Development of a real-time full-field range imaging system

This article describes the development of a full-field range imaging system employing a high frequency amplitude modulated light source and image sensor. Depth images are produced at video frame rates in which each pixel in the image represents distance from the sensor to objects in the scene. The various hardware subsystems are described as are the details about the firmware and software implementation for processing the images in real-time. The system is flexible in that precision can be traded off for decreased acquisition time. Results are reported to illustrate this versatility for both high-speed (reduced precision) and high-precision operating modes

Search for gravitational waves from Scorpius X-1 in the second Advanced LIGO observing run with an improved hidden Markov model

We present results from a semicoherent search for continuous gravitational waves from the low-mass x-ray binary Scorpius X-1, using a hidden Markov model (HMM) to track spin wandering. This search improves on previous HMM-based searches of LIGO data by using an improved frequency domain matched filter, the J-statistic, and by analyzing data from Advanced LIGO's second observing run. In the frequency range searched, from 60 to 650 Hz, we find no evidence of gravitational radiation. At 194.6 Hz, the most sensitive search frequency, we report an upper limit on gravitational wave strain (at 95% confidence) of h095%=3.47×10-25 when marginalizing over source inclination angle. This is the most sensitive search for Scorpius X-1, to date, that is specifically designed to be robust in the presence of spin wandering. © 2019 American Physical Society

Search for Tensor, Vector, and Scalar Polarizations in the Stochastic Gravitational-Wave Background

The detection of gravitational waves with Advanced LIGO and Advanced Virgo has enabled novel tests of general relativity, including direct study of the polarization of gravitational waves. While general relativity allows for only two tensor gravitational-wave polarizations, general metric theories can additionally predict two vector and two scalar polarizations. The polarization of gravitational waves is encoded in the spectral shape of the stochastic gravitational-wave background, formed by the superposition of cosmological and individually unresolved astrophysical sources. Using data recorded by Advanced LIGO during its first observing run, we search for a stochastic background of generically polarized gravitational waves. We find no evidence for a background of any polarization, and place the first direct bounds on the contributions of vector and scalar polarizations to the stochastic background. Under log-uniform priors for the energy in each polarization, we limit the energy densities of tensor, vector, and scalar modes at 95% credibility to Ω0T<5.58×10-8, Ω0V<6.35×10-8, and Ω0S<1.08×10-7 at a reference frequency f0=25 Hz. © 2018 American Physical Society

Erratum: "A Gravitational-wave Measurement of the Hubble Constant Following the Second Observing Run of Advanced LIGO and Virgo" (2021, ApJ, 909, 218)

[no abstract available

Search for Gravitational Waves Associated with Gamma-Ray Bursts Detected by Fermi and Swift during the LIGO-Virgo Run O3b

We search for gravitational-wave signals associated with gamma-ray bursts (GRBs) detected by the Fermi and Swift satellites during the second half of the third observing run of Advanced LIGO and Advanced Virgo (2019 November 1 15:00 UTC-2020 March 27 17:00 UTC). We conduct two independent searches: A generic gravitational-wave transients search to analyze 86 GRBs and an analysis to target binary mergers with at least one neutron star as short GRB progenitors for 17 events. We find no significant evidence for gravitational-wave signals associated with any of these GRBs. A weighted binomial test of the combined results finds no evidence for subthreshold gravitational-wave signals associated with this GRB ensemble either. We use several source types and signal morphologies during the searches, resulting in lower bounds on the estimated distance to each GRB. Finally, we constrain the population of low-luminosity short GRBs using results from the first to the third observing runs of Advanced LIGO and Advanced Virgo. The resulting population is in accordance with the local binary neutron star merger rate. © 2022. The Author(s). Published by the American Astronomical Society

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

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

Desenvolvimento testicular, espermatogênese e concentrações hormonais em touros Angus Testicular development, spermatogenesis and hormonal concentrations in Angus bulls

Este estudo foi realizado com a finalidade de avaliar a evolução das secreções hormonais e do epitélio seminífero em touros da raça Angus de 10 a 38 semanas de idade. Foram castrados 1 a 5 animais em intervalos de quatro semanas (total de 25 touros) para coleta de amostras do parênquima testicular e do plasma sanguíneo. As variáveis relacionadas ao crescimento testicular, aos aspectos quantitativos da espermatogênese e aos níveis hormonais foram transformadas em logaritmo e avaliadas por meio de análise de variância. O diâmetro dos testículos e túbulos seminíferos e o peso testicular apresentaram variações mais acentuadas após 26 semanas de idade. A porcentagem do parênquima testicular ocupado pelos túbulos seminíferos aumentou de 49,3 para 75,2% durante o experimento. A maioria dos túbulos (>90%) apresentou-se com células de Sertoli somente entre 10 e 14 semanas, mas na 18ª (13,8&plusmn;1,7%) e 22ª semanas (19&plusmn;1%), o número de túbulos com gonócitos e espermatogônias aumentou em relação às semanas iniciais. Espermatogônias intermediárias e B predominaram na 26ª semana (24,5&plusmn;8,2%) e a porcentagem de túbulos com espermatócitos foi mais elevada na 30ª semana (42,3&plusmn;9,9%). Espermátides arredondadas foram detectadas partir da 26ª semana e, na 38ª semana, 62,3&plusmn;1,5% dos túbulos seminíferos continham espermátides alongadas ou maduras. As variações mais acentuadas no crescimento testicular e, principalmente, no peso testicular após as 26 semanas coincidiram com o estabelecimento da meiose, com as alterações morfológicas do núcleo e nucléolo das células de Sertoli (indicativos do processo de diferenciação das mesmas), com os níveis reduzidos de androstenediona e os incrementos significativos de testosterona e estradiol 17beta. As associações entre o crescimento testicular e os níveis de FSH e LH na circulação periférica foram menos evidentes.<br>This study aimed to evaluate changes in hormone secretion and in seminiferous epithelium of Angus bulls between 10 and 38 weeks of age. Samples of testicular parenchyma and blood were collected from 25 animals castrated in 4 week intervals. Traits associated to testicular development and quantitative aspects of spermatogenesis and hormonal concentrations were transformed by logarithm before analyses of variance. Changes in testis and seminiferous tubule diameter and testis weight were more pronounced after 26 weeks of age. The percentage of testicular parenchyma occupied by seminiferous tubules increased from 49.3 to 75.2% from 10 to 38 weeks. Most tubules (>90%) had only Sertoli cells at 10 and 14 weeks, but the number of tubules with gonocytes and A spermatogonia increased at 18 (13.8&plusmn;1.7%) and 22 weeks (19&plusmn;1%). Tubules with B and intermediate spermatogonia became predominant at 26 weeks (24.5&plusmn;8.2%) and those with spermatocytes as the most advanced germ cell type were more evident at 30 weeks (42.3&plusmn;9.9%). Round spermatids were detected at 26 weeks and at 38 weeks of age, 62.3&plusmn;1.5% of all tubules had either elongate or mature spermatids. Variations in testis growth (specially testis weight) after 26 weeks were coincident with the establishment of meiosis in the seminiferous tubules, morphological alterations in nucleus and nucleolus of the Sertoli cells (indicators of Sertoli cell differentiation), lower levels of androstenedione and significant increases in testosterone and estradiol 17beta. Associations between testis development and concentrations of FSH and LH were less evident

Low-latency gravitational-wave alerts for multimessenger astronomy during the second Advanced LIGO and Virgo observing run

Advanced LIGO's second observing run (O2), conducted from 2016 November 30 to 2017 August 25, combined with Advanced Virgo's first observations in 2017 August, witnessed the birth of gravitational-wave multimessenger astronomy. The first ever gravitational-wave detection from the coalescence of two neutron stars, GW170817, and its gamma-ray counterpart, GRB 170817A, led to an electromagnetic follow-up of the event at an unprecedented scale. Several teams from across the world searched for EM/neutrino counterparts to GW170817, paving the way for the discovery of optical, X-ray, and radio counterparts. In this article, we describe the online identification of gravitational-wave transients and the distribution of gravitational-wave alerts by the LIGO and Virgo collaborations during O2. We also describe the gravitational-wave observables that were sent in the alerts to enable searches for their counterparts. Finally, we give an overview of the online candidate alerts shared with observing partners during O2. Alerts were issued for 14 candidates, 6 of which have been confirmed as gravitational-wave events associated with the merger of black holes or neutron stars. Of the 14 alerts, 8 were issued less than an hour after data acquisition