Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
- Discipline
- Keyword
Articles 1 - 20 of 20
Full-Text Articles in Physical Sciences and Mathematics
Search For Gravitational-Wave Signals Associated With Gamma-Ray Bursts During The Second Observing Run Of Advanced Ligo And Advanced Virgo, Tiffany Summerscales, Ligo Scientific Collaboration And The Virgo Collaboration
Search For Gravitational-Wave Signals Associated With Gamma-Ray Bursts During The Second Observing Run Of Advanced Ligo And Advanced Virgo, Tiffany Summerscales, Ligo Scientific Collaboration And The Virgo Collaboration
Faculty Publications
We present the results of targeted searches for gravitational-wave transients associated with gamma-ray bursts during the second observing run of Advanced LIGO and Advanced Virgo, which took place from 2016 November to 2017 August. We have analyzed 98 gamma-ray bursts using an unmodeled search method that searches for generic transient gravitational waves and 42 with a modeled search method that targets compact-binary mergers as progenitors of short gamma-ray bursts. Both methods clearly detect the previously reported binary merger signal GW170817, with p-values of <9.38 × 10−6 (modeled) and 3.1 × 10−4 (unmodeled). We do not find any significant evidence for …
Tests Of General Relativity With The Binary Black Hole Signals From The Ligo-Virgo Catalog Gwtc-1, Tiffany Summerscales, Ligo Scientific Collaboration And The Virgo Collaboration
Tests Of General Relativity With The Binary Black Hole Signals From The Ligo-Virgo Catalog Gwtc-1, Tiffany Summerscales, Ligo Scientific Collaboration And The Virgo Collaboration
Faculty Publications
The detection of gravitational waves by Advanced LIGO and Advanced Virgo provides an opportunity to test general relativity in a regime that is inaccessible to traditional astronomical observations and laboratory tests. We present four tests of the consistency of the data with binary black hole gravitational waveforms predicted by general relativity. One test subtracts the best-fit waveform from the data and checks the consistency of the residual with detector noise. The second test checks the consistency of the low- and high-frequency parts of the observed signals. The third test checks that phenomenological deviations introduced in the waveform model (including in …
Evolution Of A Relativistic Electron Beam For Tracing Magnetospheric Field Lines, Andrew T. Powis, Peter Porazik, Michael Greklek-Mckeon, Kailas Amin, David Shaw, Igor D. Kaganovich, Jay R. Johnson, Ennio Sanchez
Evolution Of A Relativistic Electron Beam For Tracing Magnetospheric Field Lines, Andrew T. Powis, Peter Porazik, Michael Greklek-Mckeon, Kailas Amin, David Shaw, Igor D. Kaganovich, Jay R. Johnson, Ennio Sanchez
Faculty Publications
Tracing magnetic field-lines of the Earth's magnetosphere using beams of relativistic electrons will open up new insights into space weather and magnetospheric physics. Analytic models and a single-particle-motion code were used to explore the dynamics of an electron beam emitted from an orbiting satellite and propagating until impact with the Earth. The impact location of the beam on the upper atmosphere is strongly influenced by magnetospheric conditions, shifting up to several degrees in latitude between different phases of a simulated storm. The beam density cross-section evolves due to cyclotron motion of the beam centroid and oscillations of the beam envelope. …
Relativistic Particle Beams As A Resource To Solve Outstanding Problems In Space Physics, Ennio R. Sanchez, Andrew T. Powis, Igor D. Kaganovich, Robert Marshall, Peter Porazik, Jay R. Johnson, Michael Greklek-Mckeon, Kailas S. Amin, David Shaw, Micale Nicolls
Relativistic Particle Beams As A Resource To Solve Outstanding Problems In Space Physics, Ennio R. Sanchez, Andrew T. Powis, Igor D. Kaganovich, Robert Marshall, Peter Porazik, Jay R. Johnson, Michael Greklek-Mckeon, Kailas S. Amin, David Shaw, Micale Nicolls
Faculty Publications
The Sun's connection with the Earth's magnetic field and atmosphere is carried out through the exchange of electromagnetic and mass flux and is regulated by a complex interconnection of processes. During space weather events, solar flares, or fast streams of solar atmosphere strongly disturb the Earth's environment. Often the electric currents that connect the different parts of the Sun-Earth system become unstable and explosively release the stored electromagnetic energy in one of the more dramatic expressions of space weather—the geomagnetic storm and substorm. Some aspects of the magnetosphere-ionosphere connection that generates auroral arcs during space weather events are well-known. However, …
Search For Eccentric Binary Black Hole Mergers With Advanced Ligo And Advanced Virgo During Their First And Second Observing Runs, Tiffany Summerscales, Ligo Scientific Collaboration And The Virgo Collaboration
Search For Eccentric Binary Black Hole Mergers With Advanced Ligo And Advanced Virgo During Their First And Second Observing Runs, Tiffany Summerscales, Ligo Scientific Collaboration And The Virgo Collaboration
Faculty Publications
When formed through dynamical interactions, stellar-mass binary black holes (BBHs) may retain eccentric orbits (e > 0.1 at 10 Hz) detectable by ground-based gravitational-wave detectors. Eccentricity can therefore be used to differentiate dynamically formed binaries from isolated BBH mergers. Current template-based gravitational-wave searches do not use waveform models associated with eccentric orbits, rendering the search less efficient for eccentric binary systems. Here we present the results of a search for BBH mergers that inspiral in eccentric orbits using data from the first and second observing runs (O1 and O2) of Advanced LIGO and Advanced Virgo. We carried out the search …
Search For Intermediate Mass Black Hole Binaries In The First And Second Observing Runs Of The Advanced Ligo And Virgo Network, Tiffany Summerscales, Ligo Scientific Collaboration And The Virgo Collaboration
Search For Intermediate Mass Black Hole Binaries In The First And Second Observing Runs Of The Advanced Ligo And Virgo Network, Tiffany Summerscales, Ligo Scientific Collaboration And The Virgo Collaboration
Faculty Publications
Gravitational-wave astronomy has been firmly established with the detection of gravitational waves from the merger of ten stellar-mass binary black holes and a neutron star binary. This paper reports on the all-sky search for gravitational waves from intermediate mass black hole binaries in the first and second observing runs of the Advanced LIGO and Virgo network. The search uses three independent algorithms: two based on matched filtering of the data with waveform templates of gravitational-wave signals from compact binaries, and a third, model-independent algorithm that employs no signal model for the incoming signal. No intermediate mass black hole binary event …
Method For Approximating Field-Line Curves Using Ionospheric Observations Of Energy-Variable Electron Beams Launched From Satellites, Jake M. Willard, Jay R. Johnson, Jesse M. Snelling, Andrew T. Powis, Igor D, Kaganovich, Ennio R. Sanchez
Method For Approximating Field-Line Curves Using Ionospheric Observations Of Energy-Variable Electron Beams Launched From Satellites, Jake M. Willard, Jay R. Johnson, Jesse M. Snelling, Andrew T. Powis, Igor D, Kaganovich, Ennio R. Sanchez
Faculty Publications
Using electron beam accelerators attached to satellites in Earth orbit, it may be possible to measure arc length and curvature of field-lines in the inner magnetosphere if the accelerator is designed with the capability to vary the beam energy. In combination with additional information, these measurements would be very useful in modeling the magnetic field of the inner magnetosphere. For this purpose, a three step data assimilation modeling approach is discussed. The first step in the procedure would be to use prior information to obtain an initial forecast of the inner magnetosphere. Then, a family of curves would be defined …
Gwtc-1: A Gravitational-Wave Transient Catalog Of Compact Binary Mergers Observed By Ligo And Virgo During The First And Second Observing Runs, Tiffany Summerscales, Ligo Scientific Collaboration And The Virgo Collaboration
Gwtc-1: A Gravitational-Wave Transient Catalog Of Compact Binary Mergers Observed By Ligo And Virgo During The First And Second Observing Runs, Tiffany Summerscales, Ligo Scientific Collaboration And The Virgo Collaboration
Faculty Publications
We present the results from three gravitational-wave searches for coalescing compact binaries with component masses above 1 M⊙ during the first and second observing runs of the advanced gravitational-wave detector network. During the first observing run (O1), from September 12, 2015 to January 19, 2016, gravitational waves from three binary black hole mergers were detected. The second observing run (O2), which ran from November 30, 2016 to August 25, 2017, saw the first detection of gravitational waves from a binary neutron star inspiral, in addition to the observation of gravitational waves from a total of seven binary black hole …
Search For The Isotropic Stochastic Background Using Data From Advanced Ligo's Second Observing Run, Tiffany Summerscales, Ligo Scientific Collaboration And The Virgo Collaboration
Search For The Isotropic Stochastic Background Using Data From Advanced Ligo's Second Observing Run, Tiffany Summerscales, Ligo Scientific Collaboration And The Virgo Collaboration
Faculty Publications
The stochastic gravitational-wave background is a superposition of sources that are either too weak or too numerous to detect individually. In this study we present the results from a cross-correlation analysis on data from Advanced LIGO's second observing run (O2), which we combine with the results of the first observing run (O1). We do not find evidence for a stochastic background, so we place upper limits on the normalized energy density in gravitational waves at the 95% credible level of ΩGW<6.0×10−8 for a frequency-independent (flat) background and ΩGW<4.8×10−8 at 25 Hz for a background of compact …
Connecting Theory And Practice, Hannah Gallant
Connecting Theory And Practice, Hannah Gallant
World Changers Made Here
No abstract provided.
Effect Of Field-Line Curvature On The Ionospheric Accessibility Of Relativistic Electron Beam Experiments, Jake M. Willard, Jay R. Johnson, Jesse M. Snelling, Andrew T. Powis, Igor D. Kaganovich, Ennio R, Sanchez
Effect Of Field-Line Curvature On The Ionospheric Accessibility Of Relativistic Electron Beam Experiments, Jake M. Willard, Jay R. Johnson, Jesse M. Snelling, Andrew T. Powis, Igor D. Kaganovich, Ennio R, Sanchez
Faculty Publications
Magnetosphere-ionosphere coupling is a particularly important process that regulates and controls magnetospheric dynamics such as storms and substorms. However, in order to understand magnetosphere-ionosphere coupling it is necessary to understand how regions of the magnetosphere are connected to the ionosphere. It has been proposed that this connection may be established by firing electron beams from satellites that can reach an ionospheric footpoint creating detectable emissions. This type of experiment would greatly aid in identifying the relationship between convection processes in the magnetotail and the ionosphere and how the plasma sheet current layer evolves during the growth phase preceding substorms. For …
Electron Energization By Parallel Electric Fields In Poloidal Standing Waves, P. A. Damiano, Eun-Hwa Kim, Jay R. Johnson, P. Porazik
Electron Energization By Parallel Electric Fields In Poloidal Standing Waves, P. A. Damiano, Eun-Hwa Kim, Jay R. Johnson, P. Porazik
Faculty Publications
A hybrid gyrofluid‐kinetic electron model is adapted and used to simulate poloidal standing modes for different electron temperatures and azimuthal mode numbers. As in previous studies of toroidal standing modes, mirror force effects lead to increased parallel potential drops, monoenergetic electron energization, and wave energy dissipation as the ambient electron temperature is increased. A similar trend is also observed when the electron temperature is held fixed and the azimuthal mode number increased—owing to the narrowing of the azimuthal flux tube width, which necessitates more electron energization to carry the increased parallel current density. In both cases, the increase in electron …
All-Sky Search For Continuous Gravitational Waves From Isolated Neutron Stars Using Advanced Ligo O2 Data, Tiffany Summerscales
All-Sky Search For Continuous Gravitational Waves From Isolated Neutron Stars Using Advanced Ligo O2 Data, Tiffany Summerscales
Faculty Publications
We present results of an all-sky search for continuous gravitational waves (CWs), which can be produced by fast spinning neutron stars with an asymmetry around their rotation axis, using data from the second observing run of the Advanced LIGO detectors. Three different semicoherent methods are used to search in a gravitational-wave frequency band from 20 to 1922 Hz and a first frequency derivative from −1×10−8 to 2×10−9 Hz/s. None of these searches has found clear evidence for a CW signal, so upper limits on the gravitational-wave strain amplitude are calculated, which for this broad range in parameter space …
Tests Of General Relativity With Gw170817, Tiffany Summerscales, Ligo Scientific Collaboration And The Virgo Collaboration
Tests Of General Relativity With Gw170817, Tiffany Summerscales, Ligo Scientific Collaboration And The Virgo Collaboration
Faculty Publications
The recent discovery by Advanced LIGO and Advanced Virgo of a gravitational wave signal from a binary neutron star inspiral has enabled tests of general relativity (GR) with this new type of source. This source, for the first time, permits tests of strong-field dynamics of compact binaries in the presence of matter. In this Letter, we place constraints on the dipole radiation and possible deviations from GR in the post-Newtonian coefficients that govern the inspiral regime. Bounds on modified dispersion of gravitational waves are obtained; in combination with information from the observed electromagnetic counterpart we can also constrain effects due …
Narrow-Band Search For Gravitational Waves From Known Pulsars Using The Second Ligo Observing Run, Tiffany Summerscales, Ligo Scientific Collaboration And The Virgo Collaboration
Narrow-Band Search For Gravitational Waves From Known Pulsars Using The Second Ligo Observing Run, Tiffany Summerscales, Ligo Scientific Collaboration And The Virgo Collaboration
Faculty Publications
Isolated spinning neutron stars, asymmetric with respect to their rotation axis, are expected to be sources of continuous gravitational waves. The most sensitive searches for these sources are based on accurate matched filtering techniques that assume the continuous wave to be phase locked with the pulsar beamed emission. While matched filtering maximizes the search sensitivity, a significant signal-to-noise ratio loss will happen in the case of a mismatch between the assumed and the true signal phase evolution. Narrow-band algorithms allow for a small mismatch in the frequency and spin-down values of the pulsar while coherently integrating the entire dataset. In …
Searches For Gravitational Waves From Known Pulsars At Two Harmonics In 2015–2017 Ligo Data, Tiffany Summerscales, Ligo Scientific Collaboration And The Virgo Collaboration
Searches For Gravitational Waves From Known Pulsars At Two Harmonics In 2015–2017 Ligo Data, Tiffany Summerscales, Ligo Scientific Collaboration And The Virgo Collaboration
Faculty Publications
We present a search for gravitational waves from 222 pulsars with rotation frequencies 10 Hz. We use advanced LIGO data from its first and second observing runs spanning 2015–2017, which provides the highest-sensitivity gravitational-wave data so far obtained. In this search we target emission from both the l = m = 2 mass quadrupole mode, with a frequency at twice that of the pulsar's rotation, and the l = 2, m = 1 mode, with a frequency at the pulsar rotation frequency. The search finds no evidence for gravitational-wave emission from any pulsar at either frequency. For the l = …
The Most Powerful Thing, Caitlin Jankiewicz
Searches For Continuous Gravitational Waves From 15 Supernova Remnants And Fomalhaut B With Advanced Ligo, B. P. Abbott, R. Abbott, T. D. Abbott, S. Abraham, F. Acernese, K. Ackley, C. Adams, R. X. Adhikari, V. B. Adya, C. Affeldt, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, P. Ajith, G. Allen, A. Allocca, M. A. Aloy, P. A. Altin, A. Amato, A. Ananyeva, S. B. Anderson, W. G. Anderson, S. V. Angelova, S. Antier, S. Appert, K. Arai, M. C. Araya, J. S. Areeda, Tiffany Z. Summerscales
Searches For Continuous Gravitational Waves From 15 Supernova Remnants And Fomalhaut B With Advanced Ligo, B. P. Abbott, R. Abbott, T. D. Abbott, S. Abraham, F. Acernese, K. Ackley, C. Adams, R. X. Adhikari, V. B. Adya, C. Affeldt, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, P. Ajith, G. Allen, A. Allocca, M. A. Aloy, P. A. Altin, A. Amato, A. Ananyeva, S. B. Anderson, W. G. Anderson, S. V. Angelova, S. Antier, S. Appert, K. Arai, M. C. Araya, J. S. Areeda, Tiffany Z. Summerscales
Faculty Publications
© 2019. The American Astronomical Society. All rights reserved. We describe directed searches for continuous gravitational waves (GWs) from 16 well-localized candidate neutron stars, assuming none of the stars has a binary companion. The searches were directed toward 15 supernova remnants and Fomalhaut b, a directly imaged extrasolar planet candidate that has been suggested to be a nearby old neutron star. Each search covered a broad band of frequencies and first and second time derivatives. After coherently integrating spans of data from the first Advanced LIGO observing run of 3.5-53.7 days per search, applying data-based vetoes, and discounting known instrumental …
Forgotten Women In Adventism, Caitlin Jankiewicz
Forgotten Women In Adventism, Caitlin Jankiewicz
Lake Union Herald
No abstract provided.
Applications Of Information Theory In Solar And Space Physics, Jay R. Johnson, Simon Wing
Applications Of Information Theory In Solar And Space Physics, Jay R. Johnson, Simon Wing
Faculty Publications
Characterizing and modeling processes at the sun and space plasma in our solar system are difficult because the underlying physics is often complex, nonlinear, and not well understood. The drivers of a system are often nonlinearly correlated with one another, which makes it a challenge to understand the relative effects caused by each driver. However, entropy-based information theory can be a valuable tool that can be used to determine the information flow among various parameters, causalities, untangle the drivers, and provide observational constraints that can help guide the development of the theories and physics-based models. We review two examples of …