The gravitational wave detector "Mario Schenberg": status of the project

Aguiar, O. D.; Andrade, L A; Filho, Luiz C. Gonçalves; Costa, C. A.; Araújo, J. C. N. de; Neto, E.C. del Rey; Souza, S T de; Fauth, A. C.; Frajuca, Carlos; Frossati, G.; Furtado, S R; Furtado, V.G.S.; Magalhães, Nadja S.; Marinho, R. M.; Matos, E S; Meliani, M. T.; Melo, J. L.; Miranda, Oswaldo D.; Oliveira, N. F.; Ribeiro, K L; Salles, Karla Beatriz M.; Stellati, C; Velloso, W. F.

doi:10.1590/s0103-97332002000500008

Cited by 33 publications

(22 citation statements)

References 13 publications

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“…SCHENBERG was designed to have a resonant frequency near 3.2 kHz with a bandwidth around 200 Hz (Aguiar et al 2002). This narrow band, typical of resonant-mass detectors, limits the kinds of sources that can be observed.…”

Section: F I G U R Ementioning

confidence: 99%

The challenge of calibrating a laser‐interferometric gravitational wave detector

et al. 2021

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In 2015, the first direct detection of gravitational waves was reported. Data analysis indicated that the waves had originated from the violent collision of two black holes, which scattered them through space-time as Einstein predicted. That detection was made possible by many advances in measurement technology, mainly vibration isolation of the detector optics, since, at 10 Hz, the motion of the laser-interferometric detector mirrors is at least one billion times smaller than the seismic motion of the ground. As well, it is difficult to lock the laser in the detection configuration in a large band of the spectrum; this was made possible by using many feedback and feed-forward control loops. However, in order to meet the many demanding requirements, more than a hundred of such active systems are included in a detector to allow locked acquisition and locked stability to, eventually, reach the desired sensitivity. In this work, challenges faced to reach some of these requirements will be described and we analyze how this scenario impacts the calibration of such detectors. In order to help reduce false alarm rates and provide data for veto systems, in this work we propose a specific kind of resonant-mass detector to operate in coincidence with laser-interferometric ones.

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Section: F I G U R Ementioning

confidence: 99%

The challenge of calibrating a laser‐interferometric gravitational wave detector

et al. 2021

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“…Odylio D. Aguiar (INPE) told us about the status of the Mario Schenberg gravitation wave detector, which is being constructed in the Institute of Physics of the University of São Paulo, and is expected to start to operate in 2002. This detector has a spherical antenna, will operate at temperature of less than 0.1K, and will be sensitive to signals of amplitude h > 10 −21 Hz −1/2 in the bandwidth 3.0 -3.4kHz (for more details on this talk see Aguiar's paper in this issue [12,13]).…”

Section: Plenary and Parallel Talksmentioning

confidence: 99%

Summary talk on Cosmology and Gravitation XXII Brazilian National Meeting on Particles and fields

Rebouças¹

2002

Braz. J. Phys.

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“…The first attempts to detect GWs started in the early 60s (Richard 1984) with resonant-mass detectors that were continuously improved during the following decades (Aguiar et al 2002;Andrade et al 2004;Bortoli et al 2010Bortoli et al , 2016Bortoli et al , 2019Frajuca et al 2000Frajuca et al , 2002Frajuca et al , 2004Frajuca et al , 2005Frajuca et al , 2006Frajuca et al , 2008Frajuca et al , 2012Magalhaes et al 1995Magalhaes et al , 1997aMagalhaes et al , 1997bMagalhaes et al , 2012Magalhaes et al , 2016Oliveira et al 2018;Ribeiro et al 2004). These investigations include works of the Graviton group.…”

Section: Introductionmentioning

confidence: 99%

The influence of rotation deceleration on the shape of a pulsar may reflect on the star's braking index

2021

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Pulsars are stars whose electromagnetic radiation is observed to pulsate in well-defined time intervals while they rotate as long as the electromagnetic signal is not emitted in the direction of the rotation axis. The frequencies of the pulses decay with time as quantified by the braking index (n). In the canonical model, n = 3 for all pulsars, but observational data yield n < 3. In this work, this model is modified to allow time change in the moment of inertia. According to that model, as the neutron star loses energy by the emission of electromagnetic radiation, its rotation decelerates under constant moment of inertia. Here, we propose that, as the rotation decelerates, the shape of the star changes due to an increasingly weaker centrifugal force that reduces its moment of inertia, a change that, under normal circumstances, would accelerate the star's rotation. In the case of pulsars, as the rotation decreases in view of electromagnetic energy loss, the rotation would decelerate less than in the canonical model, yielding a braking index less than three. This is a good result from our model, especially regarding stars with indices close to three. For lower indices, our model requires refinements as a complete explanation of braking index values probably demands that a series of phenomena be incorporated into the process.

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The gravitational wave detector "Mario Schenberg": status of the project

Cited by 33 publications

References 13 publications

The challenge of calibrating a laser‐interferometric gravitational wave detector

The challenge of calibrating a laser‐interferometric gravitational wave detector

Summary talk on Cosmology and Gravitation XXII Brazilian National Meeting on Particles and fields

The influence of rotation deceleration on the shape of a pulsar may reflect on the star's braking index

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