for the searches to achieve 50 percent and 90 percent efficiencies, and (c) variance and bias for the estimation of the arrival time of a gravitational wave burst.Comment: GWDAW9 proceeding

First search for gravitational waves from the youngest known neutron star

We present a search for periodic gravitational waves from the neutron star in the supernova remnant Cassiopeia A. The search coherently analyzes data in a 12 day interval taken from the fifth science run of the Laser Interferometer Gravitational-Wave Observatory. It searches gravitational-wave frequencies from 100 to 300 Hz and covers a wide range of first and second frequency derivatives appropriate for the age of the remnant and for different spin-down mechanisms. No gravitational-wave signal was detected. Within the range of search frequencies, we set 95% confidence upper limits of (0.7–1.2) × 10^(−24) on the intrinsic gravitational-wave strain, (0.4–4) × 10^(−4) on the equatorial ellipticity of the neutron star, and 0.005–0.14 on the amplitude of r-mode oscillations of the neutron star. These direct upper limits beat indirect limits derived from energy conservation and enter the range of theoretical predictions involving crystalline exotic matter or runaway r-modes. This paper is also the first gravitational-wave search to present upper limits on the r-mode amplitude

On the Schrödinger-Newton equation and its symmetries: a geometric view

LaTeX 29 pages; minor correctionsInternational audienceThe \SN (SN) equation is recast on purely geometrical grounds, namely in terms of Bargmann structures over (\d+1)-dimensional Newton-Cartan (NC) spacetimes. Its maximal group of invariance, which we call the SN group, is determined as the group of conformal Bargmann automorphisms that preserve the coupled Schr\"odinger and NC gravitational field equations. Canonical unitary representations of the SN group are worked out, helping us recover, in particular, a very specific occurrence of dilations with dynamical exponent z=(\d+2)/3