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338 full-text articles. Page 1 of 13.

A Gravitational-Wave Standard Siren Measurement Of The Hubble Constant, B. P. Abbott, K. AultONeal, S. Gaudio, K. Gill, E. M. Gretarrson, B. Hughey, M. Muratore, J. W. W. Pratt, S. G. Schwalde, K. Staats, M. J. Szczepańczyk, M. Zanolin, et al. 2017 California Institute of Technology

A Gravitational-Wave Standard Siren Measurement Of The Hubble Constant, B. P. Abbott, K. Aultoneal, S. Gaudio, K. Gill, E. M. Gretarrson, B. Hughey, M. Muratore, J. W. W. Pratt, S. G. Schwalde, K. Staats, M. J. Szczepańczyk, M. Zanolin, Et Al.

Publications

The detection of GW170817 (Abbott et al. 2017a) in both gravitational waves and electromagnetic waves heralds the age of gravitational-wave multi-messenger astronomy. On 17 August 2017 the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO) (LIGO Scientific Collaboration et al. 2015) and Virgo (Acernese et al. 2015) detectors observed GW170817, a strong signal from the merger of a binary neutron-star system. Less than 2 seconds after the merger, a gamma-ray burst (GRB 170817A) was detected within a region of the sky consistent with the LIGO-Virgo-derived location of the gravitational-wave source (Abbott et al. 2017b; Goldstein et al. 2017; Savchenko et al. 2017 ...


Multi-Messenger Observations Of A Binary Neutron Star Merger, B. P. Abbott, K. AultONeal, S. Gaudio, K. Gill, E. M. Gretarsson, B. Hughey, M. Muratore, J. W. W. Pratt, S. G. Schwalbe, K. Staats, M. J. Szczepańczyk, Michele Zanolin, et al. 2017 California Institute of Technology

Multi-Messenger Observations Of A Binary Neutron Star Merger, B. P. Abbott, K. Aultoneal, S. Gaudio, K. Gill, E. M. Gretarsson, B. Hughey, M. Muratore, J. W. W. Pratt, S. G. Schwalbe, K. Staats, M. J. Szczepańczyk, Michele Zanolin, Et Al.

Publications

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of $\sim 1.7\,{\rm{s}}$ with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of ${40}_{-8}^{+8}$ Mpc and with component masses consistent with neutron stars. The component masses were later ...


Gravitational Waves And Gamma-Rays From A Binary Neutron Star Merger: Gm170817 And Grb 170817a, B. P. Abbott, K. AultONeal, S. Gaudio, K. Gill, E. M. Gretarsson, B. Hughey, M. Muratore, J. W. W. Pratt, S. G. Schwalbe, K. Staats, M. J. Szczepańczyk, M. Zanolin, et al. 2017 California Institute of Technology

Gravitational Waves And Gamma-Rays From A Binary Neutron Star Merger: Gm170817 And Grb 170817a, B. P. Abbott, K. Aultoneal, S. Gaudio, K. Gill, E. M. Gretarsson, B. Hughey, M. Muratore, J. W. W. Pratt, S. G. Schwalbe, K. Staats, M. J. Szczepańczyk, M. Zanolin, Et Al.

Publications

On 2017 August 17, the gravitational-wave event GW170817 was observed by the Advanced LIGO and Virgo detectors, and the gamma-ray burst (GRB) GRB 170817A was observed independently by the Fermi Gamma-ray Burst Monitor, and the Anti-Coincidence Shield for the Spectrometer for the International Gamma-Ray Astrophysics Laboratory. The probability of the near-simultaneous temporal and spatial observation of GRB 170817A and GW170817 occurring by chance is $5.0\times {10}^{-8}$. We therefore confirm binary neutron star mergers as a progenitor of short GRBs. The association of GW170817 and GRB 170817A provides new insight into fundamental physics and the origin of short ...


Knotty Inflation And The Dimensionality Of Spacetime, Arjun Berera, Roman V. Buniy, Thomas W. Kephart, Heinrich Päs, João G. Rosa 2017 University of Edinburgh

Knotty Inflation And The Dimensionality Of Spacetime, Arjun Berera, Roman V. Buniy, Thomas W. Kephart, Heinrich Päs, João G. Rosa

Mathematics, Physics, and Computer Science Faculty Articles and Research

We suggest a structure for the vacuum comprised of a network of tightly knotted/linked flux tubes formed in a QCD-like cosmological phase transition and show that such a network can drive cosmological inflation. As the network can be topologically stable only in three space dimensions, this scenario provides a dynamical explanation for the existence of exactly three large spatial dimensions in our Universe.


Upper Limits On Gravitational Waves From Scorpius X-1 From A Model-Based Cross-Correlation Search In Advanced Ligo Data, B. P. Abbott, K. AultONeal, S. Gaudio, K. Gill, B. Hughey, J. W. W. Pratt, E. Schmidt, S. G. Schwalbe, M. J. Szczepańczyk, M. Zanolin, et al. 2017 California Institute of Technology

Upper Limits On Gravitational Waves From Scorpius X-1 From A Model-Based Cross-Correlation Search In Advanced Ligo Data, B. P. Abbott, K. Aultoneal, S. Gaudio, K. Gill, B. Hughey, J. W. W. Pratt, E. Schmidt, S. G. Schwalbe, M. J. Szczepańczyk, M. Zanolin, Et Al.

Publications

We present the results of a semicoherent search for continuous gravitational waves from the low-mass X-ray binary Scorpius X-1, using data from the first Advanced LIGO observing run. The search method uses details of the modeled, parametrized continuous signal to combine coherently data separated by less than a specified coherence time, which can be adjusted to trade off sensitivity against computational cost. A search was conducted over the frequency range 25–$2000\,\mathrm{Hz}$, spanning the current observationally constrained range of binary orbital parameters. No significant detection candidates were found, and frequency-dependent upper limits were set using a combination of ...


Sources Of Gravity.Docx, Vildyan Yanbikov 2017 Yanbikov Vildyan Shavkyatovich

Sources Of Gravity.Docx, Vildyan Yanbikov

Vildyan Yanbikov

Computed coefficients of gravity. (gravitational constant) in the center and the surface of the Sun. The computed critical parameters. a slowly rotating neutron star. In her state of the instability (before it exploded). Checked the assumption about the rate of transmission of gravitational interactions. Using the given method it is possible to calculate the coefficient of gravity away from the powerful gravity source.                                                                  


Empty Universe.Docx, Vildyan Yanbikov 2017 Yanbikov Vildyan Shavkyatovich

Empty Universe.Docx, Vildyan Yanbikov

Vildyan Yanbikov

Calculated the speed of propagation of gravity in space. ( the speed of gravity waves). The computed gravitational constant for the “empty” space.


Magnetospherically-Trapped Dust And A Possible Model For The Unusual Transits At Wd1145+017, J. Farihi, Ted von Hippel, J. E. Pringle 2017 University College London

Magnetospherically-Trapped Dust And A Possible Model For The Unusual Transits At Wd1145+017, J. Farihi, Ted Von Hippel, J. E. Pringle

Publications

The rapidly evolving dust and gas extinction observed towardsWD1145+017 has opened a real-time window onto the mechanisms for destruction-accretion of planetary bodies onto white dwarf stars, and has served to underline the importance of considering the dynamics of dust particles around such objects. Here it is argued that the interaction between (charged) dust grains and the stellar magnetic field is an important ingredient in understanding the physical distribution of infrared emitting particles in the vicinity of such white dwarfs. These ideas are used to suggest a possible model for WD 1145+017 in which the unusual transit shapes are ...


Quantum Physics And Relativity In Lovecraft's Fiction, Garrison McCammon 2017 Ursinus College

Quantum Physics And Relativity In Lovecraft's Fiction, Garrison Mccammon

English Summer Fellows

The early twentieth century brought about some of the best and most influential horror or weird tales ever written in the English speaking world. The most impressive and most lauded author of the group composed of such figures as Algernon Blackwood, M. R. James, Arthur Machen, Clark A. Smith, and Robert E. Howard was H. P. Lovecraft. Posthumously declared the literary successor to Edgar Allan Poe, Lovecraft’s fiction and tales of terror have cast such a huge shadow that every significant author in weird writing since his passing has claimed him as a literary heir. Lovecraft’s works were ...


Search For Gravitational Waves Associated With Gamma-Ray Bursts During The First Advanced Ligo Observing Run And Implications For The Origin Of Grb 150906b, B. P. Abbott, K. Gill, B. Hughey, J. W. W. Pratt, E. Rhoades, E. Schmidt, S. G. Schwalbe, M. J. Szczepańczyk, M. Zanolin, et al. 2017 California Institute of Technology

Search For Gravitational Waves Associated With Gamma-Ray Bursts During The First Advanced Ligo Observing Run And Implications For The Origin Of Grb 150906b, B. P. Abbott, K. Gill, B. Hughey, J. W. W. Pratt, E. Rhoades, E. Schmidt, S. G. Schwalbe, M. J. Szczepańczyk, M. Zanolin, Et Al.

Publications

We present the results of the search for gravitational waves (GWs) associated with γ-ray bursts detected during the first observing run of the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO). We find no evidence of a GW signal for any of the 41 γ-ray bursts for which LIGO data are available with sufficient duration. For all γ-ray bursts, we place lower bounds on the distance to the source using the optimistic assumption that GWs with an energy of ${10}^{-2}{M}_{\odot }{c}^{2}$ were emitted within the $16$–$500$ Hz band, and we find a median 90% confidence limit ...


Gravitational Wave Behavior At A Vacuum-Matter Interface, Jake Litterer 2017 University of Puget Sound

Gravitational Wave Behavior At A Vacuum-Matter Interface, Jake Litterer

Honors Program Theses

In classical electrodynamics, boundary conditions of the E and B fields are derived from Maxwell's equations, which are used to derive the Fresnel equations describing the behavior of a wave at an interface between media with given indices of refraction. Though electrodynamics and gravity are in some instances strikingly analogous, boundary conditions in general relativity are somewhat more opaque. We will see that while while continuity of the metric must be true in general, discontinuity of the extrinsic curvature of spacetime, while allowed by the Einstein field equations, results in a singularity in the energy-momentum tensor. This singularity is ...


Literature Review: Biomimetic And Conventional Aircraft Wing Tips, Naseeb Ahmed Siddiqui, Waqar Asrar, Erwin Sulaeman 2017 International Islamic University - Malaysia

Literature Review: Biomimetic And Conventional Aircraft Wing Tips, Naseeb Ahmed Siddiqui, Waqar Asrar, Erwin Sulaeman

International Journal of Aviation, Aeronautics, and Aerospace

This paper is an attempt to summarize the effect of wing tip devices employed by birds, as well as aeronautical engineers in the past to improve the performance characteristics of aircraft. The focus is on reduction of the induced drag or drag due to lift also known as inviscid drag. This paper will provide an insight on both biomimetic and conventional wing tip approaches to reduce the induced drag. Prior analysis and experiments on the aerodynamics of airplane performance due to both these separate studies have been discussed. The needs of the industry and their past inventions have been described ...


An Analysis Of The Effects Of Isocurvature Fluctuations In Dantes Inferno Multi-Field Inflation Models, Brandon M. Buncher 2017 College of William and Mary

An Analysis Of The Effects Of Isocurvature Fluctuations In Dantes Inferno Multi-Field Inflation Models, Brandon M. Buncher

Undergraduate Honors Theses

Although there is significant evidence of inflation (a period of rapid expansion of the early universe), a definitive model of the epoch has not yet been widely accepted. A variety of models exist which describe this period; however, current technology cannot adequately measure several key factors that would demonstrate the veracity of these models. A major differentiator between classes of models is the number of fields that contribute to the inflationary epoch. Single-field inflation models assume the existence of a single field, though the details of this field vary depending on the model, while multi-field inflation models assume the existence ...


Fermi-Lat Daily Monitoring Observations Of The Microquasar Cygnus X-1, Austin P. Waldron, Stephen R. Hood, Arash Bodaghee 2017 Georgia College and State University

Fermi-Lat Daily Monitoring Observations Of The Microquasar Cygnus X-1, Austin P. Waldron, Stephen R. Hood, Arash Bodaghee

Georgia College Student Research Events

Detection of gamma-ray emission from microquasars is important for understanding particle acceleration in the jet, and for constraining leptonic/hadronic emission models. We present a continuation of a 1-d likelihood analysis on gamma-ray observations by Fermi-LAT (0.1-10 GeV) of the accreting black hole candidate Cygnus X-1. Combining this gamma-ray data with available X-ray monitoring data from Swift and MAXI allowed us to reveal over a dozen days (in 2008-2016) during which Cyg X-1 displayed low-significance (3-4 sigma) excesses, many of which were contemporaneous with apparent transitions in the X-rays.


Lorentz-Symmetry Test At Planck-Scale Suppression With Nucleons In A Spin-Polarized 133 Cs Cold Atom Clock, H. Pihan-Le Bars, C. Guerlin, R.-D. Lasseri, J.-P. Ebran, Q. G. Bailey, S. Bize, E. Khan, P. Wolf 2017 PSL Research University

Lorentz-Symmetry Test At Planck-Scale Suppression With Nucleons In A Spin-Polarized 133 Cs Cold Atom Clock, H. Pihan-Le Bars, C. Guerlin, R.-D. Lasseri, J.-P. Ebran, Q. G. Bailey, S. Bize, E. Khan, P. Wolf

Publications

The authors introduce an improved model that links the frequency of the 133 Cs hyperfine Zeeman transitions.


Vacuum.Doc, Vildyan Yanbikov 2017 Yanbikov Vildyan Shavkyatovich

Vacuum.Doc, Vildyan Yanbikov

Vildyan Yanbikov

The calculated density of the physical vacuum. The high density of physical vacuum.              


The Ages Of The Thin Disk, Thick Disk, And The Halo From Nearby White Dwarfs, Mukremin Kilic, Ted von Hippel, Jeffrey A. Munn, Hugh C. Harris, James W. Liebert, et al. 2017 University of Oklahoma

The Ages Of The Thin Disk, Thick Disk, And The Halo From Nearby White Dwarfs, Mukremin Kilic, Ted Von Hippel, Jeffrey A. Munn, Hugh C. Harris, James W. Liebert, Et Al.

Publications

We present a detailed analysis of the white dwarf luminosity functions derived from the local 40 pc sample and the deep proper motion catalog of Munn et al. (2014, 2017). Many of the previous studies ignored the contribution of thick disk white dwarfs to the Galactic disk luminosity function, which results in an erronous age measurement. We demonstrate that the ratio of thick/thin disk white dwarfs is roughly 20% in the local sample. Simultaneously fitting for both disk components, we derive ages of 6.8-7.0 Gyr for the thin disk and 8.7 ± 0.1 Gyr for the ...


Evolution Of Cosmic Filaments And Of Their Galaxy Population From Mhd Cosmological Simulations., C. Gheller, F. Vazza, M. Brüggen, M. Alpaslan, Benne W. Holwerda 2017 Swiss National Supercomputing Centre

Evolution Of Cosmic Filaments And Of Their Galaxy Population From Mhd Cosmological Simulations., C. Gheller, F. Vazza, M. Brüggen, M. Alpaslan, Benne W. Holwerda

Benne Holwerda

Despite containing about a half of the total matter in the Universe, at most wavelengths the filamentary structure of the cosmic web is difficult to observe. In this work, we use large unigrid cosmological simulations to investigate how the geometrical, thermodynamical and magnetic properties of cosmological filaments vary with mass and redshift (z ≤ 1). We find that the average temperature, length, volume and magnetic field of filaments scales well with their total mass. This reflects the role of self-gravity in shaping their properties and enables statistical predictions of their observational properties based on their mass. We also focus on the ...


Effects Of Low-Temperature Reheating On The Matter Power Spectrum, Jonah Kudler-Flam 2017 Colgate University

Effects Of Low-Temperature Reheating On The Matter Power Spectrum, Jonah Kudler-Flam

Senior Honors Theses

The thermal and expansion history of the universe between inflation and big bang nucleosynthesis is largely unconstrained. In standard cosmological theories, highly relativistic standard model particles dominate the universe’s energy density during this epoch. We consider a non-standard cosmology consisting of an era dominated by an oscillating scalar field that behaves similarly to matter. The growth of density perturbations is strongly enhanced in an early matter dominated era (EMDE), leading to potentially profound consequences regarding the dynamics of the early universe and the scales of the first bound dark matter structures. We investigate the applications and validity of the ...


Gravity Wave And Turbulence Transport In The Mesopause Region, Yafang Guo 2017 Embry-Riddle Aeronautical University

Gravity Wave And Turbulence Transport In The Mesopause Region, Yafang Guo

Dissertations and Theses

Vertical transport due to dissipating gravity waves and turbulence in the mesopause region (85-100 km) are analyzed with observational data obtained from a narrow-band sodium wind/temperature lidar located at Andes Lidar Observatory (ALO), Cerro Pach´on (30.25 S, 70.73 W), Chile. The Na lidar at ALO has been in regular operation since 2010. The upgrade of the lidar system in May 2014 resulted in great improvements of the signal levels, which enabled data acquisition of high temporal and vertical resolutions reaching 6 s and 25 m. Traditional data processing utilizes signals at lower resolutions, typically at 60 ...


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