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Articles 91 - 120 of 120
Full-Text Articles in Physics
Secular Damping Of Stellar Bars In Spinning Dark Matter Halos, Stacy Long, Isaac Shlosman, Clayton Heller
Secular Damping Of Stellar Bars In Spinning Dark Matter Halos, Stacy Long, Isaac Shlosman, Clayton Heller
Physics and Astronomy Faculty Publications
We demonstrate using numerical simulations of isolated galaxies that growth of stellar bars in spinning dark matter halos is heavily suppressed in the secular phase of evolution. In a representative set of models, we show that for values of the cosmological spin parameter λ ≳ 0.03, bar growth (in strength and size) becomes increasingly quenched. Furthermore, the slowdown of the bar pattern speed weakens considerably with increasing λ until it ceases completely. The terminal structure of the bars is affected as well, including extent and shape of their boxy/peanut bulges. The essence of this effect lies in the modified angular …
Minisuperspace Canonical Quantization Of The Reissner-Nordström Black Hole Via Conditional Symmetries, T. Christodoulakis, N. Dimakis, Petros A. Terzis, Babak Vakili, E. Melas, Th. Grammenos
Minisuperspace Canonical Quantization Of The Reissner-Nordström Black Hole Via Conditional Symmetries, T. Christodoulakis, N. Dimakis, Petros A. Terzis, Babak Vakili, E. Melas, Th. Grammenos
Physics and Astronomy Faculty Publications and Presentations
We use the conditional symmetry approach to study the r evolution of a minisuperspace spherically symmetric model both at the classical and the quantum level. After integration of the coordinates t, θ and ϕ in the gravitational plus electromagnetic action the configuration space dependent dynamical variables turn out to correspond to the r-dependent metric functions and the electrostatic field. In the context of the formalism for constrained systems (Dirac-Bergmann, Arnowitt-Deser-Misner) with respect to the radial coordinate r, we set up a pointlike reparametrization invariant Lagrangian. It is seen that, in the constant potential parametrization of the lapse, the corresponding minisuperspace …
Two-Neutron Transfer Reaction Mechanisms In 12C(6He, 4He) 14C Using A Realistic Three-Body 6He Model, D. Smalley, F. Sarazin, F. M. Nunes, B. A. Brown, P. Adsley, H. Al-Falou, C. Andreoiu, B. Baartman, G. C. Ball, J. C. Blackmon, H. C. Boston, W. N. Catford, S. Chagnon-Lessard, A. Chester, R. M. Churchman, D. S. Cross, C. Aa. Diget, D. Di Valentino, S. P. Fox, B. R. Fulton, A. Garnsworthy, G. Hackman, U. Hager, R. Kshetri, J. N. Orce, N. A. Orr, E. Paul, M. Pearson, E. T. Rand, J. Rees, S. Sjue, C. E. Svensson, E. Tardiff, A. Diaz Varela, S. J. Williams, Steven W. Yates
Two-Neutron Transfer Reaction Mechanisms In 12C(6He, 4He) 14C Using A Realistic Three-Body 6He Model, D. Smalley, F. Sarazin, F. M. Nunes, B. A. Brown, P. Adsley, H. Al-Falou, C. Andreoiu, B. Baartman, G. C. Ball, J. C. Blackmon, H. C. Boston, W. N. Catford, S. Chagnon-Lessard, A. Chester, R. M. Churchman, D. S. Cross, C. Aa. Diget, D. Di Valentino, S. P. Fox, B. R. Fulton, A. Garnsworthy, G. Hackman, U. Hager, R. Kshetri, J. N. Orce, N. A. Orr, E. Paul, M. Pearson, E. T. Rand, J. Rees, S. Sjue, C. E. Svensson, E. Tardiff, A. Diaz Varela, S. J. Williams, Steven W. Yates
Physics and Astronomy Faculty Publications
The reaction mechanisms of the two-neutron transfer reaction 12C(6He,4He) have been studied at Elab=30 MeV at the TRIUMF ISAC-II facility using the Silicon Highly-segmented Array for Reactions and Coulex (SHARC) charged-particle detector array. Optical potential parameters have been extracted from the analysis of the elastic scattering angular distribution. The new potential has been applied to the study of the transfer angular distribution to the 2+2 8.32 MeV state in 14C, using a realistic three-body 6He model and advanced shell-model calculations for the carbon structure, allowing to calculate the relative contributions …
Oscillatory Motor Network Activity During Rest And Movement: An Fnirs Study, Sahil Bajaj, Daniel Drake, Andrew Butler, Mukesh Dhamala
Oscillatory Motor Network Activity During Rest And Movement: An Fnirs Study, Sahil Bajaj, Daniel Drake, Andrew Butler, Mukesh Dhamala
Physics and Astronomy Faculty Publications
Coherent network oscillations (<0.1 Hz) linking distributed brain regions are commonly observed in the brain during both rest and task conditions. What oscillatory network exists and how network oscillations change in connectivity strength, frequency and direction when going from rest to explicit task are topics of recent inquiry. Here, we study network oscillations within the sensorimotor regions of able-bodied individuals using hemodynamic activity as measured by functional near-infrared spectroscopy (fNIRS). Using spectral interdependency methods, we examined how the supplementary motor area (SMA), the left premotor cortex (LPMC) and the left primary motor cortex (LM1) are bound as a network during extended resting state (RS) and between-tasks resting state (btRS), and how the activity of the network changes as participants execute left, right, and bilateral hand (LH, RH, and BH) finger movements. We found: (i) power, coherence and Granger causality (GC) spectra had significant peaks within the frequency band (0.01–0.04 Hz) during RS whereas the peaks shifted to a bit higher frequency range (0.04–0.08 Hz) during btRS and finger movement tasks, (ii) there was significant bidirectional connectivity between all the nodes during RS and unidirectional connectivity from the LM1 to SMA and LM1 to LPMC during btRS, and (iii) the connections from SMA to LM1 and from LPMC to LM1 were significantly modulated in LH, RH, and BH finger movements relative to btRS. The unidirectional connectivity from SMA to LM1 just before the actual task changed to the bidirectional connectivity during LH and BH finger movement. The uni-directionality could be associated with movement suppression and the bi-directionality with preparation, sensorimotor update and controlled execution. These results underscore that fNIRS is an effective tool for monitoring spectral signatures of brain activity, which may serve as an important precursor before monitoring the recovery progress following brain injury.
Dilute Magnetism And Spin-Orbital Percolation Effects In Sr2Ir1−XRhXO4, J. P. Clancy, A. Lupascu, H. Gretarsson, Z. Islam, Y. F. Hu, D. Casa, C. S. Nelson, S. C. Lamarra, Gang Cao, Young-June Kim
Dilute Magnetism And Spin-Orbital Percolation Effects In Sr2Ir1−XRhXO4, J. P. Clancy, A. Lupascu, H. Gretarsson, Z. Islam, Y. F. Hu, D. Casa, C. S. Nelson, S. C. Lamarra, Gang Cao, Young-June Kim
Physics and Astronomy Faculty Publications
We have used a combination of resonant magnetic x-ray scattering and x-ray absorption spectroscopy to investigate the properties of the doped spin-orbital Mott insulator Sr2Ir1−xRhxO4 (0.07 ≤ x ≤ 0.70). We show that Sr2Ir1−xRhxO4 represents a unique model system for the study of dilute magnetism in the presence of strong spin-orbit coupling, and provide evidence of a doping-induced change in magnetic structure and a suppression of magnetic order at xc ∼ 0.17. We demonstrate that Rh-doping introduces Rh3+/Ir5+ ions which …
Novel Magnetism Of Ir5+(5D4) Ions In The Double Perovskite Sr2Yiro6, Gang Cao, Tongfei Qi, Li Li, Jsaminka Terzic, Shujuan Yuan, Lance E. De Long, Ganpathy Murthy, Ribhu K. Kaul
Novel Magnetism Of Ir5+(5D4) Ions In The Double Perovskite Sr2Yiro6, Gang Cao, Tongfei Qi, Li Li, Jsaminka Terzic, Shujuan Yuan, Lance E. De Long, Ganpathy Murthy, Ribhu K. Kaul
Physics and Astronomy Faculty Publications
We synthesize and study single crystals of a new double-perovskite Sr2YIrO6. Despite two strongly unfavorable conditions for magnetic order, namely, pentavalent Ir5+(5d4) ions which are anticipated to have Jeff=0 singlet ground states in the strong spin-orbit coupling (SOC) limit and geometric frustration in a face-centered cubic structure formed by the Ir5+ ions, we observe this iridate to undergo a novel magnetic transition at temperatures below 1.3 K. We provide compelling experimental and theoretical evidence that the origin of magnetism is in an unusual interplay between strong noncubic crystal …
Light-By-Light Scattering Nonlogarithmic Corrections To Hyperfine Splitting In Muonium, Michael I. Eides, Valery A. Shelyuto
Light-By-Light Scattering Nonlogarithmic Corrections To Hyperfine Splitting In Muonium, Michael I. Eides, Valery A. Shelyuto
Physics and Astronomy Faculty Publications
We consider three-loop corrections to hyperfine splitting in muonium generated by the gauge invariant set of diagrams with a virtual light-by-light scattering block. These diagrams produce both recoil and nonrecoil contributions to hyperfine splitting. Recoil corrections are enhanced by large logarithms of the muon-electron mass ratio. Both nonrecoil and logarithmically enhanced radiative-recoil corrections were calculated some time ago. Here we calculate nonlogarithmic radiative-recoil corrections generated by the insertions of the light-by-light scattering block.
Energy Dependence Of Moments Of Net-Proton Multiplicity Distributions At Rhic, James K. Atkins, Renee H. Fatemi, Wolfgang Korsch, Suvarna Ramachandran, G. Webb, L. Adamczyk, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, J. Alford, C. D. Anson, A. Aparin, D. Arkhipkin, E. C. Aschenauer, G. S. Averichev, J. Balewski, A. Banerjee, Z. Barnovska, D. R. Beavis, R. Bellwied, A. Bhasin, A. K. Bhati, P. Bhattarai, H. Bichsel, J. Bielcik, J. Bielcikova, L. C. Bland, I. G. Bordyuzhin, W. Borowski
Energy Dependence Of Moments Of Net-Proton Multiplicity Distributions At Rhic, James K. Atkins, Renee H. Fatemi, Wolfgang Korsch, Suvarna Ramachandran, G. Webb, L. Adamczyk, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, J. Alford, C. D. Anson, A. Aparin, D. Arkhipkin, E. C. Aschenauer, G. S. Averichev, J. Balewski, A. Banerjee, Z. Barnovska, D. R. Beavis, R. Bellwied, A. Bhasin, A. K. Bhati, P. Bhattarai, H. Bichsel, J. Bielcik, J. Bielcikova, L. C. Bland, I. G. Bordyuzhin, W. Borowski
Physics and Astronomy Faculty Publications
We report the beam energy(√8NN = 7.7-200 GeV) and collision centrality dependence of the mean (M), standard deviation (σ), skewness (S), and kurtosis (κ) of the net-proton multiplicity distributions in Au+Au collisions. The measurements are carried out by the STAR experiment at midrapidity (|y|<0.5) and within the transverse momentum range 0.4<ρτ<0.8 GeV/c in the first phase of the Beam Energy Scan program at the Relativistic Heavy Ion Collider. These measurements are important for understanding the quantum chromodynamic phase diagram. The products of the moments, Sσ and κσ2, are sensitive to the correlation length of the hot and dense …
Interpreting The Ionization Sequence In Agn Emission-Line Spectra, Chris T. Richardson, James T. Allen, Jack A. Baldwin, Paul C. Hewett, Gary J. Ferland
Interpreting The Ionization Sequence In Agn Emission-Line Spectra, Chris T. Richardson, James T. Allen, Jack A. Baldwin, Paul C. Hewett, Gary J. Ferland
Physics and Astronomy Faculty Publications
We investigate the physical cause of the great range in the ionization level seen in the spectra of narrow-lined active galactic nuclei (AGN). We used a recently developed technique called mean field independent component analysis to identify examples of individual Sloan Digital Sky Survey galaxies whose spectra are not dominated by emission due to star formation (SF), which we therefore designate as AGN. We assembled high signal-to-noise ratio (S/N) composite spectra of a sequence of these AGN defined by the ionization level of their narrow-line regions (NLR), and extending down to very low ionization cases. We then used a local …
Self-Heating Model Of Spherical Aluminum Nanoparticle Oxidation, Karen S. Martirosyan, Zamart Ramazanova, Maxim Zyskin
Self-Heating Model Of Spherical Aluminum Nanoparticle Oxidation, Karen S. Martirosyan, Zamart Ramazanova, Maxim Zyskin
Physics and Astronomy Faculty Publications and Presentations
Aluminum-oxygen reaction is important in highly energetic and high pressure generating systems. Nanoenergetic thermites include mixtures of nanostructured Al and oxidizer particles. The main distinguishing features of these reactive systems are their significant enthalpy release and tunable rate of energy discharge, which gives rise to a wide range of combustion rates, energy release, and ignition sensitivity. In this paper, we consider rapid oxidation of a spherically symmetric aluminum particle. We use the Cabrera Mott oxidation model to describe the kinetics of oxide growth of an aluminum nanoparticle and to predict reaction temperature and oxidation time. We assume that aluminum particle …
Neutral Pion Cross Section And Spin Asymmetries At Intermediate Pseudorapidity In Polarized Proton Collisions At √S=200 Gev, L. Adamczyk, James K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, J. Alford, C. D. Anson, A. Aparin, D. Arkhipkin, Renee H. Fatemi, Robert G. Fersch, Wolfgang Korsch, Suvarna Ramachandran, G. Webb
Neutral Pion Cross Section And Spin Asymmetries At Intermediate Pseudorapidity In Polarized Proton Collisions At √S=200 Gev, L. Adamczyk, James K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, J. Alford, C. D. Anson, A. Aparin, D. Arkhipkin, Renee H. Fatemi, Robert G. Fersch, Wolfgang Korsch, Suvarna Ramachandran, G. Webb
Physics and Astronomy Faculty Publications
The differential cross section and spin asymmetries for neutral pions produced within the intermediate pseudorapidity range 0.8<ηpT/c and is found to agree with a next-to-leading order perturbative QCD calculation. The longitudinal double-spin asymmetry ALL is measured in the same pseudorapidity range and spans a range of Bjorken-x down to x≈0.01. The measured ALL is consistent with model predictions for varying degrees of gluon polarization. The parity-violating asymmetry AL is also measured and found to be consistent with zero. The transverse single-spin asymmetry AN is measured over a previously unexplored kinematic range in …
Energy Dependence Of The (E,2E) Recoil Peak To Binary Peak Ratio Across He (2P2)1D And (2S2P)1P Autoionizing Levels, B. A. Deharak, K. Bartschat, Nicholas L. S. Martin
Energy Dependence Of The (E,2E) Recoil Peak To Binary Peak Ratio Across He (2P2)1D And (2S2P)1P Autoionizing Levels, B. A. Deharak, K. Bartschat, Nicholas L. S. Martin
Physics and Astronomy Faculty Publications
The (e,2e) recoil peak to binary peak ratio as a function of the ejected-electron energy is reported for helium autoionizing levels (2p2)1D and (2s2p)1P. A special out-of-plane geometry is used where the ejected electrons are detected in a plane that includes the momentum transfer axis but is perpendicular to the scattering plane. The measured recoil peak to binary peak ratio is a dimensionless quantity that can be directly compared with calculations. A second-order model in the projectile-target interaction correctly reproduces the observed energy dependence …
Annual Solar Motion And Spy Satellites, Margaret Jensen, Shane L. Larson
Annual Solar Motion And Spy Satellites, Margaret Jensen, Shane L. Larson
Browse All Undergraduate research
A topic often taught in introductory astronomy courses is the changing position of the Sun in the sky as a function of time of day, and season. The relevance and importance of this motion is explained in the context of seasons and the impact it has on human activities such as agriculture. The geometry of the ob- served motion in the sky is usually reduced to graphical representations and visualizations that can be difficult to render and grasp. Sometimes students are asked to observe the Suns changing motion and record their data, but this is a long-term project requiring several …
Cold Gas Dynamics In Hydra-A: Evidence For A Rotating Disc, S. L. Hamer, A. C. Edge, A. M. Swinbank, J. B. R. Oonk, R. Mittal, B. R. Mcnamara, H. R. Russell, M. N. Bremer, F. Combes, A. C. Fabian, N. P. H. Nesvadba, C. P. O'Dea, S. A. Baum, P. Salomé, G. Tremblay, M. Donahue, Gary J. Ferland, C. L. Sarazin
Cold Gas Dynamics In Hydra-A: Evidence For A Rotating Disc, S. L. Hamer, A. C. Edge, A. M. Swinbank, J. B. R. Oonk, R. Mittal, B. R. Mcnamara, H. R. Russell, M. N. Bremer, F. Combes, A. C. Fabian, N. P. H. Nesvadba, C. P. O'Dea, S. A. Baum, P. Salomé, G. Tremblay, M. Donahue, Gary J. Ferland, C. L. Sarazin
Physics and Astronomy Faculty Publications
We present multifrequency observations of the radio galaxy Hydra-A (3C218) located in the core of a massive, X-ray luminous galaxy cluster. Integral field unit spectroscopy is used to trace the kinematics of the ionized and warm molecular hydrogen which are consistent with an ∼5 kpc rotating disc. Broad, double-peaked lines of CO(2–1), [C II] 157 μm and [O I] 63 μm are detected. We estimate the mass of the cold gas within the disc to be Mgas = 2.3 ± 0.3 × 109 M⊙. These observations demonstrate that the complex line profiles found in the cold …
Surface Plasmon Resonance Sensing Properties Of A 3d Nanostructure Consisting Of Aligned Nanohole And Nanocone Arrays, Mohamadreza Najiminaini, Erden Ertorer, Bozena Kaminska, Silvia Mittler, Jeffrey J.L. Carson
Surface Plasmon Resonance Sensing Properties Of A 3d Nanostructure Consisting Of Aligned Nanohole And Nanocone Arrays, Mohamadreza Najiminaini, Erden Ertorer, Bozena Kaminska, Silvia Mittler, Jeffrey J.L. Carson
Physics and Astronomy Publications
Molecular surface plasmon resonance (SPR) sensing is one of the most common applications of an array of periodic nanoholes in a metal film. However, metallic nanohole arrays (NHAs) with low-hole count have lower resolution and SPR sensing performance compared to NHAs with high-hole count. In this paper, we present a compact three-dimensional (3D) plasmonic nanostructure with extraordinary optical transmission properties benefiting from surface plasmon matching and enhanced localized surface plasmon coupling. The 3D nanostructure consisted of a gold film containing a NHA with an underlying cavity and a gold nanocone array (NCA) at the bottom of the cavity. Each nanocone …
Cross Sections Fall 2013/Winter 2014, Department Of Physics And Astronomy
Cross Sections Fall 2013/Winter 2014, Department Of Physics And Astronomy
Cross Sections
No abstract provided.
A Transition Mass For Black Holes To Show Broad Emission Lines, Susmita Chakravorty, Martin Elvis, Gary J. Ferland
A Transition Mass For Black Holes To Show Broad Emission Lines, Susmita Chakravorty, Martin Elvis, Gary J. Ferland
Physics and Astronomy Faculty Publications
Although the supermassive (AGN) and stellar mass (BHBs) black holes have many properties in common, the broad emission lines (BELs) are exclusively signatures of the active galactic nuclei (AGN). Based on the detection of these lines from Sloan Digital Sky Survey (SDSS) data bases, there seems to be no AGN with mass MBH ≲ 105 M⊙. In this paper, we investigate if such low-mass black holes are really non-existent or they are undetected because the BELs in them are not produced efficiently. Using the ionizing spectral energy distribution for a wide range of black hole mass, …
Suppression Of Dielectronic Recombination At Finite Densities, T. W. Gorczyca, D. Nikolić, N. R. Badnell, Gary J. Ferland
Suppression Of Dielectronic Recombination At Finite Densities, T. W. Gorczyca, D. Nikolić, N. R. Badnell, Gary J. Ferland
Physics and Astronomy Faculty Publications
Density-dependent effective dielectronic recombination rate coefficients are determined in order to explore finite-density effects on the ionization balance of plasmas.
Treatment Of Calibration Uncertainty In Multi-Baseline Cross-Correlation Searches For Gravitational Waves, J. T. Whelan, E. L. Robinson, Joseph D. Romano, E. H. Thrane
Treatment Of Calibration Uncertainty In Multi-Baseline Cross-Correlation Searches For Gravitational Waves, J. T. Whelan, E. L. Robinson, Joseph D. Romano, E. H. Thrane
Physics and Astronomy Faculty Publications and Presentations
Uncertainty in the calibration of gravitational wave (GW) detector data leads to systematic errors, which must be accounted for in setting limits on the strength of GW signals. When cross-correlation measurements are made using data from a pair of instruments, as in searches for a stochastic GW background, the calibration uncertainties of the individual instruments can be combined into an uncertainty associated with the pair. With the advent of multi-baseline GW observation (e.g., networks consisting of multiple detectors such as the LIGO observatories and Virgo), a more sophisticated treatment is called for. We have described how the correlations between calibration …
Neutral Pion Cross Section And Spin Asymmetries At Intermediate Pseudorapidity In Polarized Proton Collisions At √ S = 200 Gev, L. Adamczyk, J. K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, S. Bültmann, I. Koralt, D. Plyku, Star Collaboration
Neutral Pion Cross Section And Spin Asymmetries At Intermediate Pseudorapidity In Polarized Proton Collisions At √ S = 200 Gev, L. Adamczyk, J. K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, S. Bültmann, I. Koralt, D. Plyku, Star Collaboration
Physics Faculty Publications
The differential cross section and spin asymmetries for neutral pions produced within the intermediate pseudorapidity range 0.8<η/c and is found to agree with a next-to-leading order perturbative QCD calculation. The longitudinal double-spin asymmetry ALL is measured in the same pseudorapidity range and spans a range of Bjorken-x down to x≈0.01. The measured ALL is consistent with model predictions for varying degrees of gluon polarization. The parity-violating asymmetry AL is also measured and found to be consistent with zero. The transverse single-spin asymmetry AN is measured over a previously unexplored kinematic range in Feynman-x and PT. Such measurements may aid our understanding of the onset and kinematic dependence of the large asymmetries observed …
Implementation Of An F-Statistic All-Sky Search For Continuous Gravitational Waves In Virgo Vsr1 Data, J. Aasi, B. P. Abbott, R. Abbott, T. Abbott, M. R. Abernathy, Mario C. Diaz, Malik Rakhmanov, Joseph D. Romano, Soma Mukherjee, Volker Quetschke, Teviet Creighton, Robert Stone
Implementation Of An F-Statistic All-Sky Search For Continuous Gravitational Waves In Virgo Vsr1 Data, J. Aasi, B. P. Abbott, R. Abbott, T. Abbott, M. R. Abernathy, Mario C. Diaz, Malik Rakhmanov, Joseph D. Romano, Soma Mukherjee, Volker Quetschke, Teviet Creighton, Robert Stone
Physics and Astronomy Faculty Publications and Presentations
We present an implementation of the -statistic to carry out the first search in data from the Virgo laser interferometric gravitational wave detector for periodic gravitational waves from a priori unknown, isolated rotating neutron stars. We searched a frequency f0 range from 100 Hz to 1 kHz and the frequency dependent spindown f1 range from Hz s−1 to zero. A large part of this frequency–spindown space was unexplored by any of the all-sky searches published so far. Our method consisted of a coherent search over two-day periods using the -statistic, followed by a search for coincidences among the …
A Program For Optical Observations Of Advanced Ligo Early Triggers In The Southern Hemisphere, Matthew Benacquista, Chris Belczynski, Martin Beroiz, Maria Branchesi, Carlos Colazo, Mario C. Diaz, Mancheno Dominguez, Diego Garcia Lambas, Shengnan Liang, Lucas Macri, Tania Peñuela, B. Sanchez, Marcos Schneiter, Cristina V. Torres
A Program For Optical Observations Of Advanced Ligo Early Triggers In The Southern Hemisphere, Matthew Benacquista, Chris Belczynski, Martin Beroiz, Maria Branchesi, Carlos Colazo, Mario C. Diaz, Mancheno Dominguez, Diego Garcia Lambas, Shengnan Liang, Lucas Macri, Tania Peñuela, B. Sanchez, Marcos Schneiter, Cristina V. Torres
Physics and Astronomy Faculty Publications and Presentations
In this poster we present a plan to follow-up optically early triggers from the Advanced LIGO gravitational wave detectors, which will start operating in scientific mode in the northern summer of 2015.
Application Of A Hough Search For Continuous Gravitational Waves On Data From The Fifth Ligo Science Run, J. Aasi, J. Abadie, B. P. Abbott, R. Abbott, T. Abbott, M. R. Abernathy, Daniel Bessis, Teviet Creighton, H. Daveloza, Mario C. Diaz, S. R. Morriss, Soma Mukherjee, M. E. Normandin, W. Ortega Larcher, O. Puncken, Volker Quetschke, Malik Rakhmanov, Robert Stone, A. S. Stroeer, Lappoon R. Tang, Cristina V. Torres, D. Vrinceanu
Application Of A Hough Search For Continuous Gravitational Waves On Data From The Fifth Ligo Science Run, J. Aasi, J. Abadie, B. P. Abbott, R. Abbott, T. Abbott, M. R. Abernathy, Daniel Bessis, Teviet Creighton, H. Daveloza, Mario C. Diaz, S. R. Morriss, Soma Mukherjee, M. E. Normandin, W. Ortega Larcher, O. Puncken, Volker Quetschke, Malik Rakhmanov, Robert Stone, A. S. Stroeer, Lappoon R. Tang, Cristina V. Torres, D. Vrinceanu
Physics and Astronomy Faculty Publications and Presentations
We report on an all-sky search for periodic gravitational waves in the frequency range 50–1000 Hz with the first derivative of frequency in the range −8.9 × 10−10 Hz s−1 to zero in two years of data collected during LIGO's fifth science run. Our results employ a Hough transform technique, introducing a χ2 test and analysis of coincidences between the signal levels in years 1 and 2 of observations that offers a significant improvement in the product of strain sensitivity with compute cycles per data sample compared to previously published searches. Since our search yields no surviving candidates, we present …
Biosensors And Nanobiosensors: Design And Applications, Ahmed Touhami
Biosensors And Nanobiosensors: Design And Applications, Ahmed Touhami
Physics and Astronomy Faculty Publications and Presentations
The goal of this chapter is to cover the full scope of biosensors. It offers a survey of the principles, design, operation, and biomedical applications of the most popular types of biosensing devices in use today. By discussing recent research and future trends based on many excellent books and reviews, it is hoped to give the readers a comprehensive view on this fast growing field.
First All-Sky Search For Continuous Gravitational Waves From Unknown Sources In Binary Systems, J. Aasi, B. P. Abbott, Teviet Creighton, H. Daveloza, Mario C. Diaz, S. R. Morriss, Soma Mukherjee, M. E. Normandin, Volker Quetschke, O. Puncken, Malik Rakhmanov, K. E. Ramirez, Robert Stone, Cristina V. Torres, G. Valdes
First All-Sky Search For Continuous Gravitational Waves From Unknown Sources In Binary Systems, J. Aasi, B. P. Abbott, Teviet Creighton, H. Daveloza, Mario C. Diaz, S. R. Morriss, Soma Mukherjee, M. E. Normandin, Volker Quetschke, O. Puncken, Malik Rakhmanov, K. E. Ramirez, Robert Stone, Cristina V. Torres, G. Valdes
Physics and Astronomy Faculty Publications and Presentations
We present the first results of an all-sky search for continuous gravitational waves from unknown spinning neutron stars in binary systems using LIGO and Virgo data. Using a specially developed analysis program, the TwoSpect algorithm, the search was carried out on data from the sixth LIGO science run and the second and third Virgo science runs. The search covers a range of frequencies from 20 Hz to 520 Hz, a range of orbital periods from 2 to ∼2; 254 h and a frequency- and period-dependent range of frequency modulation depths from 0.277 to 100 mHz. This corresponds to a range …
Constraints On Cosmic Strings From The Ligo-Virgo Gravitational-Wave Detectors, Daniel Bessis, Teviet Creighton, H. Daveloza, Mario C. Diaz, S. R. Morriss, Soma Mukherjee, M. E. Normandin, W. Ortega Larcher, O. Puncken, Volker Quetschke, Malik Rakhmanov, Robert Stone, Lappoon R. Tang, Cristina V. Torres
Constraints On Cosmic Strings From The Ligo-Virgo Gravitational-Wave Detectors, Daniel Bessis, Teviet Creighton, H. Daveloza, Mario C. Diaz, S. R. Morriss, Soma Mukherjee, M. E. Normandin, W. Ortega Larcher, O. Puncken, Volker Quetschke, Malik Rakhmanov, Robert Stone, Lappoon R. Tang, Cristina V. Torres
Physics and Astronomy Faculty Publications and Presentations
Cosmic strings can give rise to a large variety of interesting astrophysical phenomena. Among them, powerful bursts of gravitational waves (GWs) produced by cusps are a promising observational signature. In this Letter we present a search for GWs from cosmic string cusps in data collected by the LIGO and Virgo gravitational wave detectors between 2005 and 2010, with over 625 days of live time. We find no evidence of GW signals from cosmic strings. From this result, we derive new constraints on cosmic string parameters, which complement and improve existing limits from previous searches for a stochastic background of GWs …
Search For Gravitational Radiation From Intermediate Mass Black Hole Binaries In Data From The Second Ligo-Virgo Joint Science Run, J. Aasi, B. P. Abbott, H. Daveloza, S. R. Morriss, Soma Mukherjee, M. E. Normandin, O. Puncken, Volker Quetschke, Malik Rakhmanov, K. E. Ramirez, Robert Stone, Cristina V. Torres, G. Valdes
Search For Gravitational Radiation From Intermediate Mass Black Hole Binaries In Data From The Second Ligo-Virgo Joint Science Run, J. Aasi, B. P. Abbott, H. Daveloza, S. R. Morriss, Soma Mukherjee, M. E. Normandin, O. Puncken, Volker Quetschke, Malik Rakhmanov, K. E. Ramirez, Robert Stone, Cristina V. Torres, G. Valdes
Physics and Astronomy Faculty Publications and Presentations
This paper reports on an unmodeled, all-sky search for gravitational waves from merging intermediate mass black hole binaries (IMBHB). The search was performed on data from the second joint science run of the LIGO and Virgo detectors (July 2009–October 2010) and was sensitive to IMBHBs with a range up to ∼200 Mpc, averaged over the possible sky positions and inclinations of the binaries with respect to the line of sight. No significant candidate was found. Upper limits on the coalescence-rate density of nonspinning IMBHBs with total masses between 100 and 450 M⊙ and mass ratios between 0.25 and 1 were …
Search For Gravitational Wave Ringdowns From Perturbed Intermediate Mass Black Holes In Ligo-Virgo Data From 2005–2010, J. Aasi, B. P. Abbott, Matthew Benacquista, H. Daveloza, Mario C. Diaz, S. R. Morriss, Soma Mukherjee, Volker Quetschke, O. Puncken, Malik Rakhmanov, K. E. Ramirez, Robert Stone, Cristina V. Torres, G. Valdes
Search For Gravitational Wave Ringdowns From Perturbed Intermediate Mass Black Holes In Ligo-Virgo Data From 2005–2010, J. Aasi, B. P. Abbott, Matthew Benacquista, H. Daveloza, Mario C. Diaz, S. R. Morriss, Soma Mukherjee, Volker Quetschke, O. Puncken, Malik Rakhmanov, K. E. Ramirez, Robert Stone, Cristina V. Torres, G. Valdes
Physics and Astronomy Faculty Publications and Presentations
We report results from a search for gravitational waves produced by perturbed intermediate mass black holes (IMBH) in data collected by LIGO and Virgo between 2005 and 2010. The search was sensitive to astrophysical sources that produced damped sinusoid gravitational wave signals, also known as ringdowns, with frequency 50 ≤ f0=Hz ≤ 2000 and decay timescale 0.0001 ≲ τ=s ≲ 0.1 characteristic of those produced in mergers of IMBH pairs. No significant gravitational wave candidate was detected. We report upper limits on the astrophysical coalescence rates of IMBHs with total binary mass 50 ≤ M=M⊙ ≤ 450 and component mass …
Search For Gravitational Waves Associated With Γ-Ray Bursts Detected By The Interplanetary Network, J. Aasi, B. P. Abbott, H. Daveloza, Mario C. Diaz, S. R. Morriss, Soma Mukherjee, M. E. Normandin, Volker Quetschke, O. Puncken, Malik Rakhmanov, K. E. Ramirez, Robert Stone, G. Tellez, Cristina V. Torres, G. Valdes
Search For Gravitational Waves Associated With Γ-Ray Bursts Detected By The Interplanetary Network, J. Aasi, B. P. Abbott, H. Daveloza, Mario C. Diaz, S. R. Morriss, Soma Mukherjee, M. E. Normandin, Volker Quetschke, O. Puncken, Malik Rakhmanov, K. E. Ramirez, Robert Stone, G. Tellez, Cristina V. Torres, G. Valdes
Physics and Astronomy Faculty Publications and Presentations
We present the results of a search for gravitational waves associated with 223 γ-ray bursts (GRBs) detected by the InterPlanetary Network (IPN) in 2005–2010 during LIGO’s fifth and sixth science runs and Virgo’s first, second, and third science runs. The IPN satellites provide accurate times of the bursts and sky localizations that vary significantly from degree scale to hundreds of square degrees. We search for both a well-modeled binary coalescence signal, the favored progenitor model for short GRBs, and for generic, unmodeled gravitational wave bursts. Both searches use the event time and sky localization to improve the gravitational wave search …
Unidirectional Lasing Emerging From Frozen Light In Nonreciprocal Cavities, Hamidreza Ramezani, S. Kalish, I. Vitebskiy, T. Kottos
Unidirectional Lasing Emerging From Frozen Light In Nonreciprocal Cavities, Hamidreza Ramezani, S. Kalish, I. Vitebskiy, T. Kottos
Physics and Astronomy Faculty Publications and Presentations
We introduce a class of unidirectional lasing modes associated with the frozen mode regime of nonreciprocal slow-wave structures. Such asymmetric modes can only exist in cavities with broken timereversal and space inversion symmetries. Their lasing frequency coincides with a spectral stationary inflection point of the underlying passive structure and is virtually independent of its size. These unidirectional lasers can be indispensable components of photonic integrated circuitry.