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Articles 1 - 24 of 24
Full-Text Articles in Physical Sciences and Mathematics
Search For Subsolar-Mass Ultracompact Binaries In Advanced Ligo's First Observing Run, B. P. Abbott, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, C. Adams, T. Adams, P. Addesso, R. X. Adhikari, V. B. Adya, C. Affeldt, B. Agarwal, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, P. Ajith, B. Allen, 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
Search For Subsolar-Mass Ultracompact Binaries In Advanced Ligo's First Observing Run, B. P. Abbott, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, C. Adams, T. Adams, P. Addesso, R. X. Adhikari, V. B. Adya, C. Affeldt, B. Agarwal, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, P. Ajith, B. Allen, 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
Physics and Astronomy Faculty Publications and Presentations
We present the first Advanced LIGO and Advanced Virgo search for ultracompact binary systems with component masses between 0.2 M-1.0 M using data taken between September 12, 2015 and January 19, 2016. We find no viable gravitational wave candidates. Our null result constrains the coalescence rate of monochromatic (delta function) distributions of nonspinning (0.2 M, 0.2 M) ultracompact binaries to be less than 1.0×106 Gpc-3 yr-1 and the coalescence rate of a similar distribution of (1.0 M, 1.0 M) ultracompact binaries to be less than 1.9×104 Gpc-3 yr-1 (at 90% confidence). Neither black holes nor neutron stars are expected to …
Gw170817: Measurements Of Neutron Star Radii And Equation Of State, B. P. Abbott, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, C. Adams, T. Adams, P. Addesso, R. X. Adhikari, V. B. Adya, C. Affeldt, B. Agarwal, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, P. Ajith, B. Allen, 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
Gw170817: Measurements Of Neutron Star Radii And Equation Of State, B. P. Abbott, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, C. Adams, T. Adams, P. Addesso, R. X. Adhikari, V. B. Adya, C. Affeldt, B. Agarwal, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, P. Ajith, B. Allen, 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
Physics and Astronomy Faculty Publications and Presentations
On 17 August 2017, the LIGO and Virgo observatories made the first direct detection of gravitational waves from the coalescence of a neutron star binary system. The detection of this gravitational-wave signal, GW170817, offers a novel opportunity to directly probe the properties of matter at the extreme conditions found in the interior of these stars. The initial, minimal-assumption analysis of the LIGO and Virgo data placed constraints on the tidal effects of the coalescing bodies, which were then translated to constraints on neutron star radii. Here, we expand upon previous analyses by working under the hypothesis that both bodies were …
An Acoustical Analogue Of A Galactic-Scale Gravitational-Wave Detector, Michael T. Lam, Joseph D. Romano, Joey Key, M. E. Normandin, Jeffrey S. Hazboun
An Acoustical Analogue Of A Galactic-Scale Gravitational-Wave Detector, Michael T. Lam, Joseph D. Romano, Joey Key, M. E. Normandin, Jeffrey S. Hazboun
Physics and Astronomy Faculty Publications and Presentations
By precisely monitoring the “ticks” of Nature's most precise clocks (millisecond pulsars), scientists are trying to detect the “ripples in spacetime” (gravitational waves) produced by the inspirals of supermassive black holes in the centers of distant merging galaxies. Here, we describe a relatively simple demonstration that uses two metronomes and a microphone to illustrate several techniques used by pulsar astronomers to search for and detect gravitational waves. An adapted version of this demonstration could be used as an instructional laboratory investigation at the undergraduate level.
Underwater Adhesive Using Solid–Liquid Polymer Mixes, Alin Cristian Chipara, T. Tsafack, P. S. Owuor, J. Yeon, C. E. Junkermeier, A. C. T. Van Duin, S. Bhowmick, S. A. S. Asif, S. Radhakrishnan, Mircea Chipara
Underwater Adhesive Using Solid–Liquid Polymer Mixes, Alin Cristian Chipara, T. Tsafack, P. S. Owuor, J. Yeon, C. E. Junkermeier, A. C. T. Van Duin, S. Bhowmick, S. A. S. Asif, S. Radhakrishnan, Mircea Chipara
Physics and Astronomy Faculty Publications and Presentations
Instantaneous adhesion between different materials is a requirement for several applications ranging from electronics to biomedicine. Approaches such as surface patterning, chemical cross-linking, surface modification, and chemical synthesis have been adopted to generate temporary adhesion between various materials and surfaces. Because of the lack of curing times, temporary adhesives are instantaneous, a useful property for specific applications that need quick bonding. However, to this day, temporary adhesives have been mainly demonstrated under dry conditions and do not work well in submerged or humid environments. Furthermore, most rely on chemical bonds resulting from strong interactions with the substrate such as acrylate …
Asymmetric Free-Space Light Transport At Nonlinear Metasurfaces, Nir Shitrit, Jeongmin Kim, David S. Barth, Hamidreza Ramezani, Yuan Wang, Xiang Zhang
Asymmetric Free-Space Light Transport At Nonlinear Metasurfaces, Nir Shitrit, Jeongmin Kim, David S. Barth, Hamidreza Ramezani, Yuan Wang, Xiang Zhang
Physics and Astronomy Faculty Publications and Presentations
Asymmetric light transport has significantly contributed to fundamental science and revolutionized advanced technology in various aspects such as unidirectional photonic devices, optical diodes, and isolators. While metasurfaces mold wave fronts at will with an ultrathin flat optical element, asymmetric transport of light cannot be fundamentally achieved by any linear system including linear metasurfaces. We report asymmetric transport of free-space light at nonlinear metasurfaces upon transmission and reflection. Moreover, we theoretically derive the nonlinear generalized Snell's laws that were experimentally confirmed by the anomalous nonlinear refraction and reflection. The asymmetric transport at optically thin nonlinear interfaces is revealed by the concept …
The Implementation Of A Fast-Folding Pipeline For Long-Period Pulsar Searching In The Palfa Survey, E. Parent, V. M. Kaspi, S. M. Ransom, M. Krasteva, C. Patel, P. Scholz, A. Brazier, M. A. Mclaughlin, M. Boyce, W. W. Zhu, Z. Pleunis, B. Allen, S. Bogdanov, K. Caballero, F. Camilo, R. Camuccio, S. Chatterjee, J. M. Cordes, F. Crawford, J. S. Deneva, R. Ferdman, P. C.C. Freire, J. W.T. Hessels, F. A. Jenet, B. Knispel, P. Lazarus, J. Van Leeuwen, A. G. Lyne, R. Lynch, A. Seymour
The Implementation Of A Fast-Folding Pipeline For Long-Period Pulsar Searching In The Palfa Survey, E. Parent, V. M. Kaspi, S. M. Ransom, M. Krasteva, C. Patel, P. Scholz, A. Brazier, M. A. Mclaughlin, M. Boyce, W. W. Zhu, Z. Pleunis, B. Allen, S. Bogdanov, K. Caballero, F. Camilo, R. Camuccio, S. Chatterjee, J. M. Cordes, F. Crawford, J. S. Deneva, R. Ferdman, P. C.C. Freire, J. W.T. Hessels, F. A. Jenet, B. Knispel, P. Lazarus, J. Van Leeuwen, A. G. Lyne, R. Lynch, A. Seymour
Physics and Astronomy Faculty Publications and Presentations
The Pulsar Arecibo L-Band Feed Array (PALFA) survey, the most sensitive blind search for radio pulsars yet conducted, is ongoing at the Arecibo Observatory in Puerto Rico. The vast majority of the 180 pulsars discovered by PALFA have spin periods shorter than 2 s. Pulsar surveys may miss long-period radio pulsars owing to the summing of a finite number of harmonic components in conventional Fourier analyses (typically ∼16), or as a result of the strong effect of red noise at low modulation frequencies. We address this reduction in sensitivity by using a time-domain search technique: the fast-folding algorithm (FFA). We …
Charge Transfer Dynamical Processes At Graphene-Transition Metal Oxides/Electrolyte Interface For Energy Storage: Insights From In-Situ Raman Spectroelectrochemistry, S. Gupta, S. B. Carrizosa, J. Jasinski, N. Dimakis
Charge Transfer Dynamical Processes At Graphene-Transition Metal Oxides/Electrolyte Interface For Energy Storage: Insights From In-Situ Raman Spectroelectrochemistry, S. Gupta, S. B. Carrizosa, J. Jasinski, N. Dimakis
Physics and Astronomy Faculty Publications and Presentations
Hybrids consisting of supercapacitive functionalized graphene (graphene oxide; GO reduced graphene oxide; rGO multilayer graphene; MLG, electrochemically reduced GO; ErGO) and three-dimensional graphene scaffold (rGO HT ; hydrothermally prepared) decorated with cobalt nanoparticles (CoNP), nanostructured cobalt (CoO and Co 3 O 4 ) and manganese (MnO 2 ) oxide polymorphs, assembled electrochemically facilitate chemically bridged interfaces with tunable properties. Since Raman spectroscopy can capture variations in structural and chemical bonding, Raman spectro-electrochemistry in operando i.e. under electrochemical environment with applied bias is employed to 1) probe graphene/metal bonding and dynamic processes, 2) monitor the spectral changes with successive redox interfacial …
The Green Bank North Celestial Cap Pulsar Survey. Iii. 45 New Pulsar Timing Solutions, Ryan S. Lynch, Joseph K. Swiggum, Vlad I. Kondratiev, David L. Kaplan, Kevin Stovall, Emmanuel Fonseca, Mallory S.E. Roberts, Lina Levin, Megan E. Decesar, Bingyi Cui, S. Bradley Cenko, Pradip Gatkine, Anne M. Archibald, Shawn Banaszak, Christopher M. Biwer, Jason Boyles, Pragya Chawla, Louis P. Dartez, David Day, Anthony J. Ford, Joseph Flanigan, Jason W.T. Hessels, Jesus Hinojosa, Fredrick A. Jenet, Chen Karako-Argaman, Victoria M. Kaspi, Sean Leake, Grady Lunsford, José G. Martinez, Alberto Mata
The Green Bank North Celestial Cap Pulsar Survey. Iii. 45 New Pulsar Timing Solutions, Ryan S. Lynch, Joseph K. Swiggum, Vlad I. Kondratiev, David L. Kaplan, Kevin Stovall, Emmanuel Fonseca, Mallory S.E. Roberts, Lina Levin, Megan E. Decesar, Bingyi Cui, S. Bradley Cenko, Pradip Gatkine, Anne M. Archibald, Shawn Banaszak, Christopher M. Biwer, Jason Boyles, Pragya Chawla, Louis P. Dartez, David Day, Anthony J. Ford, Joseph Flanigan, Jason W.T. Hessels, Jesus Hinojosa, Fredrick A. Jenet, Chen Karako-Argaman, Victoria M. Kaspi, Sean Leake, Grady Lunsford, José G. Martinez, Alberto Mata
Physics and Astronomy Faculty Publications and Presentations
We provide timing solutions for 45 radio pulsars discovered by the Robert C. Byrd Green Bank Telescope. These pulsars were found in the Green Bank North Celestial Cap pulsar survey, an all-GBT-sky survey being carried out at a frequency of 350 MHz. We include pulsar timing data from the Green Bank Telescope and Low Frequency Array. Our sample includes five fully recycled millisecond pulsars (MSPs, three of which are in a binary system), a new relativistic double neutron star system, an intermediate-mass binary pulsar, a mode-changing pulsar, a 138 ms pulsar with a very low magnetic field, and several nulling …
The Nanograv 11 Year Data Set: Pulsar-Timing Constraints On The Stochastic Gravitational-Wave Background, Zaven Arzoumanian, P. T. Baker, A. Brazier, S. Burke-Spolaor, S. J. Chamberlin, S. Chatterjee, B. Christy, Jeffrey S. Hazboun, Jing Luo
The Nanograv 11 Year Data Set: Pulsar-Timing Constraints On The Stochastic Gravitational-Wave Background, Zaven Arzoumanian, P. T. Baker, A. Brazier, S. Burke-Spolaor, S. J. Chamberlin, S. Chatterjee, B. Christy, Jeffrey S. Hazboun, Jing Luo
Physics and Astronomy Faculty Publications and Presentations
We search for an isotropic stochastic gravitational-wave background (GWB) in the newly released 11 year data set from the North American Nanohertz Observatory for Gravitational Waves (NANOGrav). While we find no evidence for a GWB, we place constraints on a population of inspiraling supermassive black hole (SMBH) binaries, a network of decaying cosmic strings, and a primordial GWB. For the first time, we find that the GWB constraints are sensitive to the solar system ephemeris (SSE) model used and that SSE errors can mimic a GWB signal. We developed an approach that bridges systematic SSE differences, producing the first pulsar-timing …
Search For Tensor Vector And Scalar Polarizations In The Stochastic Gravitational-Wave Background, B. P. Abbott, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, C. Adams, T. Adams, P. Addesso, R. X. Adhikari, V. B. Adya, C. Affeldt, M. Afrough, B. Agarwal, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, P. Ajith, B. Allen, G. Allen, A. Allocca, P. A. Altin, A. Amato, A. Ananyeva, S. B. Anderson, W. G. Anderson, S. V. Angelova, S. Antier
Search For Tensor Vector And Scalar Polarizations In The Stochastic Gravitational-Wave Background, B. P. Abbott, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, C. Adams, T. Adams, P. Addesso, R. X. Adhikari, V. B. Adya, C. Affeldt, M. Afrough, B. Agarwal, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, P. Ajith, B. Allen, G. Allen, A. Allocca, P. A. Altin, A. Amato, A. Ananyeva, S. B. Anderson, W. G. Anderson, S. V. Angelova, S. Antier
Physics and Astronomy Faculty Publications and Presentations
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 …
Constraints On Cosmic Strings Using Data From The First Advanced Ligo Observing Run, B. P. Abbott, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, C. Adams, T. Adams, P. Addesso, R. X. Adhikari, V. B. Adya, C. Affeldt, M. Afrough, B. Agarwal, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, P. Ajith, B. Allen, G. Allen, A. Allocca, P. A. Altin, A. Amato, A. Ananyeva, S. B. Anderson, W. G. Anderson, S. Antier, S. Appert
Constraints On Cosmic Strings Using Data From The First Advanced Ligo Observing Run, B. P. Abbott, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, C. Adams, T. Adams, P. Addesso, R. X. Adhikari, V. B. Adya, C. Affeldt, M. Afrough, B. Agarwal, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, P. Ajith, B. Allen, G. Allen, A. Allocca, P. A. Altin, A. Amato, A. Ananyeva, S. B. Anderson, W. G. Anderson, S. Antier, S. Appert
Physics and Astronomy Faculty Publications and Presentations
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 …
Full Band All-Sky Search For Periodic Gravitational Waves In The O1 Ligo Data, C. J. Haster, K. Haughian, J. Healy, A. Heidmann, M. C. Heintze, H. Heitmann, P. Hello, G. Hemming, M. Hendry, I. S. Heng, J. Hennig, A. W. Heptonstall, M. Heurs, S. Hild, T. Hinderer, D. Hoak, D. Hofman, K. Holt, D. E. Holz, P. Hopkins, C. Horst, J. Hough, E. A. Houston, E. J. Howell, A. Hreibi, Y. M. Hu, E. A. Huerta, D. Huet, B. Hughey, S. Husa
Full Band All-Sky Search For Periodic Gravitational Waves In The O1 Ligo Data, C. J. Haster, K. Haughian, J. Healy, A. Heidmann, M. C. Heintze, H. Heitmann, P. Hello, G. Hemming, M. Hendry, I. S. Heng, J. Hennig, A. W. Heptonstall, M. Heurs, S. Hild, T. Hinderer, D. Hoak, D. Hofman, K. Holt, D. E. Holz, P. Hopkins, C. Horst, J. Hough, E. A. Houston, E. J. Howell, A. Hreibi, Y. M. Hu, E. A. Huerta, D. Huet, B. Hughey, S. Husa
Physics and Astronomy Faculty Publications and Presentations
We report on a new all-sky search for periodic gravitational waves in the frequency band 475-2000 Hz and with a frequency time derivative in the range of [-1.0,+0.1]×10-8 Hz/s. Potential signals could be produced by a nearby spinning and slightly nonaxisymmetric isolated neutron star in our Galaxy. This search uses the data from Advanced LIGO's first observational run O1. No gravitational-wave signals were observed, and upper limits were placed on their strengths. For completeness, results from the separately published low-frequency search 20-475 Hz are included as well. Our lowest upper limit on worst-case (linearly polarized) strain amplitude h0 is ∼4×10-25 …
The Nanograv 11-Year Data Set: High-Precision Timing Of 45 Millisecond Pulsars, Z. Arzoumanian, Adam Brazier, Sarah Burke-Spolaor, Sydney Chamberlin, Shami Chatterjee, Brian Christy, James M. Cordes, Neil J. Cornish, Fronefield Crawford, H. Thankful Cromartie, Kathryn Crowter, Megan E. Decesar, Paul B. Demorest, Timothy Dolch, Justin A. Ellis, Robert D. Ferdman, Elizabeth C. Ferrara, Emmanuel Fonseca, Nathan Garver-Daniels, Peter A. Gentile, Daniel Halmrast, E. A. Huerta, Fredrick A. Jenet, Cody Jessup, Glenn Jones, Megan L. Jones, David L. Kaplan, Michael T. Lam, T. Joseph W. Lazio, Lina Levin
The Nanograv 11-Year Data Set: High-Precision Timing Of 45 Millisecond Pulsars, Z. Arzoumanian, Adam Brazier, Sarah Burke-Spolaor, Sydney Chamberlin, Shami Chatterjee, Brian Christy, James M. Cordes, Neil J. Cornish, Fronefield Crawford, H. Thankful Cromartie, Kathryn Crowter, Megan E. Decesar, Paul B. Demorest, Timothy Dolch, Justin A. Ellis, Robert D. Ferdman, Elizabeth C. Ferrara, Emmanuel Fonseca, Nathan Garver-Daniels, Peter A. Gentile, Daniel Halmrast, E. A. Huerta, Fredrick A. Jenet, Cody Jessup, Glenn Jones, Megan L. Jones, David L. Kaplan, Michael T. Lam, T. Joseph W. Lazio, Lina Levin
Physics and Astronomy Faculty Publications and Presentations
We present high-precision timing data over time spans of up to 11 years for 45 millisecond pulsars observed as part of the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) project, aimed at detecting and characterizing low-frequency gravitational waves. The pulsars were observed with the Arecibo Observatory and/or the Green Bank Telescope at frequencies ranging from 327 MHz to 2.3 GHz. Most pulsars were observed with approximately monthly cadence, and six high-timing-precision pulsars were observed weekly. All were observed at widely separated frequencies at each observing epoch in order to fit for time-variable dispersion delays. We describe our methods for …
Gw170817: Implications For The Stochastic Gravitational-Wave Background From Compact Binary Coalescences, B. P. Abbott, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, C. Adams, T. Adams, P. Addesso, R. X. Adhikari, V. B. Adya, C. Affeldt, M. Afrough, B. Agarwal, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, P. Ajith, B. Allen, G. Allen, A. Allocca, P. A. Altin, A. Amato, A. Ananyeva, S. B. Anderson, W. G. Anderson, S. V. Angelova, S. Antier
Gw170817: Implications For The Stochastic Gravitational-Wave Background From Compact Binary Coalescences, B. P. Abbott, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, C. Adams, T. Adams, P. Addesso, R. X. Adhikari, V. B. Adya, C. Affeldt, M. Afrough, B. Agarwal, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, P. Ajith, B. Allen, G. Allen, A. Allocca, P. A. Altin, A. Amato, A. Ananyeva, S. B. Anderson, W. G. Anderson, S. V. Angelova, S. Antier
Physics and Astronomy Faculty Publications and Presentations
The LIGO Scientific and Virgo Collaborations have announced the event GW170817, the first detection of gravitational waves from the coalescence of two neutron stars. The merger rate of binary neutron stars estimated from this event suggests that distant, unresolvable binary neutron stars create a significant astrophysical stochastic gravitational-wave background. The binary neutron star component will add to the contribution from binary black holes, increasing the amplitude of the total astrophysical background relative to previous expectations. In the Advanced LIGO-Virgo frequency band most sensitive to stochastic backgrounds (near 25 Hz), we predict a total astrophysical background with amplitude ΩGW(f=25 Hz)=1.8-1.3+2.7×10-9 with …
Palfa Discovery Of A Highly Relativistic Double Neutron Star Binary, K. Stovall, P. C.C. Freire, S. Chatterjee, P. B. Demorest, D. R. Lorimer, M. A. Mclaughlin, N. Pol, J. Van Leeuwen, R. S. Wharton, B. Allen, M. Boyce, A. Brazier, K. Caballero, F. Camilo, R. Camuccio, J. M. Cordes, F. Crawford, J. S. Deneva, R. D. Ferdman, J. W.T. Hessels, F. A. Jenet, V. M. Kaspi, B. Knispel, P. Lazarus, R. Lynch, E. Parent, C. Patel, Z. Pleunis, S. M. Ransom, P. Scholz
Palfa Discovery Of A Highly Relativistic Double Neutron Star Binary, K. Stovall, P. C.C. Freire, S. Chatterjee, P. B. Demorest, D. R. Lorimer, M. A. Mclaughlin, N. Pol, J. Van Leeuwen, R. S. Wharton, B. Allen, M. Boyce, A. Brazier, K. Caballero, F. Camilo, R. Camuccio, J. M. Cordes, F. Crawford, J. S. Deneva, R. D. Ferdman, J. W.T. Hessels, F. A. Jenet, V. M. Kaspi, B. Knispel, P. Lazarus, R. Lynch, E. Parent, C. Patel, Z. Pleunis, S. M. Ransom, P. Scholz
Physics and Astronomy Faculty Publications and Presentations
We report the discovery and initial follow-up of a double neutron star (DNS) system, PSR J1946+2052, with the Arecibo L-Band Feed Array pulsar (PALFA) survey. PSR J1946+2052 is a 17 ms pulsar in a 1.88 hr, eccentric (e = 0.06) orbit with a 1.2 M o companion. We have used the Jansky Very Large Array to localize PSR J1946+2052 to a precision of 0.″09 using a new phase binning mode. We have searched multiwavelength catalogs for coincident sources but did not find any counterparts. The improved position enabled a measurement of the spin period derivative of the pulsar (P = …
Nonreciprocal Localization Of Photons, Hamidreza Ramezani, Pankaj K. Jha, Yuan Wang, Xiang Zhang
Nonreciprocal Localization Of Photons, Hamidreza Ramezani, Pankaj K. Jha, Yuan Wang, Xiang Zhang
Physics and Astronomy Faculty Publications and Presentations
We demonstrate that it is possible to localize photons nonreciprocally in a moving photonic lattice made by spatiotemporally modulating the atomic response, where the dispersion acquires a spectral Doppler shift with respect to the probe direction. A static defect placed in such a moving lattice produces a spatial localization of light in the band gap with a shifting frequency that depends on the direction of incident field with respect to the moving lattice. This phenomenon has an impact not only in photonics but also in broader areas such as condensed matter and acoustics, opening the doors for designing new devices …
First Search For Nontensorial Gravitational Waves From Known Pulsars, B. P. Abbott, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, C. Adams, T. Adams, P. Addesso, R. X. Adhikari, V. B. Adya, C. Affeldt, M. Afrough, B. Agarwal, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, P. Ajith, G. Allen, A. Allocca, P. A. Altin, A. Amato, A. Ananyeva, S. B. Anderson, W. G. Anderson, S. Antier, S. Appert, K. Arai
First Search For Nontensorial Gravitational Waves From Known Pulsars, B. P. Abbott, R. Abbott, T. D. Abbott, F. Acernese, K. Ackley, C. Adams, T. Adams, P. Addesso, R. X. Adhikari, V. B. Adya, C. Affeldt, M. Afrough, B. Agarwal, M. Agathos, K. Agatsuma, N. Aggarwal, O. D. Aguiar, L. Aiello, A. Ain, P. Ajith, G. Allen, A. Allocca, P. A. Altin, A. Amato, A. Ananyeva, S. B. Anderson, W. G. Anderson, S. Antier, S. Appert, K. Arai
Physics and Astronomy Faculty Publications and Presentations
We present results from the first directed search for nontensorial gravitational waves. While general relativity allows for tensorial (plus and cross) modes only, a generic metric theory may, in principle, predict waves with up to six different polarizations. This analysis is sensitive to continuous signals of scalar, vector, or tensor polarizations, and does not rely on any specific theory of gravity. After searching data from the first observation run of the advanced LIGO detectors for signals at twice the rotational frequency of 200 known pulsars, we find no evidence of gravitational waves of any polarization. We report the first upper …
Effect Of Non-Hermiticity On Adiabatic Elimination In Coupled Waveguides, Rahman Sharaf, M. Dehghani, Hamidreza Ramezani
Effect Of Non-Hermiticity On Adiabatic Elimination In Coupled Waveguides, Rahman Sharaf, M. Dehghani, Hamidreza Ramezani
Physics and Astronomy Faculty Publications and Presentations
We investigate the influence of non-Hermiticity on the adiabatic elimination in coupled waveguides.We show that although the total norm of the system is not conserved in parity-time symmetric phase, the dark state intensity remains constant. However, in broken phase the eliminated waveguide loses its darkness, i.e., its field amplitude starts increasing. In both exact and broken phases, the effective Hamiltonian derived from the adiabatic elimination condition describes the dynamics of all states except the dark state. Specifically, it cannot predict the amplification in the intensity of the dark state. Our results can strengthen the control of the dynamics in cavities …
Toxicity Evaluation Of A Novel Magnetic Resonance Imaging Marker Cocl2-N-Acetylcysteine In Rats, Li Wang, Mihai Gagea, Karen S. Martirosyan, Mary Johansen, Timothy Madden, Lisa Norberg, Kirk S. Culotta, Steven J. Frank
Toxicity Evaluation Of A Novel Magnetic Resonance Imaging Marker Cocl2-N-Acetylcysteine In Rats, Li Wang, Mihai Gagea, Karen S. Martirosyan, Mary Johansen, Timothy Madden, Lisa Norberg, Kirk S. Culotta, Steven J. Frank
Physics and Astronomy Faculty Publications and Presentations
C4 (cobalt dichloride-N-acetylcysteine [1% CoCl 2 :2% NAC]) is a novel magnetic resonance imaging contrast marker that facilitates visualization of implanted radioactive seeds in cancer brachytherapy. We evaluated the toxicity of C4. Rats were assigned to control (0% CoCl 2 :NAC), low-dose (0.1% CoCl 2 :2% NAC), reference-dose (C4), and high-dose (10% CoCl 2 :2% NAC) groups. Agent was injected into the left quadriceps femoris muscle of the rats. Endpoints were organ and body weights, hematology, and serum chemistry and histopathologic changes of tissues at 48 hours and 28 and 63 days after dosing. Student's t tests were used. No …
The Origin Of The First Neutron Star - Neutron Star Merger, K. Belczynski, A. Askar, M. Arca-Sedda, M. Chruslinska, M. Donnari, M. Giersz, M. Benacquista, R. Spurzem, D. Jin, G. Wiktorowicz, D. Belloni
The Origin Of The First Neutron Star - Neutron Star Merger, K. Belczynski, A. Askar, M. Arca-Sedda, M. Chruslinska, M. Donnari, M. Giersz, M. Benacquista, R. Spurzem, D. Jin, G. Wiktorowicz, D. Belloni
Physics and Astronomy Faculty Publications and Presentations
The first neutron star-neutron star (NS-NS) merger was discovered on August 17, 2017 through gravitational waves (GW170817) and followed with electromagnetic observations. This merger was detected in an old elliptical galaxy with no recent star formation. We perform a suite of numerical calculations to understand the formation mechanism of this merger. We probe three leading formation mechanisms of double compact objects: classical isolated binary star evolution, dynamical evolution in globular clusters, and nuclear cluster formation to test whether they are likely to produce NS-NS mergers in old host galaxies. Our simulations with optimistic assumptions show current NS-NS merger rates at …
Identification And Mitigation Of Narrow Spectral Artifacts That Degrade Searches For Persistent Gravitational Waves In The First Two Observing Runs Of Advanced Ligo, P. B. Covas, A. Effler, E. Goetz, P. M. Meyers, A. Neunzert, M. Oliver, B. L. Pearlstone, Volker Quetschke, Karla E. Ramirez, Darkhan Tuyenbayev
Identification And Mitigation Of Narrow Spectral Artifacts That Degrade Searches For Persistent Gravitational Waves In The First Two Observing Runs Of Advanced Ligo, P. B. Covas, A. Effler, E. Goetz, P. M. Meyers, A. Neunzert, M. Oliver, B. L. Pearlstone, Volker Quetschke, Karla E. Ramirez, Darkhan Tuyenbayev
Physics and Astronomy Faculty Publications and Presentations
Searches are under way in Advanced LIGO and Virgo data for persistent gravitational waves from continuous sources, e.g. rapidly rotating galactic neutron stars, and stochastic sources, e.g. relic gravitational waves from the Big Bang or superposition of distant astrophysical events such as mergers of black holes or neutron stars. These searches can be degraded by the presence of narrow spectral artifacts (lines) due to instrumental or environmental disturbances. We describe a variety of methods used for finding, identifying and mitigating these artifacts, illustrated with particular examples. Results are provided in the form of lists of line artifacts that can safely …
Block Copolymer Elastomer With Graphite Filler: Effect Of Processing Conditions And Silane Coupling Agent On The Composite Properties, Denis M. Panaitescu, Raluca Augusta Gabor, Cristian Andi Nicolae, Anca Constantina Parau, Catalin Vitelaru, Valentin Raditoiu, Mircea Chipara
Block Copolymer Elastomer With Graphite Filler: Effect Of Processing Conditions And Silane Coupling Agent On The Composite Properties, Denis M. Panaitescu, Raluca Augusta Gabor, Cristian Andi Nicolae, Anca Constantina Parau, Catalin Vitelaru, Valentin Raditoiu, Mircea Chipara
Physics and Astronomy Faculty Publications and Presentations
The control of morphology and interface in poly(styrene-ethylene/butylene-styrene) (SEBS) composites with graphitic fillers is extremely important for the design of piezoresistive sensors for body motion or flexible temperature sensors. The effects of a high amount of graphite (G) and silane coupling agent on the morphology and properties of SEBS composites with anisotropic mechanical properties are reported. The physical and chemical bonding of silane to both G and SEBS surface was proved by EDX and TGA results; this improved interface influenced both the thermal and mechanical properties of the composite. The vinyltriethoxysilane (VS) promoted the formation of char residue and, being …
The Green Bank Northern Celestial Cap Pulsar Survey. Ii. The Discovery And Timing Of 10 Pulsars, A. M. Kawash, M. A. Mclaughlin, D. L. Kaplan, M. E. Decesar, L. Levin, D. R. Lorimer, R. S. Lynch, K. Stovall, J. K. Swiggum, E. Fonseca, A. M. Archibald, S. Banaszak, C. M. Biwer, J. Boyles, B. Cui, L. P. Dartez, D. Day, S. Ernst, A. J. Ford, J. Flanigan, S. A. Heatherly, J. W.T. Hessels, J. Hinojosa, F. A. Jenet, C. Karako-Argaman, V. M. Kaspi, V. I. Kondratiev, S. Leake, G. Lunsford, J. G. Martinez
The Green Bank Northern Celestial Cap Pulsar Survey. Ii. The Discovery And Timing Of 10 Pulsars, A. M. Kawash, M. A. Mclaughlin, D. L. Kaplan, M. E. Decesar, L. Levin, D. R. Lorimer, R. S. Lynch, K. Stovall, J. K. Swiggum, E. Fonseca, A. M. Archibald, S. Banaszak, C. M. Biwer, J. Boyles, B. Cui, L. P. Dartez, D. Day, S. Ernst, A. J. Ford, J. Flanigan, S. A. Heatherly, J. W.T. Hessels, J. Hinojosa, F. A. Jenet, C. Karako-Argaman, V. M. Kaspi, V. I. Kondratiev, S. Leake, G. Lunsford, J. G. Martinez
Physics and Astronomy Faculty Publications and Presentations
We present timing solutions for 10 pulsars discovered in 350 MHz searches with the Green Bank Telescope. Nine of these were discovered in the Green Bank Northern Celestial Cap survey and one was discovered by students in the Pulsar Search Collaboratory program during an analysis of drift-scan data. Following the discovery and confirmation with the Green Bank Telescope, timing has yielded phase-connected solutions with high-precision measurements of rotational and astrometric parameters. Eight of the pulsars are slow and isolated, including PSR J0930-2301, a pulsar with a nulling fraction lower limit of ∼30% and a nulling timescale of seconds to minutes. …
Reactive Oxygen Species Generation In Human Cells By A Novel Magnetic Resonance Imaging Contrast Agent, Li Wang, Eric Lin, Mary J. Johansen, Timothy Madden, Edward Felix, Karen S. Martirosyan, Steven J. Frank
Reactive Oxygen Species Generation In Human Cells By A Novel Magnetic Resonance Imaging Contrast Agent, Li Wang, Eric Lin, Mary J. Johansen, Timothy Madden, Edward Felix, Karen S. Martirosyan, Steven J. Frank
Physics and Astronomy Faculty Publications and Presentations
The novel positive-contrast magnetic resonance imaging (MRI) marker C4 consists of an aqueous solution of cobalt chloride (CoCl 2 ) complexed with the chelator N-acetylcysteine (NAC). We evaluated whether the presence of C4 or its components would produce reactive oxygen species (ROS, including hydroxyl, peroxyl, or other reactive oxygen species) in cultured cells. Human cancer or normal cells were incubated with 1% (w/v) CoCl 2 ·6H 2 O or 2% NAC or a combination of both (1% CoCl 2 ·6H 2 O: 2% NAC in an aqueous solution, abbreviated as Co: NAC) in the presence or absence of H 2 …