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

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

A First Search for coincident Gravitational Waves and High Energy Neutrinos using LIGO, Virgo and ANTARES data from 2007

We present the results of the first search for gravitational wave bursts associated with high energy neutrinos. Together, these messengers could reveal new, hidden sources that are not observed by conventional photon astronomy, particularly at high energy. Our search uses neutrinos detected by the underwater neutrino telescope ANTARES in its 5 line configuration during the period January - September 2007, which coincided with the fifth and first science runs of LIGO and Virgo, respectively. The LIGO-Virgo data were analysed for candidate gravitational-wave signals coincident in time and direction with the neutrino events. No significant coincident events were observed. We place limits on the density of joint high energy neutrino - gravitational wave emission events in the local universe, and compare them with densities of merger and core-collapse events.Comment: 19 pages, 8 figures, science summary page at http://www.ligo.org/science/Publication-S5LV_ANTARES/index.php. Public access area to figures, tables at https://dcc.ligo.org/cgi-bin/DocDB/ShowDocument?docid=p120000

All-sky search for long-duration gravitational wave transients with initial LIGO

We present the results of a search for long-duration gravitational wave transients in two sets of data collected by the LIGO Hanford and LIGO Livingston detectors between November 5, 2005 and September 30, 2007, and July 7, 2009 and October 20, 2010, with a total observational time of 283.0 days and 132.9 days, respectively. The search targets gravitational wave transients of duration 10-500 s in a frequency band of 40-1000 Hz, with minimal assumptions about the signal waveform, polarization, source direction, or time of occurrence. All candidate triggers were consistent with the expected background; as a result we set 90% confidence upper limits on the rate of long-duration gravitational wave transients for different types of gravitational wave signals. For signals from black hole accretion disk instabilities, we set upper limits on the source rate density between 3.4×10-5 and 9.4×10-4 Mpc-3 yr-1 at 90% confidence. These are the first results from an all-sky search for unmodeled long-duration transient gravitational waves. © 2016 American Physical Society

All-sky search for long-duration gravitational wave transients with initial LIGO

We present the results of a search for long-duration gravitational wave transients in two sets of data collected by the LIGO Hanford and LIGO Livingston detectors between November 5, 2005 and September 30, 2007, and July 7, 2009 and October 20, 2010, with a total observational time of 283.0 days and 132.9 days, respectively. The search targets gravitational wave transients of duration 10-500 s in a frequency band of 40-1000 Hz, with minimal assumptions about the signal waveform, polarization, source direction, or time of occurrence. All candidate triggers were consistent with the expected background; as a result we set 90% confidence upper limits on the rate of long-duration gravitational wave transients for different types of gravitational wave signals. For signals from black hole accretion disk instabilities, we set upper limits on the source rate density between 3.4×10-5 and 9.4×10-4 Mpc-3 yr-1 at 90% confidence. These are the first results from an all-sky search for unmodeled long-duration transient gravitational waves. © 2016 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

On the progenitor of binary neutron star merger GW170817

On 2017 August 17 the merger of two compact objects with masses consistent with two neutron stars was discovered through gravitational-wave (GW170817), gamma-ray (GRB 170817A), and optical (SSS17a/AT 2017gfo) observations. The optical source was associated with the early-type galaxy NGC 4993 at a distance of just ∼40 Mpc, consistent with the gravitational-wave measurement, and the merger was localized to be at a projected distance of ∼2 kpc away from the galaxy's center. We use this minimal set of facts and the mass posteriors of the two neutron stars to derive the first constraints on the progenitor of GW170817 at the time of the second supernova (SN). We generate simulated progenitor populations and follow the three-dimensional kinematic evolution from binary neutron star (BNS) birth to the merger time, accounting for pre-SN galactic motion, for considerably different input distributions of the progenitor mass, pre-SN semimajor axis, and SN-kick velocity. Though not considerably tight, we find these constraints to be comparable to those for Galactic BNS progenitors. The derived constraints are very strongly influenced by the requirement of keeping the binary bound after the second SN and having the merger occur relatively close to the center of the galaxy. These constraints are insensitive to the galaxy's star formation history, provided the stellar populations are older than 1 Gyr

Constraints on cosmic strings using data from the first Advanced LIGO observing run

Cosmic strings are topological defects which can be formed in grand unified theory scale phase transitions in the early universe. They are also predicted to form in the context of string theory. The main mechanism for a network of Nambu-Goto cosmic strings to lose energy is through the production of loops and the subsequent emission of gravitational waves, thus offering an experimental signature for the existence of cosmic strings. Here we report on the analysis conducted to specifically search for gravitational-wave bursts from cosmic string loops in the data of Advanced LIGO 2015-2016 observing run (O1). No evidence of such signals was found in the data, and as a result we set upper limits on the cosmic string parameters for three recent loop distribution models. In this paper, we initially derive constraints on the string tension Gμ and the intercommutation probability, using not only the burst analysis performed on the O1 data set but also results from the previously published LIGO stochastic O1 analysis, pulsar timing arrays, cosmic microwave background and big-bang nucleosynthesis experiments. We show that these data sets are complementary in that they probe gravitational waves produced by cosmic string loops during very different epochs. Finally, we show that the data sets exclude large parts of the parameter space of the three loop distribution models we consider

Improving Seed Spacing Uniformity of Precision Vegetable Planters

Equidistant, uniform seed placement is important in lettuce production as seeds are densely planted within the row, typically only about 5 cm apart. When seeds are sown too close together, it is time consuming to thin seedlings to the desired plant spacing of 20 to 30 cm by hand and very difficult to do mechanically. The overall goal of the project was to improve lettuce seed placement accuracy and reduce the percentage of seeds spaced closely together. Specific objectives were: 1) to compare vacuum and belt-type planters to determine which style of planter provides better planting performance, 2) to evaluate belt planter seeding performance with different types of furrow openers, and 3) to develop practical modifications for vacuum planters to improve lettuce seed placement accuracy. Three vacuum planter configurations, an unmodified and two reduced seed drop height designs and a belt planter equipped with two types of furrow openers were tested in situ with pelleted lettuce seed at four travel speeds ranging from 1.6 to 4.0 kph. Belt planter performance was significantly better than that of the vacuum planter. Vacuum and belt planters both provided acceptable levels of performance at speeds below 2.4 kph, but at higher speeds, seed placement accuracy declined rapidly. No differences in planter performance were found between the two belt planter configurations tested. The mid-level drop height vacuum planter configuration had significantly better seed placement precision and fewer closely spaced seed spacings as compared to the unmodified vacuum planter. These findings illustrate the significant effect planter type, travel speed, and drop height have on planter performance. They also contradict the common perception that vacuum planters deliver seed more precisely and with fewer closely-spaced seeds as compared to belt planters. Further study is needed to determine the extent to which planter performance affects hand thinning labor costs, automated machine performance, final plant stand uniformity, and crop yield.The Arizona Department of Agriculture, Agricultural Consultation and Training provided partial project funding using Specialty Crop Block Grant funds provided by the USDA, Agricultural Marketing Service. The views or findings presented are the authors and do not necessarily represent those of the Arizona Department of Agriculture, the State of Arizona or the USDA.If my manuscript is accepted for publication by ASABE, I hereby assign and transfer to ASABE all right, title, and interest in and to the copyright in said manuscript. ASABE in turn hereby grants to the author and, in the case of a work made for hire, his or her employer, a nonexclusive, royalty-free license to use and distribute the article by print, email, employer website, or personal website, provided that each copy includes the copyright notice appearing on the published article.This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Comparison of Runoff, Soil Erosion, and Winter Wheat Yields from No-Till and Inversion Tillage Production Systems in Northeastern Oregon

Conservation tillage systems that reduce soil erosion and maintain or increase soil carbon offer long-term benefits for producers in the inland Pacific Northwestern United States but could result in reduced grain yields due to increased pressure from weeds, disease, and insect pests. Our objective was to compare runoff, soil erosion, and crop yields from a conventional tillage, wheat-fallow two-year rotation and a no-till four-year rotation. The experiment was undertaken within a small watershed to provide results that would be repre¬sentative of conservation effectiveness at the field scale. Two neighboring drainages, 5.8 and 10.7 ha (14 and 26 ac), in the 340 mm y-1 (13.4 in yr-1) precipitation zone of northeastern Oregon, were instrumented to record rainfall, runoff, and erosion over a four-year period (2001 through 2004). One drainage was cropped to a winter wheat–fallow rotation and received inversion tillage (tillage fallow). The second drainage was cropped in a four-year no-till rotation: winter wheat–chemical fallow–winter wheat–chickpea (no-till fallow). We recorded 13 runoff events from the inversion tillage system and 3 from the no-till system. Total runoff and erosion values from inversion tillage drainage were 5.1 mm (0.20 in) and 0.42 Mg ha-1 (0.19 tn ac-1) versus 0.7 mm (0.03 in) and 0.01 Mg ha-1 (-1) from no-till drainage. The no-till rotation was substantially more effective in conserving soil and water in this field-scale comparison. Soil erosion observed in this research is a fraction of that reported for similar tillage practices outside of the Pacific Northwestern. Mean wheat yields did not significantly differ between inversion tillage and no-till treatments despite intensify¬ing the rotation by replacing one year of fallow with a chickpea crop in the four-year rota¬tion. Because of high year-to-year variability in yield and limited sample size, more study is needed to compare winter wheat yields in no-till production systems with inversion tillage. The no-till cropping system was more effective in reducing runoff and soil erosion and provides producers with an ability to protect soil and water resources in the dryland Pacific Northwest