A Relativistic Long-term Precession of the Earth
Tang, K.
2016-05-01
A long-term precession represents a secular motion of the ecliptic and th equator in a long time interval. With Vondrák et al. (2011), we assume that precession covers all periods longer than 100 centuries, while the shorter ones are included in the nutation. This thesis deals with the long-term precession in a relativistic framework. Compared with the P03 precession theory which is only valid for several centuries around the epoch J2000.0, the new theory better reflects the realistic long-term behavior of precession. All previous works are not fully consistent with General Relativity. They only consider the dominant relativistic corrections: the first-order post-Newtonian corrections due to the Sun and the geodetic precession. Their standard way to account for the geodetic precession is to solve the purely Newtonian equations of rotational motion and add the geodetic precession as a correction to the solution. In this thesis, we aim to determine the acceleration of the SSB from astrometric and geodetic observations obtained by Very Long Baseline Interferometry (VLBI), which is a technique using the telescopes globally distributed on the Earth to observe a radio source simultaneously, and with the capacity of angular positioning for compact radio sources at 10-milliarcsecond level. The method of the global solution, which allows the acceleration vector to be estimated as a global parameter in the data analysis, is developed. Through the formal error given by the solution, this method shows directly the VLBI observations' capability to constrain the acceleration of the SSB, and demonstrates the significance level of the result. In the next step, the impact of the acceleration on the ICRS is studied in order to obtain the correction of the celestial reference frame (CRF) orientation. Recently, Klioner, Gerlach, and Soffel (2010) have constructed a relativistic theory of Earth's rotation. According to the post-Newtonian equations of rotational motion given by Klioner
Evolution of pulsar high-energy pulse profiles due to geodetic precession in the striped wind model
Petri, J
2014-01-01
Geodetic precession has been observed directly in the double pulsar system PSR J0737-3039. Its rate has even been measured and is in agreement with predictions of general relativity. Very recently, the double pulsar has been detected in X-rays and gamma-rays. This opens up the hope to observe geodetic precession in the high-energy pulse profile of this system. Unfortunately the geometric configuration of the binary renders unlikely any detection of such an effect. Nevertheless, this precession should be present in other relativistic binaries or double neutron star systems containing at least one X-ray or gamma-ray pulsar.}{In this paper we compute the variation of the high-energy pulse profile expected from this geodetic motion according to the striped wind model. We compare our results with two-pole caustic and outer gap emission patterns.}{We show that for a sufficient misalignment between the orbital angular momentum and the spin angular momentum, significant change in the pulse profile due to geodetic pre...
Relativistic Perihelion Precession of Orbits of Venus and the Earth
Biswas, Abhijit
2008-01-01
Among all the theories proposed to explain the 'anomalous' perihelion precession of Mercury's orbit announced in 1859 by Le Verrier, the general theory of relativity proposed by Einstein in November 1915, alone could calculate Mercury's 'anomalous' precession with a precision demanded by observational accuracy. Since Mercury's precession was a directly derived result of the full general theory, it was viewed by Einstein as the most critical test of general relativity, amongst the three tests proposed by him. With the advent of the space age, the observational accuracy level has improved further and it became possible to detect this precession for other planetary orbits of the solar system -- viz., Venus and the Earth. This conclusively proved that the phenomenon of 'anomalous' perihelion precession of planetary orbits is really a relativistic effect. Our previous papers presented the mathematical model and the computed value of the relativistic perihelion precession of Mercury's orbit using an alternate relat...
Observability of the General Relativistic Precession of Periastra in Exoplanets
Jordan, Andres
2008-01-01
The general relativistic precession rate of periastra in close-in exoplanets can be orders of magnitude larger than the magnitude of the same effect for Mercury. The realization that some of the close-in exoplanets have significant eccentricities raises the possibility that this precession might be detectable. We explore in this work the observability of the periastra precession using radial velocity and transit light curve observations. Our analysis is independent of the source of precession, which can also have significant contributions due to additional planets and tidal deformations. We find that precession of the periastra of the magnitude expected from general relativity can be detectable in timescales of <~ 10 years with current observational capabilities by measuring the change in the primary transit duration or in the time difference between primary and secondary transits. Radial velocity curves alone would be able to detect this precession for super-massive, close-in exoplanets orbiting inactive ...
Predicting Mercury's Precession using Simple Relativistic Newtonian Dynamics
Friedman, Y
2016-01-01
We present a new simple relativistic model for planetary motion describing accurately the anomalous precession of the perihelion of Mercury and its origin. The model is based on transforming Newton's classical equation for planetary motion from absolute to real spacetime influenced by the gravitational potential and introducing the concept of influenced direction.
Investigating relativity using lunar laser ranging - Geodetic precession and the Nordtvedt effect
Dickey, J. O.; Newhall, X. X.; Williams, J. G.
1989-01-01
The emplacement of retroreflectors on the moon by Apollo astronauts and the Russian Lunakhod spacecraft marked the inception of lunar laser ranging (LLR) and provided a natural laboratory for the study of general relativity. Continuing acquisition of increasingly accurate LLR data has provided enhanced sensitivity to general relativity parameters. Two relativistic effects are investigated in this paper: (1) the Nordtvedt effect, yielding a test of the strong equivalence principle, would appear as a distortion of the geocentric lunar orbit in the direction of the sun. The inclusion of recent LLR data limits the size of any such effect to 3 + or - 4 cm. The sensitivities to the various PPN quantities are also highlighted. (2) the geodetic precession of the lunar perigee is predicted by general relativity as a consequence of the motion of the earth-moon system about the sun; its theoretical magnitude is 19.2 mas/yr. Analysis presented here confirms this value and determines this quality to a 2 percent level.
Relativistic Precessing Jets and Cosmological $\\gamma$ Ray Bursts
Blackman, E G; Field, G B; Blackman, Eric G.; Yi, Insu; Field, George B.
1996-01-01
We discuss the possibility that gamma-ray bursts may result from cosmological relativistic blob emitting neutron star jets that precess past the line of sight. Beaming reduces the energy requirements, so that the jet emission can last longer than the observed burst duration. One precession mode maintains a short duration time scale, while a second keeps the beam from returning to the line of sight, consistent with the paucity of repeaters. The long life of these objects reduces the number required for production as compared to short lived jets. Blobs can account for the time structure of the bursts. Here we focus largely on kinematic and time scale considerations of beaming, precession, and blobs--issues which are reasonably independent of the acceleration and jet collimation mechanisms. We do suggest that large amplitude electro-magnetic waves could be a source of blob acceleration.
Christillin, Paolo
2012-01-01
Gravitomagnetism resulting from SR has been applied to geodetic precession and frame dragging. The substantial contribution of the "fictitious" Coriolis force, due to the relative rotation of the rest of the Universe in the non inertial frame of the free falling but rotating satellite, has to be taken into account, giving another quantitative confirmation of Mach's arguments and of the black hole nature of our Universe. Also the gravitational clock effect has an elementary prediction in the present post Newtonian formulation.
MOONLIGHT: A NEW LUNAR LASER RANGING RETROREFLECTOR AND THE LUNAR GEODETIC PRECESSION
M. Martini
2013-12-01
Full Text Available Since the 1970s Lunar Laser Ranging (LLR to the Apollo Cube Corner Retroreflector (CCR arrays (developed by the University of Maryland, UMD supplied almost all significant tests of General Relativity (Alley et al., 1970; Chang et al., 1971; Bender et al.,1973: possible changes in the gravitational constant, gravitational self-energy, weak equivalence principle, geodetic precession, inverse-square force-law. The LNF group, in fact, has just completed a new measurement of the lunar geodetic precession with Apollo array, with accuracy of 9 × 10−3, comparable to the best measurement to date. LLR has also provided significant information on the composition and origin of the moon. This is the only Apollo experiment still in operation. In the 1970s Apollo LLR arrays contributed a negligible fraction of the ranging error budget. Since the ranging capabilities of ground stations improved by more than two orders of magnitude, now, because of the lunar librations, Apollo CCR arrays dominate the error budget. With the project MoonLIGHT (Moon Laser Instrumentation for General relativity High-accuracy Tests, in 2006 INFN-LNF joined UMD in the development and test of a new-generation LLR payload made by a single, large CCR (100mm diameter unaffected by the effect of librations. With MoonLIGHT CCRs the accuracy of the measurement of the lunar geodetic precession can be improved up to a factor 100 compared to Apollo arrays. From a technological point of view, INFN-LNF built and is operating a new experimental apparatus (Satellite/lunar laser ranging Characterization Facility, SCF and created a new industry-standard test procedure (SCF-Test to characterize and model the detailed thermal behavior and the optical performance of CCRs in accurately laboratory-simulated space conditions, for industrial and scientific applications. Our key experimental innovation is the concurrent measurement and modeling of the optical Far Field Diffraction Pattern (FFDP and the
General Relativistic Precession in Small Solar System Bodies
Sekhar, Aswin; Werner, Stephanie; Hoffmann, Volker; Asher, David; Vaubaillon, Jeremie; Hajdukova, Maria; Li, Gongjie
2016-10-01
Introduction: One of the greatest successes of the Einstein's General Theory of Relativity (GR) was the correct prediction of the precession of perihelion of Mercury. The closed form expression to compute this precession tells us that substantial GR precession would occur only if the bodies have a combination of both moderately small perihelion distance and semi-major axis. Minimum Orbit Intersection Distance (MOID) is a quantity which helps us to understand the closest proximity of two orbits in space. Hence evaluating MOID is crucial to understand close encounters and collision scenarios better. In this work, we look at the possible scenarios where a small GR precession in argument of pericentre (ω) can create substantial changes in MOID for small bodies ranging from meteoroids to comets and asteroids.Analytical Approach and Numerical Integrations: Previous works have looked into neat analytical techniques to understand different collision scenarios and we use those standard expressions to compute MOID analytically. We find the nature of this mathematical function is such that a relatively small GR precession can lead to drastic changes in MOID values depending on the initial value of ω. Numerical integrations were done with package MERCURY incorporating the GR code to test the same effects. Numerical approach showed the same interesting relationship (as shown by analytical theory) between values of ω and the peaks/dips in MOID values. Previous works have shown that GR precession suppresses Kozai oscillations and this aspect was verified using our integrations. There is an overall agreement between both analytical and numerical methods.Summary and Discussion: We find that GR precession could play an important role in the calculations pertaining to MOID and close encounter scenarios in the case of certain small solar system bodies (depending on their initial orbital elements). Previous works have looked into impact probabilities and collision scenarios on
Sekhar, Aswin; Asher, David; Morbidelli, Alessandro; Werner, Stephanie; Vaubaillon, Jeremie; Li, Gongjie
2017-06-01
Two well known phenomena in orbital dynamics associated with low perihelion distance bodies are general relativistic (GR) precession and Lidov-Kozai (LK) oscillations.In this work, we are interested to identify bodies evolving in the near future (i.e. thousands of years in this case) into rapid sungrazing and sun colliding phases and undergoing inclination flips, due to LK like oscillations and being GR active at the same time. We find that LK mechanism leads to secular lowering of perihelion distance which in turn leads to a huge increase in GR precession of the argument of pericentre depending on the initial orbital elements. This in turn gives feedback to the LK mechanism as the eccentricity, inclination and argument of pericentre in Kozai cycles are closely correlated. In this work, we find real examples of solar system bodies which show rapid enhancement in GR precession rates due to LK like oscillations and there are cases where GR precession rate peaks to about 60 times that of the GR precession of Mercury thus showing the strength and complementary nature between these two dynamical phenomena.An analytical treatment is done on few bodies to understand the difference in their orbital evolution in the context of LK mechanism with and without GR precession term by incorporating suitable Hamiltonian dynamics. This result is subsequently matched using numerical integrations to find direct correlations. Real solar system bodies showing both GR precession and LK like oscillations are identified using compiled observational records from IAU-Minor Planet Center, Cometary Catalogue, IAU-Meteor Data Center and performing analytical plus numerical tests on them. This intermediate state (where GR and LK effects are comparable and co-exist) brings up the interesting possibility of drastic changes in GR precession rates during orbital evolution due to sungrazing and sun colliding phases induced by the LK like mechanism, thus combining both these important effects in a
Geodetic Precession of the Spin in a Non-Singular Gravitational Potential
Haranas I. I.
2008-01-01
Full Text Available Using a non-singular gravitational potential which appears in the literature we analyti- cally derived and investigated the equations describing the precession of a body’s spin orbiting around a main spherical body of mass M . The calculation has been performed using a non-exact Schwarzschild solution, and further assuming that the gravitational field of the Earth is more than that of a rotating mass. General theory of relativity pre- dicts that the direction of the gyroscope will change at a rate of 6.6 arcsec / year for a gyroscope in a 650 km high polar orbit. In our case a precession rate of the spin of a very similar magnitude to that predicted by general relativity was calculated resulting to a Delta S geo / S geo = -5.570E-2.
Geodetic Precession of the Spin in a Non-Singular Gravitational Potential
Haranas I. I.
2008-01-01
Full Text Available Using a non-singular gravitational potential which appears in the literature we analytically derived and investigated the equations describing the precession of a body's spin orbiting around a main spherical body of mass M. The calculation has been performed using a non-exact Schwarzschild solution, and further assuming that the gravitational field of the Earth is more than that of a rotating mass. General theory of relativity predicts that the direction of the gyroscope will change at a rate of 6.6 arcsec/year for a gyroscope in a 650 km high polar orbit. In our case a precession rate of the spin of a very similar magnitude to that predicted by general relativity was calculated resulting to a $Delta S_{geo}/S_{geo} = - 5.570 x 10^{-2}$.
The Evolution of PSR J0737-3039B and a Model for Relativistic Spin Precession
Perera, Benetge; Kramer, Michael; Stairs, Ingrid; Ferdman, Robert; Freire, Paulo; Possenti, Andrea; Breton, Rene; Manchester, Richard N; Burgay, Marta; Lyne, Andrew; Camilo, Fernando
2010-01-01
We present the evolution of the radio emission from the 2.8-s pulsar of the double pulsar system PSR J0737-3039A/B. We provide an update on the Burgay et al. (2005) analysis by describing the changes in the pulse profile and flux density over five years of observations, culminating in the B pulsar's radio disappearance in 2008 March. Over this time, the flux density decreases by 0.177 mJy/yr at the brightest orbital phases and the pulse profile evolves from a single to a double peak, with a separation rate of 2.6 deg/yr. The pulse profile changes are most likely caused by relativistic spin precession, but can not be easily explained with a circular hollow-cone beam as in the model of Clifton & Weisberg (2008). Relativistic spin precession, coupled with an elliptical beam, can model the pulse profile evolution well. This particular beam shape predicts geometrical parameters for the two bright orbital phases which are consistent and similar to those derived by Breton et al. (2008). However, the observed dec...
Change in General Relativistic precession rates due to Lidov-Kozai oscillations in the Solar System
Sekhar, Aswin; Asher, David J.; Werner, Stephanie C.; Vaubaillon, Jeremie; Li, Gongjie
2017-04-01
Introduction: Two well known phenomena associated with low perihelion distance bodies in orbital dynamics are general relativistic (GR) precession and Lidov-Kozai (LK) oscillations. The accurate prediction of the perihelion shift of Mercury in accord with real observations is one of the significant triumphs of the general theory of relativity developed by Einstein. The Lidov-Kozai mechanism was first proposed and derived by Kozai and independently by Lidov explaining the periodic exchange between eccentricities e and inclinations i thereby increasing or decreasing the perihelion distance q secularly in the orbiting body. Co-existence of GR Precession and LK Oscillations: In this work, we were interested to identify bodies evolving in the near future (i.e. thousands of years in this case) into rapid sungrazing and sun colliding phases and undergoing inclination flips, due to LK oscillations and being GR active at the same time. Of all the bodies we checked from the IAU-Minor Planet Center, and Marsden plus Kracht families from the comet catalogue, 96P/Machholz 1 stands out because it shows all these trends in the near future. LK leads to secular lowering of q which in turn leads to a huge increase in GR precession of argument of pericentre. This in turn gives feedback to the LK mechanism as the e,i and argument of pericentre in Kozai cycles are closely correlated. In this work, we find real examples of solar system bodies which show the continuum nature between GR precession domi-nant and LK mechanism dominant regimes. Results and Discussion: We have shown that there are bodies in the solar system in which both GR precession and LK mechanism can co-exist at the same time and for which these effects can be measured and identified using analytical and numerical techniques. Thus there is a continuum of bodies encompassing, firstly GR precession dominant, secondly GR precession plus LK mechanism co-existing and finally LK mechanism dominant states which are all
3D Simulations of Relativistic Precessing Jets Probing the Structure of Superluminal Sources
Aloy, M A; Gómez, J L; Agudo, I; Müller, E; Ibanyez, J M; Aloy, Miguel Angel; Marti, Jose Maria; Gomez, Jose Luis; Agudo, Ivan; Mueller, Ewald; Ibanyez, Jose Maria
2003-01-01
We present the results of a three-dimensional, relativistic, hydrodynamic simulation of a precessing jet into which a compact blob of matter is injected. A comparison of synthetic radio maps computed from the hydrodynamic model, taking into account the appropriate light travel time delays, with those obtained from observations of actual superluminal sources shows that the variability of the jet emission is the result of a complex combination of phase motions, viewing angle selection effects, and non-linear interactions between perturbations and the underlying jet and/or the external medium. These results question the hydrodynamic properties inferred from observed apparent motions and radio structures, and reveal that shock-in-jet models may be overly simplistic.
van Doesburgh, Marieke
2016-01-01
We analyze all available RXTE data on a sample of 13 low mass X-ray binaries with known neutron star spin that are not persistent pulsars. We carefully measure the correlations between the centroid frequencies of the quasi-periodic oscillations (QPOs). We compare these correlations to the prediction of the relativistic precession model (RPM) that, due to frame dragging, a QPO will occur at the Lense-Thirring precession frequency $\
Sekhar, Aswin; Valsecchi, Giovanni B.; Asher, David; Werner, Stephanie; Vaubaillon, Jeremie; Li, Gongjie
2017-06-01
One of the greatest successes of Einstein's General Theory of Relativity (GR) was the correct prediction of the perihelion precession of Mercury. The closed form expression to compute this precession tells us that substantial GR precession would occur only if the bodies have a combination of both moderately small perihelion distance and semi-major axis. Minimum Orbit Intersection Distance (MOID) is a quantity which helps us to understand the closest proximity of two orbits in space. Hence evaluating MOID is crucial to understand close encounters and collision scenarios better. In this work, we look at the possible scenarios where a small GR precession in argument of pericentre can create substantial changes in MOID for small bodies ranging from meteoroids to comets and asteroids.Previous works have looked into neat analytical techniques to understand different collision scenarios and we use those standard expressions to compute MOID analytically. We find the nature of this mathematical function is such that a relatively small GR precession can lead to drastic changes in MOID values depending on the initial value of argument of pericentre. Numerical integrations were done with the MERCURY package incorporating GR code to test the same effects. A numerical approach showed the same interesting relationship (as shown by analytical theory) between values of argument of pericentre and the peaks or dips in MOID values. There is an overall agreement between both analytical and numerical methods.We find that GR precession could play an important role in the calculations pertaining to MOID and close encounter scenarios in the case of certain small solar system bodies (depending on their initial orbital elements) when long term impact risk possibilities are considered. Previous works have looked into impact probabilities and collision scenarios on planets from different small body populations. This work aims to find certain sub-sets of small bodies where GR could play an
Fokas, Athanassios S; Grigoriou, D
2015-01-01
Let $r(\\varphi)$ denote the orbit of Mercury and other planets. We compare the formula of General Relativity (GR) for $r(\\varphi)$, as well as the formula for the corresponding perihelion precession angle $\\Delta \\varphi$, with the formulae obtained via the relativistic gravitational law, $F=GMm\\gamma^3/r^2$. The latter law can be derived from Newton's gravitational law by employing the gravitational rather than the rest mass of the rotating body and using special relativity (SR) together with the equivalence principle to compute the inertial and hence the gravitational, mass. Remarkably, it is found that the two expressions for $r(\\varphi)$ differ only by a factor of 2 and by an additive constant. This constant does not affect the formula for the $\\Delta \\varphi$, thus the two expressions for $\\Delta\\varphi$ differ only by a factor of 2.
van Doesburgh, Marieke; van der Klis, Michiel
2017-03-01
We analyse all available RXTE data on a sample of 13 low-mass X-ray binaries with known neutron star spin that are not persistent pulsars. We carefully measure the correlations between the centroid frequencies of the quasi-periodic oscillations (QPOs). We compare these correlations to the prediction of the relativistic precession model that, due to frame dragging, a QPO will occur at the Lense-Thirring precession frequency νLT of a test-particle orbit whose orbital frequency is the upper kHz QPO frequency νu. Contrary to the most prominent previous studies, we find two different oscillations in the range predicted for νLT that are simultaneously present over a wide range of νu. Additionally, one of the low-frequency noise components evolves into a (third) QPO in the νLT range when νu exceeds 600 Hz. The frequencies of these QPOs all correlate to νu following power laws with indices between 0.4 and 3.3, significantly exceeding the predicted value of 2.0 in 80 per cent of the cases (at 3 to >20σ). Also, there is no evidence that the neutron star spin frequency affects any of these three QPO frequencies, as would be expected for frame dragging. Finally, the observed QPO frequencies tend to be higher than the νLT predicted for reasonable neutron star specific moment of inertia. In the light of recent successes of precession models in black holes, we briefly discuss ways in which such precession can occur in neutron stars at frequencies different from test-particle values and consistent with those observed. A precessing torus geometry and other torques than frame dragging may allow precession to produce the observed frequency correlations, but can only explain one of the three QPOs in the νLT range.
Freeman Dyson and Gravitational Spin Precession
Dass, N D Hari
2013-01-01
In 1974 Hulse and Taylor discovered the binary pulsar. At that time Prof. Dyson was visiting the Max Planck Institute for Physics at Munich, where I was also working. He initiated a number of discussions on this object. During them it occurred to me that this system could be used to test Geodetic Precession in Einsteins theory, which, even after years of work by the Stanford gyroscope expt, had remained a challenge. I showed some preliminary calculations to Prof Dyson and he encouraged me to do a more refined job. To be applicable to the binary pulsar, one needed to generalise the general relativistic calculations to beyond the so called test particle assumption. Barker and OConnell had obtained such a result from analysing the gravitational interactions of spin half Dirac fermions in linearized spin 2 theories of gravitation. With C.F. Cho I produced a purely classical calculation, using Schwingers Source theory. Boerner, Ehlers and Rudolf confirmed this result with their general relativistic calculations sh...
Relativistic gravity gradiometry
Bini, Donato; Mashhoon, Bahram
2016-12-01
In general relativity, relativistic gravity gradiometry involves the measurement of the relativistic tidal matrix, which is theoretically obtained from the projection of the Riemann curvature tensor onto the orthonormal tetrad frame of an observer. The observer's 4-velocity vector defines its local temporal axis and its local spatial frame is defined by a set of three orthonormal nonrotating gyro directions. The general tidal matrix for the timelike geodesics of Kerr spacetime has been calculated by Marck [Proc. R. Soc. A 385, 431 (1983)]. We are interested in the measured components of the curvature tensor along the inclined "circular" geodesic orbit of a test mass about a slowly rotating astronomical object of mass M and angular momentum J . Therefore, we specialize Marck's results to such a "circular" orbit that is tilted with respect to the equatorial plane of the Kerr source. To linear order in J , we recover the gravitomagnetic beating phenomenon [B. Mashhoon and D. S. Theiss, Phys. Rev. Lett. 49, 1542 (1982)], where the beat frequency is the frequency of geodetic precession. The beat effect shows up as a special long-period gravitomagnetic part of the relativistic tidal matrix; moreover, the effect's short-term manifestations are contained in certain post-Newtonian secular terms. The physical interpretation of this effect is briefly discussed.
Geodetic Control Points - National Geodetic Survey Benchmarks
NSGIC GIS Inventory (aka Ramona) — This data contains a set of geodetic control stations maintained by the National Geodetic Survey. Each geodetic control station in this dataset has either a precise...
Thomas Precession by Uniform Acceleration
Pardy, Miroslav
2015-01-01
We determine the nonlinear transformations between coordinate systems which are mutually in a constant symmetrical accelerated motion. The maximal acceleration limit follows from the kinematical origin and it is an analogue of the maximal velocity in special relativity. We derive the dependence of mass, length, time, Doppler effect, Cherenkov effect and transition radiation angle on acceleration as an analogue phenomena in special theory of relativity. The last application of our method is the Thomas precession by uniform acceleration with the possible role in the modern physics and cosmology. The comparison of derived results with other relativistic methods is necessary.
Using geodetic VLBI to test Standard-Model Extension
Hees, Aurélien; Lambert, Sébastien; Le Poncin-Lafitte, Christophe
2016-04-01
The modeling of the relativistic delay in geodetic techniques is primordial to get accurate geodetic products. And geodetic techniques can also be used to measure the relativistic delay and get constraints on parameters describing the relativity theory. The effective field theory framework called the Standard-Model Extension (SME) has been developed in order to systematically parametrize hypothetical violations of Lorentz symmetry (in the Standard Model and in the gravitational sector). In terms of light deflexion by a massive body like the Sun, one can expect a dependence in the elongation angle different from GR. In this communication, we use geodetic VLBI observations of quasars made in the frame of the permanent geodetic VLBI monitoring program to constrain the first SME coefficient. Our results do not show any deviation from GR and they improve current constraints on both GR and SME parameters.
Yoshiki Yoshida
2001-01-01
destabilizing in the region of negative precessing speed ratio (-0.3<Ω/ω<0, at the design flow rate; (2 At reduced flow rate, the destabilizing fluid force moments occurred at small positive precessing speed ratio (0.2<Ω/ω<0.4; (3 From the comparison of direct measured fluid force moments with those estimated from the unsteady pressure measured on the front and back casing walls, it was found that the destabilizing moments in the backward precession are mainly caused by the fluid forces on the front surface of the present impeller, where there is large clearance between the back shroud and casing.
Vermont Center for Geographic Information — The GeodeticBenchmark_GEOMON data layer consists of geodetic control monuments (points) that have a known position or spatial reference. The locations of these...
Precessing Ferromagnetic Needle Magnetometer.
Jackson Kimball, Derek F; Sushkov, Alexander O; Budker, Dmitry
2016-05-13
A ferromagnetic needle is predicted to precess about the magnetic field axis at a Larmor frequency Ω under conditions where its intrinsic spin dominates over its rotational angular momentum, Nℏ≫IΩ (I is the moment of inertia of the needle about the precession axis and N is the number of polarized spins in the needle). In this regime the needle behaves as a gyroscope with spin Nℏ maintained along the easy axis of the needle by the crystalline and shape anisotropy. A precessing ferromagnetic needle is a correlated system of N spins which can be used to measure magnetic fields for long times. In principle, by taking advantage of rapid averaging of quantum uncertainty, the sensitivity of a precessing needle magnetometer can far surpass that of magnetometers based on spin precession of atoms in the gas phase. Under conditions where noise from coupling to the environment is subdominant, the scaling with measurement time t of the quantum- and detection-limited magnetometric sensitivity is t^{-3/2}. The phenomenon of ferromagnetic needle precession may be of particular interest for precision measurements testing fundamental physics.
Gravitational Waves of Jet Precession in Gamma-ray Bursts
Sun, Mou-Yuan; Gu, Wei-Min; Lu, Ju-Fu
2012-01-01
The physical nature of gamma-ray bursts (GRBs) are believed to involve an ultra-relativistic jet. The observed complex structure of light curves motivate the idea of jet precession. In this work, we study the gravitational waves of jet precession based on neutrino-dominated accretion disks around black holes, which may account for the central engine of GRBs. In our model, the jet and the inner part of the disk may precess along with the black hole, which is driven by the outer part of the disk. Gravitational waves are therefore expected to be significant from this black hole-inner disk precession system. By comparing our numerical results with the sensitivity of some detectors, we find that it is possible for DECIGO and BBO to detect such gravitational waves, particularly for GRBs in the Local Group.
Gyroscope precession in special and general relativity from basic principles
Jonsson, Rickard M.
2007-05-01
In special relativity a gyroscope that is suspended in a torque-free manner will precess as it is moved along a curved path relative to an inertial frame S. We explain this effect, which is known as Thomas precession, by considering a real grid that moves along with the gyroscope, and that by definition is not rotating as observed from its own momentary inertial rest frame. From the basic properties of the Lorentz transformation we deduce how the form and rotation of the grid (and hence the gyroscope) will evolve relative to S. As an intermediate step we consider how the grid would appear if it were not length contracted along the direction of motion. We show that the uncontracted grid obeys a simple law of rotation. This law simplifies the analysis of spin precession compared to more traditional approaches based on Fermi transport. We also consider gyroscope precession relative to an accelerated reference frame and show that there are extra precession effects that can be explained in a way analogous to the Thomas precession. Although fully relativistically correct, the entire analysis is carried out using three-vectors. By using the equivalence principle the formalism can also be applied to static spacetimes in general relativity. As an example, we calculate the precession of a gyroscope orbiting a static black hole.
Misaligned spin and orbital axes cause the anomalous precession of DI Herculis
Albrecht, Simon; Snellen, Ignas A G; Winn, Joshua N
2009-01-01
The orbits of binary stars precess as a result of general relativistic effects, forces arising from the asphericity of the stars, and forces from additional stars or planets in the system. For most binaries, the theoretical and observed precession rates are in agreement. One system, however -- DI Herculis -- has resisted explanation for 30 years. The observed precession rate is a factor of four slower than the theoretical rate, a disagreement that once was interpreted as evidence for a failure of general relativity. Among the contemporary explanations are the existence of a circumbinary planet and a large tilt of the stellar spin axes with respect to the orbit. Here we report that both stars of DI Herculis rotate with their spin axes nearly perpendicular to the orbital axis (contrary to the usual assumption for close binary stars). The rotationally induced stellar oblateness causes precession in the direction opposite to that of relativistic precession, thereby reconciling the theoretical and observed rates.
Rotation of the swing plane of Foucault's pendulum and Thomas spin precession: Two faces of one coin
Krivoruchenko, M I
2008-01-01
Using elementary geometric tools, we derive essentially in the same way expressions for rotation angle of the swing plane of Foucault's pendulum and rotation angle of spin of relativistic particle moving along circular orbit (Thomas precession effect).
Anomalous precession of planets on a Weyl conformastatic solution
Capistrano, Abraão J S; Alárcon, Manuel S
2016-01-01
In this paper, we investigate the anomalous planets precession in the so-called nearly-newtonian gravitational regime. This limit is obtained from the application of the slow motion condition to the geodesic equations without altering the geodesic deviation equations, which leads to an intermediate gravitational field stronger than the newtonian one. Using a non-standard expression for the perihelion advance from the Weyl conformastatic vacuum solution as a model, we can describe the anomaly in planets precession compared with different observational data from Ephemerides of the Planets and the Moon (EPM2008 and EPM2011) and Planetary and Lunar Ephemeris (INPOP10a). As a result, using the Levenberg-Marquardt algorithm and calculating the related Chi-squared statistic, we find that the anomaly is statistical irrelevant in accordance with INPOP10a observations. As a complement to this work, we also do application to the relativistic precession of giant planets using observational data calibrated with the EPM201...
Anomalous precession of planets for a Weyl conformastatic solution
Capistrano, Abraão J. S.; Peñagos, Joice A. M.; Alárcon, Manuel S.
2016-12-01
In this article, we investigate the anomalous precession of planets in the nearly Newtonian gravitational regime. This limit is obtained by application of the slow motion condition to the geodesic equations without altering the geodesic deviation equations. Using a non-standard expression for the perihelion advance from the Weyl conformastatic vacuum solution as a model, we can describe the anomaly in planetary precession compared with different observational data, consisting of ephemerides of planets and the Moon (EPM2008 and EPM2011) and Fienga et al.'s planetary and lunar ephemeris (INPOP10a). As a result, using the Levenberg-Marquardt algorithm and calculating the related χ-squared statistic, we find that the anomaly is statistically irrelevant, in accordance with the INPOP10a observations. As a complement to this work, we also perform an application to the relativistic precession of giant planets using observational data calibrated with EPM2011.
Apsidal precession, disc breaking and viscosity in warped discs
Nealon, Rebecca; Price, Daniel J; King, Andrew
2015-01-01
We demonstrate the importance of general relativistic apsidal precession in warped black hole accretion discs by comparing three - dimensional smoothed particle hydrodynamic simulations in which this effect is first neglected, and then included. If apsidal precession is neglected, we confirm the results of an earlier magnetohydrodynamic simulation which made this assumption, showing that at least in this case the $\\alpha$ viscosity model produces very similar results to those of simulations where angular momentum transport is due to the magnetorotational instability. Including apsidal precession significantly changes the predicted disc evolution. For moderately inclined discs thick enough that tilt is transported by bending waves, we find a disc tilt which is nonzero at the inner disc edge and oscillates with radius, consistent with published analytic results. For larger inclinations we find disc breaking.
Relativistic GLONASS and geodesy
Mazurova, E. M.; Kopeikin, S. M.; Karpik, A. P.
2016-12-01
GNSS technology is playing a major role in applications to civil, industrial and scientific areas. Nowadays, there are two fully functional GNSS: American GPS and Russian GLONASS. Their data processing algorithms have been historically based on the Newtonian theory of space and time with only a few relativistic effects taken into account as small corrections preventing the system from degradation on a fairly long time. Continuously growing accuracy of geodetic measurements and atomic clocks suggests reconsidering the overall approach to the GNSS theoretical model based on the Einstein theory of general relativity. This is essentially more challenging but fundamentally consistent theoretical approach to relativistic space geodesy. In this paper, we overview the basic principles of the relativistic GNSS model and explain the advantages of such a system for GLONASS and other positioning systems. Keywords: relativistic GLONASS, Einstein theory of general relativity.
Jet-Intracluster Medium interaction in Hydra A. II The Effect of Jet Precession
Nawaz, M A; Wagner, A Y; Sutherland, R S; McNamara, B R
2016-01-01
We present three dimensional relativistic hydrodynamical simulations of a precessing jet interacting with the intracluster medium and compare the simulated jet structure with the observed structure of the Hydra A northern jet. For the simulations, we use jet parameters obtained in the parameter space study of the first paper in this series and probe different values for the precession period and precession angle. We find that for a precession period P = 1 Myr and a precession angle = 20 degree the model reproduces i) the curvature of the jet, ii) the correct number of bright knots within 20 kpc at approximately correct locations, and iii) the turbulent transition of the jet to a plume. The Mach number of the advancing bow shock = 1.85 is indicative of gentle cluster atmosphere heating during the early stages of the AGN's activity.
Nonextensive statistics in spin precession
Bales, Matthew J; Golub, Robert
2016-01-01
Many experiments utilize the precession of trapped particles in magnetic fields to perform high precision measurements. It had been presumed that after free precession, initially polarized particles will form a Gaussian phase distribution in the plane of precession. We show that trapped particles in the presence of magnetic field gradients and electric fields will often form a non-Gaussian distribution with power-law tails which are consistent with nonextensive statistics. As the exact shape of the distribution depends upon many experimental parameters, it provides a potential new technique to directly measure them.
Spin precession in anisotropic cosmologies
Kamenshchik, A.Yu. [Universita di Bologna, Dipartimento di Fisica e Astronomia, Bologna (Italy); L. D. Landau Institute for Theoretical Physics, Moscow (Russian Federation); INFN, Bologna (Italy); Teryaev, O.V. [Joint Institute for Nuclear Research, Bogoliubov Laboratory of Theoretical Physics, Dubna (Russian Federation); Lomonosov Moscow State University, Moscow (Russian Federation)
2016-05-15
We consider the precession of a Dirac particle spin in some anisotropic Bianchi universes. This effect is present already in the Bianchi-I universe. We discuss in some detail the geodesics and the spin precession for both the Kasner and the Heckmann-Schucking solutions. In the Bianchi-IX universe the spin precession acquires the chaotic character due to the stochasticity of the oscillatory approach to the cosmological singularity. The related helicity flip of fermions in the very early universe may produce the sterile particles contributing to dark matter. (orig.)
Geodetic Survey Water Level Observations
National Oceanic and Atmospheric Administration, Department of Commerce — Over one million images of National Coast & Geodetic Survey (now NOAA's National Geodetic Survey/NGS) forms captured from microfiche. Tabular forms and charts...
Detection of precessing circumpulsar disks
Grimani, C
2014-01-01
Experimental evidences indicate that formations of disks and planetary systems around pulsars are allowed. Unfortunately, direct detections through electromagnetic observations appear to be quite rare. In the case of PSR 1931+24, the hypothesis of a rigid precessing disk penetrating the pulsar light cylinder is found consistent with radio transient observations from this star. Disk self-occultation and precession may limit electromagnetic observations. Conversely, we show here that gravitational waves generated by disk precessing near the light cylinder of young and middle aged pulsars would be detected by future space interferometers with sensitivities like those expected for DECIGO (DECI-hertz Interferometer Gravitational Wave Observatory) and BBO (Big Bang Observer). The characteristics of circumpulsar detectable precessing disks are estimated as a function of distance from the Solar System. Speculations on upper limits to detection rates are presented.
Enhancing electron diffraction through precession
Pavia, Giuseppe; Benner, Gerd; Niebel, Harald [Carl Zeiss NTS, Oberkochen (Germany); Patout, Loic [ONERA, Paris (France)
2011-07-01
Nanostructures are often investigated in Transmission Electron Microscopy (TEM), and electron diffraction (ED) can be used to solve nanocrystals. Electrons interact very strongly with matter, and the diffracted intensities are highly dynamical. Precession Electron Diffraction (PED) is a recent technique delivering more kinematical diffraction patterns. We have used an in column energy filtered TEM equipped with precession electron diffraction hardware, which allows working up to 3 precession angle, and energy filtering of the precession patterns. High Order Laue Zones, useful for space group symmetry determination and to enhance fine structure details, appear more clearly. We have compared a microdiffraction pattern and a precession microdiffraction pattern performed along the orientation [010] of a sample TiSi{sub 2} with a space group Fddd. For cubic systems, this orientation allows to distinguish the Bravais lattice and the presence of glide mirrors. We show that with precession, we conserve the distinction of the gap and the difference of periodicity between the ZOLZ and the FOLZ is improved.
Importance of tides for periastron precession in eccentric neutron star-white dwarf binaries
Sravan, N.; Valsecchi, F.; Kalogera, V. [Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA), and Department of Physics and Astronomy, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208 (United States); Althaus, L. G., E-mail: niharika.sravan@gmail.com [Grupo de Evolución Estelar y Pulsaciones, Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata, Argentina Instituto de Astrofísica La Plata, CONICET-UNLP, Paseo del Bosque s/n, (1900) La Plata (Argentina)
2014-09-10
Although not nearly as numerous as binaries with two white dwarfs, eccentric neutron star-white dwarf (NS-WD) binaries are important gravitational-wave (GW) sources for the next generation of space-based detectors sensitive to low frequency waves. Here we investigate periastron precession in these sources as a result of general relativistic, tidal, and rotational effects; such precession is expected to be detectable for at least some of the detected binaries of this type. Currently, two eccentric NS-WD binaries are known in the galactic field, PSR J1141–6545 and PSR B2303+46, both of which have orbits too wide to be relevant in their current state to GW observations. However, population synthesis studies predict the existence of a significant Galactic population of such systems. Though small in most of these systems, we find that tidally induced periastron precession becomes important when tides contribute to more than 3% of the total precession rate. For these systems, accounting for tides when analyzing periastron precession rate measurements can improve estimates of the inferred WD component mass and, in some cases, will prevent us from misclassifying the object. However, such systems are rare, due to rapid orbital decay. To aid the inclusion of tidal effects when using periastron precession as a mass measurement tool, we derive a function that relates the WD radius and periastron precession constant to the WD mass.
Calibration of Geodetic Instruments
Marek Bajtala
2005-06-01
Full Text Available The problem of metrology and security systems of unification, correctness and standard reproducibilities belong to the preferred requirements of theory and technical practice in geodesy. Requirements on the control and verification of measured instruments and equipments increase and the importance and up-to-date of calibration get into the foreground. Calibration possibilities of length-scales (of electronic rangefinders and angle-scales (of horizontal circles of geodetic instruments. Calibration of electronic rangefinders on the linear comparative baseline in terrain. Primary standard of planar angle – optical traverse and its exploitation for calibration of the horizontal circles of theodolites. The calibration equipment of the Institute of Slovak Metrology in Bratislava. The Calibration process and results from the calibration of horizontal circles of selected geodetic instruments.
Geodesy introduction to geodetic datum and geodetic systems
Lu, Zhiping; Qiao, Shubo
2014-01-01
A full introduction to geodetic data and systems written by well-known experts in their respective fields, this book is an ideal text for courses in geodesy and geomatics covering everything from coordinate and gravimetry data to geodetic systems of all types.
Johnson, Aylmer
2004-01-01
Plane and Geodetic Surveying blends theory and practice, conventional techniques and GPS, to provide the ideal book for students of surveying.Detailed guidance is given on how and when the principle surveying instruments (theodolites, Total Stations, levels and GPS) should be used. Concepts and formulae needed to convert instrument readings into useful results are explained. Rigorous explanations of the theoretical aspects of surveying are given, while at the same time a wealth of useful advice about conducting a survey in practice is provided. An accompanying least squares adjustment program
WARPING AND PRECESSION IN EXTRAGALACTIC MASER ACCRETION DISCS
A. Caproni
2009-01-01
Full Text Available Interferometric maser observations have been used to probe the physical conditions of extragalactic accretion discs at sub-parsec scales. The inferred kinematic of the water maser spots presents small deviations from Keplerian motions, which have been attributed to the warping and twisting of the parsec-scale disc. However, their physical origin is still a matter of debate in the literature. Motivated by this, we analyzed the general relativistic Bardeen-Petterson e ect, driven by a Kerr black hole, as the potential physical mechanism responsible for the disc warping and precession in the nearby Seyfert 2 galaxies NGC 1068 and NGC 4258. Assuming a power-law accretion disc, whose parameters were constrained by the observational data, we derived the basic quantities concerning the Bardeen-Petterson e ect for both sources. Some consequences from this peculiar relativistic mechanism are also presented in this work.
Toroidal Precession as a Geometric Phase
J.W. Burby and H. Qin
2012-09-26
Toroidal precession is commonly understood as the orbit-averaged toroidal drift of guiding centers in axisymmetric and quasisymmetric configurations. We give a new, more natural description of precession as a geometric phase effect. In particular, we show that the precession angle arises as the holonomy of a guiding center's poloidal trajectory relative to a principal connection. The fact that this description is physically appropriate is borne out with new, manifestly coordinate-independent expressions for the precession angle that apply to all types of orbits in tokamaks and quasisymmetric stellarators alike. We then describe how these expressions may be fruitfully employed in numerical calculations of precession.
Constraining White Dwarf Masses Via Apsidal Precession in Eccentric Double White Dwarf Binaries
Valsecchi, Francesca; Willems, Bart; Deloye, Christopher J; Kalogera, Vicky
2011-01-01
Galactic short period double white dwarfs (DWD) are guaranteed gravitational wave (GW) sources for the next generation of space-based interferometers sensitive to low-frequency GWs (10^{-4}- 1 Hz). Here we investigate the possibility of constraining the white dwarf (WD) properties through measurements of apsidal precession in eccentric binaries. We analyze the general relativistic (GR), tidal, and rotational contributions to apsidal precession by using detailed He WD models. We find that apsidal precession can lead to a detectable shift in the emitted GW signal, the effect being stronger (weaker) for binaries hosting hot (cool) WDs. We find that in hot (cool) DWDs tides dominate the precession at orbital frequencies above ~0.01 mHz (~1 mHz). Analyzing the apsidal precession of these sources only accounting for GR would potentially lead to an extreme overestimate of the component masses. Finally, we derive a relation that ties the radius and apsidal precession constant of cool WD components to their masses, th...
Parsec-scale jet precession in BL Lacertae (2200+420)
Caproni, A.; Abraham, Z.; Monteiro, H.
2013-01-01
BL Lacertae is the prototype of the BL Lac class of active galactic nuclei, exhibiting intensive activity on parsec (pc) scales, such as intense core variability and multiple ejections of jet components. In particular, in previous works the existence of precession motions in the pc-scale jet of BL Lacertae has been suggested. In this work we revisit this issue, investigating temporal changes of the observed right ascension and declination offsets of the jet knots in terms of our relativistic jet-precession model. The seven free parameters of our precession model were optimized via a heuristic cross-entropy method, comparing the projected precession helix with the positions of the jet components on the plane of the sky and imposing constraints on their maximum and minimum superluminal velocities. Our optimized best model is compatible with a jet having a bulk velocity of 0.9824c, which is precessing with a period of about 12.1 yr in the observer's reference frame and changing its orientation in relation to the line of sight between 4° and 5°, approximately. Assuming that the jet precession has its origin in a supermassive binary black hole system, we show that the 2.3-yr periodic variation in the structural position angle of the very-long-baseline interferometry (VLBI) core of BL Lacertae reported by Stirling et al. is compatible with a nutation phenomenon if the secondary black hole has a mass higher than about six times that of the primary black hole.
Solving GRBs and SGRs puzzles by precessing Jets
Fargion, D; Oliva, P
2006-01-01
A persistent, thin, micro-nano sr. beamed gamma jet, may be ejected from BH and Pulsars, powered by ultra-relativistic electron pairs. These jet while precessing and spinning are originated by Inverse Compton and-or Synchrotron Radiation at pulsars or micro-quasars sources. They are most powerful at Supernova birth, blazing, once on axis, to us and flashing GRB detector. The trembling of thin jets explains naturally the observed erratic multi-explosive structure of different GRBs. The jets are precessing and decaying on time scales of a few hours surviving as long as thousands of years, linking huge GRB-SN jet apparent Luminosity to more modest SGR relic Jets. Therefore long-life SGR may be repeating and if they are around our galaxy they might be observed again as the few known ones and a few rarer extragalactic XRFs. The orientation of the beam respect to the line of sight plays a key role in differentiating the wide GRB morphology. The relativistic cone is as small as the inverse of the electron progenitor...
The future of Russian section of the Global Geodetic Observing System
Ipatov, Alexander; Ivanov, Dmitry; Gayazov, Iskandar; Bondarenko, Yuri
2015-04-01
The creation of Geodetic Data-processing Center for collection and transmission geodetic data from all stations of Russian geodetic network is considered. New data-processing center will be created on the technical basis of the Institute of Applied Astronomy of Russian Academy of Sciences. In future each interaction with the international services and stations of the Global Geodetic Observing System network is planned to carry out through this data-processing center. The radio interferometer of new generation, created in the Institute of Applied Astronomy at the stations of "Quasar" VLBI network will be the basis of the Russian section of the Global Geodetic Observing System. Currently this new radio interferometer consists of two antennas with a mirror diameters of 13.2 m installed at the "Badary" and "Zelenchukskaya" collocation sites. All installation works of the antenna systems as well as observations of calibration radio sources were carried out at the end of 2014. Processing and analysis of newly obtained data showed that the radio interferometer of new generation allows to operate as a part of the Global Geodetic Observing System network and having an accuracy of 3 mm for pole coordinates, 100 microsecond of arc for the nutation and precession angles and no more than 10 μs for the Universal Time determination, that meets all requirements of the VGOS program.
Chinese geodetic coordinate system 2000
YANG YuanXi
2009-01-01
The basic strategies In establishing the Chinese geodetic coordinate system 2000 have been summarized,including the definition of the coordinate system,the structure of the terrestrial reference frame,the functional and stochastic models involved in the realization of the reference frame as well as the Improvements of the adjustment procedures.First,the fundamental frame of the coordinate system is composed of the permanent GPS tracking network in China which is integrated into the international GPS service stations by combined adjustment,in order to guarantee the consistence between the international terrestrial reference system and the Chinese geodetic coordinate system.Second,the extended frame of the coordinate system is composed of the unified 2000' national GPS network which is Integrated by 6 nationwide GPS networks with more than 2500 stations under the controlling of the fundamental frame.Third,the densified frame is composed of national astronomical geodetic network with nearly 50 thousand stations which was updated by the combined adjustment with the 2000' national GPS network,thus the datum of the national astronomical geodetic network has been unified and the precision greatly improved.By the optimal data fusion method the influences of the datum errors,systematic errors and the outliers in the separated geodetic networks are weakened in the unified Chinese geodetic coordinate frame.The significance in application of the new geodetic coordinate system and the existing problems In the reference frame are described and analyzed.
Polarization modulation from Lense-Thirring precession in X-ray binaries
Ingram, Adam; Poutanen, Juri; Krawczynski, Henric
2015-01-01
It has long been recognised that quasi-periodic oscillations (QPOs) in the X-ray light curves of accreting black hole and neutron star binaries have the potential to be powerful diagnostics of strong field gravity. However, this potential cannot be fulfilled without a working theoretical model, which has remained elusive. Perhaps the most promising model associates the QPO with Lense-Thirring precession of the inner accretion flow, with the changes in viewing angle and Doppler boosting modulating the flux over the course of a precession cycle. Here, we consider the polarization signature of a precessing inner accretion flow. We use simple assumptions about the Comptonization process generating the emitted spectrum and take all relativistic effects into account, parallel transporting polarization vectors towards the observer along null geodesics in the Kerr metric. We find that both the degree of linear polarization and the polarization angle should be modulated on the QPO frequency. We calculate the predicted...
Tidally-Induced Apsidal Precession in Double White Dwarfs: a new mass measurement tool with LISA
Valsecchi, Francesca; Willems, Bart; Deloye, Christopher J; Kalogera, Vassiliki
2011-01-01
Galactic interacting double white dwarfs (DWD) are guaranteed gravitational wave (GW) sources for the GW detector LISA, with more than 10^4 binaries expected to be detected over the mission's lifetime. While the majority of DWDs are expected to be circular, dynamical interactions in globular clusters can lead to a sub-population of eccentric DWDs detectable by LISA. Here we investigate the potential for constraining the white dwarf (WD) properties through apsidal precession in these binaries. We analyze the tidal, rotational, and general relativistic contributions to apsidal precession by using detailed He WD models, where the evolution of the star's interior is followed throughout the cooling phase. In agreement with previous studies of zero-temperature WDs, we find that apsidal precession in eccentric DWDs can lead to a detectable shift in the emitted GW signal when binaries with cool (old) components are considered. This shift increases significantly for hot (young) WDs. We find that apsidal motion in hot ...
Iorio, Lorenzo
2014-01-01
Analytical expressions for the orbital precessions affecting the relative motion of the components of a local binary system induced by Lorentz-violating Preferred Frame Effects (PFE) are explicitly computed in terms of the PPN parameters {\\alpha}1, {\\alpha}2. A linear combination of the supplementary perihelion precessions of all the inner planets of the Solar System, able to remove the a-priori bias of unmodelled/mismodelled standard effects such as the general relativistic Lense-Thirring precessions and the classical rates due to the Sun's oblateness J2, allows to infer {\\alpha}1 <= 10^-6, {\\alpha}2 <= 10^-5. Such bounds should be improved in the near future after processing the data that are being collected by the MESSENGER spacecraft, currently orbiting Mercury. Further improvements may come in the mid-future from the approved BepiColombo mission to Mercury (Abridged).
Rotation of the swing plane of Foucault's pendulum and Thomas spin precession: two sides of one coin
Krivoruchenko, Mikhail I [Alikhanov Institute for Theoretical and Experimental Physics, Russian Federation State Scientific Center, Moscow (Russian Federation)
2009-08-31
Using elementary geometric tools, we apply essentially the same methods to derive expressions for the rotation angle of the swing plane of Foucault's pendulum and the rotation angle of the spin of a relativistic particle moving in a circular orbit (the Thomas precession effect). (methodological notes)
The Fresnel-Fizeau effect and the atmospheric time delay in geodetic VLBI
M., Kopeikin S
2015-01-01
The Fresnel-Fizeau effect is a special relativistic effect that makes the speed of light dependent on the velocity of a transparent, moving medium. We present a theoretical formalism for discussing propagation of electromagnetic signals through the moving Earth atmosphere with taking into account the Fresnel-Fizeau effect. It provides the rigorous relativistic derivation of the atmospheric time delay equation in the consensus model of geodetic VLBI observations which was never published before. The paper confirms the atmospheric time delay of the consensus VLBI model used in IERS Standards, and provides a firm theoretical basis for calculation of even more subtle relativistic corrections.
Earth Data Analysis Center, University of New Mexico — This data contains a set of geodetic control stations maintained by the National Geodetic Survey. Each geodetic control station in this dataset has either a precise...
National Geodetic Control Stations, Geographic NAD83, NGS (2004) [geodetic_ctrl_point_la_NGS_2004
Louisiana Geographic Information Center — This data contains a set of geodetic control stations maintained by the National Geodetic Survey. Each geodetic control station in this dataset has either a precise...
Parsec-scale jet precession in BL Lacertae (2200+420)
Caproni, Anderson; Abraham, Zulema; Monteiro, Hektor
2012-01-01
BL Lacertae is the prototype of the BL Lac class of active galactic nuclei, exhibiting intensive activity on parsec (pc) scales, such as intense core variability and multiple ejections of jet components. In particular, in previous works the existence of precession motions in the pc-scale jet of BL Lacertae has been suggested. In this work we revisit this issue, investigating temporal changes of the observed right ascension and declination offsets of the jet knots in terms of our relativistic ...
Temporal variations of the gravity field and Earth precession-nutation
Bourda, G
2007-01-01
Due to the accuracy now reached by space geodetic techniques, and also considering some modelisations, the temporal variations of some Earth Gravity Field coefficients can be determined. They are due to Earth oceanic and solid tides, as well as geophysical reservoirs masses displacements. They can be related to the variations in the Earth's orientation parameters (through the inertia tensor). Then, we can try to improve our knowledge of the Earth Rotation with those space measurements of the Gravity variations. We have undertaken such a study, using data obtained with the combination of space geodetic techniques. In particular, we use CHAMP data that are more sensitive to such variations and that complete the ones already accumulated (for example with Starlette and LAGEOS I). In this first approach, we focus on the Earth precession nutation, trying to refine it by taking into account the temporal variations of the Earth dynamical flattening. The goal is mainly to understand how Geodesy can influence this fiel...
2015-08-07
relativistic corrections comprise of Schwarzschild terms, Lense- Thirring precession (frame-dragging), and de Sitter ( geodesic ) precession. The Schwarzschild...Lense-Thirring, and de Sitter terms can be seen on lines 1, 2, and 3 respectively in Equation 1.13 ∆ −→̈ r = GME c2r3 {[ 2(β + γ) GME r − γ−→̇r · −→̇r...satellite. Figure 3. RSS Position Differences for Various Lunar Gravity Field Model Solutions It can be seen that all four lines representing each RSS
TIDALLY INDUCED APSIDAL PRECESSION IN DOUBLE WHITE DWARFS: A NEW MASS MEASUREMENT TOOL WITH LISA
Valsecchi, F.; Farr, W. M.; Willems, B.; Deloye, C. J.; Kalogera, V. [Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA), and Department of Physics and Astronomy, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208 (United States)
2012-02-01
Galactic interacting double white dwarfs (DWDs) are guaranteed gravitational wave (GW) sources for the Laser Interferometer Space Antenna GW detector, with more than 10{sup 4} binaries expected to be detected over the mission's lifetime. Part of this population is expected to be eccentric, and here we investigate the potential for constraining the white dwarf (WD) properties through apsidal precession in these binaries. We analyze the tidal, rotational, and general relativistic contributions to apsidal precession by using detailed He WD models, where the evolution of the star's interior is followed throughout the cooling phase. In agreement with previous studies of zero-temperature WDs, we find that apsidal precession in eccentric DWDs can lead to a detectable shift in the emitted GW signal when binaries with cool (old) components are considered. This shift increases significantly for hot (young) WDs. We find that apsidal motion in hot (cool) DWDs is dominated by tides at orbital frequencies above {approx}> 10{sup -4} Hz (10{sup -3} Hz). The analysis of apsidal precession in these sources while ignoring the tidal component would lead to an extreme bias in the mass determination, and could lead us to misidentify WDs as neutron stars or black holes. We use the detailed WD models to show that for older, cold WDs, there is a unique relationship that ties the radius and apsidal precession constant to the WD masses, therefore allowing tides to be used as a tool to constrain the source masses.
Parsec-scale jet precession in BL Lacertae (2200+420)
Caproni, Anderson; Monteiro, Hektor
2012-01-01
BL Lacertae is the prototype of the BL Lac class of active galactic nuclei, exhibiting intensive activity on parsec (pc) scales, such as intense core variability and multiple ejections of jet components. In particular, in previous works the existence of precession motions in the pc-scale jet of BL Lacertae has been suggested. In this work we revisit this issue, investigating temporal changes of the observed right ascension and declination offsets of the jet knots in terms of our relativistic jet-precession model. The seven free parameters of our precession model were optimized via a heuristic cross-entropy method, comparing the projected precession helix with the positions of the jet components on the plane of the sky and imposing constraints on their maximum and minimum superluminal velocities. Our optimized best model is compatible with a jet having a bulk velocity of 0.9824c, which is precessing with a period of about 12.1 yr in the observer's reference frame and changing its orientation in relation to the...
Spin precession in anisotropic media
Raes, B.; Cummings, A. W.; Bonell, F.; Costache, M. V.; Sierra, J. F.; Roche, S.; Valenzuela, S. O.
2017-02-01
We generalize the diffusive model for spin injection and detection in nonlocal spin structures to account for spin precession under an applied magnetic field in an anisotropic medium, for which the spin lifetime is not unique and depends on the spin orientation. We demonstrate that the spin precession (Hanle) line shape is strongly dependent on the degree of anisotropy and on the orientation of the magnetic field. In particular, we show that the anisotropy of the spin lifetime can be extracted from the measured spin signal, after dephasing in an oblique magnetic field, by using an analytical formula with a single fitting parameter. Alternatively, after identifying the fingerprints associated with the anisotropy, we propose a simple scaling of the Hanle line shapes at specific magnetic field orientations that results in a universal curve only in the isotropic case. The deviation from the universal curve can be used as a complementary means of quantifying the anisotropy by direct comparison with the solution of our generalized model. Finally, we applied our model to graphene devices and find that the spin relaxation for graphene on silicon oxide is isotropic within our experimental resolution.
The Binary Companion of Young, Relativistic Pulsar J1906+0746
van Leeuwen, Joeri; Stairs, Ingrid H; Lorimer, D R; Camilo, F; Chatterjee, S; Cognard, I; Desvignes, G; Freire, P C C; Janssen, G H; Kramer, M; Lyne, A G; Nice, D J; Ransom, S M; Stappers, B W; Weisberg, J M
2014-01-01
PSR J1906+0746 is a young pulsar in the relativistic binary with the second-shortest known orbital period, of 3.98 hours. We here present a timing study based on five years of observations, conducted with the 5 largest radio telescopes in the world, aimed at determining the companion nature. Through the measurement of three post-Keplerian orbital parameters we find the pulsar mass to be 1.291(11) M_sol, and the companion mass 1.322(11) M_sol respectively. These masses fit well in the observed collection of double neutron stars, but are also compatible with other white dwarfs around young pulsars such as J1906+0746. Neither radio pulsations nor dispersion-inducing outflows that could have further established the companion nature were detected. We derive an HI-absorption distance, which indicates that an optical confirmation of a white dwarf companion is very challenging. The pulsar is fading fast due to geodetic precession, limiting future timing improvements. We conclude that young pulsar J1906+0746 is likely...
THE BINARY COMPANION OF YOUNG, RELATIVISTIC PULSAR J1906+0746
Van Leeuwen, J.; Janssen, G. H. [ASTRON, The Netherlands Institute for Radio Astronomy, Postbus 2, 7990 AA Dwingeloo (Netherlands); Kasian, L.; Stairs, I. H. [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z1 (Canada); Lorimer, D. R. [Department of Physics, West Virginia University, Morgantown, WV 26506 (United States); Camilo, F. [Arecibo Observatory, HC3 Box 53995, Arecibo, PR 00612 (United States); Chatterjee, S. [Center for Radiophysics and Space Research, Cornell University, Ithaca, NY 14853 (United States); Cognard, I. [Laboratoire de Physique et Chimie de l' Environnement et de l' Espace LPC2E CNRS-Université d' Orléans, F-45071 Orléans (France); Desvignes, G.; Freire, P. C. C.; Kramer, M. [Max-Planck-Institut für Radioastronomie, D-53121 Bonn (Germany); Lyne, A. G.; Stappers, B. W. [Jodrell Bank Centre for Astrophysics, School of Physics and Astronomy, University of Manchester, Manchester M13 9PL (United Kingdom); Nice, D. J. [Department of Physics, Lafayette College, Easton, PA 18042 (United States); Ransom, S. M. [NRAO (National Radio Astronomy Observatory), Charlottesville, VA 22903 (United States); Weisberg, J. M., E-mail: leeuwen@astron.nl [Department of Physics and Astronomy, Carleton College, Northfield, MN 55057 (United States)
2015-01-10
PSR J1906+0746 is a young pulsar in the relativistic binary with the second-shortest known orbital period, of 3.98 hr. We here present a timing study based on five years of observations, conducted with the five largest radio telescopes in the world, aimed at determining the companion nature. Through the measurement of three post-Keplerian orbital parameters, we find the pulsar mass to be 1.291(11) M {sub ☉}, and the companion mass 1.322(11) M {sub ☉}, respectively. These masses fit well in the observed collection of double neutron stars (DNSs), but are also compatible with other systems where a young pulsar such as J1906+0746 is orbited by a white dwarf (WD). Neither radio pulsations nor dispersion-inducing outflows that could have further established the companion nature were detected. We derive an H I-absorption distance, which indicates that an optical confirmation of a WD companion is very challenging. The pulsar is fading fast due to geodetic precession, limiting future timing improvements. We conclude that the young pulsar J1906+0746 is likely part of a DNS, or is otherwise orbited by an older WD, in an exotic system formed through two stages of mass transfer.
Non-Mathematical Explanation of Precession
Cordell, John
2011-01-01
The phenomenon of precession is necessary to explain the motion of footballs, gyroscopes, tops, the Earth, and many other interesting physical systems, but it was very hard for me to understand as a student and is very difficult to teach to students now. Many explanations of precession in physics textbooks are highly mathematical and hard to…
Theoretical frameworks for testing relativistic gravity: A review
Thorne, K. S.; Will, C. M.; Ni, W.
1971-01-01
Metric theories of gravity are presented, including the definition of metric theory, evidence for its existence, and response of matter to gravity with test body trajectories, gravitational red shift, and stressed matter responses. Parametrized post-Newtonian framework and interpretations are reviewed. Gamma, beta and gamma, and varied other parameters were measured. Deflection of electromagnetic waves, radar time delay, geodetic gyroscope precession, perihelion shifts, and periodic effects in orbits are among various studies carried out for metric theory experimentation.
Bistable flows in precessing spheroids
Cébron, D
2015-01-01
Precession driven flows are found in any rotating container filled with liquid, when the rotation axis itself rotates about a secondary axis that is fixed in an inertial frame of reference. Because of its relevance for planetary fluid layers, many works consider spheroidal containers, where the uniform vorticity component of the bulk flow is reliably given by the well-known equations obtained by Busse in 1968. So far however, no analytical result on the solutions is available. Moreover, the cases where multiple flows can coexist have not been investigated in details since their discovery by Noir et al. (2003). In this work, we aim at deriving analytical results on the solutions, aiming in particular at, first estimating the ranges of parameters where multiple solutions exist, and second studying quantitatively their stability. Using the models recently proposed by Noir \\& C{\\'e}bron (2013), which are more generic in the inviscid limit than the equations of Busse, we analytically describe these solutions, ...
Insolation and the Precession Index
Rubincam, David Parry
2000-01-01
Simple nonlinear climate models yield a precession index-like term in the temperature. Despite its importance in the geologic record, the precession index e sin omega, where e is the Earth's orbital eccentricity and omega is the Sun's perigee in the geocentric frame, is not present in the insolation at the top of the atmosphere. Hence there is no one-for-one mapping of 23,000 and 19,000 year periodicities from the insolation to the paleoclimate record; a nonlinear climate model is needed to produce these periods. Two such models, a grey body and an energy balance climate model with an added quadratic term, produce e sin omega terms in temperature. These terms, which without feedback mechanisms achieve extreme values of about plus or minus 0.48 K for the grey body and plus or minus 0.64 K for the energy balance model, simultaneously cool one hemisphere while they warm the other. Moreover, they produce long-term cooling in the northern hemisphere when the Sun's perigee is near northern solstice and long-term warming in the northern hemisphere when the perigee is near southern solstice. Thus this seemingly paradoxical mechanism works against the standard model which requires cool northern summers (Sun far from Earth in northern summer) to build up northern ice sheets, so that if the standard model is correct it may be more efficient than previously thought. Alternatively, the new mechanism could possibly be dominant and indicate southern hemisphere control of the northern ice sheets, wherein the southern oceans undergo a long-term cooling when the Sun is close to the Earth during southern summer. The cold water eventually flows north, cooling the northern hemisphere. This might explain why the northern oceans lag the southern ones when it comes to orbital forcing.
Demianski, Marek
2013-01-01
Relativistic Astrophysics brings together important astronomical discoveries and the significant achievements, as well as the difficulties in the field of relativistic astrophysics. This book is divided into 10 chapters that tackle some aspects of the field, including the gravitational field, stellar equilibrium, black holes, and cosmology. The opening chapters introduce the theories to delineate gravitational field and the elements of relativistic thermodynamics and hydrodynamics. The succeeding chapters deal with the gravitational fields in matter; stellar equilibrium and general relativity
National Geodetic Survey's Airport Aerial Photography
National Oceanic and Atmospheric Administration, Department of Commerce — The National Geodetic Survey (NGS), formerly part of the U.S. Coast and Geodetic Survey, has been performing Aeronautical surveys since the 1920's. NGS, in...
Precession of Mercury’s Perihelion from Ranging to the MESSENGER Spacecraft
Park, Ryan S.; Folkner, William M.; Konopliv, Alexander S.; Williams, James G.; Smith, David E.; Zuber, Maria T.
2017-03-01
The perihelion of Mercury’s orbit precesses due to perturbations from other solar system bodies, solar quadrupole moment (J 2), and relativistic gravitational effects that are proportional to linear combinations of the parametrized post-Newtonian parameters β and γ. The orbits and masses of the solar system bodies are quite well known, and thus the uncertainty in recovering the precession rate of Mercury’s perihelion is dominated by the uncertainties in the parameters J 2, β, and γ. Separating the effects due to these parameters is challenging since the secular precession rate has a linear dependence on each parameter. Here we use an analysis of radiometric range measurements to the MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) spacecraft in orbit about Mercury to estimate the precession of Mercury’s perihelion. We show that the MESSENGER ranging data allow us to measure not only the secular precession rate of Mercury’s perihelion with substantially improved accuracy, but also the periodic perturbation in the argument of perihelion sensitive to β and γ. When combined with the γ estimate from a Shapiro delay experiment from the Cassini mission, we can decouple the effects due to β and J 2 and estimate both parameters, yielding (β -1)=(-2.7+/- 3.9)× {10}-5 and J 2 = (2.25 ± 0.09) × 10‑7. We also estimate the total precession rate of Mercury’s perihelion as 575.3100 ± 0.0015″/century and provide estimated contributions and uncertainties due to various perturbing effects.
About detection of precessing circumpulsar discs
Grimani, Catia
2016-08-01
Detections of circumpulsar discs and planetary systems through electromagnetic observations appear quite rare. In the case of PSR 1931+24 and B0656+14, the hypothesis of a precessing disc penetrating the pulsar light cylinder is found consistent with radio and gamma observations from these stars. Disc self-occultation and precession may affect electromagnetic measurements. We investigate here under which conditions gravitational waves generated by circumpulsar disc precession may be detected by the proposed second-generation space interferometers DECI-hertz Interferometer Gravitational Wave Observatory and Big Bang Observer. The characteristics of circumpulsar detectable precessing discs are estimated as a function of distance from the Solar system. Speculations on detection rates are presented.
Trapped Electron Precession Shear Induced Fluctuation Decorrelation
T.S. Hahm; P.H. Diamond; E.-J. Kim
2002-07-29
We consider the effects of trapped electron precession shear on the microturbulence. In a similar way the strong E x B shear reduces the radial correlation length of ambient fluctuations, the radial variation of the trapped electron precession frequency can reduce the radial correlation length of fluctuations associated with trapped electrons. In reversed shear plasmas, with the explicit dependence of the trapped electron precession shearing rate on B(subscript)theta, the sharp radial gradient of T(subscript)e due to local electron heating inside qmin can make the precession shearing mechanism more effective, and reduce the electron thermal transport constructing a positive feedback loop for the T(subscript)e barrier formation.
Foucault precession manifested in a simple system
Bharadhwaj, Praveen S
2014-01-01
This article aims to answer the question, "What is the simplest system that embodies the essence of Foucault's pendulum?" We study a very elementary idealized system that exhibits a precession behavior analogous to the classic pendulum. The system consists of a particle without inertial mass, constrained to an inclined plane that rotates about a vertical axis. Insights gained from this analysis are used to understand the rate of precession in a straightforward way.
National Oceanic and Atmospheric Administration, Department of Commerce — This data contains a set of geodetic control stations maintained by the National Geodetic Survey. Each geodetic control station in this dataset has either a precise...
Bouncing Dirac particles: compatibility between MIT boundary conditions and Thomas precession
Nicolaevici, Nistor
2016-01-01
We consider the reflection of a Dirac plane wave on a perfectly reflecting plane described by chiral MIT boundary conditions and determine the rotation of the spin in the reflected component of the wave. We solve the analogous problem for a classical particle using the evolution of the spin defined by the Thomas precession and make a comparison with the quantum result. We find that the rotation axes of the spin in the two problems coincide only for a vanishing chiral angle, in which case the rotation angles coincide in the nonrelativistic limit, and also remain remarkably close in the relativistic regime. The result shows that in the nonrelativistic limit the interaction between the spin and a reflecting surface with nonchiral boundary conditions is completely contained in the Thomas precession effect, in conformity with the fact that these boundary conditions are equivalent to an infinite repulsive scalar potential outside the boundary. By contrast, in the ultrarelativistic limit the rotation angle in the qu...
NSGIC GIS Inventory (aka Ramona) — This Geodetic Networks dataset, was produced all or in part from Field Survey/GPS information as of unknown. It is described as 'geodetic control points within the...
Precession of Magnetically Driven Warped Disks and Low-Frequency QPOs in Low-Mass X-Ray Binaries
Shirakawa, A; Shirakawa, Akiko; Lai, Dong
2000-01-01
An accretion disk around a rotating magnetized star is subjected to magnetic torques which induce disk warping and precession. These torques arise generically from interactions between the stellar field and the induced surface currents on the disk. Applying these new effects to weakly magnetized ($B\\sim$ $10^7$-$10^9$ G) neutron stars in low-mass X-ray binaries, we study the global hydrodynamical warping/precession modes of the disk under the combined influences of relativistic frame dragging and the magnetic torques. Under quite general conditions, the magnetic warping torque can overcome the ``Bardeen-Petterson'' viscous damping and makes the modes grow. The modes are confined to the inner region of the disk, and have frequencies close to the sum of the Lense-Thirring frequency and the magnetically driven precession frequency evaluated at the inner disk radius. Since the magnetically driven precession is retrograde (and opposite to the Lense-Thrring precession), the mode frequency can have a non-monotonic d...
Is 1220 Crocus a precessing, binary asteroid?
Binzel, R. P.
1985-01-01
Photoelectric data of the asteroid 1220 Crocus over a 13 night period in 1984 revealed the presence of two separate periods. The light curves were indicative of a precessing body, but not one in free precession due to motions induced by a collision. Closer examinations revealed periods of 30.7 and 7.9 hr with amplitudes of 0.87 and 0.15 mag, respectively. An analysis of the source of an external torque which could be causing a forced precession led to the hypothesis that 1220 Crocus has a satellite. Verification of the binary asteroid configuration will depend on more detailed light curves, the possible modulation of the shorter period by the longer, and possible use of the Space Telescope.
Is 1220 Crocus a precessing, binary asteroid?
Binzel, R. P.
1985-07-01
Photoelectric data of the asteroid 1220 Crocus over a 13 night period in 1984 revealed the presence of two separate periods. The light curves were indicative of a precessing body, but not one in free precession due to motions induced by a collision. Closer examinations revealed periods of 30.7 and 7.9 hr with amplitudes of 0.87 and 0.15 mag, respectively. An analysis of the source of an external torque which could be causing a forced precession led to the hypothesis that 1220 Crocus has a satellite. Verification of the binary asteroid configuration will depend on more detailed light curves, the possible modulation of the shorter period by the longer, and possible use of the Space Telescope.
Zhao, Xinyu; Kesden, Michael; Gerosa, Davide
2017-07-01
In the post-Newtonian (PN) regime, the time scale on which the spins of binary black holes precess is much shorter than the radiation-reaction time scale on which the black holes inspiral to smaller separations. On the precession time scale, the angle between the total and orbital angular momenta oscillates with nutation period τ , during which the orbital angular momentum precesses about the total angular momentum by an angle α . This defines two distinct frequencies that vary on the radiation-reaction time scale: the nutation frequency ω ≡2 π /τ and the precession frequency Ω ≡α /τ . We use analytic solutions for generic spin precession at 2PN order to derive Fourier series for the total and orbital angular momenta in which each term is a sinusoid with frequency Ω -n ω for integer n . As black holes inspiral, they can pass through nutational resonances (Ω =n ω ) at which the total angular momentum tilts. We derive an approximate expression for this tilt angle and show that it is usually less than 10-3 radians for nutational resonances at binary separations r >10 M . The large tilts occurring during transitional precession (near zero total angular momentum) are a consequence of such states being approximate n =0 nutational resonances. Our new Fourier series for the total and orbital angular momenta converge rapidly with n providing an intuitive and computationally efficient approach to understanding generic precession that may facilitate future calculations of gravitational waveforms in the PN regime.
On gravitomagnetic precession around black holes
Merloni, A; Stella, L; Bini, D
1998-01-01
We compute exactly the Lense-Thirring precession frequency for point masses in the Kerr metric, for arbitrary black hole mass and specific angular momentum. We show that this frequency, for point masses at or close to the innermost stable orbit, and for holes with moderate to extreme rotation, is less than, but comparable to the rotation frequency. Thus, if the quasi periodic oscillations (QPOs) observed in the modulation of the X-ray flux from some black holes candidates are due to Lense-Thirring precession of orbiting material, we predict that a separate, distinct QPO ought to be observed in each object.
The jet of the Low Luminosity AGN of M81. Evidence of Precession
Alberdi, A.; Martí-Vidal, I.; Marcaide, J. M.; Guirado, J. C.; Pérez-Torres, M. A.; Ros, E.; Brunthaler, A.
2013-12-01
In this contribution, we summarize our main results of a big campaign of global VLBI observations of the AGN in M81 (M81*) phase-referenced to the radio supernova SN 1993J. Thanks to the precise multi-epoch and multi-frequency astrometry, we have determined the normalized core-shift of the relativistic jet of M81* and estimated both the magnetic field and the particle density at the jet base. We have also found evidence of jet precession in M81* coming from the systematic time evolution of the jet orientation correlated with changes in the overall flux density.
Luciano, Rezzolla
2013-01-01
Relativistic hydrodynamics is a very successful theoretical framework to describe the dynamics of matter from scales as small as those of colliding elementary particles, up to the largest scales in the universe. This book provides an up-to-date, lively, and approachable introduction to the mathematical formalism, numerical techniques, and applications of relativistic hydrodynamics. The topic is typically covered either by very formal or by very phenomenological books, but is instead presented here in a form that will be appreciated both by students and researchers in the field. The topics covered in the book are the results of work carried out over the last 40 years, which can be found in rather technical research articles with dissimilar notations and styles. The book is not just a collection of scattered information, but a well-organized description of relativistic hydrodynamics, from the basic principles of statistical kinetic theory, down to the technical aspects of numerical methods devised for the solut...
Horizontal and Vertical Geodetic Control Data for the United States
National Oceanic and Atmospheric Administration, Department of Commerce — This data contains a set of geodetic control stations maintained by the National Geodetic Survey. Each geodetic control station in this dataset has either a precise...
Precession of the Earth-Moon System
Urbassek, Herbert M.
2009-01-01
The precession rate of the Earth-Moon system by the gravitational influence of the Sun is derived. Attention is focussed on a physically transparent but complete presentation accessible to first- or second-year physics students. Both a shortcut and a full analysis are given, which allows the inclusion of this material as an example of the physics…
Haba, Z
2009-02-01
We discuss relativistic diffusion in proper time in the approach of Schay (Ph.D. thesis, Princeton University, Princeton, NJ, 1961) and Dudley [Ark. Mat. 6, 241 (1965)]. We derive (Langevin) stochastic differential equations in various coordinates. We show that in some coordinates the stochastic differential equations become linear. We obtain momentum probability distribution in an explicit form. We discuss a relativistic particle diffusing in an external electromagnetic field. We solve the Langevin equations in the case of parallel electric and magnetic fields. We derive a kinetic equation for the evolution of the probability distribution. We discuss drag terms leading to an equilibrium distribution. The relativistic analog of the Ornstein-Uhlenbeck process is not unique. We show that if the drag comes from a diffusion approximation to the master equation then its form is strongly restricted. The drag leading to the Tsallis equilibrium distribution satisfies this restriction whereas the one of the Jüttner distribution does not. We show that any function of the relativistic energy can be the equilibrium distribution for a particle in a static electric field. A preliminary study of the time evolution with friction is presented. It is shown that the problem is equivalent to quantum mechanics of a particle moving on a hyperboloid with a potential determined by the drag. A relation to diffusions appearing in heavy ion collisions is briefly discussed.
Sahoo, Raghunath
2016-01-01
This lecture note covers Relativistic Kinematics, which is very useful for the beginners in the field of high-energy physics. A very practical approach has been taken, which answers "why and how" of the kinematics useful for students working in the related areas.
POLARIZATION MODULATION FROM LENSE–THIRRING PRECESSION IN X-RAY BINARIES
Ingram, Adam [Anton Pannekoek Institute, University of Amsterdam, Science Park 904, 1098 XH Amsterdam (Netherlands); Maccarone, Thomas J. [Department of Physics, Texas Tech University, Box 41051, Lubbock, TX 79409-1051 (United States); Poutanen, Juri [Tuorla Observatory, Department of Physics and Astronomy, University of Turku, Väisäläntie 20, FI-21500 Piikkiö (Finland); Krawczynski, Henric, E-mail: a.r.ingram@uva.nl [Physics Department and McDonnell Center for the Space Sciences, Washington University in St. Louis, 1 Brookings Drive, CB 1105, St. Louis, MO 63130 (United States)
2015-07-01
It has long been recognized that quasi-periodic oscillations (QPOs) in the X-ray light curves of accreting black hole and neutron star binaries have the potential to be powerful diagnostics of strong field gravity. However, this potential cannot be fulfilled without a working theoretical model, which has remained elusive. Perhaps, the most promising model associates the QPO with Lense–Thirring precession of the inner accretion flow, with the changes in viewing angle and Doppler boosting modulating the flux over the course of a precession cycle. Here, we consider the polarization signature of a precessing inner accretion flow. We use simple assumptions about the Comptonization process generating the emitted spectrum and take all relativistic effects into account, parallel transporting polarization vectors toward the observer along null geodesics in the Kerr metric. We find that both the degree of linear polarization and the polarization angle should be modulated on the QPO frequency. We calculate the predicted absolute rms variability amplitude of the polarization degree and angle for a specific model geometry. We find that it should be possible to detect these modulations for a reasonable fraction of parameter space with a future X-ray polarimeter such as NASA’s Polarization Spectroscopic Telescope Array (the satellite incarnation of the balloon experiment X-Calibur)
Importance of Tides for Periastron Precession in Eccentric Neutron Star - White Dwarf Binaries
Sravan, Niharika; Kalogera, Vassiliki; Althaus, Leandro G
2014-01-01
Although not nearly as numerous as binaries with two white dwarfs, eccentric neutron star-white dwarf (NS-WD) binaries are important gravitational wave sources for the next generation of space-based detectors sensitive to low frequency waves. Here we investigate periastron precession in these sources as a result of general relativistic, tidal, and rotational effects; such precession is expected to be detectable for at least some of the detected binaries of this type. Currently, two eccentric NS-WD binaries are known in the galactic field, PSR J1141-6545 and PSR B2303+46, both of which have orbits too wide to be relevant in their current state to gravitational-wave observations. However, population synthesis studies predict the existence of a significant Galactic population of such systems. We find that the contribution from tides should not be neglected when analyzing periastron precession signatures in gravitational-wave signals: not accounting for tides can produce errors as high as a factor of 80 in the WD...
On the recently determined anomalous perihelion precession of Saturn
Iorio, Lorenzo
2008-01-01
The astronomer E.V. Pitjeva, by analyzing with the EPM2008 ephemerides a large number of planetary observations including also two years (2004-2006) of normal points from the Cassini spacecraft, phenomenologically estimated a statistically significant non-zero correction to the usual Newtonian/Einsteinian secular precession of the longitude of the perihelion of Saturn, i.e. \\Delta\\dot\\varpi_Sat = -0.006 +/- 0.002 arcsec/cy; the formal, statistical error is 0.0007 arcsec/cy. It can be explained neither by any of the standard classical and general relativistic dynamical effects mismodelled/unmodelled in the force models of the EPM2008 ephemerides nor by several exotic modifications of gravity recently put forth to accommodate certain cosmological/astrophysical observations without resorting to dark energy/dark matter. Both independent analyses by other teams of astronomers and further processing of larger data sets from Cassini will be helpful in clarifying the nature and the true existence of the anomalous pre...
PHOTOSPHERIC EMISSION FROM COLLAPSAR JETS IN 3D RELATIVISTIC HYDRODYNAMICS
Ito, Hirotaka; Matsumoto, Jin; Nagataki, Shigehiro; Warren, Donald C.; Barkov, Maxim V., E-mail: hirotaka.ito@riken.jp [Astrophysical Big Bang Laboratory, RIKEN, Saitama 351-0198 (Japan)
2015-12-01
We explore the photospheric emission from a relativistic jet breaking out from a massive stellar envelope based on relativistic hydrodynamical simulations and post-process radiation transfer calculations in three dimensions. To investigate the impact of three-dimensional (3D) dynamics on the emission, two models of injection conditions are considered for the jet at the center of the progenitor star: one with periodic precession and another without precession. We show that structures developed within the jet due to the interaction with the stellar envelope, as well as due to the precession, have a significant imprint on the resulting emission. Particularly, we find that the signature of precession activity by the central engine is not smeared out and can be directly observed in the light curve as a periodic signal. We also show that non-thermal features, which can account for observations of gamma-ray bursts, are produced in the resulting spectra even though only thermal photons are injected initially and the effect of non-thermal particles is not considered.
Photospheric Emission from Collapsar Jets in 3D Relativistic Hydrodynamics
Ito, Hirotaka; Matsumoto, Jin; Nagataki, Shigehiro; Warren, Donald C.; Barkov, Maxim V.
2015-12-01
We explore the photospheric emission from a relativistic jet breaking out from a massive stellar envelope based on relativistic hydrodynamical simulations and post-process radiation transfer calculations in three dimensions. To investigate the impact of three-dimensional (3D) dynamics on the emission, two models of injection conditions are considered for the jet at the center of the progenitor star: one with periodic precession and another without precession. We show that structures developed within the jet due to the interaction with the stellar envelope, as well as due to the precession, have a significant imprint on the resulting emission. Particularly, we find that the signature of precession activity by the central engine is not smeared out and can be directly observed in the light curve as a periodic signal. We also show that non-thermal features, which can account for observations of gamma-ray bursts, are produced in the resulting spectra even though only thermal photons are injected initially and the effect of non-thermal particles is not considered.
Hakim, Rémi
1994-01-01
Il existe à l'heure actuelle un certain nombre de théories relativistes de la gravitation compatibles avec l'expérience et l'observation. Toutefois, la relativité générale d'Einstein fut historiquement la première à fournir des résultats théoriques corrects en accord précis avec les faits.
Legacy and future of Kilauea's geodetic studies
Montgomery-Brown, E. D.; Miklius, A.
2011-12-01
Because of its extensive and detailed history of geodetic measurements, Kilauea is one of the best-studied if not also best-understood volcanic systems in the world. Hawaiian volcanoes have a long history of deformation observations. These observations range from native legends of Pele's underground travels, through initial measurements made by the Hawaiian Volcano Observatory, and finally to current ground-based and satellite observations. Many questions still remain, relating to Kilauea's dynamics, where geodetic measurements could offer fundamental insights. For example, new geodetic experiments could lead to a better understanding of the degree of magmatic and tectonic interaction, the geometries of faults at depth, the extent of offshore deformation, and the magmatic plumbing system. While it is possible to design many experiments to address these issues, we focus on three deformation targets where geodetic improvements, including finer sampling in space and time, could yield significant advancements toward understanding Kilauea's dynamics. First, by scrutinizing spatially-dense space-borne geodetic data for signs of upper east rift zone deformation and incorporating gravity and seismic data in a high resolution tomographic model, the hydraulic connection between Kilauea's summit and the rift zone could be imaged, which would provide insight into the pathways that transport magma out to the rift zones. Second, a combination of geodetic and seismic data could be used to determine the nature of possible relationships and interactions between the Hilina fault system and Kilauea's basal decollement. Such a study would have important implications for assessments of future earthquake and sector collapse hazards. Lastly, by adding seafloor geodetic measurements and seismic data to the current geodetic network on Kilauea, we could delimit the offshore extent of transient and episodic decollement deformation. In addition to multidisciplinary approaches, future geodetic
Jones, Bernard J. T.; Markovic, Dragoljub
1997-06-01
Preface; Prologue: Conference overview Bernard Carr; Part I. The Universe At Large and Very Large Redshifts: 2. The size and age of the Universe Gustav A. Tammann; 3. Active galaxies at large redshifts Malcolm S. Longair; 4. Observational cosmology with the cosmic microwave background George F. Smoot; 5. Future prospects in measuring the CMB power spectrum Philip M. Lubin; 6. Inflationary cosmology Michael S. Turner; 7. The signature of the Universe Bernard J. T. Jones; 8. Theory of large-scale structure Sergei F. Shandarin; 9. The origin of matter in the universe Lev A. Kofman; 10. New guises for cold-dark matter suspects Edward W. Kolb; Part II. Physics and Astrophysics Of Relativistic Compact Objects: 11. On the unification of gravitational and inertial forces Donald Lynden-Bell; 12. Internal structure of astrophysical black holes Werner Israel; 13. Black hole entropy: external facade and internal reality Valery Frolov; 14. Accretion disks around black holes Marek A. Abramowicz; 15. Black hole X-ray transients J. Craig Wheeler; 16. X-rays and gamma rays from active galactic nuclei Roland Svensson; 17. Gamma-ray bursts: a challenge to relativistic astrophysics Martin Rees; 18. Probing black holes and other exotic objects with gravitational waves Kip Thorne; Epilogue: the past and future of relativistic astrophysics Igor D. Novikov; I. D. Novikov's scientific papers and books.
Spin-orbit precession for eccentric black hole binaries at first order in the mass ratio
Akcay, Sarp; Dolan, Sam
2016-01-01
We consider spin-orbit ("geodetic") precession for a compact binary in strong-field gravity. Specifically, we compute $\\psi$, the ratio of the accumulated spin-precession and orbital angles over one radial period, for a spinning compact body orbiting a non-rotating black hole. We show that $\\psi$ can be computed for eccentric orbits in both the gravitational self-force and post-Newtonian frameworks, and that the results appear to be consistent. We present a post-Newtonian expansion for $\\psi$ at next-to-next-to-leading order, and a Lorenz-gauge gravitational self-force calculation for $\\psi$ at first order in the mass ratio. The latter provides new numerical data in the strong-field regime to inform the Effective One-Body model of the gravitational two-body problem. We conclude that $\\psi$ complements the Detweiler redshift $z$ as a key invariant quantity characterizing eccentric orbits in the gravitational two-body problem.
The three-fold theoretical basis of the Gravity Probe B gyro precession calculation
Adler, Ronald J
2014-01-01
The Gravity Probe B (GP-B) experiment is complete and the results are in agreement with the predictions of general relativity (GR) for both the geodetic precession, 6.6 arcsec/yr to about 0.3%, and the Lense-Thirring precession, 39 marcsec to about 19%. This note is concerned with the theoretical basis for the predictions. The predictions depend on three elements of gravity theory, firstly that macroscopic gravity is described by a metric theory such as general relativity, secondly that the Lense-Thirring metric provides an approximate description of the gravitational field of the spinning earth, and thirdly that the spin axis of a gyroscope is parallel displaced in spacetime, which gives its equation of motion. We look at each of these three elements to show how each is solidly based on previous experiments and well-tested theory. The agreement of GP-B with theory strengthens our belief that all three elements are correct and increases our confidence in applying GR to astrophysical phenomena. Conversely, if ...
Rapid Jet Precession During the 2015 Outburst of the Black Hole X-ray Binary V404 Cygni
Sivakoff, Gregory R.; Miller-Jones, James; Tetarenko, Alex J.
2017-08-01
In stellar-mass black holes that are orbited by lower-mass companions (black hole low-mass X-ray binaries), the accretion process can undergo dramatic outbursts that can be accompanied by the launching of powerful relativistic jets. We still do not know the exact mechanism responsible for launching these jets, despite decades of research and the importance of determining this mechanism given the clear analogue of accreting super-massive black holes and their jets. The two main models for launching jets involve the extraction of the rotational energy of a spinning black hole (Blandford-Znajek) and the centrifugal acceleration of particles by open magnetic field lines rotating with the accretion flow (Blandford-Payne). Since some relativistic jets are not fully aligned with the angular momentum of the binary's orbit, the inner accretion flow of some black hole X-ray binaries may precess due to frame-dragging by a spinning black hole (Lense-Thirring precession). This precession has been previously observed close to the black hole as second-timescale quasi-periodic (X-ray) variability. In this talk we will present radio-through-sub-mm timing and high-angular resolution radio imaging (including a high-timing resolution movie) of the black hole X-ray binary V404 Cygni during its 2015 outburst. These data show that at the peak of the outburst the relativistic jets in this system were precessing on timescales of hours. We will discuss how rapid precession can be explained by Lense-Thirring precession of a vertically-extended slim disc that is maintained out to a radius of 6 X 1010 cm by a highly super-Eddington accretion rate. This would imply that the jet axis of V404 Cyg is not aligned with the black hole spin. More importantly, this places a key requirement on any model for launching jets, and may favour launching the jet from the rotating magnetic fields threading the disc.
Non-rigid precession of magnetic stars
Lander, S K
2016-01-01
Stars are, generically, rotating and magnetised objects with a misalignment between their magnetic and rotation axes. Since a magnetic field induces a permanent distortion to its host, it provides effective rigidity even to a fluid star, leading to bulk stellar motion which resembles free precession. This bulk motion is however accompanied by induced interior velocity and magnetic field perturbations, which are oscillatory on the precession timescale. Extending previous work, we show that these quantities are described by a set of second-order perturbation equations featuring cross-terms scaling with the product of the magnetic and centrifugal distortions to the star. For the case of a background toroidal field, we reduce these to a set of differential equations in radial functions, and find a method for their solution. The resulting magnetic-field and velocity perturbations show complex multipolar structure and are strongest towards the centre of the star.
New High-Precision Values of the Geodetic Rotation of the Major Planets, Pluto, the Moon and the Sun
Pashkevich, V. V.
2016-06-01
This investigation is continuation of our studies of the geodetic (relativistic) rotation of the Solar system bodies (Eroshkin and Pashkevich, 2007) and (Eroshkin and Pashkevich, 2009). For each body (the Moon, the Sun, the major planets and Pluto) the files of the values of the components of the angular velocity of the geodetic rotation are constructed over the time span from AD1000 to AD3000 with one day spacing, by using DE422/LE422 ephemeris (Folkner, 2011), with respect to the proper coordinate systems of the bodies (Seidelmann et al., 2005). For the first time in the perturbing terms of the physical librations for the Moon and in Euler angles for other bodies of the Solar system the most essential terms of the geodetic rotation are found by means of the least squares method and spectral analysis methods.
Single electron relativistic clock interferometer
Bushev, P. A.; Cole, J. H.; Sholokhov, D.; Kukharchyk, N.; Zych, M.
2016-09-01
Although time is one of the fundamental notions in physics, it does not have a unique description. In quantum theory time is a parameter ordering the succession of the probability amplitudes of a quantum system, while according to relativity theory each system experiences in general a different proper time, depending on the system's world line, due to time dilation. It is therefore of fundamental interest to test the notion of time in the regime where both quantum and relativistic effects play a role, for example, when different amplitudes of a single quantum clock experience different magnitudes of time dilation. Here we propose a realization of such an experiment with a single electron in a Penning trap. The clock can be implemented in the electronic spin precession and its time dilation then depends on the radial (cyclotron) state of the electron. We show that coherent manipulation and detection of the electron can be achieved already with present day technology. A single electron in a Penning trap is a technologically ready platform where the notion of time can be probed in a hitherto untested regime, where it requires a relativistic as well as quantum description.
Quipus and System of Coordinated Precession
Campos, T. C.
2004-05-01
The Incas of ancient Peru possessed no writing. Instead, they developed a unique system expressed on spatial arrays of colored knotted cords called Quipus to record and transmit information throughout their vast empire. In their thorough description of quipus, Ascher & Ascher observed that in two cases the numbers registered in their strings have a very special relationship to each other. For this to occur the numbers must have been obtained through the multiplication of whole numbers by fractions or decimals, operations apparently beyond the arithmetic knowledge of the Incas. The quipus AS120 and AS143, coming from Ica (Peru) and conserved in the Museum of Berlin has the suitable characteristics previously. In the AS143 there is a the relationship with the systems of coordinated precession (tilt of Earth's spin axis (40036); eccentricity of Earth's orbit (97357); and precession of equinoxes (between 18504 and 23098)). For the history of the Earth are necessary an chronometer natural to coordinate and to classify the observations and this chronometer comes to be the vernal point, defining the vernal point as" a sensitive axis of maximum conductivity" as itdemonstrates it the stability of the geomagnetic equator (inclination of the field is zero grades), in the year 1939 calculated with the IGRF from the year 1900 up to the 2004 and that it is confirmed with tabulated data of the Geophysical Institute of Huancayo (Peru),from that date until this year (2004) and this fluctuating between the 12-14 South.,on the other hand in the area of Brazil it has advanced very quickly toward the north, and above to 108 km. approximately it is located the equatorial electrojet that is but intense in the equinoxes in South America. And this stability from the point of view of the precession of the equinoxes this coinciding with the entrance of the apparent sun for the constellation of Aquarius, being this mechanism the base to establish a system of coordinated precession where it is
The geodetic numbers of graphs and digraphs
Chang-hong LU
2007-01-01
For every two vertices u and v in a graph G, a u-v geodesic is a shortest path between u and v. Let I(u, v) denote the set of all vertices lying on a u-v geodesic. For a vertex subset S, let I(S)denote the union of all I(u, v) for u, v ∈ S. The geodetic number g(G) of a graph G is the minimum cardinality of a set S with I(S) = V(G). For a digraph D, there is analogous terminology for the geodetic number g(D). The geodetic spectrum of a graph G, denoted by S(G), is the set of geodetic numbers of all orientations of graph G. The lower geodetic number is g-(G) = minS(G) and the upper geodetic number is g+ (G) = maxS(G). The main purpose of this paper is to study the relations among g(G), g-(G) and g+ (G) for connected graphs G. In addition, a sufficient and necessary condition for the equality of g(G) and g(G × K2) is presented, which improves a result of Chartrand, Harary and Zhang.
The geodetic numbers of graphs and digraphs
2007-01-01
For every two vertices u and v in a graph G,a u-v geodesic is a shortest path between u and v.Let I（u,v）denote the set of all vertices lying on a u-v geodesic.For a vertex subset S,let I（S） denote the union of all I（u,v）for u,v∈S.The geodetic number g（G）of a graph G is the minimum cardinality of a set S with I（S）=V（G）.For a digraph D,there is analogous terminology for the geodetic number g（D）.The geodetic spectrum of a graph G,denoted by S（G）,is the set of geodetic numbers of all orientations of graph G.The lower geodetic number is g-（G）=minS（G）and the upper geodetic number is g+（G）=maxS（G）.The main purpose of this paper is to study the relations among g（G）,g-（G）and g+（G）for connected graphs G.In addition,a sufficient and necessary condition for the equality of g（G）and g（G×K2）is presented,which improves a result of Chartrand,Harary and Zhang.
Study of the apsidal precession of the Physical Symmetrical Pendulum
Maya, Hector R; Herrera, William J
2013-01-01
We study the apsidal precession of a Physical Symmetrical Pendulum (Allais' precession) as a generalization of the precession corresponding to the Ideal Spherical Pendulum (Airy's Precession). Based on the Hamilton-Jacobi formalism and using the technics of variation of parameters along with the averaging method, we obtain approximate solutions, in terms of which the motion of both systems admits a simple geometrical description. The method developed in this paper is considerably simpler than the standard one in terms of elliptical functions and the numerical agreement with the exact solutions is excellent. In addition, the present procedure permits to show clearly the origin of the Airy's and Allais' precession, as well as the effect of the spin of the Physical Pendulum on the Allais' precession. Further, the method can be extended to the study of the asymmetrical pendulum in which an exact solution is not possible anymore.
Relativistic and non-relativistic geodesic equations
Giambo' , R.; Mangiarotti, L.; Sardanashvily, G. [Camerino Univ., Camerino, MC (Italy). Dipt. di Matematica e Fisica
1999-07-01
It is shown that any dynamic equation on a configuration space of non-relativistic time-dependent mechanics is associated with connections on its tangent bundle. As a consequence, every non-relativistic dynamic equation can be seen as a geodesic equation with respect to a (non-linear) connection on this tangent bundle. Using this fact, the relationships between relativistic and non-relativistic equations of motion is studied.
Ballistic missile precession frequency extraction by spectrogram's texture
Wu, Longlong; Xu, Shiyou; Li, Gang; Chen, Zengping
2013-10-01
In order to extract precession frequency, an crucial parameter in ballistic target recognition, which reflected the kinematical characteristics as well as structural and mass distribution features, we developed a dynamic RCS signal model for a conical ballistic missile warhead, with a log-norm multiplicative noise, substituting the familiar additive noise, derived formulas of micro-Doppler induced by precession motion, and analyzed time-varying micro-Doppler features utilizing time-frequency transforms, extracted precession frequency by measuring the spectrogram's texture, verified them by computer simulation studies. Simulation demonstrates the excellent performance of the method proposed in extracting the precession frequency, especially in the case of low SNR.
A Short Foucault Pendulum Free of Ellipsoidal Precession
Schumacher, Reinhard A
2009-01-01
A quantitative method is presented for stopping the intrinsic precession of a spherical pendulum due to ellipsoidal motion. Removing this unwanted precession renders the Foucault precession due to the turning of the Earth readily observable. The method is insensitive to the size and direction of the perturbative forces leading to ellipsoidal motion. We demonstrate that a short (three meter) pendulum can be pushed in a controlled way to make the Foucault precession dominant. The method makes room-height or table-top Foucault pendula more accurate and practical to build.
Relativistic magnetohydrodynamics
Hernandez, Juan; Kovtun, Pavel
2017-05-01
We present the equations of relativistic hydrodynamics coupled to dynamical electromagnetic fields, including the effects of polarization, electric fields, and the derivative expansion. We enumerate the transport coefficients at leading order in derivatives, including electrical conductivities, viscosities, and thermodynamic coefficients. We find the constraints on transport coefficients due to the positivity of entropy production, and derive the corresponding Kubo formulas. For the neutral state in a magnetic field, small fluctuations include Alfvén waves, magnetosonic waves, and the dissipative modes. For the state with a non-zero dynamical charge density in a magnetic field, plasma oscillations gap out all propagating modes, except for Alfvén-like waves with a quadratic dispersion relation. We relate the transport coefficients in the "conventional" magnetohydrodynamics (formulated using Maxwell's equations in matter) to those in the "dual" version of magnetohydrodynamics (formulated using the conserved magnetic flux).
Leardini, Fabrice
2013-01-01
This manuscript presents a problem on special relativity theory (SRT) which embodies an apparent paradox relying on the concept of simultaneity. The problem is represented in the framework of Greek epic poetry and structured in a didactic way. Owing to the characteristic properties of Lorenz transformations, three events which are simultaneous in a given inertial reference system, occur at different times in the other two reference frames. In contrast to the famous twin paradox, in the present case there are three, not two, different inertial observers. This feature provides a better framework to expose some of the main characteristics of SRT, in particular, the concept of velocity and the relativistic rule of addition of velocities.
Book Review: Precession, Nutation, and Wobble of the Earth
Sterken, Christiaan; Dehant, V.; Mathews, P. M.
2016-10-01
This great book describes and explains observational and computational aspects of three apparently tiny changes in the Earth's motion and orientation, viz., precession, nutation, and wobble. The three introductory chapters of this book present fundamental definitions, elementary geodetic theory, and celestial/terrestrial reference systems - including transformations between reference frames. The next chapter on observational techniques describes the principle of accurate measurements of the orientation of the Earth's axis, as obtained from measurements of extra-galactic radio sources using Very Long Baseline Interferometry and GPS observations. Chapter 5 handles precession and nutation of the rigid Earth (i.e., a celestial body that cannot, by definition, deform) and the subsequent chapter takes deformation into consideration, viz., the effect of a centrifugal force caused by a constant-rate rotation that causes the Earth's shape and structure to become ellipsoidal. Deformations caused by external solar-system bodies are discussed in terms of deformability parameters. The next three chapters handle additional complex deviations: non-rigid Earth and more general Earth models, anelastic Earth parameters, and the effects of the fluid layers (i.e., ocean and atmosphere) on Earth rotation. Chapter 10 complements Chapter 7 with refinements that take into account diverse small effects such as the effect of a thermal conductive layer at the top of the core, Core Mantle and Inner Boundary coupling effects on nutation, electromagnetic coupling, and so-called topographic coupling. Chapter 11 covers comparison of observation and theory, and tells us that the present-date precision of the nutation theory is at the level of milliarcseconds in the time domain, and of a tenth of a microsecond in the frequency domain (with some exceptions). This chapter is followed by a 25-page chapter of definitions of equator, equinox, celestial intermediate pole and origin, stellar angle
Evaluation of a possible upgrade of the IAU 2006 precession
Liu, J.-C.; Capitaine, N.
2017-01-01
Context. The International Astronomical Union (IAU) adopted a new precession model at its 2006 General Assembly. After more than ten years since the publication of the so-called IAU 2006 precession, we have noticed progress in solar system ephemerides and geophysical observations, which can be used to refine the precession model. Another progress is the increase by 30% since 2003, of the length of the very long baseline interferometry (VLBI) observations to be compared with the theoretical model. Aims: The aim of this paper is to investigate the possibility of upgrading the IAU 2006 precession model based on new solutions of the Earth-Moon barycenter (EMB) motion, new theoretical contributions to the precession rates, and the revised J2 long-term variation obtained from the satellite laser ranging (SLR). Methods: The new precession expressions for the ecliptic are derived by fitting the new analytical planetary theory VSOP2013 to the numerical ephemerides DE422 or INPOP10a. The solution for the precession of the equator was obtained by integrating the dynamical precession equations with the use of an updated Earth model including the J2 quadratic long-term variation. The new precession expressions (denoted LC solution in this paper) are compared with the IAU 2006 model by using the most accurate VLBI observations up to 2015. Results: For the precession of the ecliptic, the changes in the new solutions with respect to the IAU 2006 are about several tens of microarcseconds in the linear terms of PA and QA. The upgraded precession of the equator is such that the quadratic and cubic terms in the quantity ψA differ significantly from IAU 2006 due to the revised J2 model. The statistics of the VLBI celestial pole offsets (1979-2015) and least squares fits with different empirical models, show that the LC precession is slightly more consistent with the VLBI observations, but the improvement relative to the IAU 2006 model is not definitely convincing at present
Tilt, Warp, and Simultaneous Precessions in Disks
Montgomery, M M
2012-01-01
Warps are suspected in disks around massive compact objects. However, the proposed warping source -- non-axisymmetric radiation pressure -- does not apply to white dwarfs. In this letter we report the first Smoothed Particle Hydrodynamic simulations of accretion disks in SU UMa-type systems that naturally tilt, warp, and simultaneously precess in the prograde and retrograde directions using white dwarf V344 Lyrae in the Kepler field as our model. After ~79 days in V344 Lyrae, the disk angular momentum L_d becomes misaligned to the orbital angular momentum L_o. As the gas stream remains normal to L_o, hydrodynamics (e.g., the lift force) is a likely source to disk tilt. In addition to tilt, the outer disk annuli cyclically change shape from circular to highly eccentric due to tidal torques by the secondary star. The effect of simultaneous prograde and retrograde precession is a warp of the colder, denser midplane as seen along the disk rim. The simulated rate of apsidal advance to nodal regression per orbit ne...
Two spinning ways for precession dynamo.
Cappanera, L; Guermond, J-L; Léorat, J; Nore, C
2016-04-01
It is numerically demonstrated by means of a magnetohydrodynamic code that precession can trigger dynamo action in a cylindrical container. Fixing the angle between the spin and the precession axis to be 1/2π, two limit configurations of the spinning axis are explored: either the symmetry axis of the cylinder is parallel to the spin axis (this configuration is henceforth referred to as the axial spin case), or it is perpendicular to the spin axis (this configuration is referred to as the equatorial spin case). In both cases, the centro-symmetry of the flow breaks when the kinetic Reynolds number increases. Equatorial spinning is found to be more efficient in breaking the centro-symmetry of the flow. In both cases, the average flow in the reference frame of the mantle converges to a counter-rotation with respect to the spin axis as the Reynolds number grows. We find a scaling law for the average kinetic energy in term of the Reynolds number in the axial spin case. In the equatorial spin case, the unsteady asymmetric flow is shown to be capable of sustaining dynamo action in the linear and nonlinear regimes. The magnetic field is mainly dipolar in the equatorial spin case, while it is is mainly quadrupolar in the axial spin case.
precession: Dynamics of spinning black-hole binaries with python
Gerosa, Davide; Kesden, Michael
2016-06-01
We present the numerical code precession, a new open-source python module to study the dynamics of precessing black-hole binaries in the post-Newtonian regime. The code provides a comprehensive toolbox to (i) study the evolution of the black-hole spins along their precession cycles, (ii) perform gravitational-wave-driven binary inspirals using both orbit-averaged and precession-averaged integrations, and (iii) predict the properties of the merger remnant through fitting formulas obtained from numerical-relativity simulations. precession is a ready-to-use tool to add the black-hole spin dynamics to larger-scale numerical studies such as gravitational-wave parameter estimation codes, population synthesis models to predict gravitational-wave event rates, galaxy merger trees and cosmological simulations of structure formation. precession provides fast and reliable integration methods to propagate statistical samples of black-hole binaries from/to large separations where they form to/from small separations where they become detectable, thus linking gravitational-wave observations of spinning black-hole binaries to their astrophysical formation history. The code is also a useful tool to compute initial parameters for numerical-relativity simulations targeting specific precessing systems. precession can be installed from the python Package Index, and it is freely distributed under version control on github, where further documentation is provided.
Neutrino induced magnetic moment and spin precession
Ternov, A. I.
2016-07-01
When propagating through a dispersing medium, a massive neutrino acquires an induced magnetic moment that may give rise to a helicity flip in an external magnetic field with a larger probability than that caused by the anomalous magnetic moment. This phenomenon is investigated in the framework of relativistic quantum mechanics and of the generalized Bargmann-Michel-Telegdi equation.
Geodetic surveying of crane trail space relations
Ľudovít Kovanič
2010-03-01
Full Text Available Geodet´s obvious task consists of surveying crane trails of different types. These transport machines must meet precise geometricparameters, considering mainly the safety of their operation. The paper describes several geodetic methods of determining deviationsin direction and height of crane trails. Measurements were realized using special set of appliances composed for this purpose, as well asusing electronic theodolite for measurements from hall floor. Results ofmeasurements were processed using calculation programe Geus, andgraphicproramme Microstation. Used methods were compared in graphic form.
Precessing jets and molecular outflows a 3-D numerical study
Cliffe, J A; Frank, Adam
1996-01-01
We present 3-D numerical hydrodynamical simulations of precessing supersonic heavy jets to explore how well they serve as a model for generating molecular outflows from Young Stellar Objects. The dynamics are studied with a number of high resolution simulations on a Cartesian grid (128x128x128 zones) using a high order finite difference method. A range of cone angles and precession rates were included in the study. Two higher resolution runs (256x256x256 zones) were made for comparison in order to confirm numerical convergence of global flow characteristics. Morphological, kinematical and dynamical characteristics of precessing jets are described and compared to important properties of straight jets and also to observations of YSOs. In order to examine the robustness of precessing jets as a mean to produce molecular outflows around Young Stellar Objects, ``synthetic observations'' of the momentum distributions of the simulated precessing jets are compared to observations of molecular outflows. It is found tha...
Inspiralling, Non-Precessing, Spinning Black Hole Binary Spacetime via Asymptotic Matching
Ireland, Brennan; Nakano, Hiroyuki; Campanelli, Manuela
2015-01-01
We construct a new global, fully analytic, approximate spacetime which accurately describes the dynamics of non-precessing, spinning black hole binaries during the inspiral phase of the relativistic merger process. This approximate solution of the vacuum Einstein's equations can be obtained by asymptotically matching perturbed Kerr solutions near the two black holes to a post-Newtonian metric valid far from the two black holes. This metric is then matched to a post-Minkowskian metric even farther out in the wave zone. The procedure of asymptotic matching is generalized to be valid on all spatial hypersurfaces, instead of a small group of initial hypersurfaces discussed in previous works. This metric is well suited for long term dynamical simulations of spinning black hole binary spacetimes prior to merger, such as studies of circumbinary gas accretion which requires hundreds of binary orbits.
Constraints on Non-Standard Gravitomagnetism by the Anomalous Perihelion Precession of the Planets
Luis Acedo
2014-09-01
Full Text Available In 2008, a team of astronomers reported an anomalous retrograde precession of the perihelion of Saturn amounting to \\(\\Delta \\dot{\\omega}_{\\mathrm{SATURN}}=-0.006(2\\ arcsec per century (arcsec cy\\(^{-1}\\. This unexplained precession was obtained after taking into account all classical and relativistic effects in the context of the highly refined EPM2008 ephemerides. More recent analyzes have not confirmed this effect, but they have found similar discrepancies in other planets. Our objective in this paper is to discuss a non-standard model involving transversal gravitomagnetism generated by the Sun as a possible source of these potential anomalies, to be confirmed by further data analyses. In order to compute the Lense–Thirring perturbations induced by the suggested interaction, we should consider the orientation of the Sun's rotational axis in Carrington elements and the inclination of the planetary orbits with respect to the ecliptic plane. We find that an extra component of the gravitomagnetic field not predicted by General Relativity could explain the reported anomalies without conflicting with the Gravity Probe B experiment and the orbits of the geodynamics satellites.
Schmidt, Patricia; Hannam, Mark
2014-01-01
Gravitational waves (GWs) emitted by generic black-hole binaries show a rich structure that directly reflects the complex dynamics introduced by the precession of the orbital plane, which poses a real challenge to the development of generic waveform models. Recent progress in modelling these signals relies on an approximate decoupling between the non-precessing secular inspiral and a precession-induced rotation. However, the latter depends in general on all physical parameters of the binary which makes modelling efforts as well as understanding parameter-estimation prospects prohibitively complex. Here we show that the dominant precession effects can be captured by a reduced set of spin parameters. Specifically, we introduce a single \\emph{effective precession spin} parameter, $\\chi_p$, which is defined from the spin components that lie in the orbital plane at some (arbitrary) instant during the inspiral. We test the efficacy of this parameter by considering binary inspiral configurations specified by the phy...
DGP cosmology from rigid geodetic brane gravity
Cordero, Rubén; Molgado, Alberto; Rojas, Efrain
2011-01-01
We explore the cosmological implications provided by an effective geometrical action describing a codimension-one rigid brane embedded in a 5D fixed Minkowski spacetime, i.e., allowing for a term added to the geodetic brane action which depends on the extrinsic curvature of the worldvolume. In the geodetic brane gravity action we accommodate the rigidity of the brane through a linear term in the extrinsic curvature swept out by the brane. We study the resulting geodetic type equation of motion. Within a Friedmann-Robertson-Walker framework, we obtain a generalized Friedmann equation describing the associated cosmological evolution which in turn allowed us to illustrate explicitly the linkage between the geodetic brane theory and the rigidity content of this sort of branelike universes. We observe that, when the radiation-like energy contribution from the extra dimension is vanishing, this effective model leads to a self-(non-self)-accelerated expansion of the universe in dependence on the nature of the rigidi...
Considerations for improved Integration of Geodetic Techiques
Schreiber, K. U.
2012-04-01
The most demanding goal for the GGOS initiative is the definition of station positions to an accuracy of 1 mm and the corresponding velocities to 0.1 mm/year. Fundamental stations are corner stones for the geodetic reference frames because they are collocating and combining the relevant measurement techniques. However, this requires unprecedented control over local ties, intra- and inter- technique biases. The unperturbed distribution of frequency is an important requirement for all the space geodetic techniques. The distribution of time without jitter has importance for laser time transfer applications such as T2L2 and in the future ELT with ACES on the ISS. The timing system of the Geodetic Observatory Wettzell is based on a radio frequency (5 MHz) distribution scheme and a grid of coaxial cables. Uncontrolable fluctuations in the electrical ground potential and variations in the dielectric properties of these transmission lines give rise to jitter and most likely even small systematic measurement errors. Modern frequency transfer concepts differ from these earlier methods by employing active delay compensation by utilizing control loops in tight (high bandwidth) feedback systems. Furthermore they work on much higher frequencies from hundreds of megahertz up to the optical regime. The definition of a new timing system for Wettzell based on compensated signal transmission lines and the evaluation of the end to end properties of such concepts is work in progress for the coming years with the aim to create a truly common clock for all space geodetic techniques on the Geodetic Observatory Wettzell. This talk will introduce the important aspects and the potential of this next generation of timing systems.
Historical Review of Astro-Geodetic Observations in Serbia
Ogrizovic, V.; Delcev, S.; Vasilic, V.; Gucevic, J.
2008-10-01
Astro-geodetic determinations of vertical deflections in Serbia began during the first years of 20th century. The first field works were led by S. Bo\\vsković. After the 2nd World War, Military Geographic Institute, Department of Geodesy from the Faculty of Civil Engineering, and Federal Geodetic Directorate continued the determinations, needed for reductions of terrestrial geodetic measurements and the astro-geodetic geoid determination. Last years improvements of the astro-geodetic methods are carried out in the area of implementing modern measurement equipment and technologies.
Cattaneo, Carlo
2011-01-01
This title includes: Pham Mau Quam: Problemes mathematiques en hydrodynamique relativiste; A. Lichnerowicz: Ondes de choc, ondes infinitesimales et rayons en hydrodynamique et magnetohydrodynamique relativistes; A.H. Taub: Variational principles in general relativity; J. Ehlers: General relativistic kinetic theory of gases; K. Marathe: Abstract Minkowski spaces as fibre bundles; and, G. Boillat: Sur la propagation de la chaleur en relativite.
Vector solitons with locked and precessing states of polarization
Sergeyev, Sergey; Mou, Chengbo; Rozhin, Alex; Turitsyn, Sergei
2012-01-01
We demonstrate experimentally new families of vector solitons with locked and precessing states of polarization for fundamental and multipulse soliton operations in a carbon nanotube mode-locked fiber laser with anomalous dispersion laser cavity.
Precession of Toroidally Passing Particles in Tokamaks and Spherical Tori
Ya.I. Kolesnichenko; R.B.White; Yu.V. Yakovenko
2003-01-30
The toroidal precession of the well-circulating particles and particles that are passing toroidally but trapped poloidally is studied. Expressions for the precession frequency, which are convenient for practical use, are obtained and analyzed. It is found that the key parameters that determine the magnitude and the direction of the precession velocity are the plasma elongation, the magnitudes and profiles of the safety factor and beta defined as the ratio of the local plasma pressure to the magnetic field pressure at the magnetic axis. An important role of the ''paramagnetic'' precession in highly elongated plasmas is revealed. The analysis carried out is based on the obtained expressions for the equilibrium magnetic field strength and the field line curvature.
Reduction of electron channeling in EDS using precession.
Liao, Yifeng; Marks, Laurence D
2013-03-01
We demonstrated that EDS measurement can be significantly improved by precessing the electron beam, thereby reducing electron channeling effects. For a SrTiO3 specimen orientated along the [001] zone axis, the measured strontium to titanium atomic ratio was 0.74-0.80 using conventional EDS methods, and the ratio was improved to ~0.99 by precessing the electron beam for angles greater than 22.54 mRad. In ALCHEMI-like experiments in which the specimen was tilted to near two-beam condition, the strontium to titanium ratio was insensitive to the deviation from the Bragg condition using a precessed electron beam. Similar reduction of electron channeling effects was also observed in precession-assisted EDS measurements for an L21-ordered Fe2MnAl intermetallic alloy tilted to the [011] zone axis as well as near two-beam conditions.
On the occurrence of glitches in pulsar free precession candidates
Jones, D I; Prix, R
2016-01-01
The timing properties of radio pulsars provide a unique probe of neutron star interiors. Recent observations have uncovered quasi-periodicities in the timing and pulse properties of some pulsars, a phenomenon that has often been attributed to free precession of the neutron star, with profound implications for the distribution of superfluidity and superconductivity in the star. We advance this programme by developing consistency relations between free precession and pulsars glitches, and show that there are difficulties in reconciling the two phenomena in some precession candidates. This indicates that either the precession model used here needs to be modified, or some other phenomenon is at work in producing the quasi-periodicities, or even that there is something missing in terms of our understanding of glitches.
Vorticity, Gyroscopic precession, and Spin-Curvature Force
Liang, Wei Chieh; Lee, Si Chen
2012-01-01
In investigating the relation between vorticity and gyroscopic precession, we calculate the vorticity vector in Godel, Kerr, Lewis, Schwarzschild, Minkowski metric and find out the vorticity vector of the specific observers is the angular velocity of gyroscopic precession. Furthermore, considering space-time torsion will flip the vorticity and spin-curvature force to opposite sign. This result is very similar to the behavior of positive and negative helicity of quantum spin in Stern-Gerlach f...
General spin precession and betatron oscillation in storage rings
Fukuyama, Takeshi
2016-07-01
Spin precession of particles having both anomalous magnetic and electric dipole moments (EDMs) is considered. We give the generalized expression of spin precession of these particles injected with transversal extent in magnetic storage rings. This is the generalization of the Farley’s pitch correction [F. J. N. Farley, Phys. Lett. B 42, 66 (1972)], including radial oscillation as well as vertical one. The transversal betatron oscillation formulae of these particles are also reproduced.
Relativistic radiative transfer in relativistic spherical flows
Fukue, Jun
2017-02-01
Relativistic radiative transfer in relativistic spherical flows is numerically examined under the fully special relativistic treatment. We first derive relativistic formal solutions for the relativistic radiative transfer equation in relativistic spherical flows. We then iteratively solve the relativistic radiative transfer equation, using an impact parameter method/tangent ray method, and obtain specific intensities in the inertial and comoving frames, as well as moment quantities, and the Eddington factor. We consider several cases; a scattering wind with a luminous central core, an isothermal wind without a core, a scattering accretion on to a luminous core, and an adiabatic accretion on to a dark core. In the typical wind case with a luminous core, the emergent intensity is enhanced at the center due to the Doppler boost, while it reduces at the outskirts due to the transverse Doppler effect. In contrast to the plane-parallel case, the behavior of the Eddington factor is rather complicated in each case, since the Eddington factor depends on the optical depth, the flow velocity, and other parameters.
The AuScope Geodetic VLBI Array
Lovell, J E J; Reid, P B; McCulloch, P M; Baynes, B E; Dickey, J M; Shabala, S S; Watson, C S; Titov, O; Ruddick, R; Twilley, R; Reynolds, C; Tingay, S J; Shield, P; Adada, R; Ellingsen, S P; Morgan, J S; Bignall, H E; 10.1007/s00190-013-0626-3
2013-01-01
The AuScope geodetic Very Long Baseline Interferometry array consists of three new 12 m radio telescopes and a correlation facility in Australia. The telescopes at Hobart (Tasmania), Katherine (Northern Territory) and Yarragadee (Western Australia) are co-located with other space geodetic techniques including Global Navigation Satellite Systems (GNSS) and gravity infrastructure, and in the case of Yarragadee, Satellite Laser Ranging (SLR) and Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS) facilities. The correlation facility is based in Perth (Western Australia). This new facility will make significant contributions to improving the densification of the International Celestial Reference Frame in the Southern Hemisphere, and subsequently enhance the International Terrestrial Reference Frame through the ability to detect and mitigate systematic error. This, combined with the simultaneous densification of the GNSS network across Australia will enable the improved measurement of intrapl...
AR Sco: A Precessing White Dwarf Synchronar?
Katz, J. I.
2017-02-01
The emission of the white dwarf–M dwarf binary AR Sco is driven by the rapid synchronization of its white dwarf, rather than by accretion. Synchronization requires a magnetic field ∼100 Gauss at the M dwarf and ∼ {10}8 Gauss at the white dwarf, larger than the fields of most intermediate polars but within the range of fields of known magnetic white dwarfs. The spindown power is dissipated in the atmosphere of the M dwarf, within the near zone of the rotating white dwarf’s field, by magnetic reconnection, accelerating particles that produce the observed synchrotron radiation. The displacement of the optical maximum from conjunction may be explained either by dissipation in a bow wave as the white dwarf’s magnetic field sweeps past the M dwarf or by a misaligned white dwarf rotation axis and oblique magnetic moment. In the latter case the rotation axis precesses with a period of decades, predicting a drift in the orbital phase of the optical maximum. Binaries whose emission is powered by synchronization may be termed synchronars, in analogy to magnetars.
3D geodetic monitoring slope deformations
Weiss Gabriel
1996-06-01
Full Text Available For plenty of slope failures that can be found in Slovakia is necessary and very important their geodetic monitoring (because of their activity, reactivisations, checks. The paper gives new methodologies for these works, using 3D terrestrial survey technologies for measurements in convenient deformation networks. The design of an optimal type of deformation model for various kinds of landslides and their exact processing with an efficient testing procedure to determine the kinematics of the slope deformations are presented too.
PRECESSION. Dynamics of spinning black-hole binaries with python
Gerosa, Davide
2016-01-01
We present the numerical code PRECESSION: a new open-source python module to study the dynamics of precessing black-hole binaries in the post-Newtonian regime. The code provides a comprehensive toolbox to (i) study the evolution of the black-hole spins along their precession cycles, (ii) perform gravitational-wave driven binary inspirals using both orbit-averaged and precession-averaged integrations, and (iii) predict the properties of the merger remnant through fitting formulae obtained from numerical-relativity simulations. PRECESSION is a ready-to-use tool to add the black-hole spin dynamics to larger-scale numerical studies such as gravitational-wave parameter estimation codes, population synthesis models to predict gravitational-wave event rates, galaxy merger trees and cosmological simulations of structure formation. PRECESSION provides fast and reliable integration methods to propagate statistical samples of black-hole binaries from/to large separations where they form to/from small separations where t...
Photospheric Emission of Collapsar Jet in 3D Relativistic Radiation Hydrodynamical Simulation
Ito, Hirotaka; Nagataki, Shigehiro; Warren, Donald C; Barkov, Maxim V
2015-01-01
We explore the photospheric emission from a relativistic jet breaking out from a massive stellar envelope based on relativistic hydrodynamical simulations and post-process radiation transfer calculations in three dimensions (3D). To investigate the impact of 3D dynamics on the emission, two models of injection conditions are considered for the jet at the center of the progenitor star: one with periodic precession and another without precession. We show that structures developed within the jet due to the interaction with the stellar envelope, as well as due to the precession, have a significant imprint on the resulting emission. Particularly, we find that the signature of precession activity by the central engine is not smeared out and can be directly observed in the light curve as a periodic signal. We also show non-thermal features that can account for observations of gamma-ray bursts are produced in the resulting spectra, even though only thermal photons are injected initially and the effect of non-thermal ...
Relativistic Remnants of Non-Relativistic Electrons
Kashiwa, Taro
2015-01-01
Electrons obeying the Dirac equation are investigated under the non-relativistic $c \\mapsto \\infty$ limit. General solutions are given by derivatives of the relativistic invariant functions whose forms are different in the time- and the space-like region, yielding the delta function of $(ct)^2 - x^2$. This light-cone singularity does survive to show that the charge and the current density of electrons travel with the speed of light in spite of their massiveness.
Perihelion precession, polar ice and global warming
Steel, Duncan
2013-03-01
The increase in mean global temperature over the past 150 years is generally ascribed to human activities, in particular the rises in the atmospheric mixing ratios of carbon dioxide and other greenhouse gases since the Industrial Revolution began. Whilst it is thought that ice ages and interglacial periods are mainly initiated by multi-millennial variations in Earth's heliocentric orbit and obliquity, shorter-term orbital variations and consequent observable climatic effects over decadal/centurial timescales have not been considered significant causes of contemporary climate change compared to anthropogenic influences. Here it is shown that the precession of perihelion occurring over a century substantially affects the intra-annual variation of solar radiation influx at different locations, especially higher latitudes, with northern and southern hemispheres being subject to contrasting insolation changes. This north/south asymmetry has grown since perihelion was aligned with the winter solstice seven to eight centuries ago, and must cause enhanced year-on-year springtime melting of Arctic (but not Antarctic) ice and therefore feedback warming because increasing amounts of land and open sea are denuded of high-albedo ice and snow across boreal summer and into autumn. The accelerating sequence of insolation change now occurring as perihelion moves further into boreal winter has not occurred previously during the Holocene and so would not have been observed before by past or present civilisations. Reasons are given for the significance of this process having been overlooked until now. This mechanism represents a supplementary - natural - contribution to climate change in the present epoch and may even be the dominant fundamental cause of global warming, although anthropogenic effects surely play a role too.
Determination of Displacement Geodetic Network Points, Fredericton Approach
Vrečko, Anja
2010-01-01
This graduate thesis deals with the Fredericton approach for determining displacements in geodetic networks. In the introduction strain analysis is presented from a geodetic point of view. Special emphasis is placed on the problem of geodetic datum. It is followed by a theoretical explanation of the method in five steps: adjustment of observation for each epoch, preliminary identification of deformation models, estimation of deformation parameters, checking the deformation models and selectin...
Relativistic quantum mechanics
Wachter, Armin
2010-01-01
Which problems do arise within relativistic enhancements of the Schrödinger theory, especially if one adheres to the usual one-particle interpretation, and to what extent can these problems be overcome? And what is the physical necessity of quantum field theories? In many books, answers to these fundamental questions are given highly insufficiently by treating the relativistic quantum mechanical one-particle concept very superficially and instead introducing field quantization as soon as possible. By contrast, this monograph emphasizes relativistic quantum mechanics in the narrow sense: it extensively discusses relativistic one-particle concepts and reveals their problems and limitations, therefore motivating the necessity of quantized fields in a physically comprehensible way. The first chapters contain a detailed presentation and comparison of the Klein-Gordon and Dirac theory, always in view of the non-relativistic theory. In the third chapter, we consider relativistic scattering processes and develop the...
ZHANG Peng-Fei; RUAN Tu-Nan
2001-01-01
A systematic theory on the appropriate spin operators for the relativistic states is developed. For a massive relativistic particle with arbitrary nonzero spin, the spin operator should be replaced with the relativistic one, which is called in this paper as moving spin. Further the concept of moving spin is discussed in the quantum field theory. A new is constructed. It is shown that, in virtue of the two operators, problems in quantum field concerned spin can be neatly settled.
Relativistic Guiding Center Equations
White, R. B. [PPPL; Gobbin, M. [Euratom-ENEA Association
2014-10-01
In toroidal fusion devices it is relatively easy that electrons achieve relativistic velocities, so to simulate runaway electrons and other high energy phenomena a nonrelativistic guiding center formalism is not sufficient. Relativistic guiding center equations including flute mode time dependent field perturbations are derived. The same variables as used in a previous nonrelativistic guiding center code are adopted, so that a straightforward modifications of those equations can produce a relativistic version.
Relativistic Linear Restoring Force
Clark, D.; Franklin, J.; Mann, N.
2012-01-01
We consider two different forms for a relativistic version of a linear restoring force. The pair comes from taking Hooke's law to be the force appearing on the right-hand side of the relativistic expressions: d"p"/d"t" or d"p"/d["tau"]. Either formulation recovers Hooke's law in the non-relativistic limit. In addition to these two forces, we…
MALFLIET, R
1993-01-01
We discuss the present status of relativistic transport theory. Special emphasis is put on problems of topical interest: hadronic features, thermodynamical consistent approximations and spectral properties.
Geodetic and Geodynamic Studies at Department of Geodesy and Geodetic Astronomy Wut
Brzeziński Aleksander
2016-06-01
Full Text Available The article presents current issues and research work conducted in the Department of Geodesy and Geodetic Astronomy at the Faculty of Geodesy and Cartography at Warsaw University of Technology. It contains the most important directions of research in the fields of physical geodesy, satellite measurement techniques, GNSS meteorology, geodynamic studies, electronic measurement techniques and terrain information systems.
The Apsidal Precession for Low Earth Sun Synchronized Orbits
Shkelzen Cakaj
2015-09-01
Full Text Available By nodal regression and apsidal precession, the Earth flattering at satellite low Earth orbits (LEO is manifested. Nodal regression refers to the shift of the orbit’s line of nodes over time as Earth revolves around the Sun. Nodal regression is orbit feature utilized for circular orbits to be Sun synchronized. A sun¬-synchronized orbit lies in a plane that maintains a fixed angle with respect to the Earth-Sun direction. In the low Earth Sun synchronized circular orbits are suited the satellites that accomplish their photo imagery missions. Nodal regression depends on orbital altitude and orbital inclination angle. For the respective orbital altitudes the inclination window for the Sun synchronization to be attained is determined. The apsidal precession represents major axis shift, respectively the argument of perigee deviation. The apsidal precession simulation, for inclination window of sun synchronized orbital altitudes, is provided through this paper.
Analytic gravitational waveforms for generic precessing compact binaries
Chatziioannou, Katerina; Cornish, Neil; Yunes, Nicolas
2016-01-01
Binary systems of two compact objects circularize and spiral toward each other via the emission of gravitational waves. The coupling of the spins of each object with the orbital angular momentum causes the orbital plane to precess, which leads to modulation of the gravitational wave signal. Until now, generating frequency-domain waveforms for fully precessing systems for use in gravitational wave data analysis meant numerically integrating the equations of motion, then Fourier transforming the result, which is very computationally intensive for systems that complete hundreds or thousands of cycles in the sensitive band of a detector. Previously, analytic solutions were only available for certain special cases or for simplified models. Here we describe the construction of closed-form, frequency-domain waveforms for fully-precessing, quasi-circular binary inspirals.
Gravitational-wave modes from precessing black-hole binaries
Boyle, Michael; Ossokine, Serguei; Pfeiffer, Harald P
2014-01-01
Gravitational waves from precessing black-hole binaries exhibit features that are absent in nonprecessing systems. The most prominent of these is a parity-violating asymmetry that beams energy and linear momentum preferentially along or opposite to the orbital angular momentum, leading to recoil of the binary. The asymmetry will appear as amplitude and phase modulations at the orbital frequency. For strongly precessing systems, it accounts for at least 3% amplitude modulation for binaries in the sensitivity band of ground-based gravitational-wave detectors, and can exceed 50% for massive systems. Such asymmetric features are also clearly visible when the waves are decomposed into modes of spin-weighted spherical harmonics, and are inherent in the waves themselves---rather than resulting from residual eccentricity in numerical simulations, or from mode-mixing due to precession. In particular, there is generically no instantaneous frame for which the mode decomposition will have any symmetry. We introduce a met...
Spinning, Precessing, Black Hole Binary Spacetime via Asymptotic Matching
Nakano, Hiroyuki; Campanelli, Manuela; West, Eric J
2016-01-01
We briefly discuss a method to construct a global, analytic, approximate spacetime for precessing, spinning binary black holes. The spacetime construction is broken into three parts: the inner zones are the spacetimes close to each black hole, and are approximated by perturbed Kerr solutions; the near zone is far from the two black holes, and described by the post-Newtonian metric; and finally the wave (far) zone, where retardation effects need to be taken into account, is well modeled by the post-Minkowskian metric. These individual spacetimes are then stitched together using asymptotic matching techniques to obtain a global solution that approximately satisfies the Einstein field equations. Precession effects are introduced by rotating the black hole spin direction according to the precessing equations of motion, in a way that is consistent with the global spacetime construction.
Phase and precession evolution in the Burgers equation
Buzzicotti, Michele; Biferale, Luca; Bustamante, Miguel D
2015-01-01
We present a phenomenological study of the phase dynamics of the one-dimensional stochastically forced Burgers equation. We propose a way to link coherent structures in real space with the evolution of triads in Fourier space. The method is based on the idea that the real space structures can be associated with entangled correlations amongst the phase precession frequencies and the amplitude evolution of triads in Fourier space. As a result, triad precession frequencies show a non-Gaussian distribution with multiple peaks and fat tails, and there is a significant correlation between triad precession frequencies and amplitude growth. Links with dynamical systems approach are briefly discussed, such as the role of unstable critical points in state space. This analysis has been further developed for Burgers equation evolved on a fractal Fourier set. In this latter case, we observe a depletion of intermittency as a function of the fractal dimension $D$, and the simultaneous reduction of the correlation between th...
Relativistic quantum mechanics; Mecanique quantique relativiste
Ollitrault, J.Y. [CEA Saclay, 91 - Gif-sur-Yvette (France). Service de Physique Theorique]|[Universite Pierre et Marie Curie, 75 - Paris (France)
1998-12-01
These notes form an introduction to relativistic quantum mechanics. The mathematical formalism has been reduced to the minimum in order to enable the reader to calculate elementary physical processes. The second quantification and the field theory are the logical followings of this course. The reader is expected to know analytical mechanics (Lagrangian and Hamiltonian), non-relativistic quantum mechanics and some basis of restricted relativity. The purpose of the first 3 chapters is to define the quantum mechanics framework for already known notions about rotation transformations, wave propagation and restricted theory of relativity. The next 3 chapters are devoted to the application of relativistic quantum mechanics to a particle with 0,1/5 and 1 spin value. The last chapter deals with the processes involving several particles, these processes require field theory framework to be thoroughly described. (A.C.) 2 refs.
Towards relativistic quantum geometry
Ridao, Luis Santiago [Instituto de Investigaciones Físicas de Mar del Plata (IFIMAR), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Mar del Plata (Argentina); Bellini, Mauricio, E-mail: mbellini@mdp.edu.ar [Departamento de Física, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Funes 3350, C.P. 7600, Mar del Plata (Argentina); Instituto de Investigaciones Físicas de Mar del Plata (IFIMAR), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Mar del Plata (Argentina)
2015-12-17
We obtain a gauge-invariant relativistic quantum geometry by using a Weylian-like manifold with a geometric scalar field which provides a gauge-invariant relativistic quantum theory in which the algebra of the Weylian-like field depends on observers. An example for a Reissner–Nordström black-hole is studied.
Vorticity, gyroscopic precession, and spin-curvature force
Liang, Wei Chieh; Lee, Si Chen
2013-02-01
In investigating the relationship between vorticity and gyroscopic precession, we calculate the vorticity vector in Godel, Kerr, Lewis, Schwarzschild, and Minkowski metrics and find that the vorticity vector of the specific observers is the angular velocity of the gyroscopic precession. Furthermore, when space-time torsion is included, the vorticity and spin-curvature force change sign. This result is very similar to the behavior of the positive and negative helicities of quantum spin in the Stern-Gerlach force. It implies that the inclusion of torsion will lead to an analogous property of quantum spin even in classical treatment.
Vorticity, Gyroscopic precession, and Spin-Curvature Force
Liang, Wei Chieh
2012-01-01
In investigating the relation between vorticity and gyroscopic precession, we calculate the vorticity vector in Godel, Kerr, Lewis, Schwarzschild, Minkowski metric and find out the vorticity vector of the specific observers is the angular velocity of gyroscopic precession. Furthermore, considering space-time torsion will flip the vorticity and spin-curvature force to opposite sign. This result is very similar to the behavior of positive and negative helicity of quantum spin in Stern-Gerlach force. It implies that the inclusion of torsion will lead to analogous property of quantum spin even in classical treatment.
Nonlinear dynamo action in a precessing cylindrical container.
Nore, C; Léorat, J; Guermond, J-L; Luddens, F
2011-07-01
It is numerically demonstrated by means of a magnetohydrodynamics code that precession can trigger the dynamo effect in a cylindrical container. When the Reynolds number, based on the radius of the cylinder and its angular velocity, increases, the flow, which is initially centrosymmetric, loses its stability and bifurcates to a quasiperiodic motion. This unsteady and asymmetric flow is shown to be capable of sustaining dynamo action in the linear and nonlinear regimes. The magnetic field thus generated is unsteady and quadrupolar. These numerical evidences of dynamo action in a precessing cylindrical container may be useful for an experiment now planned at the Dresden sodium facility for dynamo and thermohydraulic studies in Germany.
Reduction of Electron Channeling in EDS using Precession
Liao, Yifeng; Marks, Laurence D.
2012-01-01
We demonstrate that EDS measurement can be significantly improved by precessing the electron beam, thereby reducing electron channeling effects. For a SrTiO3 specimen orientated along [001] zone axis, the measured strontium to titanium atomic ratio was 0.74 – 0.80 using conventional EDS methods, and the ratio was improved to ~0.99 by precessing the electron beam for angles greater than 22.54 mRad. In ALCHEMI-like experiments in which the specimen was tilted to near two-beam condition, the str...
Geodetic sensor systems and sensor networks: positioning and applications
Verhagen, S.; Grejner-Brzezinska, D.; Retscher, G.; Santos, M.; Ding, X.; Gao, Y.; Jin, S.
2009-01-01
This contribution focuses on geodetic sensor systems and sensor networks for positioning and applications. The key problems in this area will be addressed together with an overview of applications. Global Navigation Satellite Systems (GNSS) and other geodetic techniques play a central role in many a
Geodetic sensor systems and sensor networks: positioning and applications
Verhagen, S.; Grejner-Brzezinska, D.; Retscher, G.; Santos, M.; Ding, X.; Gao, Y.; Jin, S.
2009-01-01
This contribution focuses on geodetic sensor systems and sensor networks for positioning and applications. The key problems in this area will be addressed together with an overview of applications. Global Navigation Satellite Systems (GNSS) and other geodetic techniques play a central role in many
GINFEST: Geodetic Intercomparison Network for Evaluating Space Techniques
Ashkenazi, Vidal
Details are given of a geodetic network connecting the major radio telescopes and SLR facilities in Western and Central Europe, which is to be used in a co-location exercise involving VLBI, CERI, SLR and GPS observations, with the aim of evaluating the relative accuracies and system biases of these geodetic space observation techniques.
Relativistic and Non-relativistic Equations of Motion
Mangiarotti, L
1998-01-01
It is shown that any second order dynamic equation on a configuration space $X$ of non-relativistic time-dependent mechanics can be seen as a geodesic equation with respect to some (non-linear) connection on the tangent bundle $TX\\to X$ of relativistic velocities. Using this fact, the relationship between relativistic and non-relativistic equations of motion is studied.
Spin precession in a black hole and naked singularity spacetimes
Chakraborty, Chandrachur; Kocherlakota, Prashant; Joshi, Pankaj S.
2017-02-01
We propose here a specific criterion to address the existence or otherwise of Kerr naked singularities, in terms of the precession of the spin of a test gyroscope due to the frame dragging by the central spinning body. We show that there is indeed an important characteristic difference in the behavior of gyro spin precession frequency in the limit of approach to these compact objects, and this can be used, in principle, to differentiate the naked singularity from a black hole. Specifically, if gyroscopes are fixed all along the polar axis up to the horizon of a Kerr black hole, the precession frequency becomes arbitrarily high, blowing up as the event horizon is approached. On the other hand, in the case of naked singularity, this frequency remains always finite and well behaved. Interestingly, this behavior is intimately related to and is governed by the geometry of the ergoregion in each of these cases, which we analyze here. One intriguing behavior that emerges is, in the Kerr naked singularity case, the Lense-Thirring precession frequency (ΩLT ) of the gyroscope due to frame-dragging effect decreases as (ΩLT∝r ) after reaching a maximum, in the limit of r =0 , as opposed to r-3 dependence in all other known astrophysical cases.
Combined obliquity and precession pacing of late Pleistocene deglaciations.
Huybers, Peter
2011-12-08
Milankovitch proposed that Earth resides in an interglacial state when its spin axis both tilts to a high obliquity and precesses to align the Northern Hemisphere summer with Earth's nearest approach to the Sun. This general concept has been elaborated into hypotheses that precession, obliquity or combinations of both could pace deglaciations during the late Pleistocene. Earlier tests have shown that obliquity paces the late Pleistocene glacial cycles but have been inconclusive with regard to precession, whose shorter period of about 20,000 years makes phasing more sensitive to timing errors. No quantitative test has provided firm evidence for a dual effect. Here I show that both obliquity and precession pace late Pleistocene glacial cycles. Deficiencies in time control that have long stymied efforts to establish orbital effects on deglaciation are overcome using a new statistical test that focuses on maxima in orbital forcing. The results are fully consistent with Milankovitch's proposal but also admit the possibility that long Southern Hemisphere summers contribute to deglaciation.
Transit probability of precessing circumstellar planets in binaries and exomoons
Martin, David. V.
2017-05-01
Over two decades of exoplanetology has yielded thousands of discoveries, yet some types of systems are still to be observed. Circumstellar planets around one star in a binary have been found, but not for tight binaries (≲5 au). Additionally, extra-solar moons are yet to be found. This paper motivates finding both types of three-body system by calculating analytic and numerical probabilities for all transit configurations, accounting for any mutual inclination and orbital precession. The precession and relative three-body motion can increase the transit probability to as high as tens of per cent, and make it inherently time-dependent over a precession period as short as 5-10 yr. Circumstellar planets in such tight binaries present a tempting observational challenge: enhanced transit probabilities but with a quasi-periodic signature that may be difficult to identify. This may help explain their present non-detection, or maybe they simply do not exist. Whilst this paper considers binaries of all orientations, it is demonstrated how eclipsing binaries favourably bias the transit probabilities, sometimes to the point of being guaranteed. Transits of exomoons exhibit a similar behaviour under precession, but unfortunately only have one star to transit rather than two.
Radio source stability and geodetic VLBI
Gattano, César; Lambert, Sébastien
2016-04-01
The observation of the Earth's rotation by VLBI is conditioned by the celestial reference frame that should be as stable as possible. The selection of the most stable sources therefore constitutes a major step in the construction of a celestial reference frame since their stability prevents time deformation of the axes with time. The assessment of astrometric stability, i.e., the time stability the radiocenter location as detected by the VLBI, is one of the methods that were used in previous ICRF realizations (works of M. Feissel-Vernier and ICRF2). We think the same method should be addressed for the construction of the ICRF3. We analyzed the radio source time series obtained from the analysis of the data from the permanent geodetic VLBI monitoring program of the IVS. We used several utils based on basic statistics and more advanced methods (Allan variance) in order to provide a preliminary classification of sources.
Schmidt, Patricia; Husa, Sascha
2012-01-01
One of the greatest theoretical challenges in the build-up to the era of second-generation gravitational-wave detectors is the modeling of generic binary waveforms. We introduce an approximation that has the potential to significantly simplify this problem. We show that generic precessing-binary inspiral waveforms (covering a seven-dimensional parameter space) can be mapped to only a two-dimensional space of non-precessing binaries, characterized by the mass ratio and a single effective total spin. The mapping consists of a time-dependent rotation of the waveforms into the quadrupole-aligned frame, and is extremely accurate (matches $> 0.99$ with parameter biases in the total spin of $\\Delta \\chi \\leq 0.04$), even in the case of transitional precession. In addition, we demonstrate a simple method to construct hybrid post-Newtonian--numerical-relativity precessing-binary waveforms in the quadrupole-aligned frame, and provide evidence that our approximate mapping can be used all the way to the merger. Finally, ...
Relativistic spherical plasma waves
Bulanov, S. S.; Maksimchuk, A.; Schroeder, C. B.; Zhidkov, A. G.; Esarey, E.; Leemans, W. P.
2012-02-01
Tightly focused laser pulses that diverge or converge in underdense plasma can generate wake waves, having local structures that are spherical waves. Here we study theoretically and numerically relativistic spherical wake waves and their properties, including wave breaking.
Bliokh, Konstantin Y
2011-01-01
We consider the relativistic deformation of quantum waves and mechanical bodies carrying intrinsic angular momentum (AM). When observed in a moving reference frame, the centroid of the object undergoes an AM-dependent transverse shift. This is the relativistic analogue of the spin Hall effect, which occurs in free space without any external fields. Remarkably, the shifts of the geometric and energy centroids differ by a factor of 2, and both centroids are crucial for the correct Lorentz transformations of the AM tensor. We examine manifestations of the relativistic Hall effect in quantum vortices, mechanical flywheel, and discuss various fundamental aspects of the phenomenon. The perfect agreement of quantum and relativistic approaches allows applications at strikingly different scales: from elementary spinning particles, through classical light, to rotating black-holes.
Lense-Thirring precession in neutron-star low-mass X-ray binaries
Homan, Jeroen
Quasi-periodic oscillations (QPOs) with low frequencies (0.01-70 Hz) have been observed in the X-ray light curves of most neutron-star and black-hole low-mass X-ray binaries. Despite having been discovered more than 25 years ago, their origin is still not well understood. Similarities between the low-frequency QPOs in the two types of systems suggest that they have a common origin in the accretion flows around black holes and neutron stars. Some of the proposed models that attempt to explain low- frequency QPOs invoke a General Relativistic effect known as Lense-Thirring precession (or "frame dragging"). However, for Lense-Thirring precession to produce substantial modulations of the X-ray flux through relativistic beaming and gravitational lensing, the rotation axis of the inner part of the accretion disk needs to have a substantial tilt (10-20 degrees) with respect to the spin axis of the compact object. We argue that observational evidence for such titled inner accretion disks can be found in the variability of neutron- star low-mass X-ray binaries that are viewed at inclination angles of 60-80 degrees. In these systems low-frequency QPOs at ~0.1-15 Hz are observed that modulate the emission from the neutron star by quasi-periodic obscuration, presumably by a titled inner disc. The goal of our proposed program is to test whether the frequency evolution and spectral state dependence of these QPOs is similar to what is observed for the low-frequency QPOs that are observed in lower-inclination neutron-star X-ray binaries. To make such a comparison, we need to better characterize the properties and behavior of these QPOs. Our study will make use of almost 1300 RXTE observations of 11 sources, totaling 5.7 Ms of data. Signatures of strong gravity have long been sought after in accreting compact objects. While strong evidence from spectral features has emerged in the last decade (e.g. gravitationally broadened iron emission lines), there have only been hints of such
Exact Relativistic 'Antigravity' Propulsion
Felber, F S
2006-01-01
The Schwarzschild solution is used to find the exact relativistic motion of a payload in the gravitational field of a mass moving with constant velocity. At radial approach or recession speeds faster than 3^-1/2 times the speed of light, even a small mass gravitationally repels a payload. At relativistic speeds, a suitable mass can quickly propel a heavy payload from rest nearly to the speed of light with negligible stresses on the payload.
Exact Relativistic `Antigravity' Propulsion
Felber, Franklin S.
2006-01-01
The Schwarzschild solution is used to find the exact relativistic motion of a payload in the gravitational field of a mass moving with constant velocity. At radial approach or recession speeds faster than 3-1/2 times the speed of light, even a small mass gravitationally repels a payload. At relativistic speeds, a suitable mass can quickly propel a heavy payload from rest nearly to the speed of light with negligible stresses on the payload.
Relativistic quantum revivals.
Strange, P
2010-03-26
Quantum revivals are now a well-known phenomena within nonrelativistic quantum theory. In this Letter we display the effects of relativity on revivals and quantum carpets. It is generally believed that revivals do not occur within a relativistic regime. Here we show that while this is generally true, it is possible, in principle, to set up wave packets with specific mathematical properties that do exhibit exact revivals within a fully relativistic theory.
无
2001-01-01
In order to improve the anti-jamming performance of a vortex precession meter, the disciplinarian of the vortex precession and the mechanism of hydrodynamic oscillation inside the vortex precession meter are numerically investigated by using the large eddy simulation. The results show that the periodical eccentric motion of the vortexes initiates a hydrodynamic oscillation inside the vortex precession meter. The visualized time dependent flow fields indicate that the pressures at axisymmetric points oscillate with a same intensity and frequency but 180° phase shift. By using differential sensing technique,a new prototype of double-sensor vortex precession meter,aimed to improve measurement accuracy, is developed.
Ballistic missile precession frequency extraction based on the Viterbi & Kalman algorithm
Wu, Longlong; Xie, Yongjie; Xu, Daping; Ren, Li
2015-12-01
Radar Micro-Doppler signatures are of great potential for target detection, classification and recognition. In the mid-course phase, warheads flying outside the atmosphere are usually accompanied by precession. Precession may induce additional frequency modulations on the returned radar signal, which can be regarded as a unique signature and provide additional information that is complementary to existing target recognition methods. The main purpose of this paper is to establish a more actual precession model of conical ballistic missile warhead and extract the precession parameters by utilizing Viterbi & Kalman algorithm, which improving the precession frequency estimation accuracy evidently , especially in low SNR.
Relativistic viscoelastic fluid mechanics.
Fukuma, Masafumi; Sakatani, Yuho
2011-08-01
A detailed study is carried out for the relativistic theory of viscoelasticity which was recently constructed on the basis of Onsager's linear nonequilibrium thermodynamics. After rederiving the theory using a local argument with the entropy current, we show that this theory universally reduces to the standard relativistic Navier-Stokes fluid mechanics in the long time limit. Since effects of elasticity are taken into account, the dynamics at short time scales is modified from that given by the Navier-Stokes equations, so that acausal problems intrinsic to relativistic Navier-Stokes fluids are significantly remedied. We in particular show that the wave equations for the propagation of disturbance around a hydrostatic equilibrium in Minkowski space-time become symmetric hyperbolic for some range of parameters, so that the model is free of acausality problems. This observation suggests that the relativistic viscoelastic model with such parameters can be regarded as a causal completion of relativistic Navier-Stokes fluid mechanics. By adjusting parameters to various values, this theory can treat a wide variety of materials including elastic materials, Maxwell materials, Kelvin-Voigt materials, and (a nonlinearly generalized version of) simplified Israel-Stewart fluids, and thus we expect the theory to be the most universal description of single-component relativistic continuum materials. We also show that the presence of strains and the corresponding change in temperature are naturally unified through the Tolman law in a generally covariant description of continuum mechanics.
Palge, Veiko; Dunningham, Jacob; Hasegawa, Yuji
2016-01-01
In quantum physics Wigner's rotation is commonly regarded as confirmed by the Thomas precession in a hydrogen like atom. In this paper we show that a direct experimental verification of Wigner's rotation is in principle accessible in the regime of non-relativistic velocities at $2 \\cdot 10^3\\,$m/s and propose an experiment using thermal neutrons. The experiment can be carried out in a laboratory and it provides a test of relativity in the quantum domain.
Relativistic 3D jet simulations for the X-ray binary SS433
Monceau-Baroux, Remi; Meliani, Zakaria; Porth, Oliver
2013-01-01
Context. Modern high resolution observations allow to view closer into the objects powering relativistic jets. This is especially the case for SS433, an X-ray binary from which a precessing jet is observed down to the sub-parsec scale. Aims. We want to study full 3D dynamics of relativistic jets associated with AGN or XRB. We study the precessing motion of a jet as a model for the jet associated with the XRB SS433. Our study of the jet dynamics in this system focuses on the sub-parsec scales. We investigate the impact of jet precession and the variation of the Lorentz factor of the injected matter on the general 3D jet dynamics and its energy transfer to the surrounding medium. We realize synthetic radio mapping of the data, to compare our results with observations. Methods. For our study we use the code MPI-AMRVAC with SRHD model of a baryonic jet. We use a AMR scheme and an inner time-dependent boundary prescription to inject the jets. Parameters extracted from observations were used. 3D jet realizations th...
Geodetic Control Points - Multi-State Control Point Database
NSGIC GIS Inventory (aka Ramona) — The Multi-State Control Point Database (MCPD) is a database of geodetic and mapping control covering Idaho and Montana. The control were submitted by registered land...
Geodetic Control Points, Published in 2004, Jones County GIS.
NSGIC GIS Inventory (aka Ramona) — This Geodetic Control Points dataset, was produced all or in part from Field Survey/GPS information as of 2004. Data by this publisher are often provided in State...
Geodetic Control Points - Multi-State Control Point Database
NSGIC State | GIS Inventory — The Multi-State Control Point Database (MCPD) is a database of geodetic and mapping control covering Idaho and Montana. The control were submitted by registered land...
Relativistic HD and MHD modelling for AGN jets
Keppens, R.; Porth, O.; Monceau-Baroux, R.; Walg, S.
2013-12-01
Relativistic hydro and magnetohydrodynamics (MHD) provide a continuum fluid description for plasma dynamics characterized by shock-dominated flows approaching the speed of light. Significant progress in its numerical modelling emerged in the last two decades; we highlight selected examples of modern grid-adaptive, massively parallel simulations realized by our open-source software MPI-AMRVAC (Keppens et al 2012 J. Comput. Phys. 231 718). Hydrodynamical models quantify how energy transfer from active galactic nuclei (AGN) jets to their surrounding interstellar/intergalactic medium (ISM/IGM) gets mediated through shocks and various fluid instability mechanisms (Monceau-Baroux et al 2012 Astron. Astrophys. 545 A62). With jet parameters representative for Fanaroff-Riley type-II jets with finite opening angles, we can quantify the ISM volumes affected by jet injection and distinguish the roles of mixing versus shock-heating in cocoon regions. This provides insight in energy feedback by AGN jets, usually incorporated parametrically in cosmological evolution scenarios. We discuss recent axisymmetric studies up to full 3D simulations for precessing relativistic jets, where synthetic radio maps can confront observations. While relativistic hydrodynamic models allow one to better constrain dynamical parameters like the Lorentz factor and density contrast between jets and their surroundings, the role of magnetic fields in AGN jet dynamics and propagation characteristics needs full relativistic MHD treatments. Then, we can demonstrate the collimating properties of an overal helical magnetic field backbone and study differences between poloidal versus toroidal field dominated scenarios (Keppens et al 2008 Astron. Astrophys. 486 663). Full 3D simulations allow one to consider the fate of non-axisymmetric perturbations on relativistic jet propagation from rotating magnetospheres (Porth 2013 Mon. Not. R. Astron. Soc. 429 2482). Self-stabilization mechanisms related to the detailed
Post-Newtonian reference ellipsoid for relativistic geodesy
Kopeikin, Sergei; Han, Wenbiao; Mazurova, Elena
2016-02-01
We apply general relativity to construct the post-Newtonian background manifold that serves as a reference spacetime in relativistic geodesy for conducting a relativistic calculation of the geoid's undulation and the deflection of the plumb line from the vertical. We chose an axisymmetric ellipsoidal body made up of a perfect homogeneous fluid uniformly rotating around a fixed axis, as a source generating the reference geometry of the background manifold through Einstein's equations. We then reformulate and extend hydrodynamic calculations of rotating fluids done by a number of previous researchers for astrophysical applications to the realm of relativistic geodesy to set up algebraic equations defining the shape of the post-Newtonian reference ellipsoid. To complete this task, we explicitly perform all integrals characterizing gravitational field potentials inside the fluid body and represent them in terms of the elementary functions depending on the eccentricity of the ellipsoid. We fully explore the coordinate (gauge) freedom of the equations describing the post-Newtonian ellipsoid and demonstrate that the fractional deviation of the post-Newtonian level surface from the Maclaurin ellipsoid can be made much smaller than the previously anticipated estimate based on the astrophysical application of the coordinate gauge advocated by Bardeen and Chandrasekhar. We also derive the gauge-invariant relations of the post-Newtonian mass and the constant angular velocity of the rotating fluid with the parameters characterizing the shape of the post-Newtonian ellipsoid including its eccentricity, a semiminor axis, and a semimajor axis. We formulate the post-Newtonian theorems of Pizzetti and Clairaut that are used in geodesy to connect the geometric parameters of the reference ellipsoid to the physically measurable force of gravity at the pole and equator of the ellipsoid. Finally, we expand the post-Newtonian geodetic equations describing the post-Newtonian ellipsoid to
A geometric approach to the precession of compact binaries
Boyle, Michael; Pfeiffer, Harald P
2011-01-01
We propose a geometrical method to define a preferred reference frame for precessing binary systems. This minimal-rotation frame is aligned with the angular-momentum axis and fixes the rotation about that axis up to a constant angle, resulting in an essentially invariant frame. Gravitational waveforms decomposed in this frame are similarly invariant under rotations of the inertial frame and exhibit relatively smoothly varying phase. By contrast, earlier prescriptions for radiation-aligned frames induce extraneous features in the gravitational-wave phase which depend on the orientation of the inertial frame, which leads to fluctuations in the frequency and may compound to many gravitational-wave cycles. We suggest that the minimal-rotation frame provides a simplified framework for post-Newtonian approximations of precessing systems and describe the construction of analytical/numerical hybrid waveforms for such systems.
Triadic instability of a non-resonant precessing fluid cylinder
Lagrange, R; Eloy, C
2015-01-01
Flows forced by a precessional motion can exhibit instabilities of crucial importance, whether they concern the fuel of a flying object or the liquid core of a telluric planet. So far, stability analyses of these flows have focused on the special case of a resonant forcing. Here, we address the instability of the flow inside a precessing cylinder in the general case. We first show that the base flow forced by the cylinder precession is a superposition of a vertical or horizontal shear flow and an infinite sum of forced modes. We then perform a linear stability analysis of this base flow by considering its triadic resonance with two free Kelvin modes. Finally, we derive the amplitude equations of the free Kelvin modes and obtain an expression of the instability threshold and growth rate.
First Evidence of a Precessing Jet Excavating a Protostellar Envelope
Ybarra, J E; Haisch, K E; Jarrett, T H; Sahai, R; Weinberger, A J; Ybarra, Jason E.; Barsony, Mary; Haisch, Karl E.; Jarrett, Thomas H.; Sahai, Raghvendra; Weinberger, Alycia J.
2006-01-01
We present new, sensitive, near-infrared images of the Class I protostar, Elias 29, in the Ophiuchus cloud core. To explore the relationship between the infall envelope and the outflow, narrowband H2 1-0 S(1), Br-gamma, and narrowband K-continuum filters were used to image the source with the Wide-Field Infrared Camera on the Hale 5m telescope and with Persson's Auxiliary Nasmyth Infrared Camera on the Baade 6.5 m telescope. The source appears as a bipolar, scattered light nebula, with a wide opening angle in all filters, as is typical for late-stage protostars. However, the pure H2 emission-line images point to the presence of a heretofore undetected precessing jet. It is argued that high-velocity, narrow, precessing jets provide the mechanism for creating the observed wide-angled outflow cavity in this source.
Spin precession of Dirac particles in Kerr geometry
Farooqui, Anusar
2017-01-01
We isolate and study the transformation of the intrinsic spin of Dirac particles as they propagate along timelike geodesics in Kerr geometry. Reference frames play a crucial role in the definition and measurement of the intrinsic spin of test particles. We show how observers located in the outer geometry of Kerr black holes may exploit the symmetries of the geometry to set up reference frames using purely geometric, locally-available information. Armed with these geometrically-defined reference frames, we obtain a closed-form expression for the geometrically-induced spin precession of Dirac particles in the outer geometry of Kerr black holes. We show that the spin of Dirac particles does not precess on the equatorial place of Kerr geometry; and hence, in Schwarzschild geometry.
Precession-driven flows in non-axisymmetric ellipsoids
Noir, Jerome
2014-01-01
We study the flow forced by precession in rigid non-axisymmetric ellipsoidal containers. To do so, we revisit the inviscid and viscous analytical models that have been previously developed for the spheroidal geometry by, respectively, Poincar\\'e (Bull. Astronomique, vol. XXVIII, 1910, pp. 1-36) and Busse (J. Fluid Mech., vol. 33, 1968, pp. 739-751), and we report the first numerical simulations of flows in such a geometry. In strong contrast with axisymmetric spheroids, where the forced flow is systematically stationary in the precessing frame, we show that the forced flow is unsteady and periodic. Comparisons of the numerical simulations with the proposed theoretical model show excellent agreement for both axisymmetric and non-axisymmetric containers. Finally, since the studied configuration corresponds to a tidally locked celestial body such as the Earth's Moon, we use our model to investigate the challenging but planetary-relevant limit of very small Ekman numbers and the particular case of our Moon.
NSGIC GIS Inventory (aka Ramona) — The following is excerpted from the metadata named "Horizontal and Vertical Geodetic Control Data" provided by NOAA: "This data contains a set of geodetic control...
Successful suppression of magnetization precession after short field pulses
Bauer, Martin; Lopusnik, Radek; Fassbender, Jürgen; Hillebrands, Burkard; Dötsch, H.
2000-01-01
For the next generation of high data rate magnetic recording above 1 Gbit/s, a better understanding of the switching processes for both recording heads and media will be required. In order to maximize the switch-ing speed for such devices, the magnetization precession after the magnetic field pulse termination needs to be suppressed to a maximum degree. It is demonstrated experimentally for ferrite films that the appropriate adjustment of the field pulse parameters and/or the static applied f...
Laser-driven relativistic tunneling from p-states
Klaiber, Michael
2014-01-01
The tunneling ionization of an electron from a p-state in a highly charged ion in the relativistic regime is investigated in a linearly polarized strong laser field. In contrast to the case of an s-state, the tunneling ionization from the p-state is spin asymmetric. We have singled out two reasons for the spin asymmetry: first, the difference of the electron energy Zeeman splitting in the bound state and during tunneling, and second, the relativistic momentum shift along the laser propagation direction during the under-the barrier motion. Due to the latter, those states are predominantly ionized where the electron rotation is opposite to the electron relativistic shift during the under-the-barrier motion. We have investigated the dependence of the ionization rate on the laser intensity for different projections of the total angular momentum and identified the intensity parameter which governs this behaviour. The significant change of the ionization rate is originated from the different precession dynamics of ...
WOBBLING AND PRECESSING JETS FROM WARPED DISKS IN BINARY SYSTEMS
Sheikhnezami, Somayeh [School of Astronomy, Institute for Research in Fundamental Sciences (IPM), Tehran (Iran, Islamic Republic of); Fendt, Christian, E-mail: nezami@mpia.de, E-mail: fendt@mpia.de [Max Planck Institute for Astronomy, Heidelberg (Germany)
2015-12-01
We present results of the first ever three-dimensional (3D) magnetohydrodynamic (MHD) simulations of the accretion–ejection structure. We investigate the 3D evolution of jets launched symmetrically from single stars but also jets from warped disks in binary systems. We have applied various model setups and tested them by simulating a stable and bipolar symmetric 3D structure from a single star–disk–jet system. Our reference simulation maintains a good axial symmetry and also a bipolar symmetry for more than 500 rotations of the inner disk, confirming the quality of our model setup. We have then implemented a 3D gravitational potential (Roche potential) due by a companion star and run a variety of simulations with different binary separations and mass ratios. These simulations show typical 3D deviations from axial symmetry, such as jet bending outside the Roche lobe or spiral arms forming in the accretion disk. In order to find indications of precession effects, we have also run an exemplary parameter setup, essentially governed by a small binary separation of only ≃200 inner disk radii. This simulation shows a strong indication that we observe the onset of a jet precession caused by the wobbling of the jet-launching disk. We estimate the opening angle of the precession cone defined by the lateral motion of the jet axis to be about 4° after about 5000 dynamical time steps.
3D Relativistic MHD Simulation of a Tilted Accretion Disk Around a Rapidly Rotating Black Hole
Fragile, P Chris; Blaes, Omer M; Salmonson, Jay D
2016-01-01
We posit that accreting compact objects, including stellar mass black holes and neutron stars as well as supermassive black holes, may undergo extended periods of accretion during which the angular momentum of the disk at large scales is misaligned with that of the compact object. In such a scenario, Lense-Thirring precession caused by the rotating compact object can dramatically affect the disk. In this presentation we describe results from a three-dimensional relativistic magnetohydrodynamic simulation of an MRI turbulent disk accreting onto a tilted rapidly rotating black hole. For this case, the disk does not achieve the commonly described Bardeen-Petterson configuration; rather, it remains nearly planar, undergoing a slow global precession. Accretion from the disk onto the hole occurs predominantly through two opposing plunging streams that start from high latitudes with respect to both the black-hole and disk midplanes. This is a consequence of the non-sphericity of the gravitational spacetime of the bl...
Relativistic theories of materials
Bressan, Aldo
1978-01-01
The theory of relativity was created in 1905 to solve a problem concerning electromagnetic fields. That solution was reached by means of profound changes in fundamental concepts and ideas that considerably affected the whole of physics. Moreover, when Einstein took gravitation into account, he was forced to develop radical changes also in our space-time concepts (1916). Relativistic works on heat, thermodynamics, and elasticity appeared as early as 1911. However, general theories having a thermodynamic basis, including heat conduction and constitutive equations, did not appear in general relativity until about 1955 for fluids and appeared only after 1960 for elastic or more general finitely deformed materials. These theories dealt with materials with memory, and in this connection some relativistic versions of the principle of material indifference were considered. Even more recently, relativistic theories incorporating finite deformations for polarizable and magnetizable materials and those in which couple s...
Relativistic Quantum Communication
Hosler, Dominic
2013-01-01
In this Ph.D. thesis, I investigate the communication abilities of non-inertial observers and the precision to which they can measure parametrized states. I introduce relativistic quantum field theory with field quantisation, and the definition and transformations of mode functions in Minkowski, Schwarzschild and Rindler spaces. I introduce information theory by discussing the nature of information, defining the entropic information measures, and highlighting the differences between classical and quantum information. I review the field of relativistic quantum information. We investigate the communication abilities of an inertial observer to a relativistic observer hovering above a Schwarzschild black hole, using the Rindler approximation. We compare both classical communication and quantum entanglement generation of the state merging protocol, for both the single and dual rail encodings. We find that while classical communication remains finite right up to the horizon, the quantum entanglement generation tend...
Relativistic quantum mechanics
Horwitz, Lawrence P
2015-01-01
This book describes a relativistic quantum theory developed by the author starting from the E.C.G. Stueckelberg approach proposed in the early 40s. In this framework a universal invariant evolution parameter (corresponding to the time originally postulated by Newton) is introduced to describe dynamical evolution. This theory is able to provide solutions for some of the fundamental problems encountered in early attempts to construct a relativistic quantum theory. A relativistically covariant construction is given for which particle spins and angular momenta can be combined through the usual rotation group Clebsch-Gordan coefficients. Solutions are defined for both the classical and quantum two body bound state and scattering problems. The recently developed quantum Lax-Phillips theory of semigroup evolution of resonant states is described. The experiment of Lindner and coworkers on interference in time is discussed showing how the property of coherence in time provides a simple understanding of the results. Th...
Detection of jet precession in the active nucleus of M 81
Martí-Vidal, I.; Marcaide, J. M.; Alberdi, A.; Pérez-Torres, M. A.; Ros, E.; Guirado, J. C.
2011-09-01
We report on very-long-baseline-interferometry (VLBI) monitoring observations of the low-luminosity active galactic nucleus (LLAGN) in the galaxy M 81 at the frequencies of 1.7, 2.3, 5.0, and 8.4 GHz. The observations reported here are phase-referenced to the supernova SN 1993J (located in the same galaxy) and cover from late 1993 to late 2005. The large amount of available observations allows us to study the stability of the AGN position in the frame of its host galaxy at different frequencies and chromatic effects in the jet morphology, together with their time evolution. The source consists at all frequencies of a slightly resolved core and a small jet extension towards the northeast direction (position angle of ~65 degrees) in agreement with previous publications. We find that the position of the intensity peak in the images at 8.4 GHz is very stable in the galactic frame of M 81 (proper motion upper limit about 10 μas per year). We confirm previous reports that the peaks at all frequencies are systematically shifted among them, possibly due to opacity effects in the jet as predicted by the standard relativistic jet model. We use this model, under plausible assumptions, to estimate the magnetic field in the jet close to the jet base and the mass of the central black hole. We obtain a black-hole mass of ~2 × 107 M⊙, comparable to estimates previously reported using different approaches, but the magnetic fields obtained are 103-104 times lower than previous estimates. We find that the positions of the cores at 1.7, 2.3, and 5.0 GHz are less stable than that at 8.4 GHz and evolve systematically, shifting southward at a rate of several tens of μas per year. The evolution in the jet orientation seems to be related to changes in the inclination of the cores at all frequencies. These results can be interpreted as due to a precessing jet. The evolving jet orientation also seems to be related to a flare in the peak flux densities at 5.0 and 8.4 GHz, which lasts ~4
Handbook of relativistic quantum chemistry
Liu, Wenjian (ed.) [Peking Univ., Beijing (China). Center for Computational Science and Engineering
2017-03-01
This handbook focuses on the foundations of relativistic quantum mechanics and addresses a number of fundamental issues never covered before in a book. For instance: How can many-body theory be combined with quantum electrodynamics? How can quantum electrodynamics be interfaced with relativistic quantum chemistry? What is the most appropriate relativistic many-electron Hamiltonian? How can we achieve relativistic explicit correlation? How can we formulate relativistic properties? - just to name a few. Since relativistic quantum chemistry is an integral component of computational chemistry, this handbook also supplements the ''Handbook of Computational Chemistry''. Generally speaking, it aims to establish the 'big picture' of relativistic molecular quantum mechanics as the union of quantum electrodynamics and relativistic quantum chemistry. Accordingly, it provides an accessible introduction for readers new to the field, presents advanced methodologies for experts, and discusses possible future perspectives, helping readers understand when/how to apply/develop the methodologies.
The precessing jets of 1E 1740.7-2942
Luque-Escamilla, Pedro L.; Martí, Josep; Martínez-Aroza, José
2015-12-01
Context. The source 1E 1740.7-2942 is believed to be one of the two prototypical microquasars towards the Galactic center region whose X-ray states strongly resemble those of Cygnus X-1. Yet, the bipolar radio jets of 1E 1740.7-2942 are very reminiscent of a radio galaxy. The true nature of the object has thus remained an open question for nearly a quarter of a century. Aims: Our main goal here is to confirm the Galactic membership of 1E 1740.7-2942 by searching for morphological changes of its extended radio jets in human timescales. This work was triggered as a result of recent positive detection of fast structural changes in the large-scale jets of the very similar source GRS 1758-258. Methods: We carried out an in-depth exploration of the Very Large Array public archives and fully recalibrated all 1E 1740.7-2942 extended data sets in the C configuration of the array. We obtained and analyzed matching beam radio maps for five epochs, covering years 1992, 1993, 1994, 1997 and 2000, with an angular resolution of a few arcseconds. Results: We clearly detected structural changes in the arc-minute jets of 1E 1740.7-2942 on timescales of roughly a year, which set a firm distance upper limit of 12 kpc. Moreover, a simple precessing twin-jet model was simultaneously fitted to the five observing epochs available. The observed changes in the jet flow are strongly suggestive of a precession period of ~1.3 yr. Conclusions: The fitting of the precession model to the data yields a distance of ~5 kpc. This value, and the observed changes, rule out any remaining doubts about the 1E 1740.7-2942 Galactic nature. To our knowledge, this microquasar is the second whose jet precession ephemeris become available after SS433. This kind of information is relevant to the physics of compact objects, since the genesis of the precession phenomenon occurs very close to the interplay region between the accretion disk and the compact object in the system. Appendix A and a movie associated to
Relativistic electronic dressing
Attaourti, Y
2002-01-01
We study the effects of the relativistic electronic dressing in laser-assisted electron-hydrogen atom elastic collisions. We begin by considering the case when no radiation is present. This is necessary in order to check the consistency of our calculations and we then carry out the calculations using the relativistic Dirac-Volkov states. It turns out that a simple formal analogy links the analytical expressions of the differential cross section without laser and the differential cross section in presence of a laser field.
Fabian, A C; Parker, M L
2014-01-01
Broad emission lines, particularly broad iron-K lines, are now commonly seen in the X-ray spectra of luminous AGN and Galactic black hole binaries. Sensitive NuSTAR spectra over the energy range of 3-78 keV and high frequency reverberation spectra now confirm that these are relativistic disc lines produced by coronal irradiation of the innermost accretion flow around rapidly spinning black holes. General relativistic effects are essential in explaining the observations. Recent results are briefly reviewed here.
Relativistic Rotating Vector Model
Lyutikov, Maxim
2016-01-01
The direction of polarization produced by a moving source rotates with the respect to the rest frame. We show that this effect, induced by pulsar rotation, leads to an important correction to polarization swings within the framework of rotating vector model (RVM); this effect has been missed by previous works. We construct relativistic RVM taking into account finite heights of the emission region that lead to aberration, time-of-travel effects and relativistic rotation of polarization. Polarizations swings at different frequencies can be used, within the assumption of the radius-to-frequency mapping, to infer emission radii and geometry of pulsars.
The special relativistic shock tube
Thompson, Kevin W.
1986-01-01
The shock-tube problem has served as a popular test for numerical hydrodynamics codes. The development of relativistic hydrodynamics codes has created a need for a similar test problem in relativistic hydrodynamics. The analytical solution to the special relativistic shock-tube problem is presented here. The relativistic shock-jump conditions and rarefaction solution which make up the shock tube are derived. The Newtonian limit of the calculations is given throughout.
The SCEC geodetic transient detection validation exercise
Lohman, Rowena B.; Murray, Jessica R.
2013-01-01
Over the past decade the number and size of continuously operating Global Positioning System (GPS) networks has grown substantially worldwide. A steadily increasing volume of freely available GPS measurements, combined with the application of new approaches for mining these data for signals of interest, has led to the identification of a large and diverse collection of time‐varying Earth processes. One phenomenon that has been observed is transient fault slip (also termed slow slip events or silent earthquakes) occurring over time spans of days to years (e.g., Linde et al., 1996; Hirose et al., 1999; Dragert et al., 2001; Miller et al., 2002; Kostoglodov et al., 2003; Douglas et al., 2005; Shelly et al., 2006; Ide et al., 2007; Lohman and McGuire, 2007; Schwartz and Rokosky, 2007; Szeliga et al., 2008). Such events have been widely observed in subduction zones but are also found in other tectonic settings (Linde et al., 1996; Cervelli et al., 2002; Murray and Segall, 2005; Lohman and McGuire, 2007; Montgomery‐Brown et al., 2009; Shelly, 2010; and references therein). Although retrospective study of slow‐slip events using geodetic observations is driving the formulation of new models for fault‐zone behavior and constitutive laws (e.g., Lapusta et al., 2000; Liu and Rice, 2007; Lapusta and Liu, 2009; Segall and Bradley, 2012a), much of the research on near‐real‐time detection and characterization of anomalous behaviors along fault zones has focused solely on the use of seismic tremor (e.g., Rogers and Dragert, 2003; Shelly et al., 2006; Ito et al., 2007).
A Geodetic View on Isostatic Models
Göttl, Franziska; Rummel, Reiner
2009-09-01
Before the background of more accurate and denser gravity data it is worthwhile to reassess geodetic isostasy. Currently, in geodesy isostatic models are primarily applied to gravity reduction as needed by geoid and gravity modeling. The selection of the isostatic model is based on four criteria: Isostatically reduced gravity anomalies should be (1) geophysically meaningful, (2) easy to compute, (3) small, smooth and therefore easy to interpolate and (4) the indirect effect, i.e. the change of potential and gravity due to isostatic mass replacement, should be small. In this study we analyze free air anomalies as well as isostatic anomalies based on the Airy-Heiskanen model and on the Pratt-Hayford model in regard to these criteria. Several facts suggest that free air anomalies are the most realistic type of isostatic anomalies. They reflect the actual isostatic compensation, are easy to compute and their indirect effect is negligibly small. However, they are not smooth due to the fact that local topographic loads are only partially compensated. Smoothness can be achieved by introducing either a mathematical low-pass filter or a hydrostatic isostatic model, such as the Airy-Heiskanen or the Pratt-Hayford model. In both cases the resulting isostatically reduced gravity anomalies fulfill all requirements. In order to improve the numerical efficiency, a new mathematical description of the Pratt-Hayford model is formulated. The level of smoothing with respect to free air anomalies is analyzed in global and regional contexts. It turns out that the mechanism of mass compensation in regions of large topographic loads is better described by the Airy-Heiskanen model, whereas the Pratt-Hayford model is more suitable for regions of deep ocean trenches.
Bruce, Adam L
2015-01-01
We show the traditional rocket problem, where the ejecta velocity is assumed constant, can be reduced to an integral quadrature of which the completely non-relativistic equation of Tsiolkovsky, as well as the fully relativistic equation derived by Ackeret, are limiting cases. By expanding this quadrature in series, it is shown explicitly how relativistic corrections to the mass ratio equation as the rocket transitions from the Newtonian to the relativistic regime can be represented as products of exponential functions of the rocket velocity, ejecta velocity, and the speed of light. We find that even low order correction products approximate the traditional relativistic equation to a high accuracy in flight regimes up to $0.5c$ while retaining a clear distinction between the non-relativistic base-case and relativistic corrections. We furthermore use the results developed to consider the case where the rocket is not moving relativistically but the ejecta stream is, and where the ejecta stream is massless.
The combined effect of precession and convection on the dynamo action
Wei, Xing
2016-01-01
To understand the generation of the Earth's and planetary magnetic fields, we investigate numerically the combined effect of precession and convection on the dynamo action in a spherical shell. The convection alone, the precession alone and the combined effect of convection and precession are studied at the low Ekman number at which the precessing flow is already unstable. The key result is that although the precession or convection alone is not strong to support the dynamo action the combined effect of precession and convection can support the dynamo action because of the resonance of precessional and convective instabilities. This result may interpret why the geodynamo maintains for such a long history compared to the Martian dynamo.
Inspiral waveforms for spinning compact binaries in a new precessing convention
Gupta, Anuradha
2016-01-01
It is customary to use a precessing convention, based on Newtonian orbital angular momentum ${\\bf L}_{\\rm N}$, to model inspiral gravitational waves from generic spinning compact binaries. A key feature of such a precessing convention is its ability to remove all spin precession induced modulations from the orbital phase evolution. However, this convention usually employs a post-Newtonian (PN) accurate precessional equation, appropriate for the PN accurate orbital angular momentum ${\\bf L}$, to evolve the ${\\bf L}_{\\rm N}$-based precessing source frame. This motivated us to develop inspiral waveforms for spinning compact binaries in a precessing convention that explicitly use ${\\bf L}$ to describe the binary orbits. Our approach introduces certain additional 3PN order terms in the orbital phase and frequency evolution equations with respect to the usual ${\\bf L}_{\\rm N}$-based implementation of the precessing convention. The implications of these additional terms are explored by computing the match between in...
Post-newtonian analysis of precessing convention for spinning compact binaries
Gupta, Anuradha
2015-01-01
A precessing source frame, constructed using the Newtonian orbital angular momentum ${\\bf L_{\\rm N}}$, can be invoked to model inspiral gravitational waves from generic spinning compact binaries. An attractive feature of such a precessing convention is its ability to remove all spin precession induced modulations from the orbital phase evolution. However, this convention usually employs a post-Newtonian (PN) accurate precessional equation, appropriate for the PN accurate orbital angular momentum ${\\bf L}$, to evolve the ${\\bf L_{\\rm N}}$-based precessing source frame. This influenced us to develop inspiral waveforms for spinning compact binaries in a precessing convention that explicitly employ ${\\bf L}$ to describe the binary orbits. Our approach introduces certain additional 3PN order terms in the evolution equations for the orbital phase and frequency with respect to the usual ${\\bf L_{\\rm N}}$-based implementation of the precessing convention. We examine the practical implications of these additional term...
Relativistic cosmology; Cosmologia Relativista
Bastero-Gil, M.
2015-07-01
Relativistic cosmology is nothing but the study of the evolution of our universe expanding from the General Theory of Relativity, which describes the gravitational interaction at any scale and given its character far-reaching is the force that dominate the evolution of the universe. (Author)
Relativistic impulse dynamics.
Swanson, Stanley M
2011-08-01
Classical electrodynamics has some annoying rough edges. The self-energy of charges is infinite without a cutoff. The calculation of relativistic trajectories is difficult because of retardation and an average radiation reaction term. By reconceptuallizing electrodynamics in terms of exchanges of impulses rather than describing it by forces and potentials, we eliminate these problems. A fully relativistic theory using photonlike null impulses is developed. Numerical calculations for a two-body, one-impulse-in-transit model are discussed. A simple relationship between center-of-mass scattering angle and angular momentum was found. It reproduces the Rutherford cross section at low velocities and agrees with the leading term of relativistic distinguishable-particle quantum cross sections (Møller, Mott) when the distance of closest approach is larger than the Compton wavelength of the particle. Magnetism emerges as a consequence of viewing retarded and advanced interactions from the vantage point of an instantaneous radius vector. Radiation reaction becomes the local conservation of energy-momentum between the radiating particle and the emitted impulse. A net action is defined that could be used in developing quantum dynamics without potentials. A reinterpretation of Newton's laws extends them to relativistic motion.
Antippa, Adel F.
2009-01-01
We solve the problem of the relativistic rocket by making use of the relation between Lorentzian and Galilean velocities, as well as the laws of superposition of successive collinear Lorentz boosts in the limit of infinitesimal boosts. The solution is conceptually simple, and technically straightforward, and provides an example of a powerful…
Relativistic length agony continued
Redžić D.V.
2014-01-01
Full Text Available We made an attempt to remedy recent confusing treatments of some basic relativistic concepts and results. Following the argument presented in an earlier paper (Redžić 2008b, we discussed the misconceptions that are recurrent points in the literature devoted to teaching relativity such as: there is no change in the object in Special Relativity, illusory character of relativistic length contraction, stresses and strains induced by Lorentz contraction, and related issues. We gave several examples of the traps of everyday language that lurk in Special Relativity. To remove a possible conceptual and terminological muddle, we made a distinction between the relativistic length reduction and relativistic FitzGerald-Lorentz contraction, corresponding to a passive and an active aspect of length contraction, respectively; we pointed out that both aspects have fundamental dynamical contents. As an illustration of our considerations, we discussed briefly the Dewan-Beran-Bell spaceship paradox and the ‘pole in a barn’ paradox. [Projekat Ministarstva nauke Republike Srbije, br. 171028
Gyroscope precession along bound equatorial plane orbits around a Kerr black hole
Bini, Donato; Jantzen, Robert T
2016-01-01
The precession of a test gyroscope along stable bound equatorial plane orbits around a Kerr black hole is analyzed and the precession angular velocity of the gyro's parallel transported spin vector and the increment in precession angle after one orbital period is evaluated. The parallel transported Marck frame which enters this discussion is shown to have an elegant geometrical explanation in terms of the electric and magnetic parts of the Killing-Yano 2-form and a Wigner rotation effect.
Gyroscope precession along bound equatorial plane orbits around a Kerr black hole
Bini, Donato; Geralico, Andrea; Jantzen, Robert T.
2016-09-01
The precession of a test gyroscope along stable bound equatorial plane orbits around a Kerr black hole is analyzed, and the precession angular velocity of the gyro's parallel transported spin vector and the increment in the precession angle after one orbital period is evaluated. The parallel transported Marck frame which enters this discussion is shown to have an elegant geometrical explanation in terms of the electric and magnetic parts of the Killing-Yano 2-form and a Wigner rotation effect.
The Australian Geodetic Observing Program. Current Status and Future Plans
Johnston, G.; Dawson, J. H.
2015-12-01
Over the last decade, the Australian government has through programs like AuScope, the Asia Pacific Reference Frame (APREF), and the Pacific Sea Level Monitoring (PSLM) Project made a significant contribution to the Global Geodetic Observing Program. In addition to supporting the national research priorities, this contribution is justified by Australia's growing economic dependence on precise positioning to underpin efficient transportation, geospatial data management, and industrial automation (e.g., robotic mining and precision agriculture) and the consequent need for the government to guarantee provision of precise positioning products to the Australian community. It is also well recognised within Australia that there is an opportunity to exploit our near unique position as being one of the few regions in the world to see all new and emerging satellite navigation systems including Galileo (Europe), GPS III (USA), GLONASS (Russia), Beidou (China), QZSS (Japan) and IRNSS (India). It is in this context that the Australian geodetic program will build on earlier efforts and further develop its key geodetic capabilities. This will include the creation of an independent GNSS analysis capability that will enable Australia to contribute to the International GNSS Service (IGS) and an upgrade of key geodetic infrastructure including the national VLBI and GNSS arrays. This presentation will overview the significant geodetic activities undertaken by the Australian government and highlight its future plans.
Finocchiaro, S.; Iess, L.; Folkner, W. M.; Asmar, S.
2011-12-01
In its one-year mission around Jupiter (Oct. 2016 - Oct. 2017), the Juno spacecraft will carry out a precise determination of the gravity field, with the goal of unveiling the interior structure of the planet. Juno will be inserted in a polar, highly eccentric orbit (e = 0,9466) with a period of nearly 11 days. The very low pericenter (about 5000 km altitude) makes the orbit especially sensitive to the zonal gravity field. In addition to the perturbations due to classical gravity, the spacecraft is also exposed to significant relativistic effects. In particular, the high velocity at pericenter (60 km/s), in combination with Jupiter's fast rotation (T=10 h), induces a significant acceleration due to the Lense-Thirring (LT) precession. In the low-velocity, weak field approximation, the acceleration is proportional to the angular momentum of the central body and to the velocity of the test particle, and orthogonal to them. A measurement of the LT precession would therefore provide also the angular momentum of the planet. As the perturbing field rapidly decreases with the radial distance, by far the largest acceleration occurs during the pericenter pass (about 6 h). This unique opportunity to observe the LT precession on a planet other than the Earth was first pointed out in [1]. However, the suggested approach, used for the LAGEOS satellites orbiting the Earth, cannot be applied to Juno because large longitude-keeping maneuvers destroy the dynamical coherence of the orbit. We have adopted a different approach, based upon the direct estimation of the LT parameter using a multi-arc, least squares filter. During a pericenter pass, the LT acceleration produces a line-of-sight velocity variation of 0.35 mm/s and a displacement of several meters. These variations can be observed as Doppler shifts on the two-way tracking radio signal. The onboard radio system supports a highly stable, two-way, Ka-band radio link (34 GHz uplink, 32.5 GHz downlink), providing two-way range
Non-thermal optical excitation of terahertz-spin precession in a magneto-optical insulator
Parchenko, Sergii; Maziewski, Andrzej; Stupakiewicz, Andrzej, E-mail: and@uwb.edu.pl [Laboratory of Magnetism, Faculty of Physics, University of Bialystok, 15-245 Bialystok (Poland); Satoh, Takuya [Department of Physics, Kyushu University, 819-0395 Fukuoka (Japan); Yoshimine, Isao [Institute of Industrial Science, The University of Tokyo, 153-8505 Tokyo (Japan); Stobiecki, Feliks [Institute of Molecular Physics Polish Academy of Sciences, 60-179 Poznan (Poland)
2016-01-18
We demonstrate non-thermal ultrafast laser excitation of spin precession with THz frequency in Gd-Bi-substituted iron garnet via the inverse Faraday effect. The modulation of THz precession by about 60 GHz below the compensation temperature of magnetic moment was observed. The THz frequency precession was caused by the exchange resonance between the Gd and Fe sublattices; we attributed the low-frequency modulation to dielectric resonance mode with a magnetic contribution. We demonstrate the possibility of polarization-sensitive control of spin precession under THz generation by laser pulses, helping to develop high-speed magneto-optical devices.
Orbital Precession Effect in the Reissner-Nordstr(o)m Field with a Global Monopole
GONG Tian-Xi; WANG Yong-Jiu
2009-01-01
Using an elegant mathematical method advanced by us,we calculate the orbital precession effect in the gravitational field of the centre mass with electric charge and a global monopole.Analysing the results,we obtain that the orbital precession effect increases on account of the global symmetry breaking,but the orbital precession effect aroused by the electric charge of the field source reduces the orbital precession effect aroused by the mass of the field source.Generalizing the effect in the Schwarzschild field,we obtain interesting results by discussing the parameters of the celestial body,which provide a feasible experimental verification of the general relativity.
The forced precession of the Moon's inner core
Dumberry, Mathieu; Wieczorek, Mark A.
2016-07-01
The tilt angle of the 18.6 year precession of the Moon's solid inner core is unknown, but it is set by a balance between gravitational and pressure torques acting on its elliptical figure. We show here that to first order, the angle of precession of the inner core of a planetary body is determined by the frequency of the free inner core nutation, ωficn, relative to the precession frequency, Ωp. If |ωficn|≪|Ωp|, the inner core is blind to the gravitational influence of the mantle. If |ωficn|≫|Ωp|, the inner core is gravitationally locked to the mantle and is nearly aligned with it. If ωficn≈Ωp, large inner core tilt angles can result from resonant excitation. Viscous inner core relaxation and electromagnetic coupling can attenuate large tilt angles. For the specific case of the Moon, we show that ωficn is to within a factor of 2 of Ωp = 2π/18.6 yr-1. For a rigid inner core, this implies a tilt of 2 to 5° with respect to the mantle, and larger if ωficn is very close to Ωp. More modest tilt angles between 0 and 0.5° result if viscous relaxation within the inner core occurs on a timescale of one lunar day. Predictions from our model may be used in an attempt to detect the gravity signal resulting from a tilted inner core, to determine the past history of the inner core tilt angle, and to assess models of dynamo generation powered by differential rotation at the core-mantle and inner core boundaries.
Evolution and precession of accretion disk in tidal disruption events
Matzner C.D.
2012-12-01
Full Text Available In a supermassive black hole (BH tidal disruption event (TDE, the tidally disrupted star feeds the BH via an accretion disk. Most often it is assumed that the accretion rate history, hence the emission light curve, tracks the rate at which new debris mass falls back onto the disk, notably the t−5/3 power law. But this is not the case when the disk evolution due to viscous spreading - the driving force for accretion - is carefully considered. We construct a simple analytical model that comprehensively describes the accretion rate history across 4 different phases of the disk evolution, in the presence of mass fallback and disk wind loss. Accretion rate evolves differently in those phases which are governed by how the disk heat energy is carried away, early on by advection and later by radiation. The accretion rate can decline as steeply as t−5/3 only if copious disk wind loss is present during the early advection-cooled phase. Later, the accretion rate history is t−8/7 or shallower. These have great implications on the TDE flare light curve. A TDE accretion disk is most likely misaligned with the equatorial plane of the spinning BH. Moreover, in the TDE the accretion rate is super- or near-Eddington thus the disk is geometrically thick, for which case the BH’s frame dragging effect may cause the disk precess as a solid body, which may manifest itself as quasi-periodic signal in the TDE light curve. Our disk evolution model predicts the disk precession period increases with time, typically as ∝ t. The results are applied to the recently jetted TDE flare Swift transient J1644 + 57 which shows numerous, quasi-periodic dips in its long-term X-ray light curve. As the current TDE sample increases, the identification of the disk precession signature provides a unique way of measuring BH spin and studying BH accretion physics.
Non-time-orthogonality, Gravitational Orbits, and Thomas Precession
Klauber, R D
2000-01-01
Non-time-orthogonal analysis of rotating frames is applied to objects in gravitational orbits and found to be internally consistent. The object's surface speed about its axis of rotation, but not its orbital speed, is shown to be readily detectable by any "enclosed box" experimenter on the surface of such an object. Sagnac type effects manifest readily, but by somewhat subtle means. The analysis is extended to objects bound in non-gravitational orbit, where it is found to be fully in accord with the traditional analysis of Thomas precession.
The Perihelion Precession of Mercury and the Generalized Uncertainty Principle
Majumder, Barun
2011-01-01
Very recently authors in [1] proposed a new Generalized Uncertainty Principle (or GUP) with a linear term in Plank length. In this Letter the effect of this linear term is studied perturbatively in the context of Keplerian orbits. The angle by which the perihelion of the orbit revolves over a complete orbital cycle is computed. The result is applied in the context of the precession of the perihelion of Mercury. As a consequence we get a lower bound of the new intermediate length scale offered by the GUP which is approximately 40 orders of magnitude below Plank length.
Three-axis atomic magnetometer based on spin precession modulation
Huang, H. C.; Dong, H. F., E-mail: hfdong@buaa.edu.cn; Hu, X. Y.; Chen, L.; Gao, Y. [School of Instrumentation Science and Opto-Electronics Engineering, Beihang University, Beijing 100191 (China)
2015-11-02
We demonstrate a three-axis atomic magnetometer with one intensity-modulated pump beam and one orthogonal probe beam. The main field component is measured using the resonance of the pumping light, while the transverse field components are measured simultaneously using the optical rotation of the probe beam modulated by the spin precession. It is an all-optical magnetometer without using any modulation field or radio frequency field. Magnetic field sensitivity of 0.8 pT/Hz{sup 1∕2} is achieved under a bias field of 2 μT.
Coulomb Interaction in Quantum Dot with a Precessing Magnetic Field
无
2007-01-01
We study electronic transport through a quantum dot (QD) with a precessing magnetic field. By using the Keldysh nonequilibrium Green function method, formulas of local density of states (LDOS) and conductance of QD are derived self-consistently. It shows that the LDOS and conductance have obvious changes with the Coulomb blockade interaction. The intensity and angle of the magnetic field or temperatures, which reflect the mesoscopic structure of the QD are derived. The superiority of this device is that the QD can be controlled easily by the magnetic field, so it is valuable to apply in generating, manipulating and probing spin state.
Using the Nordic Geodetic Observing System for land uplift studies
Nordman, M.; Poutanen, M.; Kairus, A.; Virtanen, J.
2014-07-01
Geodetic observing systems have been planned and developed during the last decade. An ideal observing system consists of a network of geodetic observing stations with several techniques at the same site, publicly accessible databases, and as a product delivers data time series, combination of techniques or some other results obtained from the data sets. Globally, there is the International Association of Geodesy (IAG) Global Geodetic Observing System (GGOS), and there are ongoing attempts to create also regional observing systems. In this paper we introduce one regional system, the Nordic Geodetic Observing System (NGOS) hosted by the Nordic Geodetic Commission (NKG). Data availability and accessibility are one of the major issues today. We discuss in general data-related topics, and introduce a pilot database project of NGOS. As a demonstration of the use of such a database, we apply it for postglacial rebound studies in the Fennoscandian area. We compare land uplift values from three techniques, GNSS, tide gauges and absolute gravity, with the Nordic Geodetic Commission NKG2005LU land uplift model for Fennoscandia. The purpose is to evaluate the data obtained from different techniques and different sources and get the most reliable values for the uplift using publicly available data. The primary aim of observing systems will be to produce data and other products needed by multidisciplinary projects, such as Upper Mantle Dynamics and Quaternary Climate in Cratonic Areas (DynaQlim) or the European Plate Observing System (EPOS), but their needs may currently exceed the scope of an existing observing system. We discuss what requirements the projects pose to observing systems and their development. To make comparisons between different studies possible and reliable, the researcher should document what they have in detail, either in appendixes, supplementary material or some other available format.
The University, the Market, and the Geodetic Engineer or
Stubkjær, Erik
2002-01-01
of universities have changed profoundly, largely due to an increased emphasis on market norms. The changes within university teaching of geodetic engineers may be seen from the above perspective. Several fora for deliberations on the education exist, including the Commission 2 of the International Federation...... project, which concerned the education of geodetic engineers in Slovenia. The body of the paper presents a selection of ideas that shaped the university through the centuries, with a view to balance the present interest in advancing market-directed behaviour....
Shirakawa, Akiko
This thesis consists of three parts. In the first part, we study the magnetically driven precession of warped disks. An accretion disk around a rotating magnetized star is subjected to the magnetic torques that induce warping and precession of the disk. We study the global hydrodynamical warping/ precession modes of the disk under the combined influences of the magnetic torques, relativistic frame dragging, and the classical precession due to oblateness of the neutron star. We apply our analysis to two types of accreting systems: low-mass X-ray binaries (LMXBs) and accreting X-ray pulsars. We argue that some features of low-frequency quasi-periodic oscillations (QPOs) in LMXBs and milli-Hertz QPOs in accreting X-ray pulsars can be explained by the magnetically driven precession of warped disks. The second part is related to the hydrodynamically-driven mechanism for asymmetric supernova explosions/neutron star kicks. We explore the possibility that the gravity modes in the core of a presupernova star may be amplified in the silicon burning shell to produce the global asymmetric perturbations that lead to an asymmetric supernova explosion. By performing a linear analysis of the oscillations in the cores of presupernova stars, we estimate the growth/ damping rates of the modes. We find that most of the modes are damping modes with a few exceptions. We also find that, even for a growing mode, the timescale of mode growth is much longer than the remaining time before the core collapse. We conclude that the gravity modes in a presupernova core cannot provide the global asymmetric perturbations that lead to an asymmetric supernova explosion. In the last part, we attempt to predict the innate chemical composition of a neutron star atmosphere. There has been great progress in X-ray observations and now thermal radiation from neutron stars is being studied in detail. There has also been significant progress in modeling thermal spectra from neutron stars. However, the unknown
An algorithm for determination of geodetic path for application in long-range acoustic propagation
Murty, T.V.R.; Sivakholundu, K.M.; Navelkar, G.S.; Somayajulu, Y.K.; Murty, C.S.
A computer program has been developed for the construction of geodetic path between two points on the spheroidal surface for application in long range acoustic propagation in the ocean. Geodetic equations have integrated numerically upto...
Relativistic Hydrodynamics with Wavelets
DeBuhr, Jackson; Anderson, Matthew; Neilsen, David; Hirschmann, Eric W
2015-01-01
Methods to solve the relativistic hydrodynamic equations are a key computational kernel in a large number of astrophysics simulations and are crucial to understanding the electromagnetic signals that originate from the merger of astrophysical compact objects. Because of the many physical length scales present when simulating such mergers, these methods must be highly adaptive and capable of automatically resolving numerous localized features and instabilities that emerge throughout the computational domain across many temporal scales. While this has been historically accomplished with adaptive mesh refinement (AMR) based methods, alternatives based on wavelet bases and the wavelet transformation have recently achieved significant success in adaptive representation for advanced engineering applications. This work presents a new method for the integration of the relativistic hydrodynamic equations using iterated interpolating wavelets and introduces a highly adaptive implementation for multidimensional simulati...
Obliquity and precession as pacemakers of Pleistocene deglaciations
Feng, Fabo
2015-01-01
The Milankovitch theory states that the orbital eccentricity, precession, and obliquity of the Earth influence our climate by modulating the summer insolation at high latitudes in the northern hemisphere. Despite considerable success of this theory in explaining climate change over the Pleistocene epoch (2.6 to 0.01 Myr ago), it is inconclusive with regard to which combination of orbital elements paced the 100 kyr glacial-interglacial cycles over the late Pleistocene. Here we explore the role of the orbital elements in pacing the Pleistocene deglaciations by modeling ice-volume variations in a Bayesian approach. When comparing models, this approach takes into account the uncertainties in the data as well as the different degrees of model complexity. We find that the Earth's obliquity (axial tilt) plays a dominant role in pacing the glacial cycles over the whole Pleistocene, while precession only becomes important in pacing major deglaciations after the transition of the dominant period from 41 kyr to 100 kyr ...
Accretion-disc precession in UX Ursae Majoris
de Miguel, E.; Patterson, J.; Cejudo, D.; Ulowetz, J.; Jones, J. L.; Boardman, J.; Barret, D.; Koff, R.; Stein, W.; Campbell, T.; Vanmunster, T.; Menzies, K.; Slauson, D.; Goff, W.; Roberts, G.; Morelle, E.; Dvorak, S.; Hambsch, F.-J.; Starkey, D.; Collins, D.; Costello, M.; Cook, M. J.; Oksanen, A.; Lemay, D.; Cook, L. M.; Ogmen, Y.; Richmond, M.; Kemp, J.
2016-04-01
We report the results of a long campaign of time series photometry on the nova-like variable UX Ursae Majoris during 2015. It spanned 150 nights, with ˜ 1800 h of coverage on 121 separate nights. The star was in its normal `high state' near magnitude V = 13, with slow waves in the light curve and eclipses every 4.72 h. Remarkably, the star also showed a nearly sinusoidal signal with a full amplitude of 0.44 mag and a period of 3.680 ± 0.007 d. We interpret this as the signature of a retrograde precession (wobble) of the accretion disc. The same period is manifest as a ±33 s wobble in the timings of mid-eclipse, indicating that the disc's centre of light moves with this period. The star also showed strong `negative superhumps' at frequencies ωorb + N and 2ωorb + N, where ωorb and N are, respectively, the orbital and precession frequencies. It is possible that these powerful signals have been present, unsuspected, throughout the more than 60 yr of previous photometric studies.
Spin-Induced Disk Precession in Sagittarius A*
Rockefeller, G M; Melia, F; Rockefeller, Gabriel; Fryer, Christopher L.; Melia, Fulvio
2005-01-01
In Sgr A* at the Galactic center, by far the closest and easiest supermassive black hole we can study, the observational evidence is increasingly pointing to the presence of a compact, hot, magnetized disk feeding the accretor. In such low-Mach-number plasmas, forces arising, e.g., from pressure gradients in the plasma, can altogether negate the warping of disks around Kerr black holes caused by the Bardeen-Petterson effect and can lead to coherent precession of the entire disk. In this Letter, we present for the first time highly detailed 3D SPH simulations of the accretion disk evolution in Sgr A*, guided by observational constraints on its physical characteristics, and conclude that indeed the Bardeen-Petterson effect is probably absent in this source. Given what we now understand regarding the emission geometry in this object, we suggest that a ~ 50-500-day modulation in Sgr A*'s spectrum, arising from the disk precession, could be an important observational signature; perhaps the ~ 106-day period seen ea...
Equatorial insolation: from precession harmonics to eccentricity frequencies
A. Berger
2006-01-01
Full Text Available Since the paper by Hays et al. (1976, spectral analyses of climate proxy records provide substantial evidence that a fraction of the climatic variance is driven by insolation changes in the frequency ranges of obliquity and precession variations. However, it is the variance components centered near 100 kyr which dominate most Upper Pleistocene climatic records, although the amount of insolation perturbation at the eccentricity driven periods close to 100-kyr (mainly the 95 kyr- and 123 kyr-periods is much too small to cause directly a climate change of ice-age amplitude. Many attempts to find an explanation to this 100-kyr cycle in climatic records have been made over the last decades. Here we show that the double maximum which characterizes the daily irradiation received in tropical latitudes over the course of the year is at the origin in equatorial insolation of not only strong 95 kyr and 123 kyr periods related to eccentricity, but also of a 11-kyr and a 5.5-kyr periods related to precession.
Measuring the Polarization of a Rapidly Precessing Deuteron Beam
Bagdasarian, Z; Chiladze, D; Ciullo, G; Dietrich, J; Dymov, S; Eversmann, D; Fanourakis, G; Gaisser, M; Gebel, R; Gou, B; Guidoboni, G; Hejny, V; Kacharava, A; Kamerdzhiev, V; Lehrach, A; Lenisa, P; Lorentz, B; Magallanes, L; Maier, R; Mchedlishvili, D; Morse, W M; Nass, A; Oellers, D; Pesce, A; Prasuhn, D; Pretz, J; Rathmann, F; Shmakova, V; Semertzidis, Y K; Stephenson, E J; Stockhorst, H; Ströher, H; Talman, R; Engblom, P Thörngren; Valdau, Yu; Weidemann, C; Wüstner, P
2014-01-01
This paper describes a time-marking system that enables a measurement of the in-plane (horizontal) polarization of a 0.97-GeV/c deuteron beam circulating in the Cooler Synchrotron (COSY) at the Forschungszentrum J\\"ulich. The clock time of each polarimeter event is used to unfold the 120-kHz spin precession and assign events to bins according to the direction of the horizontal polarization. After accumulation for one or more seconds, the down-up scattering asymmetry can be calculated for each direction and matched to a sinusoidal function whose magnitude is proportional to the horizontal polarization. This requires prior knowledge of the spin tune or polarization precession rate. An initial estimate is refined by re-sorting the events as the spin tune is adjusted across a narrow range and searching for the maximum polarization magnitude. The result is biased toward polarization values that are too large, in part because of statistical fluctuations but also because sinusoidal fits to even random data will prod...
Searching for Gravitational Waves from Compact Binaries with Precessing Spins
Harry, Ian; Bohé, Alejandro; Buonanno, Alessandra
2016-01-01
Current searches for gravitational waves from compact-object binaries with the LIGO and Virgo observatories employ waveform models with spins aligned (or anti-aligned) with the orbital angular momentum. Here, we derive a new statistic to search for compact objects carrying generic (precessing) spins. Applying this statistic, we construct banks of both aligned- and generic-spin templates for binary black holes and neutron-star--black-hole binaries, and compare the effectualness of these banks towards simulated populations of generic-spin systems. We then use these banks in a pipeline analysis of Gaussian noise to measure the increase in background incurred by using generic- instead of aligned-spin banks. Although the generic-spin banks have a factor of ten to twenty more templates than the aligned-spin banks, we find an overall improvement in signal recovery at fixed false-alarm rate for systems with high-mass ratio and highly precessing spins ---up to 60\\% for neutron-star--black-hole mergers. This gain in se...
Accretion-disc precession in UX Ursae Majoris
de Miguel, E; Cejudo, D; Ulowetz, J; Jones, J L; Boardman, J; Barret, D; Koff, R; Stein, W; Campbell, T; Vanmunster, T; Menzies, K; Slauson, D; Goff, W; Roberts, G; Morelle, E; Dvorak, S; Hambsch, F -J; Starkey, D; Collins, D; Costello, M; Cook, M J; Oksanen, A; Lemay, D; Cook, L M; Ogmen, Y; Richmond, M; Kemp, J
2015-01-01
We report the results of a long campaign of time-series photometry on the nova-like variable UX Ursae Majoris during 2015. It spanned 150 nights, with ~1800 hours of coverage on 121 separate nights. The star was in its normal `high state' near magnitude V=13, with slow waves in the light curve and eclipses every 4.72 hours. Remarkably, the star also showed a nearly sinusoidal signal with a full amplitude of 0.44 mag and a period of 3.680 +/- 0.007 d. We interpret this as the signature of a retrograde precession (wobble) of the accretion disc. The same period is manifest as a +/-33 s wobble in the timings of mid-eclipse, indicating that the disc's centre of light moves with this period. The star also showed strong `negative superhumps' at frequencies w_orb+N and 2w_orb+N, where w_orb and N are respectively the orbital and precession frequencies. It is possible that these powerful signals have been present, unsuspected, throughout the more than 60 years of previous photometric studies.
Ballistic reentry vehicles dispersion due to precession stoppage
Lin, T. C.; Grabowsky, W. R.; Yelmgren, K. E.; Landa, M.
1982-08-01
Ballistic reentry vehicle (RV) precession stoppage phenomena are investigated analytically and several postulated reasons for its occurrence are discussed. Both analytical solutions and six-degree-of-freedom (6DOF) simulations are presented. In addition to the familiar phenomena of roll through zero (RTZ), roll near zero (RNZ) and angle-of-attack divergence, there are four additional aerodynamic forcing functions that are found to be particularly interesting and significant since they can induce the so-called 'space-fixed-trim' phenomena, i.e., the lift-vector becomes momentarily stationary in space. These four forcing functions are: (1) a shift from body-fixed to wind-fixed trim moment in high freestream dynamic pressure environments; (2) RV with transient unstable aerodynamic stability derivative; (3) trim plane migrations induced by a series of asymmetric nose spallations, and (4) a Magnus-type out-of-plane moment in conjunction with the wind-fixed moment induced by ablation lag phenomena. When this occurs, the trajectory deflection becomes prohibitively large. According to the present analytical/numerical results, the initial spin rate can be crucial for the magnitude as well as the direction of the RV dispersion. Finally, some possible physical mechanisms which would cause RV precession stoppage are suggested.
Precessing collimated outflows in the planetary nebula IC 4846
Miranda, L F; Torrelles, J M; Miranda, Luis F; Guerrero, Martin A; Torrelles, Jose M
2000-01-01
We present [N II] and H-alpha images and high resolution long-slit spectra of the planetary nebula IC 4846, which reveal, for the first time, its complex structure and the existence of collimated outflows. The object consists of a moderately elongated shell, two (and probably three) pairs of collimated bipolar outflows at different orientations, and an attached circular shell. One of the collimated pairs is constituted by two curved, extended filaments whose properties indicate a high velocity, bipolar precessing jet. A difference of \\~10 km/s is found between the systemic velocity of the precessing jets and the centroid velocity of the nebula, as recently report for Hu 2-1. We propose that this difference is due to orbital motion of the ejection source in a binary central star. The orbital separation and period estimates for the binary star are less than or equal to 30 AU and 100 yr, respectively. These are similar to those previously estimated for Hu 2-1, linking the central stars of both planetary nebulae ...
Relativistic heavy ion reactions
Brink, D.M.
1989-08-01
The theory of quantum chromodynamics predicts that if nuclear matter is heated to a sufficiently high temperature then quarks might become deconfined and a quark-gluon plasma could be produced. One of the aims of relativistic heavy ion experiments is to search for this new state of matter. These lectures survey some of the new experimental results and give an introduction to the theories used to interpret them. 48 refs., 4 tabs., 11 figs.
Relativistic spherical plasma waves
Bulanov, S S; Schroeder, C B; Zhidkov, A G; Esarey, E; Leemans, W P
2011-01-01
Tightly focused laser pulses as they diverge or converge in underdense plasma can generate wake waves, having local structures that are spherical waves. Here we report on theoretical study of relativistic spherical wake waves and their properties, including wave breaking. These waves may be suitable as particle injectors or as flying mirrors that both reflect and focus radiation, enabling unique X-ray sources and nonlinear QED phenomena.
Relativistic Quantum Noninvasive Measurements
Bednorz, Adam
2014-01-01
Quantum weak, noninvasive measurements are defined in the framework of relativity. Invariance with respect to reference frame transformations of the results in different models is discussed. Surprisingly, the bare results of noninvasive measurements are invariant for certain class of models, but not the detection error. Consequently, any stationary quantum realism based on noninvasive measurements will break, at least spontaneously, relativistic invariance and correspondence principle at zero temperature.
Relativistic cosmological hydrodynamics
Hwang, J
1997-01-01
We investigate the relativistic cosmological hydrodynamic perturbations. We present the general large scale solutions of the perturbation variables valid for the general sign of three space curvature, the cosmological constant, and generally evolving background equation of state. The large scale evolution is characterized by a conserved gauge invariant quantity which is the same as a perturbed potential (or three-space curvature) in the comoving gauge.
Gravitationally confined relativistic neutrinos
Vayenas, C. G.; Fokas, A. S.; Grigoriou, D.
2017-09-01
Combining special relativity, the equivalence principle, and Newton’s universal gravitational law with gravitational rather than rest masses, one finds that gravitational interactions between relativistic neutrinos with kinetic energies above 50 MeV are very strong and can lead to the formation of gravitationally confined composite structures with the mass and other properties of hadrons. One may model such structures by considering three neutrinos moving symmetrically on a circular orbit under the influence of their gravitational attraction, and by assuming quantization of their angular momentum, as in the Bohr model of the H atom. The model contains no adjustable parameters and its solution, using a neutrino rest mass of 0.05 eV/c2, leads to composite state radii close to 1 fm and composite state masses close to 1 GeV/c2. Similar models of relativistic rotating electron - neutrino pairs give a mass of 81 GeV/c2, close to that of W bosons. This novel mechanism of generating mass suggests that the Higgs mass generation mechanism can be modeled as a latent gravitational field which gets activated by relativistic neutrinos.
Relativistic Radiation Mediated Shocks
Budnik, Ran; Sagiv, Amir; Waxman, Eli
2010-01-01
The structure of relativistic radiation mediated shocks (RRMS) propagating into a cold electron-proton plasma is calculated and analyzed. A qualitative discussion of the physics of relativistic and non relativistic shocks, including order of magnitude estimates for the relevant temperature and length scales, is presented. Detailed numerical solutions are derived for shock Lorentz factors $\\Gamma_u$ in the range $6\\le\\Gamma_u\\le30$, using a novel iteration technique solving the hydrodynamics and radiation transport equations (the protons, electrons and positrons are argued to be coupled by collective plasma processes and are treated as a fluid). The shock transition (deceleration) region, where the Lorentz factor $ \\Gamma $ drops from $ \\Gamma_u $ to $ \\sim 1 $, is characterized by high plasma temperatures $ T\\sim \\Gamma m_ec^2 $ and highly anisotropic radiation, with characteristic shock-frame energy of upstream and downstream going photons of a few~$\\times\\, m_ec^2$ and $\\sim \\Gamma^2 m_ec^2$, respectively.P...
Parker, Edward
2017-08-01
A nonrelativistic particle released from rest at the edge of a ball of uniform charge density or mass density oscillates with simple harmonic motion. We consider the relativistic generalizations of these situations where the particle can attain speeds arbitrarily close to the speed of light; generalizing the electrostatic and gravitational cases requires special and general relativity, respectively. We find exact closed-form relations between the position, proper time, and coordinate time in both cases, and find that they are no longer harmonic, with oscillation periods that depend on the amplitude. In the highly relativistic limit of both cases, the particle spends almost all of its proper time near the turning points, but almost all of the coordinate time moving through the bulk of the ball. Buchdahl's theorem imposes nontrivial constraints on the general-relativistic case, as a ball of given density can only attain a finite maximum radius before collapsing into a black hole. This article is intended to be pedagogical, and should be accessible to those who have taken an undergraduate course in general relativity.
Point form relativistic quantum mechanics and relativistic SU(6)
Klink, W. H.
1993-01-01
The point form is used as a framework for formulating a relativistic quantum mechanics, with the mass operator carrying the interactions of underlying constituents. A symplectic Lie algebra of mass operators is introduced from which a relativistic harmonic oscillator mass operator is formed. Mass splittings within the degenerate harmonic oscillator levels arise from relativistically invariant spin-spin, spin-orbit, and tensor mass operators. Internal flavor (and color) symmetries are introduced which make it possible to formulate a relativistic SU(6) model of baryons (and mesons). Careful attention is paid to the permutation symmetry properties of the hadronic wave functions, which are written as polynomials in Bargmann spaces.
The Pole Orientation, Pole Precession, and Moment of Inertia Factor of Saturn
Jacobson, R. A.; French, R. G.; Nicholson, P. D.; Hedman, M.; Colwell, J. E.; Marouf, E.; Rappaport, N.; McGhee, C.; Sepersky, T.; Lonergan, K.
2011-01-01
This paper discusses our determination of the Saturn's pole orientation and precession using a combination of Earthbased and spacecraft based observational data. From our model of the polar motion and the observed precession rate we obtain a value for Saturn's polar moment of inertia
Relativistic magnetohydrodynamics in one dimension.
Lyutikov, Maxim; Hadden, Samuel
2012-02-01
We derive a number of solutions for one-dimensional dynamics of relativistic magnetized plasma that can be used as benchmark estimates in relativistic hydrodynamic and magnetohydrodynamic numerical codes. First, we analyze the properties of simple waves of fast modes propagating orthogonally to the magnetic field in relativistically hot plasma. The magnetic and kinetic pressures obey different equations of state, so that the system behaves as a mixture of gases with different polytropic indices. We find the self-similar solutions for the expansion of hot strongly magnetized plasma into vacuum. Second, we derive linear hodograph and Darboux equations for the relativistic Khalatnikov potential, which describe arbitrary one-dimensional isentropic relativistic motion of cold magnetized plasma and find their general and particular solutions. The obtained hodograph and Darboux equations are very powerful: A system of highly nonlinear, relativistic, time-dependent equations describing arbitrary (not necessarily self-similar) dynamics of highly magnetized plasma reduces to a single linear differential equation.
Precession-driven dynamos in a full sphere and the role of large scale cyclonic vortices
Lin, Yufeng; Noir, Jerome; Jackson, Andrew
2016-01-01
Precession has been proposed as an alternative power source for planetary dynamos. Previous hydrodynamic simulations suggested that precession can generate very complex flows in planetary liquid cores [Y. Lin, P. Marti, and J. Noir, "Shear-driven parametric instability in a precessing sphere," Physics of Fluids 27, 046601 (2015)]. In the present study, we numerically investigate the magnetohydrodynamics of a precessing sphere. We demonstrate precession driven dynamos in different flow regimes, from laminar to turbulent flows. In particular, we highlight the magnetic field generation by large scale cyclonic vortices, which has not been explored previously. In this regime, dynamos can be sustained at relatively low Ekman numbers and magnetic Prandtl numbers, which paves the way for planetary applications.
The Precession Index, A Nonlinear Energy Balance Model, And Seversmith Psychroterms
Rubincam, David Parry
2004-01-01
An important component of Milankovitch's astronomical theory of climate change is the precession index. The precession index, along with the Earth's tilt and orbital eccentricity, are believed to be the major controlling factors of climate change in the last few million years. The precession index is e sin omega(sub s) where e is the Earth's orbital eccentricity and omega(sub s) measures how close the Sun is to the Earth at midsummer. When omega(sub s) = 90deg the Sun is close to the Earth during northern summer, and at 270deg it is far from the Earth during northern summer. The precession index varies with time, because both the eccentricity e and the parameter omega(sub s) are constantly changing due to disturbances in the Earth's orbit by other planets, and due to the precession of the Earth, The change is largely periodic, with a period of about 23,000 years.
A computational predictor of human episodic memory based on a theta phase precession network.
Naoyuki Sato
Full Text Available In the rodent hippocampus, a phase precession phenomena of place cell firing with the local field potential (LFP theta is called "theta phase precession" and is considered to contribute to memory formation with spike time dependent plasticity (STDP. On the other hand, in the primate hippocampus, the existence of theta phase precession is unclear. Our computational studies have demonstrated that theta phase precession dynamics could contribute to primate-hippocampal dependent memory formation, such as object-place association memory. In this paper, we evaluate human theta phase precession by using a theory-experiment combined analysis. Human memory recall of object-place associations was analyzed by an individual hippocampal network simulated by theta phase precession dynamics of human eye movement and EEG data during memory encoding. It was found that the computational recall of the resultant network is significantly correlated with human memory recall performance, while other computational predictors without theta phase precession are not significantly correlated with subsequent memory recall. Moreover the correlation is larger than the correlation between human recall and traditional experimental predictors. These results indicate that theta phase precession dynamics are necessary for the better prediction of human recall performance with eye movement and EEG data. In this analysis, theta phase precession dynamics appear useful for the extraction of memory-dependent components from the spatio-temporal pattern of eye movement and EEG data as an associative network. Theta phase precession may be a common neural dynamic between rodents and humans for the formation of environmental memories.
The Contribution of the Geodetic Community (WG4) to EPOS
Fernandes, R. M. S.; Bastos, L. C.; Bruyninx, C.; D'Agostino, N.; Dousa, J.; Ganas, A.; Lidberg, M.; Nocquet, J.-M.
2012-04-01
WG4 - "EPOS Geodetic Data and Infrastructure" is the Working Group of the EPOS project responsible to define and prepare the integration of the existing Pan-European Geodetic Infrastructures into a unique future consistent infrastructure that supports the European Geosciences, which is the ultimate goal of the EPOS project. The WG4 is formed by representatives of the participating EPOS countries and from EUREF (European Reference Frame), which also ensures the inclusion and the contact with countries that formally are not part of the current phase of EPOS. In reality, the fact that Europe is formed by many countries (having different laws and policies) lacking an infrastructure similar to UNAVCO (which concentrates the effort of the local geo-science community) raises the difficulties to create a common geodetic infrastructure serving not only the entire geo-science community, but also many other areas of great social-economic impact. The benefits of the creation of such infrastructure (shared and easily accessed by all) are evident in order to optimize the existing and future geodetic resources. This presentation intends to detail the work being produced within the working group WG4 related with the definition of strategies towards the implementation of the best solutions that will permit to the end-users, and in particular geo-scientists, to access the geodetic data, derived solutions, and associated metadata using transparent and uniform processes. Discussed issues include the access to high-rate data in near real-time, storage and backup of historical and future data, the sustainability of the networks in order to achieve long-term stability in the observation infrastructure, seamless access to the data, open data policies, and processing tools.
Spinning gas clouds: III. Solutions of minimal energy with precession
Gaffet, B
2003-01-01
We consider the model of rotating and expanding gas cloud originally proposed by Ovsiannikov (1956 Dokl. Akad. Nauk SSSR 111 47) and Dyson (1968 J. Math. Mech. 18 91). Under the restricting assumptions of an adiabatic index gamma = 5/3 and of vorticity-free motion, this has been shown (Gaffet 2001 J. Phys. A: Math. Gen. 34 2097) to be a Liouville integrable Hamiltonian system. In the present work, we consider the precessing solutions where the cloud does not retain a fixed rotation axis. Choosing for definiteness a particular set of constants of motion (which corresponds to a minimum of the energy), we show that a separation of variables occurs, and that the equations of motion are reducible to the form of a Riccati equation, whose integration merely involves an elliptic integral.
Spinning gas clouds: III. Solutions of minimal energy with precession
Gaffet, B.
2003-05-01
We consider the model of rotating and expanding gas cloud originally proposed by Ovsiannikov (1956 Dokl. Akad. Nauk SSSR 111 47) and Dyson (1968 J. Math. Mech. 18 91). Under the restricting assumptions of an adiabatic index gamma = 5/3 and of vorticity-free motion, this has been shown (Gaffet 2001 J. Phys. A: Math. Gen. 34 2097) to be a Liouville integrable Hamiltonian system. In the present work, we consider the precessing solutions where the cloud does not retain a fixed rotation axis. Choosing for definiteness a particular set of constants of motion (which corresponds to a minimum of the energy), we show that a separation of variables occurs, and that the equations of motion are reducible to the form of a Riccati equation, whose integration merely involves an elliptic integral.
Thomas-Wigner rotation and Thomas precession: actualized approach
Kholmetskii, Alexander
2014-01-01
We show that the explanation of Thomas-Wigner rotation (TWR) and Thomas precession (TP) in the framework of special theory of relativity (STR) contains a number of points of inconsistency, in particular, with respect to physical interpretation of the Einstein velocity composition law in successive space-time transformations. In addition, we show that the common interpretation of TP falls into conflict with the causality principle. In order to eliminate such a conflict, we suggest considering the velocity parameter, entering into expression for the frequency of TP, as being always related to a rotation-free Lorentz transformation. Such an assumption (which actually resolves any causal paradoxes with respect to TP), comes however to be in contradiction with the spirit of STR. The results obtained are discussed.
Test of Lorentz invariance with spin precession of ultracold neutrons
Altarev, I; Ban, G; Bison, G; Bodek, K; Daum, M; Fierlinger, P; Geltenbort, P; Green, K; van der Grinten, M G D; Gutsmiedl, E; Harris, P G; Heil, W; Henneck, R; Horras, M; Iaydjiev, P; Ivanov, S N; Khomutov, N; Kirch, K; Kistryn, S; Knecht, A; Knowles, P; Kozela, A; Kuchler, F; Kuźniak, M; Lauer, T; Lauss, B; Lefort, T; Mtchedlishvili, A; Naviliat-Cuncic, O; Pazgalev, A; Pendlebury, J M; Petzoldt, G; Pierre, E; Pignol, G; Quéméner, G; Rebetez, M; Rebreyend, D; Roccia, S; Rogel, G; Severijns, N; Shiers, D; Sobolev, Yu; Weis, A; Zejma, J; Zsigmond, G
2009-01-01
A clock comparison experiment, analyzing the ratio of spin precession frequencies of stored ultracold neutrons and 199Hg atoms is reported. No daily variation of this ratio could be found, from which is set an upper limit on the Lorentz invariance violating cosmic anisotropy field b < 2 * 10^{-20} eV (95% C.L.). This is the first limit for the free neutron. This result is also interpreted as a direct limit on the gravitational dipole moment of the neutron |g_n| < 0.3 eV.c^{-2}.m from a spin-dependent interaction with the Sun. Analyzing the gravitational interaction with the Earth, based on previous data, yields a more stringent limit |g_n| < 3 * 10^{-4} eV.c^{-2}.m.
Highly stable atomic vector magnetometer based on free spin precession.
Afach, S; Ban, G; Bison, G; Bodek, K; Chowdhuri, Z; Grujić, Z D; Hayen, L; Hélaine, V; Kasprzak, M; Kirch, K; Knowles, P; Koch, H-C; Komposch, S; Kozela, A; Krempel, J; Lauss, B; Lefort, T; Lemière, Y; Mtchedlishvili, A; Naviliat-Cuncic, O; Piegsa, F M; Prashanth, P N; Quéméner, G; Rawlik, M; Ries, D; Roccia, S; Rozpedzik, D; Schmidt-Wellenburg, P; Severjins, N; Weis, A; Wursten, E; Wyszynski, G; Zejma, J; Zsigmond, G
2015-08-24
We present a magnetometer based on optically pumped Cs atoms that measures the magnitude and direction of a 1 μT magnetic field. Multiple circularly polarized laser beams were used to probe the free spin precession of the Cs atoms. The design was optimized for long-time stability and achieves a scalar resolution better than 300 fT for integration times ranging from 80 ms to 1000 s. The best scalar resolution of less than 80 fT was reached with integration times of 1.6 to 6 s. We were able to measure the magnetic field direction with a resolution better than 10 μrad for integration times from 10 s up to 2000 s.
Hopping Precession of Molecules in Crystalline Carbon Dioxide Films
Krainyukova, Nina; Kuchta, Bogdan
2016-11-01
We report a low-temperature transmission high-energy electron diffraction study of solid carbon dioxide films in the temperature range 15-87 K. The precise analysis of the experimental diffraction intensities shows that molecular axes noticeably deviate from the cubic space diagonals of the Paoverline{3} structure. The molecular tips tend to be oriented toward the empty spaces between two molecules in the nearest basal planes. Nevertheless, the crystal structure is still identified as Paoverline{3} but with 24 equivalent positions for oxygen atoms instead of 8 positions as it was thought before. We have shown that the relevant maximal angle deviations in the selected directions could be as big as ˜ 30° at the lowest temperatures and they decrease at higher temperature. This results in hopping precession of molecules instead of simple librations.
Effective-one-body modeling of precessing black hole binaries
Taracchini, Andrea; Babak, Stanislav; Buonanno, Alessandra
2016-03-01
Merging black hole binaries with generic spins that undergo precessional motion emit complicated gravitational-wave signals. We discuss how such waveforms can be accurately modeled within an effective-one-body approach by (i) exploiting the simplicity of the signals in a frame that corotates with the orbital plane of the binary and (ii) relying on an accurate model of nonprecessing black hole binaries. The model is validated by extensive comparisons to 70 numerical relativity simulations of precessing black hole binaries and can generate inspiral-merger-ringdown waveforms for mass ratios up to 100 and any spin configuration. This work is an essential tool for studying and characterizing candidate gravitational-wave events in science runs of advanced LIGO.
Hopping Precession of Molecules in Crystalline Carbon Dioxide Films
Krainyukova, Nina; Kuchta, Bogdan
2017-04-01
We report a low-temperature transmission high-energy electron diffraction study of solid carbon dioxide films in the temperature range 15-87 K. The precise analysis of the experimental diffraction intensities shows that molecular axes noticeably deviate from the cubic space diagonals of the Paoverline{3} structure. The molecular tips tend to be oriented toward the empty spaces between two molecules in the nearest basal planes. Nevertheless, the crystal structure is still identified as Paoverline{3} but with 24 equivalent positions for oxygen atoms instead of 8 positions as it was thought before. We have shown that the relevant maximal angle deviations in the selected directions could be as big as {˜ } 30° at the lowest temperatures and they decrease at higher temperature. This results in hopping precession of molecules instead of simple librations.
Recurrence relation for relativistic atomic matrix elements
Martínez y Romero, R P; Salas-Brito, A L
2000-01-01
Recurrence formulae for arbitrary hydrogenic radial matrix elements are obtained in the Dirac form of relativistic quantum mechanics. Our approach is inspired on the relativistic extension of the second hypervirial method that has been succesfully employed to deduce an analogous relationship in non relativistic quantum mechanics. We obtain first the relativistic extension of the second hypervirial and then the relativistic recurrence relation. Furthermore, we use such relation to deduce relativistic versions of the Pasternack-Sternheimer rule and of the virial theorem.
Relativistic twins or sextuplets?
Sheldon, E S
2003-01-01
A recent study of the relativistic twin 'paradox' by Soni in this journal affirmed that 'A simple solution of the twin paradox also shows anomalous behaviour of rigidly connected distant clocks' but entailed a pedagogic hurdle which the present treatment aims to surmount. Two scenarios are presented: the first 'flight-plan' is akin to that depicted by Soni, with constant-velocity segments, while the second portrays an alternative mission undertaken with sustained acceleration and deceleration, illustrated quantitatively for a two-way spacecraft flight from Earth to Polaris (465.9 light years distant) and back.
Numerical Relativistic Quantum Optics
2013-11-08
µm and a = 1. The condition for an atomic spectrum to be non-relativistic is Z α−1 ≈ 137, as follows from elementary Dirac theory. One concludes that...peculiar result that B0 = 1 TG is a weak field. At present, such fields are observed only in connection with astrophysical phenomena [14]. The highest...pulsars. The Astrophysical Journal, 541:367–373, Sep 2000. [15] M. Tatarakis, I. Watts, F.N. Beg, E.L. Clark, A.E. Dangor, A. Gopal, M.G. Haines, P.A
Relativistic quantum information
Mann, R. B.; Ralph, T. C.
2012-11-01
Over the past few years, a new field of high research intensity has emerged that blends together concepts from gravitational physics and quantum computing. Known as relativistic quantum information, or RQI, the field aims to understand the relationship between special and general relativity and quantum information. Since the original discoveries of Hawking radiation and the Unruh effect, it has been known that incorporating the concepts of quantum theory into relativistic settings can produce new and surprising effects. However it is only in recent years that it has become appreciated that the basic concepts involved in quantum information science undergo significant revision in relativistic settings, and that new phenomena arise when quantum entanglement is combined with relativity. A number of examples illustrate that point. Quantum teleportation fidelity is affected between observers in uniform relative acceleration. Entanglement is an observer-dependent property that is degraded from the perspective of accelerated observers moving in flat spacetime. Entanglement can also be extracted from the vacuum of relativistic quantum field theories, and used to distinguish peculiar motion from cosmological expansion. The new quantum information-theoretic framework of quantum channels in terms of completely positive maps and operator algebras now provides powerful tools for studying matters of causality and information flow in quantum field theory in curved spacetimes. This focus issue provides a sample of the state of the art in research in RQI. Some of the articles in this issue review the subject while others provide interesting new results that will stimulate further research. What makes the subject all the more exciting is that it is beginning to enter the stage at which actual experiments can be contemplated, and some of the articles appearing in this issue discuss some of these exciting new developments. The subject of RQI pulls together concepts and ideas from
Corinaldesi, Ernesto
1963-01-01
Geared toward advanced undergraduate and graduate students of physics, this text provides readers with a background in relativistic wave mechanics and prepares them for the study of field theory. The treatment originated as a series of lectures from a course on advanced quantum mechanics that has been further amplified by student contributions.An introductory section related to particles and wave functions precedes the three-part treatment. An examination of particles of spin zero follows, addressing wave equation, Lagrangian formalism, physical quantities as mean values, translation and rotat
Rössler, O E; Matsuno, K
1998-04-01
The two mindsets of absolutism and relativism are juxtaposed, and the relational or relativist stance is vindicated. The only 'absolute' entity which undeniably exists, consciousness has the reality of a dream. The escape hatch from this prison is relational, as Descartes and Levinas found out: Unfalsified relational consistency implies exteriority. Exteriority implies infinite power which in turn makes compassion inevitable. Aside from ethics as a royal way to enlightenment, a new technology called 'deep technology' may be accessible. It changes the whole world in a demonstrable fashion by manipulation of the micro frame--that is, the observer-world interface.
Measuring the polarization of a rapidly precessing deuteron beam
Bagdasarian, Z.; Bertelli, S.; Chiladze, D.; Ciullo, G.; Dietrich, J.; Dymov, S.; Eversmann, D.; Fanourakis, G.; Gaisser, M.; Gebel, R.; Gou, B.; Guidoboni, G.; Hejny, V.; Kacharava, A.; Kamerdzhiev, V.; Lehrach, A.; Lenisa, P.; Lorentz, B.; Magallanes, L.; Maier, R.; Mchedlishvili, D.; Morse, W. M.; Nass, A.; Oellers, D.; Pesce, A.; Prasuhn, D.; Pretz, J.; Rathmann, F.; Shmakova, V.; Semertzidis, Y. K.; Stephenson, E. J.; Stockhorst, H.; Ströher, H.; Talman, R.; Thörngren Engblom, P.; Valdau, Yu.; Weidemann, C.; Wüstner, P.
2014-05-01
This paper describes a time-marking system that enables a measurement of the in-plane (horizontal) polarization of a 0.97-GeV/c deuteron beam circulating in the Cooler Synchrotron (COSY) at the Forschungszentrum Jülich. The clock time of each polarimeter event is used to unfold the 120-kHz spin precession and assign events to bins according to the direction of the horizontal polarization. After accumulation for one or more seconds, the down-up scattering asymmetry can be calculated for each direction and matched to a sinusoidal function whose magnitude is proportional to the horizontal polarization. This requires prior knowledge of the spin tune or polarization precession rate. An initial estimate is refined by resorting the events as the spin tune is adjusted across a narrow range and searching for the maximum polarization magnitude. The result is biased toward polarization values that are too large, in part because of statistical fluctuations but also because sinusoidal fits to even random data will produce sizable magnitudes when the phase is left free to vary. An analysis procedure is described that matches the time dependence of the horizontal polarization to templates based on emittance-driven polarization loss while correcting for the positive bias. This information will be used to study ways to extend the horizontal polarization lifetime by correcting spin tune spread using ring sextupole fields and thereby to support the feasibility of searching for an intrinsic electric dipole moment using polarized beams in a storage ring. This paper is a combined effort of the Storage Ring EDM collaboration and the JEDI collaboration.
Exotic Non-relativistic String
Casalbuoni, Roberto; Longhi, Giorgio
2007-01-01
We construct a classical non-relativistic string model in 3+1 dimensions. The model contains a spurion tensor field that is responsible for the non-commutative structure of the model. Under double dimensional reduction the model reduces to the exotic non-relativistic particle in 2+1 dimensions.
'Antigravity' Propulsion and Relativistic Hyperdrive
Felber, F S
2006-01-01
Exact payload trajectories in the strong gravitational fields of compact masses moving with constant relativistic velocities are calculated. The strong field of a suitable driver mass at relativistic speeds can quickly propel a heavy payload from rest to a speed significantly faster than the driver, a condition called hyperdrive. Hyperdrive thresholds and maxima are calculated as functions of driver mass and velocity.
A Simple Relativistic Bohr Atom
Terzis, Andreas F.
2008-01-01
A simple concise relativistic modification of the standard Bohr model for hydrogen-like atoms with circular orbits is presented. As the derivation requires basic knowledge of classical and relativistic mechanics, it can be taught in standard courses in modern physics and introductory quantum mechanics. In addition, it can be shown in a class that…
A Simple Relativistic Bohr Atom
Terzis, Andreas F.
2008-01-01
A simple concise relativistic modification of the standard Bohr model for hydrogen-like atoms with circular orbits is presented. As the derivation requires basic knowledge of classical and relativistic mechanics, it can be taught in standard courses in modern physics and introductory quantum mechanics. In addition, it can be shown in a class that…
An Autonomous, Low Cost Platform for Seafloor Geodetic Observations
Ericksen, T.; Foster, J. H.; Bingham, B. S.; Oshiro, J.
2015-12-01
The Pacific GPS Facility and the Field Robotics Laboratory at the University of Hawaii have developed an approach to significantly reduce the costs of accurately measuring short-term vertical motions of the seafloor and maintaining a continuous long-term record of seafloor pressure. Traditional ship-based methods of acquiring these measurements are often prohibitively expensive. Our goal has been to reduce the primary barrier preventing us from acquiring the observations we need to understand geodetic processes, and the hazards they present, at subduction zones, submarine volcanoes, and subsea landslides. To this end, we have designed a payload package for the University of Hawaii Wave Glider which incorporates an acoustic telemetry package, a dual frequency geodetic-grade Global Positioning System (GPS) receiver, meteorological sensors, processing computer, and cellular communications. The Wave Glider is able to interrogate high accuracy pressure sensors on the seafloor to maintain a near-continuous stream of ocean bottom pressure and temperature data. The Wave Glider also functions as an integral part of the seafloor geodetic observing system, recording accurate sea surface elevations and barometric pressure; direct measurements of two of the primary sources of seafloor pressure change. The seafloor geodetic monument seats a sensor capable of recording pressure, temperature, and sound velocity for a deployment duration of over 5 years with an acoustic modem for communications, and an integral acoustic release for recovery and replacement of batteries. The design of the geodetic monument allows for precise repositioning of the sensor to extend the pressure record beyond a single 5+ year deployment, and includes the capability to install a mobile pressure recorder for calibration of the linear drift of the continuous pressure sensor. We will present the results of our field tests and an assessment of our ability to determine cm-scale vertical seafloor motions by
Komissarov, S S; Lyutikov, M
2015-01-01
In this paper we describe a simple numerical approach which allows to study the structure of steady-state axisymmetric relativistic jets using one-dimensional time-dependent simulations. It is based on the fact that for narrow jets with v~c the steady-state equations of relativistic magnetohydrodynamics can be accurately approximated by the one-dimensional time-dependent equations after the substitution z=ct. Since only the time-dependent codes are now publicly available this is a valuable and efficient alternative to the development of a high-specialized code for the time-independent equations. The approach is also much cheaper and more robust compared to the relaxation method. We tested this technique against numerical and analytical solutions found in literature as well as solutions we obtained using the relaxation method and found it sufficiently accurate. In the process, we discovered the reason for the failure of the self-similar analytical model of the jet reconfinement in relatively flat atmospheres a...
Robust relativistic bit commitment
Chakraborty, Kaushik; Chailloux, André; Leverrier, Anthony
2016-12-01
Relativistic cryptography exploits the fact that no information can travel faster than the speed of light in order to obtain security guarantees that cannot be achieved from the laws of quantum mechanics alone. Recently, Lunghi et al. [Phys. Rev. Lett. 115, 030502 (2015), 10.1103/PhysRevLett.115.030502] presented a bit-commitment scheme where each party uses two agents that exchange classical information in a synchronized fashion, and that is both hiding and binding. A caveat is that the commitment time is intrinsically limited by the spatial configuration of the players, and increasing this time requires the agents to exchange messages during the whole duration of the protocol. While such a solution remains computationally attractive, its practicality is severely limited in realistic settings since all communication must remain perfectly synchronized at all times. In this work, we introduce a robust protocol for relativistic bit commitment that tolerates failures of the classical communication network. This is done by adding a third agent to both parties. Our scheme provides a quadratic improvement in terms of expected sustain time compared with the original protocol, while retaining the same level of security.
A relativistic trolley paradox
Matvejev, Vadim N.; Matvejev, Oleg V.; Grøn, Ø.
2016-06-01
We present an apparent paradox within the special theory of relativity, involving a trolley with relativistic velocity and its rolling wheels. Two solutions are given, both making clear the physical reality of the Lorentz contraction, and that the distance on the rails between each time a specific point on the rim touches the rail is not equal to 2 π R , where R is the radius of the wheel, but 2 π R / √{ 1 - R 2 Ω 2 / c 2 } , where Ω is the angular velocity of the wheels. In one solution, the wheel radius is constant as the velocity of the trolley increases, and in the other the wheels contract in the radial direction. We also explain two surprising facts. First that the shape of a rolling wheel is elliptical in spite of the fact that the upper part of the wheel moves faster than the lower part, and thus is more Lorentz contracted, and second that a Lorentz contracted wheel with relativistic velocity rolls out a larger distance between two successive touches of a point of the wheel on the rails than the length of a circle with the same radius as the wheels.
Fractional Dynamics of Relativistic Particle
Tarasov, Vasily E
2011-01-01
Fractional dynamics of relativistic particle is discussed. Derivatives of fractional orders with respect to proper time describe long-term memory effects that correspond to intrinsic dissipative processes. Relativistic particle subjected to a non-potential four-force is considered as a nonholonomic system. The nonholonomic constraint in four-dimensional space-time represents the relativistic invariance by the equation for four-velocity u_{\\mu} u^{\\mu}+c^2=0, where c is a speed of light in vacuum. In the general case, the fractional dynamics of relativistic particle is described as non-Hamiltonian and dissipative. Conditions for fractional relativistic particle to be a Hamiltonian system are considered.
An Electromagnet for Precession of the Polarization of Fast-Neutrons
Aspesund, O.; Bjorkman, J.; Trumpy, G.
1965-05-15
The advantages of using a transverse magnetic field for precessing the polarization of fast-neutrons are discussed. Design details of a powerful electromagnet supplying a transverse field of approximately 20 kGauss are given. Precession characteristics for polarized fast neutrons obtained at 50 deg (lab. syst.) from the Li{sup 7} (p, n) Be{sup 7} reaction are reported, using elastic scattering at 42 deg (lab. syst.) off natural carbon as an analyser. Correlation of the precession data with theoretical predictions presented elsewhere is made, and good agreement is found.
All-optical detection of magnetization precession in tunnel junctions under applied voltage
Sasaki, Yuta; Suzuki, Kazuya; Sugihara, Atsushi; Kamimaki, Akira; Iihama, Satoshi; Ando, Yasuo; Mizukami, Shigemi
2017-02-01
An all-optical time-resolved magneto-optical Kerr effect measurement of a micron-sized tunnel junction with a CoFeB electrode was performed. The femtosecond (fs) laser-induced magnetization precession was clearly observed at various magnetic field angles. The frequency f and relaxation time τ of the magnetization precession varied with the voltage applied via a MgO barrier. The precession dynamics were in accordance with Kittel’s ferromagnetic resonance mode, and the voltage-induced changes in f and τ were well explained by the voltage-induced change in the perpendicular magnetic anisotropy of -36 fJ/Vm.
Linking Oceanic Tsunamis and Geodetic Gravity Changes of Large Earthquakes
Fu, Yuning; Song, Y. Tony; Gross, Richard S.
2017-08-01
Large earthquakes at subduction zones usually generate tsunamis and coseismic gravity changes. These two independent oceanic and geodetic signatures of earthquakes can be observed individually by modern geophysical observational networks. The Gravity Recovery and Climate Experiment twin satellites can detect gravity changes induced by large earthquakes, while altimetry satellites and Deep-Ocean Assessment and Reporting of Tsunamis buoys can observe resultant tsunamis. In this study, we introduce a method to connect the oceanic tsunami measurements with the geodetic gravity observations, and apply it to the 2004 Sumatra Mw 9.2 earthquake, the 2010 Maule Mw 8.8 earthquake and the 2011 Tohoku Mw 9.0 earthquake. Our results indicate consistent agreement between these two independent measurements. Since seafloor displacement is still the largest puzzle in assessing tsunami hazards and its formation mechanism, our study demonstrates a new approach to utilizing these two kinds of measurements for better understanding of large earthquakes and tsunamis.
Application of Geodetic Receivers to Timing and Time Transfer
NIE Guigen; LIU Jingnan
2005-01-01
Two methods for smoothing pseudorange observable by Carrier and Doppler are discussed. Then the procedure based on the RINEX observation files is tested using the Ashtech Z-XII3T geodetic receivers driven by a stable external frequency at UNSO. This paper proposes to adapt this procedure for the links between geodetic receivers, in order to take advantage of the P codes available on L1 and L2. This new procedure uses the 30-second RINEX observations files, the standard of the International GPS Service (IGS), and processes the ionosphere-free combination of the codes P1 and P2; the satellite positions are deduced from the IGS rapid orbits, available after two days.
Cartografical And Geodetical Aspects Of The Krakus Mound In Cracow
Banasik, Piotr
2015-12-01
In this work the fate of the Krakus Mound, the oldest of all existing Krakow's mounds, has been presented. The work was carried out based on selected iconographic, cartographic and geodetic documents. Using as an example old views, panoramas of the city and maps, various functions that the Krakus Mound was fulfilling over its long history were shown. An attempt was made to document the military significance of this mound and the surrounding hills. The particular astro-geodetic importance of the Krakus Mound on the scale of the city and southern Poland region was widely discussed. The Krakus Mound also inscribed itself in the history of the use of GPS technology as well as research on the local determination of the geoid in the area of Krakow.
The University, the Market, and the Geodetic Engineer or
Stubkjær, Erik
2002-01-01
In Europe, universities have existed for more than 800 years. The university is the place in society for higher learning and related research. Through the ages, the universities have enjoyed a remarkably freedom relative to religious and secular powers. In recent years, the objectives and practises...... of universities have changed profoundly, largely due to an increased emphasis on market norms. The changes within university teaching of geodetic engineers may be seen from the above perspective. Several fora for deliberations on the education exist, including the Commission 2 of the International Federation...... project, which concerned the education of geodetic engineers in Slovenia. The body of the paper presents a selection of ideas that shaped the university through the centuries, with a view to balance the present interest in advancing market-directed behaviour....
Crowdsourced Contributions to the Nation's Geodetic Elevation Infrastructure
Stone, W. A.
2014-12-01
NOAA's National Geodetic Survey (NGS), a United States Department of Commerce agency, is engaged in providing the nation's fundamental positioning infrastructure - the National Spatial Reference System (NSRS) - which includes the framework for latitude, longitude, and elevation determination as well as various geodetic models, tools, and data. Capitalizing on Global Navigation Satellite System (GNSS) technology for improved access to the nation's precise geodetic elevation infrastructure requires use of a geoid model, which relates GNSS-derived heights (ellipsoid heights) with traditional elevations (orthometric heights). NGS is facilitating the use of crowdsourced GNSS observations collected at published elevation control stations by the professional surveying, geospatial, and scientific communities to help improve NGS' geoid modeling capability. This collocation of published elevation data and newly collected GNSS data integrates together the two height systems. This effort in turn supports enhanced access to accurate elevation information across the nation, thereby benefiting all users of geospatial data. By partnering with the public in this collaborative effort, NGS is not only helping facilitate improvements to the elevation infrastructure for all users but also empowering users of NSRS with the capability to do their own high-accuracy positioning. The educational outreach facet of this effort helps inform the public, including the scientific community, about the utility of various NGS tools, including the widely used Online Positioning User Service (OPUS). OPUS plays a key role in providing user-friendly and high accuracy access to NSRS, with optional sharing of results with NGS and the public. All who are interested in helping evolve and improve the nationwide elevation determination capability are invited to participate in this nationwide partnership and to learn more about the geodetic infrastructure which is a vital component of viable spatial data for
Geodetic Volcano Monitoring Research in Canary Islands: Recent Results
Fernandez, J.; Gonzalez, P. J.; Arjona, A.; Camacho, A. G.; Prieto, J. F.; Seco, A.; Tizzani, P.; Manzo, M. R.; Lanari, R.; Blanco, P.; Mallorqui, J. J.
2009-05-01
The Canarian Archipelago is an oceanic island volcanic chain with a long-standing history of volcanic activity (> 40 Ma). It is located off the NW coast of the African continent, lying over a transitional crust of the Atlantic African passive margin. At least 12 eruptions have been occurred on the islands of Lanzarote, Tenerife and La Palma in the last 500 years. Volcanism manifest predominantly as basaltic strombolian monogenetic activity (whole archipelago) and central felsic volcanism (active only in Tenerife Island). We concentrate our studies in the two most active islands, Tenerife and La Palma. In these islands, we tested different methodologies of geodetic monitoring systems. We use a combination of ground- and space-based techniques. At Tenerife Island, a differential interferometric study was performed to detect areas of deformation. DInSAR detected two clear areas of deformation, using this results a survey-based GPS network was designed and optimized to control those deformations and the rest of the island. Finally, using SBAS DInSAR results weak spatial long- wavelength subsidence signals has been detected. At La Palma, the first DInSAR analysis have not shown any clear deformation, so a first time series analysis was performed detecting a clear subsidence signal at Teneguia volcano, as for Tenerife a GPS network was designed and optimized taking into account stable and deforming areas. After several years of activities, geodetic results served to study ground deformations caused by a wide variety of sources, such as changes in groundwater levels, volcanic activity, volcano-tectonics, gravitational loading, etc. These results proof that a combination of ground-based and space-based techniques is suitable tool for geodetic volcano monitoring in Canary Islands. Finally, we would like to strength that those results could have serious implications on the continuous geodetic monitoring system design and implementation for the Canary Islands which is under
A comparative study for the estimation of geodetic point velocity by artificial neural networks
M Yilmaz; M Gullu
2014-06-01
Space geodesy era provides velocity information which results in the positioning of geodetic points by considering the time evolution. The geodetic point positions on the Earth’s surface change over time due to plate tectonics, and these changes have to be accounted for geodetic purposes. The velocity field of geodetic network is determined from GPS sessions. Velocities of the new structured geodetic points within the geodetic network are estimated from this velocity field by the interpolation methods. In this study, the utility of Artificial Neural Networks (ANN) widely applied in diverse fields of science is investigated in order to estimate the geodetic point velocities. Back Propagation Artificial Neural Network (BPANN) and Radial Basis Function Neural Network (RBFNN) are used to estimate the geodetic point velocities. In order to evaluate the performance of ANNs, the velocities are also interpolated by Kriging (KRIG) method. The results are compared in terms of the root mean square error (RMSE) over five different geodetic networks. It was concluded that the estimation of geodetic point velocity by BPANN is more effective and accurate than by KRIG when the points to be estimated are more than the points known.
An Overview of Geodetic Volcano Research in the Canary Islands
Fernández, José; González, Pablo J.; Camacho, Antonio G.; Prieto, Juan F.; Brú, Guadalupe
2015-11-01
The Canary Islands are mostly characterized by diffuse and scattered volcanism affecting a large area, with only one active stratovolcano, the Teide-Pico Viejo complex (Tenerife). More than 2 million people live and work in the 7,447 km2 of the archipelago, resulting in an average population density three times greater than the rest of Spain. This fact, together with the growth of exposure during the past 40 years, increases volcanic risk with respect previous eruptions, as witnessed during the recent 2011-2012 El Hierro submarine eruption. Therefore, in addition to purely scientific reasons there are economic and population-security reasons for developing and maintaining an efficient volcano monitoring system. In this scenario geodetic monitoring represents an important part of the monitoring system. We describe volcano geodetic monitoring research carried out in the Canary Islands and the results obtained. We consider for each epoch the two main existing constraints: the level of volcanic activity in the archipelago, and the limitations of the techniques available at the time. Theoretical and observational aspects are considered, as well as the implications for operational volcano surveillance. Current challenges of and future perspectives in geodetic volcano monitoring in the Canaries are also presented.
Magnetic Dissipation in Relativistic Jets
Yosuke Mizuno
2016-10-01
Full Text Available The most promising mechanisms for producing and accelerating relativistic jets, and maintaining collimated structure of relativistic jets involve magnetohydrodynamical (MHD processes. We have investigated the magnetic dissipation mechanism in relativistic jets via relativistic MHD simulations. We found that the relativistic jets involving a helical magnetic field are unstable for the current-driven kink instability, which leads to helically distorted structure in relativistic jets. We identified the regions of high current density in filamentary current sheets, indicative of magnetic reconnection, which are associated to the kink unstable regions and correlated to the converted regions of magnetic to kinetic energies of the jets. We also found that an over-pressured relativistic jet leads to the generation of a series of stationary recollimation shocks and rarefaction structures by the nonlinear interaction of shocks and rarefaction waves. The differences in the recollimation shock structure due to the difference of the magnetic field topologies and strengths may be observable through mm-VLBI observations and space-VLBI mission.
Relativistic Fractal Cosmologies
Ribeiro, Marcelo B
2009-01-01
This article reviews an approach for constructing a simple relativistic fractal cosmology whose main aim is to model the observed inhomogeneities of the distribution of galaxies by means of the Lemaitre-Tolman solution of Einstein's field equations for spherically symmetric dust in comoving coordinates. This model is based on earlier works developed by L. Pietronero and J.R. Wertz on Newtonian cosmology, whose main points are discussed. Observational relations in this spacetime are presented, together with a strategy for finding numerical solutions which approximate an averaged and smoothed out single fractal structure in the past light cone. Such fractal solutions are shown, with one of them being in agreement with some basic observational constraints, including the decay of the average density with the distance as a power law (the de Vaucouleurs' density power law) and the fractal dimension in the range 1 <= D <= 2. The spatially homogeneous Friedmann model is discussed as a special case of the Lemait...
Relativistic Gravothermal Instabilities
Roupas, Zacharias
2014-01-01
The thermodynamic instabilities of the self-gravitating, classical ideal gas are studied in the case of static, spherically symmetric configurations in General Relativity taking into account the Tolman-Ehrenfest effect. One type of instabilities is found at low energies, where thermal energy becomes too weak to halt gravity and another at high energies, where gravitational attraction of thermal pressure overcomes its stabilizing effect. These turning points of stability are found to depend on the total rest mass $\\mathcal{M}$ over the radius $R$. The low energy instability is the relativistic generalization of Antonov instability, which is recovered in the limit $G\\mathcal{M} \\ll R c^2$ and low temperatures, while in the same limit and high temperatures, the high energy instability recovers the instability of the radiation equation of state. In the temperature versus energy diagram of series of equilibria, the two types of gravothermal instabilities make themselves evident as a double spiral! The two energy l...
Lock, Maximilian P E
2016-01-01
The conflict between quantum theory and the theory of relativity is exemplified in their treatment of time. We examine the ways in which their conceptions differ, and describe a semiclassical clock model combining elements of both theories. The results obtained with this clock model in flat spacetime are reviewed, and the problem of generalizing the model to curved spacetime is discussed, before briefly describing an experimental setup which could be used to test of the model. Taking an operationalist view, where time is that which is measured by a clock, we discuss the conclusions that can be drawn from these results, and what clues they contain for a full quantum relativistic theory of time.
Galilean relativistic fluid mechanics
Ván, Péter
2015-01-01
Single component Galilean-relativistic (nonrelativistic) fluids are treated independently of reference frames. The basic fields are given, their balances, thermodynamic relations and the entropy production is calculated. The usual relative basic fields, the mass, momentum and energy densities, the diffusion current density, the pressure tensor and the heat flux are the time- and spacelike components of the third order mass-momentum-energy density tensor according to a velocity field. The transformation rules of the basic fields are derived and prove that the non-equilibrium thermodynamic background theory, that is the Gibbs relation, extensivity condition and the entropy production is absolute, that is independent of the reference frame and also of the fluid velocity. --- Az egykomponensu Galilei-relativisztikus (azaz nemrelativisztikus) disszipativ folyadekokat vonatkoztatasi rendszertol fuggetlenul targyaljuk. Megadjuk az alapmennyisegeket, ezek merlegeit, a termodinamikai osszefuggeseket es kiszamoljuk az ...
Relativistic Runaway Electrons
Breizman, Boris
2014-10-01
This talk covers recent developments in the theory of runaway electrons in a tokamak with an emphasis on highly relativistic electrons produced via the avalanche mechanism. The rapidly growing population of runaway electrons can quickly replace a large part of the initial current carried by the bulk plasma electrons. The magnetic energy associated with this current is typically much greater than the particle kinetic energy. The current of a highly relativistic runaway beam is insensitive to the particle energy, which separates the description of the runaway current evolution from the description of the runaway energy spectrum. A strongly anisotropic distribution of fast electrons is generally prone to high-frequency kinetic instabilities that may cause beneficial enhancement of runaway energy losses. The relevant instabilities are in the frequency range of whistler waves and electron plasma waves. The instability thresholds reported in earlier work have been revised considerably to reflect strong dependence of collisional damping on the wave frequency and the role of plasma non-uniformity, including radial trapping of the excited waves in the plasma. The talk also includes a discussion of enhanced scattering of the runaways as well as the combined effect of enhanced scattering and synchrotron radiation. A noteworthy feature of the avalanche-produced runaway current is a self-sustained regime of marginal criticality: the inductive electric field has to be close to its critical value (representing avalanche threshold) at every location where the runaway current density is finite, and the current density should vanish at any point where the electric field drops below its critical value. This nonlinear Ohm's law enables complete description of the evolving current profile. Work supported by the U.S. Department of Energy Contract No. DEFG02-04ER54742 and by ITER contract ITER-CT-12-4300000273. The views and opinions expressed herein do not necessarily reflect those of
The Precession Index and a Nonlinear Energy Balance Climate Model
Rubincam, David
2004-01-01
A simple nonlinear energy balance climate model yields a precession index-like term in the temperature. Despite its importance in the geologic record, the precession index e sin (Omega)S, where e is the Earth's orbital eccentricity and (Omega)S is the Sun's perigee in the geocentric frame, is not present in the insolation at the top of the atmosphere. Hence there is no one-for-one mapping of 23,000 and 19,000 year periodicities from the insolation to the paleoclimate record; a nonlinear climate model is needed to produce these long periods. A nonlinear energy balance climate model with radiative terms of form T n, where T is surface temperature and n less than 1, does produce e sin (omega)S terms in temperature; the e sin (omega)S terms are called Seversmith psychroterms. Without feedback mechanisms, the model achieves extreme values of 0.64 K at the maximum orbital eccentricity of 0.06, cooling one hemisphere while simultaneously warming the other; the hemisphere over which perihelion occurs is the cooler. In other words, the nonlinear energy balance model produces long-term cooling in the northern hemisphere when the Sun's perihelion is near northern summer solstice and long-term warming in the northern hemisphere when the aphelion is near northern summer solstice. (This behavior is similar to the inertialess gray body which radiates like T 4, but the amplitude is much lower for the energy balance model because of its thermal inertia.) This seemingly paradoxical behavior works against the standard Milankovitch model, which requires cool northern summers (Sun far from Earth in northern summer) to build up northern ice sheets, so that if the standard model is correct it must be more efficient than previously thought. Alternatively, the new mechanism could possibly be dominant and indicate southern hemisphere control of the northern ice sheets, wherein the southern oceans undergo a long-term cooling when the Sun is far from the Earth during northern summer. The cold
What is "Relativistic Canonical Quantization"?
Arbatsky, D. A.
2005-01-01
The purpose of this review is to give the most popular description of the scheme of quantization of relativistic fields that was named relativistic canonical quantization (RCQ). I do not give here the full exact account of this scheme. But with the help of this review any physicist, even not a specialist in the relativistic quantum theory, will be able to get a general view of the content of RCQ, of its connection with other known approaches, of its novelty and of its fruitfulness.
TIAN Jun; WANG Pinxian; CHENG Xinrong
2004-01-01
The precession plays a dominant role in driving the tropical monsoon variations. Our high resolution, millennial scale marine isotope records from ODP Site 1143 in the southern South China Sea (SCS) present the detailed history of the upper ocean structure variations over the past 1.56 Ma on glacial/interglacial timescale. The cross spectral analyses between the Earth's orbital variations and the isotopic differences reveal a high coherency between the East-Asian-monsoon-related thermocline and nutricline variations of the SCS and the precession. The variations of monsoon-related isotopic difference between species also demonstrate periodicities of 11-, 12- and 14- thousand years near semi-precession which originates in the tropics, highlighting the importance of the precession in driving the east Asian monsoon changes.
Fast Frequency-domain Waveforms for Spin-Precessing Binary Inspirals
Klein, Antoine; Yunes, Nicolás
2014-01-01
The detection and characterization of gravitational wave signals from compact binary coalescence events relies on accurate waveform templates in the frequency domain. The stationary phase approximation (SPA) can be used to compute closed-form frequency-domain waveforms for non-precessing, quasi-circular binary inspirals. However, until now, no fast frequency-domain waveforms have existed for generic, spin-precessing quasi-circular compact binary inspirals. Templates for these systems have had to be computed via a discrete Fourier transform of finely sampled time-domain waveforms, which is far more computationally expensive than those constructed directly in the frequency-domain, especially for those systems that are dominated by the inspiral part. There are two obstacles to deriving frequency-domain waveforms for precessing systems: (i) the spin-precession equations do not admit closed-form solutions for generic systems; (ii) the SPA fails catastrophically. Presently there is no general solution to the first ...
O. Wid
2015-11-01
Full Text Available We demonstrate coherent control of time domain ferromagnetic resonance by all electrical excitation and detection. Using two ultrashort magnetic field steps with variable time delay we control the induction decay in yttrium iron garnet (YIG. By setting suitable delay times between the two steps the precession of the magnetization can either be enhanced or completely stopped. The method allows for a determination of the precession frequency within a few precession periods and with an accuracy much higher than can be achieved using fast fourier transformation. Moreover it holds the promise to massively increase precession amplitudes in pulsed inductive microwave magnetometry (PIMM using low amplitude finite pulse trains. Our experiments are supported by micromagnetic simulations which nicely confirm the experimental results.
Wid, O.; Wahler, M.; Homonnay, N.; Richter, T. [Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, D-06099 (Germany); Schmidt, G., E-mail: georg.schmidt@physik.uni-halle.de [Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, D-06099 (Germany); IZM, Martin-Luther-Universität Halle-Wittenberg, D-06099 (Germany)
2015-11-15
We demonstrate coherent control of time domain ferromagnetic resonance by all electrical excitation and detection. Using two ultrashort magnetic field steps with variable time delay we control the induction decay in yttrium iron garnet (YIG). By setting suitable delay times between the two steps the precession of the magnetization can either be enhanced or completely stopped. The method allows for a determination of the precession frequency within a few precession periods and with an accuracy much higher than can be achieved using fast fourier transformation. Moreover it holds the promise to massively increase precession amplitudes in pulsed inductive microwave magnetometry (PIMM) using low amplitude finite pulse trains. Our experiments are supported by micromagnetic simulations which nicely confirm the experimental results.
The influence of inlet flow condition on the frequency of self-excited jet precession
Mi, J.; Nathan, G. J.; Wong, C. Y.
2006-01-01
A precessing jet flow can be generated naturally by a fluidic nozzle comprising a cylindrical nozzle-chamber with a large sudden expansion at its inlet and a small lip at its outlet. Such a precessing jet flow is offset with respect to the chamber axis, about which it rotates. The aim of the present study is to investigate the influence of the chamber-inlet configuration on the frequency of such precession. Three different inlet configurations, classified as long pipe, smooth contraction, and sharp-edged orifice plate, are tested. It is found that the frequency of precession from the orifice is highest, whereas that of the pipe jet is lowest. These differences appear to result partly from the distinct differences in their respective initial boundary layers.
An improved analysis of GW150914 using a fully spin-precessing waveform model
Abbott, B P; Abbott, T D; Abernathy, M R; Acernese, F; Ackley, K; Adams, C; Adams, T; Addesso, P; Adhikari, R X; Adya, V B; Affeldt, C; Agathos, M; Agatsuma, K; Aggarwal, N; Aguiar, O D; Aiello, L; Ain, A; Ajith, P; Allen, B; Allocca, A; Altin, P A; Anderson, S B; Anderson, W G; Arai, K; Araya, M C; Arceneaux, C C; Areeda, J S; Arnaud, N; Arun, K G; Ascenzi, S; Ashton, G; Ast, M; Aston, S M; Astone, P; Aufmuth, P; Aulbert, C; Babak, S; Bacon, P; Bader, M K M; Baker, P T; Baldaccini, F; Ballardin, G; Ballmer, S W; Barayoga, J C; Barclay, S E; Barish, B C; Barker, D; Barone, F; Barr, B; Barsotti, L; Barsuglia, M; Barta, D; Bartlett, J; Bartos, I; Bassiri, R; Basti, A; Batch, J C; Baune, C; Bavigadda, V; Bazzan, M; Bejger, M; Bell, A S; Berger, B K; Bergmann, G; Berry, C P L; Bersanetti, D; Bertolini, A; Betzwieser, J; Bhagwat, S; Bhandare, R; Bilenko, I A; Billingsley, G; Birch, J; Birney, R; Birnholtz, O; Biscans, S; Bisht, A; Bitossi, M; Biwer, C; Bizouard, M A; Blackburn, J K; Blair, C D; Blair, D G; Blair, R M; Bloemen, S; Bock, O; Boer, M; Bogaert, G; Bogan, C; Bohe, A; Bond, C; Bondu, F; Bonnand, R; Boom, B A; Bork, R; Boschi, V; Bose, S; Bouffanais, Y; Bozzi, A; Bradaschia, C; Brady, P R; Braginsky, V B; Branchesi, M; Brau, J E; Briant, T; Brillet, A; Brinkmann, M; Brisson, V; Brockill, P; Broida, J E; Brooks, A F; Brown, D A; Brown, D D; Brown, N M; Brunett, S; Buchanan, C C; Buikema, A; Bulik, T; Bulten, H J; Buonanno, A; Buskulic, D; Buy, C; Byer, R L; Cabero, M; Cadonati, L; Cagnoli, G; Cahillane, C; Bustillo, J Calder'on; Callister, T; Calloni, E; Camp, J B; Cannon, K C; Cao, J; Capano, C D; Capocasa, E; Carbognani, F; Caride, S; Diaz, J Casanueva; Casentini, C; Caudill, S; Cavagli`a, M; Cavalier, F; Cavalieri, R; Cella, G; Cepeda, C B; Baiardi, L Cerboni; Cerretani, G; Cesarini, E; Chan, M; Chao, S; Charlton, P; Chassande-Mottin, E; Cheeseboro, B D; Chen, H Y; Chen, Y; Cheng, C; Chincarini, A; Chiummo, A; Cho, H S; Cho, M; Chow, J H; Christensen, N; Chu, Q; Chua, S; Chung, S; Ciani, G; Clara, F; Clark, J A; Cleva, F; Coccia, E; Cohadon, P -F; Colla, A; Collette, C G; Cominsky, L; Constancio, M; Conte, A; Conti, L; Cook, D; Corbitt, T R; Cornish, N; Corsi, A; Cortese, S; Costa, C A; Coughlin, M W; Coughlin, S B; Coulon, J -P; Countryman, S T; Couvares, P; Cowan, E E; Coward, D M; Cowart, M J; Coyne, D C; Coyne, R; Craig, K; Creighton, J D E; Cripe, J; Crowder, S G; Cumming, A; Cunningham, L; Cuoco, E; Canton, T Dal; Danilishin, S L; D'Antonio, S; Danzmann, K; Darman, N S; Dasgupta, A; Costa, C F Da Silva; Dattilo, V; Dave, I; Davier, M; Davies, G S; Daw, E J; Day, R; De, S; DeBra, D; Debreczeni, G; Degallaix, J; De Laurentis, M; Del'eglise, S; Del Pozzo, W; Denker, T; Dent, T; Dergachev, V; De Rosa, R; DeRosa, R T; DeSalvo, R; Devine, R C; Dhurandhar, S; D'iaz, M C; Di Fiore, L; Di Giovanni, M; Di Girolamo, T; Di Lieto, A; Di Pace, S; Di Palma, I; Di Virgilio, A; Dolique, V; Donovan, F; Dooley, K L; Doravari, S; Douglas, R; Downes, T P; Drago, M; Drever, R W P; Driggers, J C; Ducrot, M; Dwyer, S E; Edo, T B; Edwards, M C; Effler, A; Eggenstein, H -B; Ehrens, P; Eichholz, J; Eikenberry, S S; Engels, W; Essick, R C; Etienne, Z; Etzel, T; Evans, M; Evans, T M; Everett, R; Factourovich, M; Fafone, V; Fair, H; Fairhurst, S; Fan, X; Fang, Q; Farinon, S; Farr, B; Farr, W M; Fauchon-Jones, E; Favata, M; Fays, M; Fehrmann, H; Fejer, M M; Fenyvesi, E; Ferrante, I; Ferreira, E C; Ferrini, F; Fidecaro, F; Fiori, I; Fiorucci, D; Fisher, R P; Flaminio, R; Fletcher, M; Fournier, J -D; Frasca, S; Frasconi, F; Frei, Z; Freise, A; Frey, R; Frey, V; Fritschel, P; Frolov, V V; Fulda, P; Fyffe, M; Gabbard, H A G; Gaebel, S; Gair, J R; Gammaitoni, L; Gaonkar, S G; Garufi, F; Gaur, G; Gehrels, N; Gemme, G; Geng, P; Genin, E; Gennai, A; George, J; Gergely, L; Germain, V; Ghosh, Abhirup; Ghosh, Archisman; Ghosh, S; Giaime, J A; Giardina, K D; Giazotto, A; Gill, K; Glaefke, A; Goetz, E; Goetz, R; Gondan, L; Gonz'alez, G; Castro, J M Gonzalez; Gopakumar, A; Gordon, N A; Gorodetsky, M L; Gossan, S E; Gosselin, M; Gouaty, R; Grado, A; Graef, C; Graff, P B; Granata, M; Grant, A; Gras, S; Gray, C; Greco, G; Green, A C; Groot, P; Grote, H; Grunewald, S; Guidi, G M; Guo, X; Gupta, A; Gupta, M K; Gushwa, K E; Gustafson, E K; Gustafson, R; Haas, R; Hacker, J J; Hall, B R; Hall, E D; Hammond, G; Haney, M; Hanke, M M; Hanks, J; Hanna, C; Hannam, M D; Hanson, J; Hardwick, T; Harms, J; Harry, G M; Harry, I W; Hart, M J; Hartman, M T; Haster, C -J; Haughian, K; Healy, J; Heidmann, A; Heintze, M C; Heitmann, H; Hello, P; Hemming, G; Hendry, M; Heng, I S; Hennig, J; Henry, J; Heptonstall, A W; Heurs, M; Hild, S; Hinder, I; Hoak, D; Hofman, D; Holt, K; Holz, D E; Hopkins, P; Hough, J; Houston, E A; Howell, E J; Hu, Y M; Huang, S; Huerta, E A; Huet, D; Hughey, B; Husa, S; Huttner, S H; Huynh-Dinh, T; Indik, N; Ingram, D R; Inta, R; Isa, H N; Isac, J -M; Isi, M; Isogai, T; Iyer, B R; Izumi, K; Jacqmin, T; Jang, H; Jani, K; Jaranowski, P; Jawahar, S; Jian, L; Jim'enez-Forteza, F; Johnson, W W; Johnson-McDaniel, N K; Jones, D I; Jones, R; Jonker, R J G; Ju, L; K, Haris; Kalaghatgi, C V; Kalogera, V; Kandhasamy, S; Kang, G; Kanner, J B; Kapadia, S J; Karki, S; Karvinen, K S; Kasprzack, M; Katsavounidis, E; Katzman, W; Kaufer, S; Kaur, T; Kawabe, K; K'ef'elian, F; Kehl, M S; Keitel, D; Kelley, D B; Kells, W; Kennedy, R; Key, J S; Khalili, F Y; Khan, I; Khan, S; Khan, Z; Khazanov, E A; Kijbunchoo, N; Kim, Chi-Woong; Kim, Chunglee; Kim, J; Kim, K; Kim, N; Kim, W; Kim, Y -M; Kimbrell, S J; King, E J; King, P J; Kissel, J S; Klein, B; Kleybolte, L; Klimenko, S; Koehlenbeck, S M; Koley, S; Kondrashov, V; Kontos, A; Korobko, M; Korth, W Z; Kowalska, I; Kozak, D B; Kringel, V; Krishnan, B; Kr'olak, A; Krueger, C; Kuehn, G; Kumar, P; Kumar, R; Kuo, L; Kutynia, A; Lackey, B D; Landry, M; Lange, J; Lantz, B; Lasky, P D; Laxen, M; Lazzarini, A; Lazzaro, C; Leaci, P; Leavey, S; Lebigot, E O; Lee, C H; Lee, H K; Lee, H M; Lee, K; Lenon, A; Leonardi, M; Leong, J R; Leroy, N; Letendre, N; Levin, Y; Lewis, J B; Li, T G F; Libson, A; Littenberg, T B; Lockerbie, N A; Lombardi, A L; London, L T; Lord, J E; Lorenzini, M; Loriette, V; Lormand, M; Losurdo, G; Lough, J D; Lousto, C O; Lovelace, G; L"uck, H; Lundgren, A P; Lynch, R; Ma, Y; Machenschalk, B; MacInnis, M; Macleod, D M; Magana-Sandoval, F; Zertuche, L Magana; Magee, R M; Majorana, E; Maksimovic, I; Malvezzi, V; Man, N; Mandic, V; Mangano, V; Mansell, G L; Manske, M; Mantovani, M; Marchesoni, F; Marion, F; M'arka, S; M'arka, Z; Markosyan, A S; Maros, E; Martelli, F; Martellini, L; Martin, I W; Martynov, D V; Marx, J N; Mason, K; Masserot, A; Massinger, T J; Masso-Reid, M; Mastrogiovanni, S; Matichard, F; Matone, L; Mavalvala, N; Mazumder, N; McCarthy, R; McClelland, D E; McCormick, S; McGuire, S C; McIntyre, G; McIver, J; McManus, D J; McRae, T; McWilliams, S T; Meacher, D; Meadors, G D; Meidam, J; Melatos, A; Mendell, G; Mercer, R A; Merilh, E L; Merzougui, M; Meshkov, S; Messenger, C; Messick, C; Metzdorff, R; Meyers, P M; Mezzani, F; Miao, H; Michel, C; Middleton, H; Mikhailov, E E; Milano, L; Miller, A L; Miller, A; Miller, B B; Miller, J; Millhouse, M; Minenkov, Y; Ming, J; Mirshekari, S; Mishra, C; Mitra, S; Mitrofanov, V P; Mitselmakher, G; Mittleman, R; Moggi, A; Mohan, M; Mohapatra, S R P; Montani, M; Moore, B C; Moore, C J; Moraru, D; Moreno, G; Morriss, S R; Mossavi, K; Mours, B; Mow-Lowry, C M; Mueller, G; Muir, A W; Mukherjee, Arunava; Mukherjee, D; Mukherjee, S; Mukund, N; Mullavey, A; Munch, J; Murphy, D J; Murray, P G; Mytidis, A; Nardecchia, I; Naticchioni, L; Nayak, R K; Nedkova, K; Nelemans, G; Nelson, T J N; Neri, M; Neunzert, A; Newton, G; Nguyen, T T; Nielsen, A B; Nissanke, S; Nitz, A; Nocera, F; Nolting, D; Normandin, M E N; Nuttall, L K; Oberling, J; Ochsner, E; O'Dell, J; Oelker, E; Ogin, G H; Oh, J J; Oh, S H; Ohme, F; Oliver, M; Oppermann, P; Oram, Richard J; O'Reilly, B; O'Shaughnessy, R; Ottaway, D J; Overmier, H; Owen, B J; Pai, A; Pai, S A; Palamos, J R; Palashov, O; Palomba, C; Pal-Singh, A; Pan, H; Pankow, C; Pannarale, F; Pant, B C; Paoletti, F; Paoli, A; Papa, M A; Paris, H R; Parker, W; Pascucci, D; Pasqualetti, A; Passaquieti, R; Passuello, D; Patricelli, B; Patrick, Z; Pearlstone, B L; Pedraza, M; Pedurand, R; Pekowsky, L; Pele, A; Penn, S; Perreca, A; Perri, L M; Pfeiffer, H P; Phelps, M; Piccinni, O J; Pichot, M; Piergiovanni, F; Pierro, V; Pillant, G; Pinard, L; Pinto, I M; Pitkin, M; Poe, M; Poggiani, R; Popolizio, P; Post, A; Powell, J; Prasad, J; Predoi, V; Prestegard, T; Price, L R; Prijatelj, M; Principe, M; Privitera, S; Prix, R; Prodi, G A; Prokhorov, L; Puncken, O; Punturo, M; Puppo, P; P"urrer, M; Qi, H; Qin, J; Qiu, S; Quetschke, V; Quintero, E A; Quitzow-James, R; Raab, F J; Rabeling, D S; Radkins, H; Raffai, P; Raja, S; Rajan, C; Rakhmanov, M; Rapagnani, P; Raymond, V; Razzano, M; Re, V; Read, J; Reed, C M; Regimbau, T; Rei, L; Reid, S; Reitze, D H; Rew, H; Reyes, S D; Ricci, F; Riles, K; Rizzo, M; Robertson, N A; Robie, R; Robinet, F; Rocchi, A; Rolland, L; Rollins, J G; Roma, V J; Romano, J D; Romano, R; Romanov, G; Romie, J H; Rosi'nska, D; Rowan, S; R"udiger, A; Ruggi, P; Ryan, K; Sachdev, S; Sadecki, T; Sadeghian, L; Sakellariadou, M; Salconi, L; Saleem, M; Salemi, F; Samajdar, A; Sammut, L; Sanchez, E J; Sandberg, V; Sandeen, B; Sanders, J R; Sassolas, B; Sathyaprakash, B S; Saulson, P R; Sauter, O E S; Savage, R L; Sawadsky, A; Schale, P; Schilling, R; Schmidt, J; Schmidt, P; Schnabel, R; Schofield, R M S; Sch"onbeck, A; Schreiber, E; Schuette, D; Schutz, B F; Scott, J; Scott, S M; Sellers, D; Sengupta, A S; Sentenac, D; Sequino, V; Sergeev, A; Setyawati, Y; Shaddock, D A; Shaffer, T; Shahriar, M S; Shaltev, M; Shapiro, B; Shawhan, P; Sheperd, A; Shoemaker, D H; Shoemaker, D M; Siellez, K; Siemens, X; Sieniawska, M; Sigg, D; Silva, A D; Singer, A; Singer, L P; Singh, A; Singh, R; Singhal, A; Sintes, A M; Slagmolen, B J J; Smith, J R; Smith, N D; Smith, R J E; Son, E J; Sorazu, B; Sorrentino, F; Souradeep, T; Srivastava, A K; Staley, A; Steinke, M; Steinlechner, J; Steinlechner, S; Steinmeyer, D; Stephens, B C; Stevenson, S P; Stone, R; Strain, K A; Straniero, N; Stratta, G; Strauss, N A; Strigin, S; Sturani, R; Stuver, A L; Summerscales, T Z; Sun, L; Sunil, S; Sutton, P J; Swinkels, B L; Szczepa'nczyk, M J; Tacca, M; Talukder, D; Tanner, D B; T'apai, M; Tarabrin, S P; Taracchini, A; Taylor, R; Theeg, T; Thirugnanasambandam, M P; Thomas, E G; Thomas, M; Thomas, P; Thorne, K A; Thorne, K S; Thrane, E; Tiwari, S; Tiwari, V; Tokmakov, K V; Toland, K; Tomlinson, C; Tonelli, M; Tornasi, Z; Torres, C V; Torrie, C I; T"oyr"a, D; Travasso, F; Traylor, G; Trifir`o, D; Tringali, M C; Trozzo, L; Tse, M; Turconi, M; Tuyenbayev, D; Ugolini, D; Unnikrishnan, C S; Urban, A L; Usman, S A; Vahlbruch, H; Vajente, G; Valdes, G; Vallisneri, M; van Bakel, N; van Beuzekom, M; Brand, J F J van den; Broeck, C Van Den; Vander-Hyde, D C; van der Schaaf, L; van der Sluys, M V; van Heijningen, J V; Vano-Vinuales, A; van Veggel, A A; Vardaro, M; Vass, S; Vas'uth, M; Vaulin, R; Vecchio, A; Vedovato, G; Veitch, J; Veitch, P J; Venkateswara, K; Verkindt, D; Vetrano, F; Vicer'e, A; Vinciguerra, S; Vine, D J; Vinet, J -Y; Vitale, S; Vo, T; Vocca, H; Vorvick, C; Voss, D V; Vousden, W D; Vyatchanin, S P; Wade, A R; Wade, L E; Wade, M; Walker, M; Wallace, L; Walsh, S; Wang, G; Wang, H; Wang, M; Wang, X; Wang, Y; Ward, R L; Warner, J; Was, M; Weaver, B; Wei, L -W; Weinert, M; Weinstein, A J; Weiss, R; Wen, L; Wessels, P; Westphal, T; Wette, K; Whelan, J T; Whiting, B F; Williams, R D; Williamson, A R; Willis, J L; Willke, B; Wimmer, M H; Winkler, W; Wipf, C C; Wittel, H; Woan, G; Woehler, J; Worden, J; Wright, J L; Wu, D S; Wu, G; Yablon, J; Yam, W; Yamamoto, H; Yancey, C C; Yu, H; Yvert, M; zny, A Zadro; Zangrando, L; Zanolin, M; Zendri, J -P; Zevin, M; Zhang, L; Zhang, M; Zhang, Y; Zhao, C; Zhou, M; Zhou, Z; Zhu, X J; Zucker, M E; Zuraw, S E; Zweizig, J
2016-01-01
This paper presents updated estimates of source parameters for GW150914, a binary black-hole coalescence event detected by the Laser Interferometer Gravitational-wave Observatory (LIGO) on September 14, 2015 [1]. Reference presented parameter estimation [2] of the source using a 13-dimensional, phenomenological precessing-spin model (precessing IMRPhenom) and a 11-dimensional nonprecessing effective-one-body (EOB) model calibrated to numerical-relativity simulations, which forces spin alignment (nonprecessing EOBNR). Here we present new results that include a 15-dimensional precessing-spin waveform model (precessing EOBNR) developed within the EOB formalism. We find good agreement with the parameters estimated previously [2], and we quote updated component masses of $35^{+5}_{-3}\\mathrm{M}_\\odot$ and $30^{+3}_{-4}\\mathrm{M}_\\odot$ (where errors correspond to 90% symmetric credible intervals). We also present slightly tighter constraints on the dimensionless spin magnitudes of the two black holes, with a prima...
Eric Reifenstein
Full Text Available As a rat moves, grid cells in its entorhinal cortex (EC discharge at multiple locations of the external world, and the firing fields of each grid cell span a hexagonal lattice. For movements on linear tracks, spikes tend to occur at successively earlier phases of the theta-band filtered local field potential during the traversal of a firing field - a phenomenon termed phase precession. The complex movement patterns observed in two-dimensional (2D open-field environments may fundamentally alter phase precession. To study this question at the behaviorally relevant single-run level, we analyzed EC spike patterns as a function of the distance traveled by the rat along each trajectory. This analysis revealed that cells across all EC layers fire spikes that phase-precess; indeed, the rate and extent of phase precession were the same, only the correlation between spike phase and path length was weaker in EC layer III. Both slope and correlation of phase precession were surprisingly similar on linear tracks and in 2D open-field environments despite strong differences in the movement statistics, including running speed. While the phase-precession slope did not correlate with the average running speed, it did depend on specific properties of the animal's path. The longer a curving path through a grid-field in a 2D environment, the shallower was the rate of phase precession, while runs that grazed a grid field tangentially led to a steeper phase-precession slope than runs through the field center. Oscillatory interference models for grid cells do not reproduce the observed phenomena.
Improved analysis of GW150914 using a fully spin-precessing waveform model
2016-01-01
This paper presents updated estimates of source parameters for GW150914, a binary black-hole coalescence event detected by the Laser Interferometer Gravitational-wave Observatory (LIGO) in 2015 [Abbott et al. Phys. Rev. Lett. 116, 061102 (2016).]. Abbott et al. [Phys. Rev. Lett. 116, 241102 (2016).] presented parameter estimation of the source using a 13-dimensional, phenomenological precessing-spin model (precessing IMRPhenom) and an 11-dimensional nonprecessing effective-one-body (EOB) mode...
Gyroscope precession along unbound equatorial plane orbits around a Kerr black hole
Bini, Donato; Jantzen, Robert T
2016-01-01
The precession of a test gyroscope along unbound equatorial plane geodesic orbits around a Kerr black hole is analyzed with respect to a static reference frame whose axes point towards the "fixed stars." The accumulated precession angle after a complete scattering process is evaluated and compared with the corresponding change in the orbital angle. Limiting results for the non-rotating Schwarzschild black hole case are also discussed.
Valley precession and valley polarization in graphene with inter-valley coupling
Wu, Qing-Ping; Liu, Zheng-Fang; Chen, Ai-Xi; Xiao, Xian-Bo; Zhang, Heng; Miao, Guo-Xing
2017-10-01
We theoretically investigate the valley precession and valley polarization in graphene under inter-valley coupling. Our results show that the inter-valley coupling can induce valley polarization in graphene and also precess valleys in real space in a manner similar to the Rashba spin-orbit interaction rotating spins. Moreover, using strain modulation, we can achieve high valley polarization with large valley-polarized currents. These findings provide a new way to create and manipulate valley polarization in graphene.
Studies of the Precessing Vortex Core in Swirling Flows
M.O. Vigueras-Zuñiga
2012-10-01
Full Text Available Large scale coherent structures play an important role in the behavior of the combustion regime inside any type ofcombustor stabilized by swirl, with special impact on factors such as flame stability, blow off, emissions and theoccurrence of thermo-acoustic oscillations. Lean premixed combustion is widely used and is known to impact many ofthese factors, causing complex interrelationships with any coherent structure formed. Despite the extensiveexperimentation in this matter, the above phenomena are poorly understood. Numerical simulations have been usedto try to explain the development of different regimes, but their extremely complex nature and lack of time dependentvalidation show varied and debatable results. The precessing vortex core (PVC is a well-known coherent structurewhose development, intensity and occurrence has not been well documented. This paper thus adopts an experimentalapproach to characterize the PVC in a simple swirl burner under combustion conditions so as to reveal the effects ofswirl and other variables on the latter. Aided by a high speed photography (HSP system, the recognition and extentof several different types of PVCs were observed and discussed.
Near-IR imaging towards a puzzling YSO precessing jet
Paron, S; Ortega, M E
2016-01-01
At present there are many studies concerning jets towards low-mass young stellar objects, while equivalent studies towards massive or intermediate-mass young stellar objects are scarce. In a previous study, we found highly misaligned molecular outflows towards the infrared point source IRS. Using near-IR data acquired with Gemini-NIRI at the JHKs-broad-bands and narrow-bands centered at the emission lines of [FeII], H2 1-0 S(1), H2 2-1 S(1), Br-gamma, and CO 2-0 (bh), we studied the circumstellar environment of IRS with an angular resolution between 0.35" and 0.45". The emission in the JHKs-broad-bands shows, with great detail, the presence of a cone-like shape nebula extending to the north/northeast of the point source, which appears to be attached to it by a jet-like structure. In the three bands the nebula is resolved in a twisted-shaped feature composed by two arc-like features and a bow shock-like structure seen mainly in the Ks-band, which strongly suggests the presence of a precessing jet. An analysis ...
Local Magnetic Fields in Ferromagnetics Studied by Positive Muon Precession
2002-01-01
Positive muons are used to study local magnetic fields in different materials. A polarized muon beam is employed with energies of 30-50 MeV, and the muons are stopped in the target being studied. During its lifetime the muon will precess in the magnetic fields present, and after the decay of the muon the emitted positron is detected in plastic scintillators. The time and angle of the detected positron is used to calculate the magnetic field at the position of the muon in the sample. \\\\ \\\\ The detector system consists of plastic scintillators. Most of the measurements are made in an applied magnetic field. A dilution cryostat is used to produce temperatures down to well below $ 1 ^0 $ K. \\\\ \\\\ The present line of experiments concern mainly: \\item a)~~~~Local magnetism in the paramagnetic state of the Lave's phase type REAl$_{2} $ and RENi$_{2} $ systems ~~~where RE is a rare-earth ion. \\item b)~~~~Local magnetic fields and critical behaviour of the magnetism in Gd metal. \\item c)~~~~Investigation of flux exclu...
Black-hole binaries with non-precessing spins
Hannam, Mark; Ohme, Frank; Mueller, Doreen; Bruegmann, Bernd
2010-01-01
We present gravitational waveforms for the last orbits and merger of black-hole-binary (BBH) systems along two branches of the BBH parameter space: equal-mass binaries with equal non-precessing spins, and nonspinning unequal-mass binaries. The waveforms are calculated from numerical solutions of Einstein's equations for black-hole binaries that complete between six and ten orbits before merger. Along the equal-mass spinning branch, the spin parameter of each BH is $\\chi_i = S_i/M_i^2 \\in [-0.85,0.85]$, and along the unequal-mass branch the mass ratio is $q =M_2/M_1 \\in [1,4]$. We discuss the construction of low-eccentricity puncture initial data for these cases, the properties of the final merged BH, and compare the last 8-10 GW cycles up to $M\\omega = 0.1$ with the phase and amplitude predicted by standard post-Newtonian (PN) approximants. As in previous studies, we find that the phase from the 3.5PN TaylorT4 approximant is most accurate for nonspinning binaries. For equal-mass spinning binaries the 3.5PN Ta...
Multiple repetition time balanced steady-state free precession imaging.
Cukur, Tolga; Nishimura, Dwight G
2009-07-01
Although balanced steady-state free precession (bSSFP) imaging yields high signal-to-noise ratio (SNR) efficiency, the bright lipid signal is often undesirable. The bSSFP spectrum can be shaped to suppress the fat signal with scan-efficient alternating repetition time (ATR) bSSFP. However, the level of suppression is limited, and the pass-band is narrow due to its nonuniform shape. A multiple repetition time (TR) bSSFP scheme is proposed that creates a broad stop-band with a scan efficiency comparable with ATR-SSFP. Furthermore, the pass-band signal uniformity is improved, resulting in fewer shading/banding artifacts. When data acquisition occurs in more than a single TR within the multiple-TR period, the echoes can be combined to significantly improve the level of suppression. The signal characteristics of the proposed technique were compared with bSSFP and ATR-SSFP. The multiple-TR method generates identical contrast to bSSFP, and achieves up to an order of magnitude higher stop-band suppression than ATR-SSFP. In vivo studies at 1.5 T and 3 T demonstrate the superior fat-suppression performance of multiple-TR bSSFP.
PRECESSION: Python toolbox for dynamics of spinning black-hole binaries
Gerosa, Davide; Kesden, Michael
2016-11-01
PRECESSION is a comprehensive toolbox for exploring the dynamics of precessing black-hole binaries in the post-Newtonian regime. It allows study of the evolution of the black-hole spins along their precession cycles, performs gravitational-wave-driven binary inspirals using both orbit-averaged and precession-averaged integrations, and predicts the properties of the merger remnant through fitting formulas obtained from numerical-relativity simulations. PRECESSION can add the black-hole spin dynamics to larger-scale numerical studies such as gravitational-wave parameter estimation codes, population synthesis models to predict gravitational-wave event rates, galaxy merger trees and cosmological simulations of structure formation, and provides fast and reliable integration methods to propagate statistical samples of black-hole binaries from/to large separations where they form to/from small separations where they become detectable, thus linking gravitational-wave observations of spinning black-hole binaries to their astrophysical formation history. The code is also useful for computing initial parameters for numerical-relativity simulations targeting specific precessing systems.
Iorio, Lorenzo
2017-03-01
In the framework of the emergent gravity scenario by Verlinde, it was recently observed by Liu and Prokopec that, among other things, an anomalous pericenter precession would affect the orbital motion of a test particle orbiting an isolated central body. Here, it is shown that, if it were real, its expected magnitude for the inner planets of the Solar System would be at the same level of the present-day accuracy in constraining any possible deviations from their standard perihelion precessions as inferred from long data records spanning about the last century. The most favorable situation for testing the Verlinde-type precession seems to occur for Mars. Indeed, according to recent versions of the EPM and INPOP planetary ephemerides, non-standard perihelion precessions, of whatsoever physical origin, which are larger than some ≈ 0.02-0.11 milliarcseconds per century are not admissible, while the putative precession predicted by Liu and Prokopec amounts to 0.09 milliarcseconds per century. Other potentially interesting astronomical and astrophysical scenarios like, e.g., the Earth's LAGEOS II artificial satellite, the double pulsar system PSR J0737-3039A/B and the S-stars orbiting the Supermassive Black Hole in Sgr A^* are, instead, not viable because of the excessive smallness of the predicted precessions for them.
DeHart, Russell; Smith, Eric; Lakin, John
2015-01-01
The spin period to precession period ratio of a non-axisymmetric spin-stabilized spacecraft, the Advanced Composition Explorer (ACE), was used to estimate the remaining mass and distribution of fuel within its propulsion system. This analysis was undertaken once telemetry suggested that two of the four fuel tanks had no propellant remaining, contrary to pre-launch expectations of the propulsion system performance. Numerical integration of possible fuel distributions was used to calculate moments of inertia for the spinning spacecraft. A Fast Fourier Transform (FFT) of output from a dynamics simulation was employed to relate calculated moments of inertia to spin and precession periods. The resulting modeled ratios were compared to the actual spin period to precession period ratio derived from the effect of post-maneuver nutation angle on sun sensor measurements. A Monte Carlo search was performed to tune free parameters using the observed spin period to precession period ratio over the life of the mission. This novel analysis of spin and precession periods indicates that at the time of launch, propellant was distributed unevenly between the two pairs of fuel tanks, with one pair having approximately 20% more propellant than the other pair. Furthermore, it indicates the pair of the tanks with less fuel expelled all of its propellant by 2014 and that approximately 46 kg of propellant remains in the other two tanks, an amount that closely matches the operational fuel accounting estimate. Keywords: Fuel Distribution, Moments of Inertia, Precession, Spin, Nutation
Phase coding by grid cells in unconstrained environments: Two-dimensional (2D) phase precession
Climer, Jason R.; Newman, Ehren L.; Hasselmo, Michael E.
2014-01-01
Action potential timing is thought to play a critical role in neural representation. For example, theta phase precession is a robust phenomenon exhibited by spatial cells of the rat entorhinal-hippocampal circuit. In phase precession, the time a neuron fires relative to the phase of theta rhythm (6-10Hz) oscillations in the local field potential reduces uncertainty about the position of the animal. This relationship between neural firing and behavior has made precession an important constraint for hypothetical mechanisms of temporal coding. However, challenges exist in identifying what regulates the spike timing of these cells. We have developed novel analytical techniques for mapping between behavior and neural firing that provide sufficient sensitivity to examine features of grid cell phase coding in open environments. Here, we show robust, omnidirectional phase precession by entorhinal grid cells in openfield enclosures. We present evidence that full phase precession persists regardless of how close the animal comes to the center of a firing field. We found many conjunctive grid cells, previously thought to be phase locked, also exhibit phase coding. However, we were unable to detect directional or field specific phase coding predicted by some variants of models. Finally, we present data that suggests bursting of layer II grid cells contributes to the bimodality of phase precession. We discuss implications of these observations for models of temporal coding and propose the utility of these techniques in other domains where behavior is aligned to neural spiking. PMID:23718553
Improved Analysis of GW150914 Using a Fully Spin-Precessing Waveform Model
Abbott, B. P.; Abbott, R.; Abbott, T. D.; Abernathy, M. R.; Acernese, F.; Ackley, K.; Adams, C.; Adams, T.; Addesso, P.; Adhikari, R. X.; Adya, V. B.; Affeldt, C.; Agathos, M.; Agatsuma, K.; Aggarwal, N.; Aguiar, O. D.; Aiello, L.; Ain, A.; Ajith, P.; Allen, B.; Allocca, A.; Altin, P. A.; Anderson, S. B.; Anderson, W. G.; Arai, K.; Araya, M. C.; Arceneaux, C. C.; Areeda, J. S.; Arnaud, N.; Arun, K. G.; Ascenzi, S.; Ashton, G.; Ast, M.; Aston, S. M.; Astone, P.; Aufmuth, P.; Aulbert, C.; Babak, S.; Bacon, P.; Bader, M. K. M.; Baker, P. T.; Baldaccini, F.; Ballardin, G.; Ballmer, S. W.; Barayoga, J. C.; Barclay, S. E.; Barish, B. C.; Barker, D.; Barone, F.; Barr, B.; Barsotti, L.; Barsuglia, M.; Barta, D.; Bartlett, J.; Bartos, I.; Bassiri, R.; Basti, A.; Batch, J. C.; Baune, C.; Bavigadda, V.; Bazzan, M.; Bejger, M.; Bell, A. S.; Berger, B. K.; Bergmann, G.; Berry, C. P. L.; Bersanetti, D.; Bertolini, A.; Betzwieser, J.; Bhagwat, S.; Bhandare, R.; Bilenko, I. A.; Billingsley, G.; Birch, J.; Birney, R.; Birnholtz, O.; Biscans, S.; Bisht, A.; Bitossi, M.; Biwer, C.; Bizouard, M. A.; Blackburn, J. K.; Blair, C. D.; Blair, D. G.; Blair, R. M.; Bloemen, S.; Bock, O.; Boer, M.; Bogaert, G.; Bogan, C.; Bohe, A.; Bond, C.; Bondu, F.; Bonnand, R.; Boom, B. A.; Bork, R.; Boschi, V.; Bose, S.; Bouffanais, Y.; Bozzi, A.; Bradaschia, C.; Brady, P. R.; Braginsky, V. B.; Branchesi, M.; Brau, J. E.; Briant, T.; Brillet, A.; Brinkmann, M.; Brisson, V.; Brockill, P.; Broida, J. E.; Brooks, A. F.; Brown, D. A.; Brown, D. D.; Brown, N. M.; Brunett, S.; Buchanan, C. C.; Buikema, A.; Bulik, T.; Bulten, H. J.; Buonanno, A.; Buskulic, D.; Buy, C.; Byer, R. L.; Cabero, M.; Cadonati, L.; Cagnoli, G.; Cahillane, C.; Calderón Bustillo, J.; Callister, T.; Calloni, E.; Camp, J. B.; Cannon, K. C.; Cao, J.; Capano, C. D.; Capocasa, E.; Carbognani, F.; Caride, S.; Casanueva Diaz, C.; Casentini, J.; Caudill, S.; Cavaglià, M.; Cavalier, F.; Cavalieri, R.; Cella, G.; Cepeda, C. B.; Cerboni Baiardi, L.; Cerretani, G.; Cesarini, E.; Chamberlin, S. J.; Chan, M.; Chao, S.; Charlton, P.; Chassande-Mottin, E.; Cheeseboro, B. D.; Chen, H. Y.; Chen, Y.; Cheng, C.; Chincarini, A.; Chiummo, A.; Cho, H. S.; Cho, M.; Chow, J. H.; Christensen, N.; Chu, Q.; Chua, S.; Chung, S.; Ciani, G.; Clara, F.; Clark, J. A.; Cleva, F.; Coccia, E.; Cohadon, P.-F.; Colla, A.; Collette, C. G.; Cominsky, L.; Constancio, M.; Conte, A.; Conti, L.; Cook, D.; Corbitt, T. R.; Cornish, N.; Corsi, A.; Cortese, S.; Costa, C. A.; Coughlin, M. W.; Coughlin, S. B.; Coulon, J.-P.; Countryman, S. T.; Couvares, P.; Cowan, E. E.; Coward, D. M.; Cowart, M. J.; Coyne, D. C.; Coyne, R.; Craig, K.; Creighton, J. D. E.; Cripe, J.; Crowder, S. G.; Cumming, A.; Cunningham, L.; Cuoco, E.; Dal Canton, T.; Danilishin, S. L.; D'Antonio, S.; Danzmann, K.; Darman, N. S.; Dasgupta, A.; Da Silva Costa, C. F.; Dattilo, V.; Dave, I.; Davier, M.; Davies, G. S.; Daw, E. J.; Day, R.; De, S.; DeBra, D.; Debreczeni, G.; Degallaix, J.; De Laurentis, M.; Deléglise, S.; Del Pozzo, W.; Denker, T.; Dent, T.; Dergachev, V.; De Rosa, R.; DeRosa, R. T.; DeSalvo, R.; Devine, R. C.; Dhurandhar, S.; Díaz, M. C.; Di Fiore, L.; Di Giovanni, M.; Di Girolamo, T.; Di Lieto, A.; Di Pace, S.; Di Palma, I.; Di Virgilio, A.; Dolique, V.; Donovan, F.; Dooley, K. L.; Doravari, S.; Douglas, R.; Downes, T. P.; Drago, M.; Drever, R. W. P.; Driggers, J. C.; Ducrot, M.; Dwyer, S. E.; Edo, T. B.; Edwards, M. C.; Effler, A.; Eggenstein, H.-B.; Ehrens, P.; Eichholz, J.; Eikenberry, S. S.; Engels, W.; Essick, R. C.; Etienne, Z.; Etzel, T.; Evans, M.; Evans, T. M.; Everett, R.; Factourovich, M.; Fafone, V.; Fair, H.; Fairhurst, S.; Fan, X.; Fang, Q.; Farinon, S.; Farr, B.; Farr, W. M.; Fauchon-Jones, E.; Favata, M.; Fays, M.; Fehrmann, H.; Fejer, M. M.; Fenyvesi, E.; Ferrante, I.; Ferreira, E. C.; Ferrini, F.; Fidecaro, F.; Fiori, I.; Fiorucci, D.; Fisher, R. P.; Flaminio, R.; Fletcher, M.; Fournier, J.-D.; Frasca, S.; Frasconi, F.; Frei, Z.; Freise, A.; Frey, R.; Frey, V.; Fritschel, P.; Frolov, V. V.; Fulda, P.; Fyffe, M.; Gabbard, H. A. G.; Gaebel, S.; Gair, J. R.; Gammaitoni, L.; Gaonkar, S. G.; Garufi, F.; Gaur, G.; Gehrels, N.; Gemme, G.; Geng, P.; Genin, E.; Gennai, A.; George, J.; Gergely, L.; Germain, V.; Ghosh, Abhirup; Ghosh, Archisman; Ghosh, S.; Giaime, J. A.; Giardina, K. D.; Giazotto, A.; Gill, K.; Glaefke, A.; Goetz, E.; Goetz, R.; Gondan, L.; González, G.; Gonzalez Castro, J. M.; Gopakumar, A.; Gordon, N. A.; Gorodetsky, M. L.; Gossan, S. E.; Gosselin, M.; Gouaty, R.; Grado, A.; Graef, C.; Graff, P. B.; Granata, M.; Grant, A.; Gras, S.; Gray, C.; Greco, G.; Green, A. C.; Groot, P.; Grote, H.; Grunewald, S.; Guidi, G. M.; Guo, X.; Gupta, A.; Gupta, M. K.; Gushwa, K. E.; Gustafson, E. K.; Gustafson, R.; Hacker, J. J.
2016-10-01
This paper presents updated estimates of source parameters for GW150914, a binary black-hole coalescence event detected by the Laser Interferometer Gravitational-wave Observatory (LIGO) in 2015 [Abbott et al. Phys. Rev. Lett. 116, 061102 (2016).]. Abbott et al. [Phys. Rev. Lett. 116, 241102 (2016).] presented parameter estimation of the source using a 13-dimensional, phenomenological precessing-spin model (precessing IMRPhenom) and an 11-dimensional nonprecessing effective-one-body (EOB) model calibrated to numerical-relativity simulations, which forces spin alignment (nonprecessing EOBNR). Here, we present new results that include a 15-dimensional precessing-spin waveform model (precessing EOBNR) developed within the EOB formalism. We find good agreement with the parameters estimated previously [Abbott et al. Phys. Rev. Lett. 116, 241102 (2016).], and we quote updated component masses of 35-3+5 M⊙ and 3 0-4+3 M⊙ (where errors correspond to 90% symmetric credible intervals). We also present slightly tighter constraints on the dimensionless spin magnitudes of the two black holes, with a primary spin estimate <0.65 and a secondary spin estimate <0.75 at 90% probability. Abbott et al. [Phys. Rev. Lett. 116, 241102 (2016).] estimated the systematic parameter-extraction errors due to waveform-model uncertainty by combining the posterior probability densities of precessing IMRPhenom and nonprecessing EOBNR. Here, we find that the two precessing-spin models are in closer agreement, suggesting that these systematic errors are smaller than previously quoted.
Simulating relativistic binaries with Whisky
Baiotti, L.
We report about our first tests and results in simulating the last phase of the coalescence and the merger of binary relativistic stars. The simulations were performed using our code Whisky and mesh refinement through the Carpet driver.
Relativistic effects in atom gravimeters
Tan, Yu-Jie; Shao, Cheng-Gang; Hu, Zhong-Kun
2017-01-01
Atom interferometry is currently developing rapidly, which is now reaching sufficient precision to motivate laboratory tests of general relativity. Thus, it is extremely significant to develop a general relativistic model for atom interferometers. In this paper, we mainly present an analytical derivation process and first give a complete vectorial expression for the relativistic interferometric phase shift in an atom interferometer. The dynamics of the interferometer are studied, where both the atoms and the light are treated relativistically. Then, an appropriate coordinate transformation for the light is performed crucially to simplify the calculation. In addition, the Bordé A B C D matrix combined with quantum mechanics and the "perturbation" approach are applied to make a methodical calculation for the total phase shift. Finally, we derive the relativistic phase shift kept up to a sensitivity of the acceleration ˜1 0-14 m/s 2 for a 10 -m -long atom interferometer.
Scattering in Relativistic Particle Mechanics.
de Bievre, Stephan
The problem of direct interaction in relativistic particle mechanics has been extensively studied and a variety of models has been proposed avoiding the conclusions of the so-called no-interaction theorems. In this thesis we study scattering in the relativistic two-body problem. We use our results to analyse gauge invariance in Hamiltonian constraint models and the uniqueness of the symplectic structure in manifestly covariant relativistic particle mechanics. We first present a general geometric framework that underlies approaches to relativistic particle mechanics. This permits a model-independent and geometric definition of the notions of asymptotic completeness and of Moller and scattering operators. Subsequent analysis of these concepts divides into two parts. First, we study the kinematic properties of the scattering transformation, i.e. those properties that arise solely from the invariance of the theory under the Poincare group. We classify all canonical (symplectic) scattering transformations on the relativistic phase space for two free particles in terms of a single function of the two invariants of the theory. We show how this function is determined by the center of mass time delay and scattering angle and vice versa. The second part of our analysis of the relativistic two-body scattering problem is devoted to the dynamical properties of the scattering process. Hence, we turn to two approaches to relativistic particle mechanics: the Hamiltonian constraint models and the manifestly covariant formalism. Using general geometric arguments, we prove "gauge invariance" of the scattering transformation in the Todorov -Komar Hamiltonian constraint model. We conclude that the scattering cross sections of the Todorov-Komar models have the same angular dependence as their non-relativistic counterpart, irrespective of a choice of gauge. This limits the physical relevance of those models. We present a physically non -trivial Hamiltonian constraint model, starting from
Soliton propagation in relativistic hydrodynamics
Fogaça, D A; 10.1016/j.nuclphysa.2007.03.104
2013-01-01
We study the conditions for the formation and propagation of Korteweg-de Vries (KdV) solitons in nuclear matter. In a previous work we have derived a KdV equation from Euler and continuity equations in non-relativistic hydrodynamics. In the present contribution we extend our formalism to relativistic fluids. We present results for a given equation of state, which is based on quantum hadrodynamics (QHD).
Relativistic formulation and reference frame
Klioner, Sergei A.
2004-01-01
After a short review of experimental foundations of metric theories of gravity, the choice of general relativity as a theory to be used for the routine modeling of Gaia observations is justified. General principles of relativistic modeling of astronomical observations are then sketched and compared to the corresponding Newtonian principles. The fundamental reference system -- Barycentric Celestial Reference System, which has been chosen to be the relativistic reference system underlying the f...
Doskocz Adam
2016-01-01
Full Text Available All official data are currently integrated and harmonized in a spatial reference system. This paper outlines a national geodetic and cartographic resources in Poland. The national geodetic and cartographic resources are an important part of the spatial information infrastructure in the European Community. They also provide reference data for other resources of Spatial Data Infrastructure (SDI, including: main and detailed geodetic control networks, base maps, land and buildings registries, geodetic registries of utilities and topographic maps. This paper presents methods of producing digital map data and technical standards for field surveys, and in addition paper also presents some aspects of building Global and Regional SDI.
NSGIC GIS Inventory (aka Ramona) — This Geodetic Networks dataset, published at 1:600 (1in=50ft) scale, was produced all or in part from Field Survey/GPS information as of 2003. It is described as...
An Autonomous, Low Cost Platform for Seafloor Geodetic Observations
Ericksen, T.; Foster, J. H.; Bingham, B. S.
2013-12-01
The high cost of acquiring geodetic data from the sea floor has limited the observations available to help us understand and model the behavior of seafloor geodetic processes. To address this problem, the Pacific GPS Facility at the University of Hawaii is developing a cost effective approach for accurately measuring short-term vertical motions of the seafloor and maintaining a continuous long-term record of seafloor pressure without the requirement for costly ship time. There is a recognized need to vastly increase our underwater geodetic observing capacity. Most of the largest recorded earthquakes and most devastating tsunamis are generated at subduction zones underwater. Similarly, many volcanoes are partly (e.g. Santorini) or completely (e.g. Loihi) submerged, and are not well observed and understood. Furthermore, landslide features ring many ocean basins, and huge debris deposits surround many volcanic oceanic islands. Our approach will lower the cost of collecting sea-floor geodetic data, reducing the barriers preventing us from acquiring the information we need to observe and understand these types of structures and provide a direct societal benefit in improving hazard assessment. The capability is being developed by equipping one of the University of Hawaii Wave Gliders with an integrated acoustic telemetry package, a dual frequency geodetic-grade Global Positioning System (GPS) receiver, processing unit, and cellular communications. The Wave Glider will interrogate high accuracy pressure sensors on the sea floor to maintain a near-continuous stream of pressure and temperature data, but seafloor pressure data includes contribution from a variety of sources and on its own may not provide the accuracy required for geodetic investigations. Independent measurements of sea surface pressure and sea surface height can be used to remove these contributions from the observed sea floor pressure timeseries. We will integrate our seafloor pressure measurements with air
Pan, Yi; Taracchini, Andrea; Kidder, Lawrence E; Mroue, Abdul H; Pfeiffer, Harald P; Scheel, Mark A; Szilagyi, Bela
2013-01-01
We describe a general procedure to generate spinning, precessing waveforms that include inspiral, merger and ringdown stages in the effective-one-body (EOB) approach. The procedure uses a precessing frame in which precession-induced amplitude and phase modulations are minimized, and an inertial frame, aligned with the spin of the final black hole, in which we carry out the matching of the inspiral-plunge to merger-ringdown waveforms. As a first application, we build spinning, precessing EOB waveforms for the gravitational modes l=2 such that in the nonprecessing limit those waveforms agree with the EOB waveforms recently calibrated to numerical-relativity waveforms. Without recalibrating the EOB model, we then compare EOB and post-Newtonian precessing waveforms to two numerical-relativity waveforms produced by the Caltech-Cornell-CITA collaboration. The numerical waveforms are strongly precessing and have 35 and 65 gravitational-wave cycles. We find a remarkable agreement between EOB and numerical-relativity ...
Geodetic reference systems for long period studies in earth physics
Mather, R. S.
1973-01-01
A simple system of reference axes is defined for possible use in high precision geodetic studies over long periods of time for programs in earth physics. The proposed system is based on the gravitational and dynamic characteristics of the axis of rotation and the earth's center of mass as defined instantaneously at a given epoch. Techniques are outlined for its continuous representation over time intervals of significance for studies in earth physics. The relationship between the proposed system and the representation of extra-terrestrial objects using the celestial sphere concept is also discussed.
Geodetic Space Weather Monitoring by means of Ionosphere Modelling
Schmidt, Michael
2017-04-01
The term space weather indicates physical processes and phenomena in space caused by radiation of energy mainly from the Sun. Manifestations of space weather are (1) variations of the Earth's magnetic field, (2) the polar lights in the northern and southern hemisphere, (3) variations within the ionosphere as part of the upper atmosphere characterized by the existence of free electrons and ions, (4) the solar wind, i.e. the permanent emission of electrons and photons, (5) the interplanetary magnetic field, and (6) electric currents, e.g. the van Allen radiation belt. It can be stated that ionosphere disturbances are often caused by so-called solar storms. A solar storm comprises solar events such as solar flares and coronal mass ejections (CMEs) which have different effects on the Earth. Solar flares may cause disturbances in positioning, navigation and communication. CMEs can effect severe disturbances and in extreme cases damages or even destructions of modern infrastructure. Examples are interruptions to satellite services including the global navigation satellite systems (GNSS), communication systems, Earth observation and imaging systems or a potential failure of power networks. Currently the measurements of solar satellite missions such as STEREO and SOHO are used to forecast solar events. Besides these measurements the Earth's ionosphere plays another key role in monitoring the space weather, because it responses to solar storms with an increase of the electron density. Space-geodetic observation techniques, such as terrestrial GNSS, satellite altimetry, space-borne GPS (radio occultation), DORIS and VLBI provide valuable global information about the state of the ionosphere. Additionally geodesy has a long history and large experience in developing and using sophisticated analysis and combination techniques as well as empirical and physical modelling approaches. Consequently, geodesy is predestinated for strongly supporting space weather monitoring via
Refining a relativistic, hydrodynamic solver: Admitting ultra-relativistic flows
Bernstein, J. P.; Hughes, P. A.
2009-09-01
We have undertaken the simulation of hydrodynamic flows with bulk Lorentz factors in the range 102-106. We discuss the application of an existing relativistic, hydrodynamic primitive variable recovery algorithm to a study of pulsar winds, and, in particular, the refinement made to admit such ultra-relativistic flows. We show that an iterative quartic root finder breaks down for Lorentz factors above 102 and employ an analytic root finder as a solution. We find that the former, which is known to be robust for Lorentz factors up to at least 50, offers a 24% speed advantage. We demonstrate the existence of a simple diagnostic allowing for a hybrid primitives recovery algorithm that includes an automatic, real-time toggle between the iterative and analytical methods. We further determine the accuracy of the iterative and hybrid algorithms for a comprehensive selection of input parameters and demonstrate the latter’s capability to elucidate the internal structure of ultra-relativistic plasmas. In particular, we discuss simulations showing that the interaction of a light, ultra-relativistic pulsar wind with a slow, dense ambient medium can give rise to asymmetry reminiscent of the Guitar nebula leading to the formation of a relativistic backflow harboring a series of internal shockwaves. The shockwaves provide thermalized energy that is available for the continued inflation of the PWN bubble. In turn, the bubble enhances the asymmetry, thereby providing positive feedback to the backflow.
Current status of the EPOS WG4 - GNSS and Other Geodetic Data
Fernandes, Rui; Bastos, Luisa; Bruyninx, Carine; D'Agostino, Nicola; Dousa, Jan; Ganas, Athanassios; Lidberg, Martin; Nocquet, Jean-Mathieu
2014-05-01
WG4 - "EPOS Geodetic Data and Other Geodetic Data" is the Working Group of the EPOS project in charge of defining and preparing the integration of the existing Pan-European Geodetic Infrastructures that will support European Geosciences, which is the ultimate goal of the EPOS project. The WG4 is formed by representatives of the participating EPOS countries (23) but it is also open to the entire geodetic community. In fact, WG4 also already includes members from countries that formally are not integrating EPOS in this first step. The geodetic component of EPOS (WG4) is dealing essentially with Research Infrastructures focused on continuous operating GNSS (cGNSS) in the current phase. The option of concentrating the efforts on the presently most generalized geodetic tool supporting research on Solid Earth was decided in order to optimize the existing resources. Nevertheless, WG4 will continue to pursue the development of tools and methodologies that permit the access of the EPOS community to other geodetic information (e.g., gravimetry). Furthermore, although the focus is on Solid Earth applications, other research and technical applications (e.g., reference frames, meteorology, space weather) can also benefit from the efforts of WG4 EPOS towards the optimization of the geodetic resources in Europe. We will present and discuss the plans for the implementation of the thematic and core services (TCS) for geodetic data within EPOS and the related business plan. We will focus on strategies towards the implementation of the best solutions that will permit to the end-users, and in particular geo-scientists, to access the geodetic data, derived solutions, and associated metadata using transparent and uniform processes. Five pillars have been defined proposed for the TCS: Dissemination, Preservation, Monitoring, and Analysis of geodetic data plus the Support and Governance Infrastructure. Current proposals and remaining open questions will be discussed.
NSGIC State | GIS Inventory — Geodetic Control Points dataset current as of 1995. Benchmarks; Vertical elevation bench marks for monumented geodetic survey control points for which mean sea level...
Empirical Foundations of Relativistic Gravity
Ni, W T
2005-01-01
In 1859, Le Verrier discovered the mercury perihelion advance anomaly. This anomaly turned out to be the first relativistic-gravity effect observed. During the 141 years to 2000, the precisions of laboratory and space experiments, and astrophysical and cosmological observations on relativistic gravity have been improved by 3 orders of magnitude. In 1999, we envisaged a 3-6 order improvement in the next 30 years in all directions of tests of relativistic gravity. In 2000, the interferometric gravitational wave detectors began their runs to accumulate data. In 2003, the measurement of relativistic Shapiro time-delay of the Cassini spacecraft determined the relativistic-gravity parameter gammaγ with a 1.5-order improvement. In October 2004, Ciufolini and Pavlis reported a measurement of the Lense-Thirring effect on the LAGEOS and LAGEOS2 satellites to 10 percent of the value predicted by general relativity. In April 2004, Gravity Probe B was launched and has been accumulating science data for more than ...
NSGIC GIS Inventory (aka Ramona) — This Geodetic Control Points dataset, published at 1:24000 (1in=2000ft) scale, was produced all or in part from Published Reports/Deeds information as of 2009. It...
NSGIC GIS Inventory (aka Ramona) — This Geodetic Control Points dataset, published at 1:600 (1in=50ft) scale, was produced all or in part from Field Survey/GPS information as of 2001. It is described...
Geodetic and seismological investigation in the Ionian area
F. Riguzzi
1997-06-01
Full Text Available Geodetic and seismic evidence of crustal deformations in the Ionian area are shown in this paper. The Ionian GPS network, composed of nine sites crossing the Ionian Sea from Calabria, Southern Italy, to Northwestern Greece, was established and surveyed in 1991, 1994, 1995 within the framework of the TYRGEONET project (Anzidei et al., 1996. In 1996 a return campaign was carried out after the occurrence of seismic activity in 1995. The displacement pattern obtained for the Greek side of the network agrees well with those previously displayed, both in magnitude and direction, confirming a mean displacement rate of about 1-2 cm1/yr. The same agreement is not found for the Italian side of the network, where no significant deformations were detected between 1994 and 1996. Seismic deformation was also studied for the same area, starting from the moment tensors of events which occurred in the last 20 years with magnitude greater than 5.0; evident similarity with the displacement field exhibited by the Greek side of the Ionian Sea by geodetic surveys was inferred. On the contrary, the motion detected for the Italian area cannot be simply related to seismic activity.
Geodetic Mobil Solar Spectrometer for JASON Altimeter Satellite Calibration
Somieski, A.; Buerki, B.; Geiger, A.; Kahle, H.-G.; Becker-Ross, H.; Florek, S.; Okruss, M.
Atmospheric water vapor is a crucial factor in achieving highest accuracies for space geodetic measurements. Water vapor causes a delay of the propagation time of the altimeter satellite signal, which propagates into errors for the determination of surface heights. Knowledge of the precipitable water vapor (PW) enables a tropospheric correction of the satellite signal. Therefore, different remote sensing techniques have been pursued to measure the PW continuously. The prototype Geodetic Mobil Solar Spectrometer (GEMOSS) was developed at the Geodesy and Geodynamics Laboratory (GGL, ETH Zurich) in cooperation with the Institute of Spectrochemistry and Applied Spectroscopy (ISAS) (Berlin, Germany). A new optical approach allows the simultaneous measurement of numerous single absorption lines of water vapor in the wide range between 728 nm and 915 nm. The large number of available absorption lines increases the accuracy of the absolute PW retrievals considerably. GEMOSS has been deployed during two campaigns in Greece in the framework of the EU-project GAVDOS, which deals with the calibration of the altimeter satellite JASON. During the overfly of JASON, the ground-based determination of PW enables the correction of the satellite measurements due to tropospheric water vapor. Comparisons with radiometer and radiosondes data allow to assess the accuracy and reliability of GEMOSS. The instrumental advancement of GEMOSS is presented together with the results of the campaigns carried out.
Geodetic refraction effects of electromagnetic wave propagation through the atmosphere
1984-01-01
With very few exceptions, geodetic measurements use electro magnetic radiation in order to measure directions, distances, time delays, and Doppler frequency shifts, to name the main ter restrial and space observables. Depending on the wavelength of the radiation and the purpose of the measurements, the follow ing parameters of the electromagnetic wave are measured: ampli tude, phase, angle-of-arrival, polarisation and frequency. Ac curate corrections have to be applied to the measurements in order to take into account the effects of the intervening medium between transmitter and receiver. The known solutions use at mospheric models, special observation programs, remote sensing techniques and instrumental methods. It has been shown that the effects of the earth's atmospheric envelope present a fundamental limitation to the accuracy and precision of geodetic measurements. This applies equally to ter restrial and space applications. Instrumental accuracies are al ready below the atmospherically i...
Adjustment of positional geodetic networks by unconventional estimations
Silvia Gašincová
2010-06-01
Full Text Available The content of this paper is the adjustment of positional geodetic networks by robust estimations. The techniques (basedon the unconventional estimations of repeated least-square method which have turned out to be suitable and applicable in the practisehave been demonstrated on the example of the local geodetic network, which was founded to compose this thesis. In the thesisthe following techniques have been chosen to compare the Method of least-squares with those many published in foreign literature:M-estimation of Biweight,M-estimation of Welsch and Danish method. All presented methods are based on the repeated least-squaremethod principle with gradual changing of weight of individual measurements. In the first stage a standard least-square method wascarried out in the following steps – iterations we gradually change individual weights according to the relevant instructions/ regulation(so-called weight function. Iteration process will be stopped when no deviated measurements are found in the file of measured data.MatLab programme version 5.2 T was used to implement mathematical adjustment.
Indik, Nathaniel; Haris, K.; Dal Canton, Tito; Fehrmann, Henning; Krishnan, Badri; Lundgren, Andrew; Nielsen, Alex B.; Pai, Archana
2017-01-01
Gravitational wave searches to date have largely focused on non-precessing systems. Including precession effects greatly increases the number of templates to be searched over. This leads to a corresponding increase in the computational cost and can increase the false alarm rate of a realistic search. On the other hand, there might be astrophysical systems that are entirely missed by non-precessing searches. In this paper we consider the problem of constructing a template bank using stochastic methods for neutron star-black hole binaries allowing for precession, but with the restrictions that the total angular momentum of the binary is pointing toward the detector and that the neutron star spin is negligible relative to that of the black hole. We quantify the number of templates required for the search, and we explicitly construct the template bank. We show that despite the large number of templates, stochastic methods can be adapted to solve the problem. We quantify the parameter space region over which the non-precessing search might miss signals.
Indik, Nathaniel; Haris, K.; Dal Canton, Tito; Fehrmann, Henning; Krishnan, Badri; Lundgren, Andrew; Nielsen, Alex B.; Pai, Archana
2017-01-01
Gravitational wave searches to date have largely focused on non-precessing systems. Including precession effects greatly increases the number of templates to be searched over. This leads to a corresponding increase in the computational cost and can increase the false alarm rate of a realistic search. On the other hand, there might be astrophysical systems that are entirely missed by non-precessing searches. In this paper we consider the problem of constructing a template bank using stochastic methods for neutron star-black hole binaries allowing for precession, but with the restrictions that the total angular momentum of the binary is pointing toward the detector and that the neutron star spin is negligible relative to that of the black hole. We quantify the number of templates required for the search, and we explicitly construct the template bank. We show that despite the large number of templates, stochastic methods can be adapted to solve the problem. We quantify the parameter space region over which the non-precessing search might miss signals.
Precession in Stokes flow: spin and revolution of a bacterial flagellum
Ishikawa, Takuji; Sawano, Yoichiro; Wakebe, Hiromichi; Inoue, Yuichi; Ishijima, Akihiko; Shimogonya, Yuji
2016-11-01
The bacterial flagellar motor is an ion-driven rotary machine in the cell envelope of bacteria. When we performed a bead assay, in which the cell body was affixed to a glass surface to observe the rotation of a truncated flagellum via the positioning of a 250 nm-diameter gold nanoparticle, we often observed that the filament motion consisted of two types of rotation: spin and revolution, which resulted in precession. Since the mechanism of flagella precession was unknown, we investigated it using numerical simulations. The results show that the precession occurred due to hydrodynamic interactions between the flagellum and the wall in the Stokes flow regime. We also developed a simple theory of the precession, which validity was confirmed by comparing with the simulation. The theory could be utilized to predict both the filament tilt angle and motor torque from experimental flagellar precession data. The knowledge obtained is important in understanding mechanical properties of the bacterial motor and hook. This work was supported in part by a Japan Society Promotion of Science Grants-in-Aid for Scientific Research (JSPS KAKENHI) (Grant Nos. 25000008 and 26242039).
The impact of using jason-1 and cryosat-2 geodetic mission altimetry for gravity field modeling
Andersen, Ole Baltazar; Jain, Maulik; Knudsen, Per
2016-01-01
operating in a geodetic mission as part its end of life mission. In this presentation, we perform an investigation of the impact of the Cryosat-2 and Jason-1 geodetic missions on high resolution marine gravity field mapping through comparison with recent high quality marine gravity measured by the United...
Civicioglu, Pinar
2012-09-01
In order to solve numerous practical navigational, geodetic and astro-geodetic problems, it is necessary to transform geocentric cartesian coordinates into geodetic coordinates or vice versa. It is very easy to solve the problem of transforming geodetic coordinates into geocentric cartesian coordinates. On the other hand, it is rather difficult to solve the problem of transforming geocentric cartesian coordinates into geodetic coordinates as it is very hard to define a mathematical relationship between the geodetic latitude (φ) and the geocentric cartesian coordinates (X, Y, Z). In this paper, a new algorithm, the Differential Search Algorithm (DS), is presented to solve the problem of transforming the geocentric cartesian coordinates into geodetic coordinates and its performance is compared with the performances of the classical methods (i.e., Borkowski, 1989; Bowring, 1976; Fukushima, 2006; Heikkinen, 1982; Jones, 2002; Zhang, 2005; Borkowski, 1987; Shu, 2010 and Lin, 1995) and Computational-Intelligence algorithms (i.e., ABC, JDE, JADE, SADE, EPSDE, GSA, PSO2011, and CMA-ES). The statistical tests realized for the comparison of performances indicate that the problem-solving success of DS algorithm in transforming the geocentric cartesian coordinates into geodetic coordinates is higher than those of all classical methods and Computational-Intelligence algorithms used in this paper.
c5++ - Multi-Technique Analysis Software for Next Generation Geodetic Instruments
Hobiger, Thomas; Gotoh, Tadahiro; Otsubo, toshimichi; Kubooka, Toshihiro; Sekido, Mamoru; Takiguchi, Hiroshi; Takeuchi, Hiroshi
2010-01-01
Processing of space geodetic techniques should be carried out with consistent and utmost up-todate physical models. Therefore, c5++ is being developed, which will act as a framework under which dedicated space geodetic applications can be created. Due to its nature, combination of different techniques as well as automated processing of VLBI experiments will become possible with c5++.
Steady state relativistic stellar dynamics around a massive black hole
Bar-Or, Ben
2015-01-01
A massive black hole (MBH) consumes stars whose orbits evolve into the small phase-space volume of unstable orbits, the "loss-cone", which take them directly into the MBH, or close enough to interact strongly with it. The resulting phenomena: tidal heating and tidal disruption, binary capture and hyper-velocity star ejection, gravitational wave (GW) emission by inspiraling compact remnants, or hydrodynamical interactions with an accretion disk, are of interest as they can produce observable signatures and thereby reveal the existence of the MBH, affect its mass and spin evolution, probe strong gravity, and provide information on stars and gas near the MBH. The continuous loss of stars and the processes that resupply them shape the central stellar distribution. We investigate relativistic stellar dynamics near the loss-cone of a non-spinning MBH in steady-state analytically and by Monte Carlo simulations of the diffusion of the orbital parameters. These take into account Newtonian mass precession due to enclos...
Relativistic causality and clockless circuits
Matherat, Philippe; 10.1145/2043643.2043650
2011-01-01
Time plays a crucial role in the performance of computing systems. The accurate modelling of logical devices, and of their physical implementations, requires an appropriate representation of time and of all properties that depend on this notion. The need for a proper model, particularly acute in the design of clockless delay-insensitive (DI) circuits, leads one to reconsider the classical descriptions of time and of the resulting order and causal relations satisfied by logical operations. This questioning meets the criticisms of classical spacetime formulated by Einstein when founding relativity theory and is answered by relativistic conceptions of time and causality. Applying this approach to clockless circuits and considering the trace formalism, we rewrite Udding's rules which characterize communications between DI components. We exhibit their intrinsic relation with relativistic causality. For that purpose, we introduce relativistic generalizations of traces, called R-traces, which provide a pertinent des...
New form of geodetic coordinate system taking two length quantity as coordinate parameters
Yimin SHI; Ziyang ZHU; Yeming FAN
2009-01-01
A new form of geodetic coordinate system based on geodesic coordinates instead of geodetic long-itude and latitude was proposed. The vertical and horizontal geodesic coordinates measured with length were defined as coordinate parameters, but the two families of coordinate curves were still meridians and parallel circles. The first fundamental form on the ellipsoidal surface and its three coefficients were deduced by the geodesic coordinate. The formula for the latitudinal scale factor of length for geodetic parallel lines was derived, by which the obtained result conformed to that standard value calculated from geodetic latitude, and it is applicable in the range of 400 km from north to south. Therefore, it lays the foundation for establishing the differential equation and differential relationship based on this type of coordinate parameters; and consequently, it is convenient and accurate enough to operate on the ellipsoidal surface in this new form of geodetic coordinate system.
Relativistic RPA in axial symmetry
Arteaga, D Pena; 10.1103/PhysRevC.77.034317
2009-01-01
Covariant density functional theory, in the framework of self-consistent Relativistic Mean Field (RMF) and Relativistic Random Phase approximation (RPA), is for the first time applied to axially deformed nuclei. The fully self-consistent RMF+RRPA equations are posed for the case of axial symmetry and non-linear energy functionals, and solved with the help of a new parallel code. Formal properties of RPA theory are studied and special care is taken in order to validate the proper decoupling of spurious modes and their influence on the physical response. Sample applications to the magnetic and electric dipole transitions in $^{20}$Ne are presented and analyzed.
Multifragmentation calculated with relativistic forces
Feldmeier, H; Papp, G
1995-01-01
A saturating hamiltonian is presented in a relativistically covariant formalism. The interaction is described by scalar and vector mesons, with coupling strengths adjusted to the nuclear matter. No explicit density depe ndence is assumed. The hamiltonian is applied in a QMD calculation to determine the fragment distribution in O + Br collision at different energies (50 -- 200 MeV/u) to test the applicability of the model at low energies. The results are compared with experiment and with previous non-relativistic calculations. PACS: 25.70Mn, 25.75.+r
Relativistic Stern-Gerlach Deflection
Talman, Richard
2016-01-01
Modern advances in polarized beam control should make it possible to accurately measure Stern-Gerlach (S-G) deflection of relativistic beams. Toward this end a relativistically covariant S-G formalism is developed that respects the opposite behavior under inversion of electric and magnetic fields. Not at all radical, or even new, this introduces a distinction between electric and magnetic fields that is not otherwise present in pure Maxwell theory. Experimental configurations (mainly using polarized electron beams passing through magnetic or electric quadrupoles) are described. Electron beam preparation and experimental methods needed to detect the extremely small deflections are discussed.
Special Relativistic Hydrodynamics with Gravitation
Hwang, Jai-chan; Noh, Hyerim
2016-12-01
Special relativistic hydrodynamics with weak gravity has hitherto been unknown in the literature. Whether such an asymmetric combination is possible has been unclear. Here, the hydrodynamic equations with Poisson-type gravity, considering fully relativistic velocity and pressure under the weak gravity and the action-at-a-distance limit, are consistently derived from Einstein’s theory of general relativity. An analysis is made in the maximal slicing, where the Poisson’s equation becomes much simpler than our previous study in the zero-shear gauge. Also presented is the hydrodynamic equations in the first post-Newtonian approximation, now under the general hypersurface condition. Our formulation includes the anisotropic stress.
Special relativistic hydrodynamics with gravitation
Hwang, Jai-chan
2016-01-01
The special relativistic hydrodynamics with weak gravity is hitherto unknown in the literature. Whether such an asymmetric combination is possible was unclear. Here, the hydrodynamic equations with Poisson-type gravity considering fully relativistic velocity and pressure under the weak gravity and the action-at-a-distance limit are consistently derived from Einstein's general relativity. Analysis is made in the maximal slicing where the Poisson's equation becomes much simpler than our previous study in the zero-shear gauge. Also presented is the hydrodynamic equations in the first post-Newtonian approximation, now under the {\\it general} hypersurface condition. Our formulation includes the anisotropic stress.
Vector Theory in Relativistic Thermodynamics
刘泽文
1994-01-01
It is pointed out that five defects occur in Planck-Einstein’s relativistic thermodynamics (P-E theory). A vector theory in relativistic thermodynamics (VTRT) is established. Defining the internal energy as a 4-vector, and supposing the entropy and the number of. particles to be invariants we have derived the transformations of all quantities, and subsequently got the Lagrangian and 4-D forms of thermodynamic laws. In order to test the new theory, several exact solutions with classical limits are given. The VTRT is free from the defects of the P-E theory.
Frontiers in relativistic celestial mechanics
2014-01-01
Relativistic celestial mechanics – investigating the motion celestial bodies under the influence of general relativity – is a major tool of modern experimental gravitational physics. With a wide range of prominent authors from the field, this two-volume series consists of reviews on a multitude of advanced topics in the area of relativistic celestial mechanics – starting from more classical topics such as the regime of asymptotically-flat spacetime, light propagation and celestial ephemerides, but also including its role in cosmology and alternative theories of gravity as well as modern experiments in this area.
Subcritical transition to turbulence of a precessing flow in a cylindrical vessel
Herault, Johann; Gundrum, Thomas; Giesecke, André; Stefani, Frank
2015-12-01
The transition to turbulence in a precessing cylindrical vessel is experimentally investigated. Our measurements are performed for a nearly resonant configuration with an initially laminar flow dominated by an inertial mode with azimuthal wave number m = 1 superimposed on a solid body rotation. By increasing the precession ratio, we observe a transition from the laminar to a non-linear regime, which then breakdowns to turbulence for larger precession ratio. Our measurements show that the transition to turbulence is subcritical, with a discontinuity of the wall-pressure and the power consumption at the threshold ɛLT. The turbulence is self-sustained below this threshold, describing a bifurcation diagram with a hysteresis. In this range of the control parameters, the turbulent flows can suddenly collapse after a finite duration, leading to a definitive relaminarization of the flow. The average lifetime of the turbulence increases rapidly when ɛ tends to ɛLT.
Anomaly of the Lense-Thirring precession in Kerr-Taub-NUT spacetimes
Chakraborty, Chandrachur
2014-01-01
Exact Lense-Thirring (LT) precession in Kerr-Taub-NUT spacetime is reviewed. It is shown that the LT precession does not obey the general inverse cube law of distance at strong gravity regime in Kerr-Taub-NUT spacetime. Rather, it becomes maximum just near the horizon, falls sharply and becomes negligibly small near the horizon. The precession rate increases again and after that it falls obeying the general inverse cube law of distance. This anomaly is maximum at the polar region of this spacetime and it vanishes after crossing a certain `critical' angle towards equator from pole. In addition, we show that if the Kerr-Taub-NUT spacetime rotates with the angular momentum $J=Mn$ (Mass$\\times$Dual Mass), one horizon disappears and only {\\it event horizon} exists at the distance $r=2M$.
The Origin of Warped, Precessing Accretion Disks in X-ray Binaries
Maloney, Philip R.; Begelman, Mitchell C.
1997-01-01
The radiation-driven warping instability discovered by Pringle holds considerable promise as the mechanism responsible for producing warped, precessing accretion disks in X-ray binaries. This instability is an inherently global mode of the disk, thereby avoiding the difficulties with earlier models for the precession. Here we follow up on earlier work to study the linear behavior of the instability in the specific context of a binary system. We treat the influence of the companion as an orbit-averaged quadrupole torque on the disk. The presence of this external torque allows the existence of solutions in which the direction of precession of the warp is retrograde with respect to disk rotation, in addition to the prograde solutions that exist in the absence of external torques.
Pekowsky, Larne; Healy, Jim; Shoemaker, Deirdre
2013-01-01
Previous analytic and numerical calculations suggest that, at each instant, the emission from a precessing black hole binary closely resembles the emission from a nonprecessing analog. In this paper we quantitatively explore the validity and limitations of that correspondence, extracting the radiation from a large collection of roughly two hundred generic black hole binary merger simulations both in the simulation frame and in a corotating frame that tracks precession. To a first approximation, the corotating-frame waveforms resemble nonprecessing analogs, based on similarity over a band-limited frequency interval defined using a fiducial detector (here, advanced LIGO) and the source's total mass $M$. By restricting attention to masses $M\\in 200, 2500 M_\\odot$, we insure our comparisons are sensitive only to our simulated late-time inspiral, merger, and ringdown signals. In this mass region, every one of our precessing simulations can be fit by some physically similar member of the \\texttt{IMRPhenomB} phenome...
Subcritical transition to turbulence of a precessing flow in a cylindrical vessel
Herault, Johann; Giesecke, Andre; Stefani, Frank
2015-01-01
The transition to turbulence in a precessing cylindrical vessel is experimentally investigated. Our measurements are performed for a { nearly-resonant} configuration with an initially laminar flow dominated by an inertial mode with azimuthal wave number $m=1$ superimposed on a solid body rotation. By increasing the precession ratio, we observe a transition from the laminar to a non-linear regime, which then breakdowns to turbulence for larger precession ratio. Our measurements show that the transition to turbulence is subcritical, with a discontinuity of the wall-pressure and the power consumption at the threshold $\\epsilon_{LT}$. The turbulence is self-sustained below this threshold, describing a bifurcation diagram with a hysteresis. In this range of the control parameters, the turbulent flows can suddenly collapse after a finite duration, leading to a definitive relaminarization of the flow. The average lifetime $\\langle \\tau \\rangle$ of the turbulence increases rapidly when $\\epsilon$ tends to $\\epsilon_{...
Precessing Ball Solitons in Kinetics of a Spin-Flop Phase Transition
V. V. Nietz
2011-01-01
Full Text Available The fundamentals of precessing ball solitons (PBS, arising as a result of the energy fluctuations during spin-flop phase transition induced by a magnetic field in antiferromagnets with uniaxial anisotropy, are presented. The PBS conditions exist within a wide range of amplitudes and energies, including negative energies relative to an initial condition. For each value of the magnetic field, there exists a precession frequency for which a curve of PBS energy passes through a zero value (in bifurcation point, and hence, in the vicinity of this point the PBS originate with the highest probability. The characteristics of PBS, including the time dependences of configuration, energy, and precession frequency, are considered. As a result of dissipation, the PBS transform into the macroscopic domains of a new phase.
Precession and interference in the Aharonov-Casher and scalar Aharonov-Bohm effect
Hyllus, P; Hyllus, Philipp
2003-01-01
The ideal scalar Aharonov-Bohm (SAB) and Aharonov-Casher (AC) effect involve a magnetic dipole pointing in a certain fixed direction: along a purely time dependent magnetic field in the SAB case and perpendicular to a planar static electric field in the AC case. We extend these effects to arbitrary direction of the magnetic dipole. The precise conditions for having nondispersive precession and interference effects in these generalized set ups are delineated both classically and quantally. Under these conditions the dipole is affected by a nonvanishing torque that causes pure precession around the directions defined by the ideal set ups. It is shown that the precession angles are in the quantal case linearly related to the ideal phase differences, and that the nonideal phase differences are nonlinearly related to the ideal phase differences. It is argued that the latter nonlinearity is due the appearance of a geometric phase associated with the nontrivial spin path. It is further demonstrated that the spatial ...
Spin-dynamics simulations of vortex precession in 2-D magnetic dots
Depondt, Ph., E-mail: depondt@insp.jussieu.fr [Institut des NanoSciences de Paris, Universite Pierre et Marie Curie, UMR 7588 CNRS, 75252 Paris Cedex 05 (France); Levy, J.-C.S., E-mail: jean-claude.levy@univ-paris-diderot.fr [Materiaux et Phenomenes Quantiques, Universite Denis Diderot, UMR 7162 CNRS, 75013 Paris (France)
2011-10-31
Highlights: → Vortex precession was simulated in two-dimensional magnetic dots of finite size. → A simple qualitative explanation of the observed behaviors is proposed, including seemingly erratic ones. → Pinning of the vortex motion, unconnected with defects, is also observed and an explanation thereof provided. -- Abstract: Vortex precession was simulated in two-dimensional magnetic dots. The Landau-Lifshitz equation with exchange and dipolar interactions was integrated at a low temperature with initial conditions consisting in a single vortex situated aside from the central position. This vortex precesses around the center of the sample and either can be expelled or converges towards the center. These relaxation processes are systematically studied. A simple qualitative explanation of the observed behaviors is proposed, including seemingly somewhat erratic ones. Intrinsic pinning of the vortex motion, unconnected with defects, is also observed and an explanation thereof provided.
EELS signal enhancement by means of beam precession in the TEM
Estrade, Sonia, E-mail: sestrade@ub.edu [LENS, MIND-IN2UB, Departament d' Electronica, Universitat de Barcelona, Marti i Franques 1, 08028 Barcelona (Spain); TEM-MAT, CCiT, Universitat de Barcelona, Sole i Sabaris 1, 08028 Barcelona (Spain); Portillo, Joaquim [LENS, MIND-IN2UB, Departament d' Electronica, Universitat de Barcelona, Marti i Franques 1, 08028 Barcelona (Spain); TEM-MAT, CCiT, Universitat de Barcelona, Sole i Sabaris 1, 08028 Barcelona (Spain); Yedra, Lluis [LENS, MIND-IN2UB, Departament d' Electronica, Universitat de Barcelona, Marti i Franques 1, 08028 Barcelona (Spain); Rebled, Jose Manuel [LENS, MIND-IN2UB, Departament d' Electronica, Universitat de Barcelona, Marti i Franques 1, 08028 Barcelona (Spain); Institut de Ciencia de Materials de Barcelona-CSIC, Campus UAB, 08193 Bellaterra (Spain); Peiro, Francesca [LENS, MIND-IN2UB, Departament d' Electronica, Universitat de Barcelona, Marti i Franques 1, 08028 Barcelona (Spain)
2012-05-15
EELS is nowadays a most relevant characterization tool as it provides chemical and electronic information with an extraordinary spatial resolution. When a crystal is viewed in zone axis in the TEM, there is channelling of the electrons along the atom columns, which strongly reduce the EELS signal, so that it is generally advised to work slightly off the zone axis to collect EELS data, which may not always be possible or advantageous. In the present work, we demonstrate the use of precession to compensate for the reduction of EELS signal when in the zone axis. -- Highlights: Black-Right-Pointing-Pointer Channelling compromises EELS signal in zone axis. Black-Right-Pointing-Pointer Precession can be used to get rid of channelling effects. Black-Right-Pointing-Pointer Use of precession to enhance EELS signal in the zone axis is demonstrated.
Rouviere, Jean-Luc, E-mail: jean-luc.rouviere@cea.fr; Martin, Yannick [CEA-INAC/UJF-Grenoble UMR-E, SP2M, LEMMA, Minatec Grenoble F-38054 (France); Béché, Armand [CEA-INAC/UJF-Grenoble UMR-E, SP2M, LEMMA, Minatec Grenoble F-38054 (France); FEI Electron Optics, Achtseweg Noord 5, 5651 GG Eindhoven (Netherlands); Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Denneulin, Thibaud; Cooper, David [CEA, LETI, Minatec, F-38054 Grenoble (France)
2013-12-09
NanoBeam Electron Diffraction is a simple and efficient technique to measure strain in nanostructures. Here, we show that improved results can be obtained by precessing the electron beam while maintaining a few nanometer probe size, i.e., by doing Nanobeam Precession Electron Diffraction (N-PED). The precession of the beam makes the diffraction spots more uniform and numerous, making N-PED more robust and precise. In N-PED, smaller probe size and better precision are achieved by having diffraction disks instead of diffraction dots. Precision in the strain measurement better than 2 × 10{sup −4} is obtained with a probe size approaching 1 nm in diameter.
A semianalytic Fisher matrix for precessing binaries with a single significant spin
O'Shaughnessy, R; Lundgren, A
2015-01-01
Gravitational waves from a binary with a single dynamically significant spin, notably including precessing black hole-neutron star (BH-NS) binaries, let us constrain that binary's properties: the two masses and the dominant black hole spin. Based on a straightforward fourier transform of $h(t)$ enabled by the corotating frame, we show the Fisher matrix for precessing binaries can be well-approximated by an extremely simple semianalytic approximation. This approximation can be easily understood as a weighted average of independent information channels, each associated with one gravitational wave harmonic. Generalizing previous studies of nonprecessing binaries to include critical symmetry-breaking precession effects required to understand plausible astrophysical sources, our ansatz can be applied to address how well gravitational wave measurements can address a wide range of astrophysical and fundamental questions. Our approach provides a simple method to assess what parameters gravitational wave detectors can...
Relativistic Hydrodynamics for Heavy-Ion Collisions
Ollitrault, Jean-Yves
2008-01-01
Relativistic hydrodynamics is essential to our current understanding of nucleus-nucleus collisions at ultrarelativistic energies (current experiments at the Relativistic Heavy Ion Collider, forthcoming experiments at the CERN Large Hadron Collider). This is an introduction to relativistic hydrodynamics for graduate students. It includes a detailed…
Improved Analysis of GW150914 Using a Fully Spin-Precessing Waveform Model
2016-10-01
Full Text Available This paper presents updated estimates of source parameters for GW150914, a binary black-hole coalescence event detected by the Laser Interferometer Gravitational-wave Observatory (LIGO in 2015 [Abbott et al. Phys. Rev. Lett. 116, 061102 (2016.]. Abbott et al. [Phys. Rev. Lett. 116, 241102 (2016.] presented parameter estimation of the source using a 13-dimensional, phenomenological precessing-spin model (precessing IMRPhenom and an 11-dimensional nonprecessing effective-one-body (EOB model calibrated to numerical-relativity simulations, which forces spin alignment (nonprecessing EOBNR. Here, we present new results that include a 15-dimensional precessing-spin waveform model (precessing EOBNR developed within the EOB formalism. We find good agreement with the parameters estimated previously [Abbott et al. Phys. Rev. Lett. 116, 241102 (2016.], and we quote updated component masses of 35_{-3}^{+5} M_{⊙} and 30_{-4}^{+3} M_{⊙} (where errors correspond to 90% symmetric credible intervals. We also present slightly tighter constraints on the dimensionless spin magnitudes of the two black holes, with a primary spin estimate <0.65 and a secondary spin estimate <0.75 at 90% probability. Abbott et al. [Phys. Rev. Lett. 116, 241102 (2016.] estimated the systematic parameter-extraction errors due to waveform-model uncertainty by combining the posterior probability densities of precessing IMRPhenom and nonprecessing EOBNR. Here, we find that the two precessing-spin models are in closer agreement, suggesting that these systematic errors are smaller than previously quoted.
STEADY-STATE RELATIVISTIC STELLAR DYNAMICS AROUND A MASSIVE BLACK HOLE
Bar-Or, Ben; Alexander, Tal [Department of Particle Physics and Astrophysics, Weizmann Institute of Science, P.O. Box 26, Rehovot 76100 (Israel)
2016-04-01
A massive black hole (MBH) consumes stars whose orbits evolve into the small phase-space volume of unstable orbits, the “loss cone,” which take them into the MBH, or close enough to interact strongly with it. The resulting phenomena, e.g., tidal heating and disruption, binary capture and hyper-velocity star ejection, gravitational wave (GW) emission by inspiraling compact remnants, or hydrodynamical interactions with an accretion disk, can produce observable signatures and thereby reveal the MBH, affect its mass and spin evolution, test strong gravity, and probe stars and gas near the MBH. These continuous stellar loss and resupply processes shape the central stellar distribution. We investigate relativistic stellar dynamics near the loss cone of a non-spinning MBH in steady state, analytically and by Monte Carlo simulations of the diffusion of the orbital parameters. These take into account Newtonian mass precession due to enclosed stellar mass, in-plane precession due to general relativity, dissipation by GW, uncorrelated two-body relaxation, correlated resonant relaxation (RR), and adiabatic invariance due to secular precession, using a rigorously derived description of correlated post-Newtonian dynamics in the diffusion limit. We argue that general maximal entropy considerations strongly constrain the orbital diffusion in steady state, irrespective of the relaxation mechanism. We identify the exact phase-space separatrix between plunges and inspirals, and predict their steady-state rates. We derive the dependence of the rates on the mass of the MBH, show that the contribution of RR in steady state is small, and discuss special cases where unquenched RR in restricted volumes of phase-space may affect the steady state substantially.
Reggiani, N; Colonia, J H; De Holanda, P C
1998-01-01
Taking into account the stringent limits from helioseismology observations on possible matter density fluctuations described by magnetohydrodynamics theory, we find the corresponding time variations of solar neutrino survival probability due to the resonant spin-flavor precession phenomenon with amplitude of order O(10%). We discuss the physics potential of high statistics real time experiments, like as Superkamiokande, to observe the effects of such magnetohydrodynamics fluctuations on their data. We conclude that these observations could be thought as a test of the resonant spin-flavor precession solution to the solar neutrino anomaly.
Precession of the Equinoxes: a pedagogical proposal for secondary education teachers
Gangui, Alejandro
2009-01-01
Second part of a didactic sequence of activities on some topics of Astronomy, related mainly with the real shape of the Earth, the gravitational interactions between our planet and other celestial bodies, and the resulting movement of the rotational axis of the Earth, leading to the precession of the equinoctial points. All elements are given for the construction of a simplified Sun-Earth system model, with a zodiacal band surrounding it, in order to show in a pedagogical manner how precession involves a shift of the zodiacal constellations in time.
Okano, Genki; Nozaki, Yukio
2016-06-01
Microwave-assisted magnetization reversal utilizing a transient precession of magnetization was demonstrated in a permalloy hexagon by applying a 25-ns-wide microwave field and a 500-ps-wide pulsed field with a tunable delay to the microwave field. The switching field in a combination of these two fields becomes smaller than that in only the microwave field, and this additional reduction in switching field oscillates relative to the delay time. From the comparison with the results of micromagnetic simulations, we found that the oscillatory behavior is attributed to the beats in transient precession that occurs in the early stage of microwave-field-induced magnetization excitation.
Allmendinger, Fabian; Blümler, Peter; Doll, Michael; Grasdijk, Oliver; Heil, Werner; Jungmann, Klaus; Karpuk, Sergej; Krause, Hans-Joachim; Offenhäuser, Andreas; Repetto, Maricel; Schmidt, Ulrich; Sobolev, Yuri; Tullney, Kathlyne; Willmann, Lorenz; Zimmer, Stefan
2017-01-01
We report on precise measurements of magnetic field gradients extracted from transverse relaxation rates of precessing spin samples. The experimental approach is based on the free precession of gaseous, nuclear spin polarized 3He and 129Xe atoms in a spherical cell inside a magnetic guiding field of
Microscopic Processes in Relativistic Jets
Nishikawa, K.-I.; Hardee, P.; Mizuno, Y.; Medvedev, M.; Zhang, B.; Nordlund, A.; Fredricksen, J.; Sol, H.; Niemiec, J.; Lyubarsky, Y.;
2008-01-01
Nonthermal radiation observed from astrophysical systems containing relativistic jets and shocks, e.g., gamma-ray bursts (GRBs), active galactic nuclei (AGNs), and Galactic microquasar systems usually have power-law emission spectra. Recent PIC simulations of relativistic electron-ion (electro-positron) jets injected into a stationary medium show that particle acceleration occurs within the downstream jet. In the collisionless relativistic shock particle acceleration is due to plasma waves and their associated instabilities (e.g., the Buneman instability, other two-streaming instability, and the Weibel (filamentation) instability) created in the shocks are responsible for particle (electron, positron, and ion) acceleration. The simulation results show that the Weibel instability is responsible for generating and amplifying highly nonuniform, small-scale magnetic fields. These magnetic fields contribute to the electron's transverse deflection behind the jet head. The 'jitter' radiation from deflected electrons has different properties than synchrotron radiation which is calculated in a uniform magnetic field. This jitter radiation may be important to understanding the complex time evolution and/or spectral structure in gamma-ray bursts, relativistic jets, and supernova remnants.
The Highest Redshift Relativistic Jets
Cheung, C.C.; Stawarz, L.; Siemiginowska, A.; Harris, D.E; Schwartz, D.A.; Wardle, J.F.C.; Gobeille, D.; Lee, N.P.
2007-12-18
We describe our efforts to understand large-scale (10's-100's kpc) relativistic jet systems through observations of the highest-redshift quasars. Results from a VLA survey search for radio jets in {approx} 30 z > 3.4 quasars are described along with new Chandra observations of 4 selected targets.
Circular polarization in relativistic jets
Macquart, JP
2003-01-01
Circular polarization is observed in some relativistic jet sources at radio wavelengths. It is largely associated with activity in the cores of the radio sources, is highly variable, and is strongest during ejection episodes. VLBI imaging and interstellar scintillation arguments show that the degree
Error Propagation in Geodetic Networks Studied by FEMLAB
Borre, Kai
2009-01-01
thousand points. This leads to so large matrix problems that one starts thinking of using continous network models. They result in one or more differential equations with corresponding boundary conditions. The Green’s function works like the covariance matrix in the discrete case. If we can find the Green......’s function we also can study error propagation through large networks. Exactly this idea is exploited for error propagation studies in large geodetic networks. To solve the boundary value problems we have used the FEMLAB software. It is a powerful tool for this type of problems. The M-file was created...... and estimate the solution by using the principle of least squares. Contemporary networks often contain several thousand points. This leads to so large matrix problems that one starts thinking of using continous network models. They result in one or more differential equations with corresponding boundary...
Australian geodetic VLBI network (AuScope): present and future.
Titov, Oleg
2015-04-01
The Australian geodetic Very Long Baseline Interferometry (VLBI) array (AuScope) consisting of three new 12-meter radio telescopes in Australia (Hobart, Katherine and Yarragadee), and a correlation facility in Perth that started operations in 2011. The daily positions of the AuScope array are estimated with a precision of a few mm, whereas their daily estimates vary within a range of 20-30 mm on the annual scale. This VLBI network also provides a substantial contribution to the improvement of the Celestial Reference Frame in the southern hemisphere. The plans for extension of the network in collaboration with the New Zealand and South Africa VLBI stations during 2015-2020 are discussed in this presentation.
Results obtained by geodetic instruments of SELENE (KAGUYA)
KAWANO; Nobuyuki; VRAD/RSAT; Team; LALT; Team
2010-01-01
Japanese lunar explorer SELENE (KAGUYA) was equipped with 14 instruments for various measurements of the Moon. Three of these instruments took geodetic measurements of the Moon. These were two sub-satellites and a laser altimeter. The main results obtained by the instruments are: (1) precise orbit determination with an accuracy of ten meters by Doppler and same-beam VLBI; (2) the first precise gravity fields on the lunar far side by 4-way Doppler measurements; (3) the first topography in latitudes higher than 86 degrees; (4) a global map of the gravity anomaly by using the global topography and the global gravity fields; (5) a global map of the lunar crustal thickness and (6) an illumination rate map in the north and south polar regions.
Analysis of variance of an underdetermined geodetic displacement problem
Darby, D.
1982-06-01
It has been suggested recently that point displacements in a free geodetic network traversing a strike-slip fault may be estimated from repeated surveys by minimizing only those displacement components normal to the strike. It is desirable to justify this procedure. We construct, from estimable quantities, a deformation parameter which is an F-statistic of the type occurring in the analysis of variance of linear models not of full rank. A test of its significance provides the criterion to justify the displacement solution. It is also interesting to study its behaviour as one varies the supposed strike of the fault. Justification of a displacement solution using data from a strike-slip fault is found, but not for data from a rift valley. The technique can be generalized to more complex patterns of deformation such as those expected near the end-zone of a fault in a dislocation model.
DETECTION OF COASTLINE DEFORMATION USING REMOTE SENSING AND GEODETIC SURVEYS
A. Sabuncu
2016-06-01
Full Text Available The coastal areas are being destroyed due to the usage that effect the natural balance. Unconsciously sand mining from the sea for nearshore nourishment and construction uses are the main ones. Physical interferences for mining of sand cause an ecologic threat to the coastal environment. However, use of marine sand is inevitable because of economic reasons or unobtainable land-based sand resources. The most convenient solution in such a protection–usage dilemma is to reduce negative impacts of sand production from marine. This depends on the accurate determination of criteriaon production place, style, and amount of sand. With this motivation, nearshore geodedic surveying studies performed on Kilyos Campus of Bogazici University located on the Black Sea coast, north of Istanbul, Turkey between 2001-2002. The study area extends 1 km in the longshore. Geodetic survey was carried out in the summer of 2001 to detect the initial condition for the shoreline. Long-term seasonal changes in shoreline positions were determined biannually. The coast was measured with post-processed kinematic GPS. Besides, shoreline change has studied using Landsat imagery between the years 1986-2015. The data set of Landsat 5 imageries were dated 05.08.1986 and 31.08.2007 and Landsat 7 imageries were dated 21.07.2001 and 28.07.2015. Landcover types in the study area were analyzed on the basis of pixel based classification method. Firstly, unsupervised classification based on ISODATA (Iterative Self Organizing Data Analysis Technique has been applied and spectral clusters have been determined that gives prior knowledge about the study area. In the second step, supervised classification was carried out by using the three different approaches which are minimum-distance, parallelepiped and maximum-likelihood. All pixel based classification processes were performed with ENVI 4.8 image processing software. Results of geodetic studies and classification outputs will be
Detection of Coastline Deformation Using Remote Sensing and Geodetic Surveys
Sabuncu, A.; Dogru, A.; Ozener, H.; Turgut, B.
2016-06-01
The coastal areas are being destroyed due to the usage that effect the natural balance. Unconsciously sand mining from the sea for nearshore nourishment and construction uses are the main ones. Physical interferences for mining of sand cause an ecologic threat to the coastal environment. However, use of marine sand is inevitable because of economic reasons or unobtainable land-based sand resources. The most convenient solution in such a protection-usage dilemma is to reduce negative impacts of sand production from marine. This depends on the accurate determination of criteriaon production place, style, and amount of sand. With this motivation, nearshore geodedic surveying studies performed on Kilyos Campus of Bogazici University located on the Black Sea coast, north of Istanbul, Turkey between 2001-2002. The study area extends 1 km in the longshore. Geodetic survey was carried out in the summer of 2001 to detect the initial condition for the shoreline. Long-term seasonal changes in shoreline positions were determined biannually. The coast was measured with post-processed kinematic GPS. Besides, shoreline change has studied using Landsat imagery between the years 1986-2015. The data set of Landsat 5 imageries were dated 05.08.1986 and 31.08.2007 and Landsat 7 imageries were dated 21.07.2001 and 28.07.2015. Landcover types in the study area were analyzed on the basis of pixel based classification method. Firstly, unsupervised classification based on ISODATA (Iterative Self Organizing Data Analysis Technique) has been applied and spectral clusters have been determined that gives prior knowledge about the study area. In the second step, supervised classification was carried out by using the three different approaches which are minimum-distance, parallelepiped and maximum-likelihood. All pixel based classification processes were performed with ENVI 4.8 image processing software. Results of geodetic studies and classification outputs will be presented in this paper.
Geometry and distribution of seismic and geodetic strain in Italy
Pondrelli, S.; Serpelloni, E.; Morelli, A.
2003-04-01
We determine geometry and distribution of seismic strain in Italy, and surrounding regions, by means of seismological information, and compare results with geodetic data. We use data from the Harvard CMT Catalog, mostly supplemented by the INGV-Harvard European-Mediterranean Regional Centroid Moment Tensor (RCMT) Catalog (http://www.ingv.it/seismolgo/RCMT), including solutions for moderate-magnitude earthquakes (4.5encloses about 400 focal solutions for events occurred between 1997 and 2002, besides other significant events (e.g. the Friuli, Northern Italy, 1976 seismic sequence). We believe this to be the most complete dataset, based on instrumental data, for the last 25 years of seismic activity of the study region. Only crustal events are considered. The method used is the Kostrov summation, applied on a regular grid. We thus obtain the cumulative moment tensor, representative of the geometry of deformation. Its distribution shows NE-SW extension along the Apennines, and the compression field (rotating from NE-SW to NNE-SSW) that affects the mountain chains along the eastern coast of the Adriatic Sea and the Eastern Alps. The geometry of deformation also exhibits other intriguing trends, such as compression along the Southern Tyrrhenian, changing to strike-slip eastward, and turning to extension passing trough the Aeolian Islands and the Messina Strait. We also note the transition from compression in the outer Northern Apennines to transcurrent style in the outer Southern Apennines. Being this region a low strain rate area, a correct evaluation of strain amount requires to merge the instrumental dataset with the historical seismic moment released, as obtained from catalogs. The hypocentral distribution is taken into account to evaluate the depth of the brittle layer. Our results are compared with geodetic data recently obtained analysing more than 10 years of GPS observations collected by more than 130 stations. Significant similarity is found, especially as
Fast lattice Boltzmann solver for relativistic hydrodynamics.
Mendoza, M; Boghosian, B M; Herrmann, H J; Succi, S
2010-07-01
A lattice Boltzmann formulation for relativistic fluids is presented and numerically validated through quantitative comparison with recent hydrodynamic simulations of relativistic fluids. In order to illustrate its capability to handle complex geometries, the scheme is also applied to the case of a three-dimensional relativistic shock wave, generated by a supernova explosion, impacting on a massive interstellar cloud. This formulation opens up the possibility of exporting the proven advantages of lattice Boltzmann methods, namely, computational efficiency and easy handling of complex geometries, to the context of (mildly) relativistic fluid dynamics at large, from quark-gluon plasmas up to supernovae with relativistic outflows.
Iorio, Lorenzo
2005-01-01
The general relativistic Lense-Thirring precessions of the perihelia of the inner planets of the Solar System are about 10^-3 arcseconds per century. Recent improvements in planetary orbit determination may yield the first observational evidence of such a tiny effect. Indeed, corrections to the known perihelion rates of -0.0036 +/- 0.0050, -0.0002 +/- 0.0004 and 0.0001 +/- 0.0005 arcseconds per century were recently estimated by E.V. Pitjeva for Mercury, the Earth and Mars, respectively, on t...
A precessing jet model for the PN K 3-35: simulated radio-continuum emission
Velazquez, P; Esquivel, A; Raga, A
2007-01-01
The bipolar morphology of the planetary nebula (PN) K 3-35 observed in radio-continuum images was modelled with 3D hydrodynamic simulations with the adaptive grid code yguazu-a. We find that the observed morphology of this PN can be reproduced considering a precessing jet evolving in a dense AGB circumstellar medium, given by a mass loss rate \\dot{M}_{csm}=5x10^{-5}M_{\\odot}/yr and a terminal velocity v_{w}=10 km/s. Synthetic thermal radio-continuum maps were generated from numerical results for several frequencies. Comparing the maps and the total fluxes obtained from the simulations with the observational results, we find that a model of precessing dense jets, where each jet injects material into the surrounding CSM at a rate \\dot{M}_j=2.8x10^{-4} {M_{\\odot}/yr (equivalent to a density of 8x10^{4} {cm}^{-3}, a velocity of 1500 km/s, a precession period of 100 yr, and a semi-aperture precession angle of 20 degrees agrees well with the observations.
Babak, Stanislav; Taracchini, Andrea; Buonanno, Alessandra
2017-01-01
In Abbott et al. [Phys. Rev. X 6, 041014 (2016), 10.1103/PhysRevX.6.041014], the properties of the first gravitational wave detected by LIGO, GW150914, were measured by employing an effective-one-body (EOB) model of precessing binary black holes whose underlying dynamics and waveforms were calibrated to numerical-relativity (NR) simulations. Here, we perform the first extensive comparison of such an EOBNR model to 70 precessing NR waveforms that span mass ratios from 1 to 5, dimensionless spin magnitudes up to 0.5, generic spin orientations, and length of about 20 orbits. We work in the observer's inertial frame and include all ℓ=2 modes in the gravitational-wave polarizations. We introduce new prescriptions for the EOB ringdown signal concerning its spectrum and time of onset. For total masses between 10 M⊙ and 200 M⊙ , we find that precessing EOBNR waveforms have unfaithfulness within about 3% to NR waveforms when considering the Advanced-LIGO design noise curve. This result is obtained without recalibration of the inspiral-plunge signal of the underlying nonprecessing EOBNR model. The unfaithfulness is computed with maximization over time and phase of arrival, sky location, and polarization of the EOBNR waveform, and it is averaged over sky location and polarization of the NR signal. We also present comparisons between NR and EOBNR waveforms in a frame that tracks the orbital precession.
Moeck, Peter; Rouvimov, Sergei; Nicolopoulos, Stavros
2009-09-01
Precession electron diffraction (PED) in a transmission electron microscope (TEM) is discussed in order to illustrate its utility for structural fingerprinting of nanocrystals. While individual nanocrystals may be fingerprinted structurally from PED spot patterns, ensembles of nanocrystals may be fingerprinted from powder PED ring patterns.
Costache, M. V.; Watts, S. M.; Sladkov, M.; van der Wal, C. H.; van Wees, B. J.
2006-01-01
The on-chip resonant driving of large cone-angle magnetization precession of an individual nanoscale Permalloy element is demonstrated. Strong driving is realized by locating the element in close proximity to the shorted end of a coplanar strip waveguide, which generates a microwave magnetic field.
On the free-precession candidate PSR B1828-11: Evidence for increasing deformation
Ashton, G; Prix, R
2016-01-01
We observe that the periodic variations in spin-down rate and beam-width of the radio pulsar PSR B1828-11 are getting faster. In the context of a free precession model, this corresponds to a decrease in the precession period $P_{\\mathrm{fp}}$. We investigate how a precession model can account for such a decrease in $P_{\\mathrm{fp}}$, in terms of an increase over time in the absolute biaxial deformation ($|\\epsilon_{\\mathrm{p}}|{\\sim}10^{-8}$) of this pulsar. We perform a Bayesian model comparison against the 'base' precession model (with constant $\\epsilon_{\\mathrm{p}}$) developed in Ashton et al (2016), and we obtain decisive odds in favour of a time-varying deformation. We study two types of time-variation: (i) a linear drift with a posterior estimate of $\\dot{\\epsilon}_{\\mathrm{p}}{\\sim}10^{-18}\\,\\mathrm{s}^{-1}$ and odds of $10^{75}$ compared to the base-model, and (ii) $N$ discrete positive jumps in $\\epsilon_{\\mathrm{p}}$ with very similar odds to the linear $\\epsilon_{\\mathrm{p}}$-drift model. The phys...
Precession and accretion in circumbinary discs: The case of HD 104237
Dunhill, Alex; Dougados, Catherine
2014-01-01
We present the results of smoothed particle hydrodynamics (SPH) simulations of the disc around the young, eccentric stellar binary HD 104237. We find that the binary clears out a large cavity in the disc, driving a significant eccentricity at the cavity edge. This then precesses around the binary at a rate of $\\dot{\\varpi} = 0.48^{\\circ}T_{\\mathrm{b}}^{-1}$, which for HD 104237 corresponds to 40 years. We find that the accretion pattern into the cavity and onto the binary changes with this precession, resulting in a periodic accretion variability driven purely by the physical parameters of the binary and its orbit. For each star we find that this results in order of magnitude changes in the accretion rate. We also find that the accretion variability allows the primary to accrete gas at a higher rate than the secondary for approximately half of each precession period. Using a large number of 3-body integrations of test particles orbiting different binaries, we find good agreement between the precession rate of...
Precession of the Orbital Plane of Binary Pulsars and Significant Variabilities
Bi-Ping Gong
2005-01-01
There are two ways of expressing the precession of orbital plane of a binary pulsar system, given by Barker & O'Connell, Apostolatos et al. and Kidder, respectively. We point out that these two ways actually come from the same Lagrangian under different degrees of freedom. Damour & Schafer and Wex & Kopeikin applied Barker & O'Connell's orbital precession velocity in pulsar timing measurement. This paper applies Apostolatos et al.'s and Kidder's orbital precession velocity. We show that Damour & Schafer's treatment corresponds to negligible Spin-Orbit induced precession of periastron, while Wex & Kopeikin and this paper both found significant (but not equivalent) effects. The observational data of two typical binary pulsars, PSR J2051-0827 and PSR J1713+0747, apparently support a significant Spin-Orbit coupling effect. Specific binary pulsars with orbital plane nearly edge on could discriminate between Wex & Kopeikin and this paper: if the orbital period derivative of the double-pulsar system PSRs J0737-3039 A and B, with orbital inclination angle i =87.7+17 -29 deg, is much larger than that of the gravitational radiation induced one, then the expression in this paper is supported, otherwise Wex & Kopeikin's is supported.
On the free-precession candidate PSR B1828-11: Evidence for increasing deformation
Ashton, G.; Jones, D. I.; Prix, R.
2017-01-01
We observe that the periodic variations in spin-down rate and beam-width of the radio pulsar PSR B1828-11 are getting faster. In the context of a free precession model, this corresponds to a decrease in the precession period Pfp. We investigate how a precession model can account for such a decrease in Pfp, in terms of an increase over time in the absolute biaxial deformation (|ɛp| ˜ 10-8) of this pulsar. We perform a Bayesian model comparison against the `base' precession model (with constant ɛp) developed in Ashton et al. (2016), and we obtain decisive odds in favour of a time-varying deformation. We study two types of time-variation: (i) a linear drift with a posterior estimate of dot{ɛ }_p{˜ }10^{-18} s^{-1} and odds of 1075 compared to the base-model, and (ii) N discrete positive jumps in ɛp with very similar odds to the linear ɛp-drift model. The physical mechanism explaining this behaviour is unclear, but the observation could provide a crucial probe of the interior physics of neutron stars. We also place an upper bound on the rate at which the precessional motion is damped, and translate this into a bound on a dissipative mutual friction-type coupling between the star's crust and core.
Search for Lorentz and CPT violation effects in muon spin precession
Bennett, G. W.; Bousquet, B.; Brown, H. N.; Bunce, G.; Carey, R. M.; Cushman, P.; Danby, G. T.; Debevec, P. T.; Deile, M.; Deng, H.; Deninger, W.; Dhawan, S. K.; Druzhinin, V. P.; Duong, L.; Efstathiadis, E.; Farley, F. J. M.; Fedotovich, G. V.; Giron, S.; Gray, F. E.; Grigoriev, D.; Grosse-Perdekamp, M.; Grossmann, A.; Hare, M. F.; Hertzog, D. W.; Huang, X.; Hughes, V. W.; Iwasaki, M.; Jungmann, K.; Kawall, D.; Kawamura, M.; Khazin, B. I.; Kindem, J.; Krienen, F.; Kronkvist, I.; Lam, A.; Larsen, R.; Lee, Y. Y.; Logashenko, I.; McNabb, R.; Meng, W.; Mi, J.; Miller, J. P.; Mizumachi, Y.; Morse, W. M.; Nikas, D.; Onderwater, C. J. G.; Orlov, Y.; Oezben, C. S.; Paley, J. M.; Peng, Q.; Polly, C. C.; Pretz, J.; Prigl, R.; Putlitz, G. zu; Qian, T.; Redin, S. I.; Rind, O.; Roberts, B. L.; Ryskulov, N.; Sedykh, S.; Semertzidis, Y. K.; Shagin, P.; Shatunov, Yu. M.; Sichtermann, E. P.; Solodov, E.; Sossong, M.; Steinmetz, A.; Sulak, L. R.; Timmermans, C.; Trofimov, A.; Urner, D.; von Walter, P.; Warburton, D.; Winn, D.; Yamamoto, A.; Zimmerman, D.; Bennet, G.W.; Ozben, C.
2008-01-01
The spin precession frequency of muons stored in the (g-2) storage ring has been analyzed for evidence of Lorentz and CPT violation. Two Lorentz and CPT violation signatures were searched for a nonzero Delta omega(a)(=omega(mu+)(a)-omega(mu-)(a)) and a sidereal variation of omega(mu+)(a). No signifi
Measurement of the Nodal Precession of WASP-33 b via Doppler Tomography
Johnson, Marshall C; Cameron, Andrew Collier; Bayliss, Daniel
2015-01-01
We have analyzed new and archival time series spectra taken six years apart during transits of the hot Jupiter WASP-33 b, and spectroscopically resolved the line profile perturbation caused by the Rossiter-McLaughlin effect. The motion of this line profile perturbation is determined by the path of the planet across the stellar disk, which we show to have changed between the two epochs due to nodal precession of the planetary orbit. We measured rates of change of the impact parameter and the sky-projected spin-orbit misalignment of $db/dt=-0.0228_{-0.0018}^{+0.0050}$ yr$^{-1}$ and $d\\lambda/dt=-0.487_{-0.076}^{+0.089}$ $^{\\circ}$ yr$^{-1}$, respectively, corresponding to a rate of nodal precession of $d\\Omega/dt=0.117_{-0.029}^{+0.012}$ $^{\\circ}$ yr$^{-1}$. This is only the second measurement of nodal precession for a confirmed exoplanet transiting a single star. Finally, we used the rate of precession to set limits on the stellar gravitational quadrupole moment of $0.0017\\leq J_2\\leq0.011$.
Effective potentials and morphological transitions for binary black-hole spin precession
Kesden, Michael; O'Shaughnessy, Richard; Berti, Emanuele; Sperhake, Ulrich
2014-01-01
Binary black holes (BBHs) on quasicircular orbits are fully characterized by their total mass $M$, mass ratio $q$, spins $\\mathbf{S}_1$ and $\\mathbf{S}_2$, and orbital angular momentum $\\mathbf{L}$. When the binary separation $r \\gg GM/c^2$, the precession timescale is much shorter than the radiation-reaction time on which $L = |\\mathbf{L}|$ decreases due to gravitational-wave (GW) emission. We use conservation of the total angular momentum $\\mathbf{J} = \\mathbf{L} + \\mathbf{S}_1 + \\mathbf{S}_2$ (with magnitude $J$) and the projected effective spin $\\xi \\equiv M^{-2} [(1+q) \\mathbf{S}_1 + (1+q^{-1})\\mathbf{S}_2] \\cdot \\hat{\\mathbf{L}}$ on the precession time to derive an effective potential for BBH spin precession. This effective potential allows us to solve the orbit-averaged spin-precession equations analytically for arbitrary mass ratios and spins. These solutions are quasiperiodic functions of time: after a period $\\tau(L, J, \\xi)$ the angular momenta return to their initial relative orientations and prec...
The impact of precession and obliquity on the Late-Devonian greenhouse climate
De Vleeschouwer, D.; Crucifix, M.; Bounceur, N.; Claeys, P. F.
2012-12-01
To date, only few general circulation model (GCM) have been used to simulate the extremely warm greenhouse climate of the Late-Devonian (~370 Ma). As a consequence, the current knowledge on Devonian climate dynamics comes almost exclusively from geological proxy data. Given the fragmentary nature of these data sources, the understanding of the Devonian climate is rather limited. Nonetheless, the Late-Devonian is a key-period in the evolution of life on Earth: the continents were no longer bare but were invaded by land plants, the first forests appeared, soils were formed, fish evolved to amphibians and 70-80% of all animal species were wiped out during the Late Devonian extinction (~376 Ma). In order to better understand the functioning of the climate system during this highly important period in Earth's history, we applied the HadSM3 climate model to the Devonian period under different astronomical configurations. This approach provides insight into the response of Late-Devonian climate to astronomical forcing due to precession and obliquity. Moreover, the assessment of the sensitivity of the Late-Devonian climate to astronomical forcing, presented here, will allow cyclostratigraphers to make better and more detailed interpretations of recurring patterns often observed in Late-Devonian sections. We simulated Late-Devonian climates by prescribing palaeogeography, vegetation distribution and pCO2 concentration (2180 ppm). Different experiments were carried out under 31 different astronomical configurations: three levels for obliquity (ɛ = 22°; 23.5° and 24.5°) and eccentricity (e = 0; 0.03 and 0.07) were chosen. For precession, 8 levels were considered (longitude of the perihelion= 0°; 45°; 90°; 135°; 180°; 235°; 270°). First results suggest that the intensity of precipitation on the tropical Euramerican continent (also known as Laurussia) is highly dependent on changes in precession: During precession maxima (= maximal insolation in SH during winter
Effects of the observed J2 variations on the Earth's precession and nutation
Ferrándiz, José M.; Baenas, Tomás; Belda, Santiago
2016-04-01
The Earth's oblateness parameter J2 is closely related to the dynamical ellipticity H, which factorizes the main components of the precession and the different nutation terms. In most theoretical approaches to the Earth's rotation, with IAU2000 nutation theory among them, H is assumed to be constant. The precession model IAU2006 supposes H to have a conventional linear variation, based on the J2 time series derived mainly from satellite laser ranging (SLR) data for decades, which gives rise to an additional quadratic term of the precession in longitude and some corrections of the nutation terms. The time evolution of J2 is, however, too complex to be well approximated by a simple linear model. The effect of more general models including periodic terms and closer to the observed time series, although still unable to reproduce a significant part of the signal, has been seldom investigated. In this work we address the problem of deriving the effect of the observed J2 variations without resorting to such simplified models. The Hamiltonian approach to the Earth rotation is extended to allow the McCullagh's term of the potential to depend on a time-varying oblateness. An analytical solution is derived by means of a suitable perturbation method in the case of the time series provided by the Center for Space Research (CSR) of the University of Texas, which results in non-negligible contributions to the precession-nutation angles. The presentation focuses on the main effects on the longitude of the equator; a noticeable non-linear trend is superimposed to the linear main precession term, along with some periodic and decadal variations.
Effect of precession on the Asian summer monsoon evolution: A systematic review
LIU XiaoDong; SHI ZhengGuo
2009-01-01
Geological climatic records and model simulations on the Asian summer monsoon climate change induced by insolation forcing of the Earth's precession are systematically reviewed in this paper. The presentation of the questions on the mechanism of the Asian monsoon evolution at the precession band, currently existing debates and future research directions are discussed. Since the early 1980s, more and more observed evidence and simulated results, especially the absolute-dated stalagmite re-cords and orbital-scale transient model runs in the last few years, have indicated that the quasi-20ka period in the Quaternary monsoon climate change is caused by precession. However, debates still exist on the dynamic mechanism how precession affects the Asian monsoon. The "zero phase" hypothesis says that the Asian monsoon is merely controlled by summer insolation in the Northern Hemisphere (NH) while the "latent heat" hypothesis emphasizes the dominant effect of latent heat transport from the Southern Hemisphere (SH) besides the role of the northern insolation. The two hypotheses have separately been supported by some evidence. Although we are cognizant of the importance of northern solar radiation and the remote effect of southern insolation, it has still a long way to go before com-prehensively understanding the evolutionary mechanism of the Asian monsoon. In view of the prob-lems existing in present researches of monsoon-dominated climate change at the precession scale, we propose that studies on the environmental significance of geological monsoon proxies, feedback processes in the long-term transient simulations and intercomparisons between observations and modeling results should be strengthened in the future.
Impact of precession on the climate, vegetation and fire activity in southern Africa during MIS4
M.-N. Woillez
2013-09-01
Full Text Available The relationships between climate, vegetation and fires are a major subject of investigation in the context of climate change. In southern Africa, fire is known to play a crucial role in the existence of grasslands and Mediterranean-like biomes. Microcharcoal-based reconstructions of past fire activity in that region have shown a tight correlation between grass-fueled fires and the precessional cycle, with maximum fire activity during maxima of the climatic precession index. These changes have been interpreted as the result of changes in fuel load in response to precipitation changes in eastern southern Africa. Here we use the general circulation model IPSL_CM5A and the dynamical vegetation model LPJ-LMfire to investigate the response of climate, vegetation and fire activity to precession changes in southern Africa during Marine Isotopic Stage 4. We perform two climatic simulations, for a maximum and minimum of the precession index, and use a statistical downscaling method to increase the spatial resolution of the IPSL_CM5A outputs over southern Africa and perform high-resolution simulations of the vegetation and fire activity. Our results show an anti-correlation between the North and South African monsoons in response to precession changes. A decrease of the precession climatic index leads to a precipitation decrease in the summer rainfall area of southern Africa. The drying of climate leads to a decrease of vegetation cover and fire activity. Our results are in qualitative agreement with data and confirm that fire activity in southern Africa is strongly dependent on the vegetation type.
Relativistic electron beams above thunderclouds
Füellekrug, M.; Roussel-Dupre, R.; Symbalisty, E. M. D.;
2011-01-01
Non-luminous relativistic electron beams above thunderclouds have been detected by the radio signals of low frequency similar to 40-400 kHz which they radiate. The electron beams occur similar to 2-9 ms after positive cloud-to-ground lightning discharges at heights between similar to 22-72 km above...... thunderclouds. Intense positive lightning discharges can also cause sprites which occur either above or prior to the electron beam. One electron beam was detected without any luminous sprite which suggests that electron beams may also occur independently of sprites. Numerical simulations show that beams...... of electrons partially discharge the lightning electric field above thunderclouds and thereby gain a mean energy of similar to 7MeV to transport a total charge of similar to-10mC upwards. The impulsive current similar to 3 x 10(-3) Am-2 associated with relativistic electron beams above thunderclouds...
Relativistic electron beams above thunderclouds
M. Füllekrug
2011-05-01
Full Text Available Non-luminous relativistic electron beams above thunderclouds are detected by radio remote sensing with low frequency radio signals from 40–400 kHz. The electron beams occur 2–9 ms after positive cloud-to-ground lightning discharges at heights between 22–72 km above thunderclouds. The positive lightning discharges also cause sprites which occur either above or before the electron beam. One electron beam was detected without any luminous sprite occurrence which suggests that electron beams may also occur independently. Numerical simulations show that the beamed electrons partially discharge the lightning electric field above thunderclouds and thereby gain a mean energy of 7 MeV to transport a total charge of 10 mC upwards. The impulsive current associated with relativistic electron beams above thunderclouds is directed downwards and needs to be considered as a novel element of the global atmospheric electric circuit.
Volatility smile as relativistic effect
Kakushadze, Zura
2017-06-01
We give an explicit formula for the probability distribution based on a relativistic extension of Brownian motion. The distribution (1) is properly normalized and (2) obeys the tower law (semigroup property), so we can construct martingales and self-financing hedging strategies and price claims (options). This model is a 1-constant-parameter extension of the Black-Scholes-Merton model. The new parameter is the analog of the speed of light in Special Relativity. However, in the financial context there is no ;speed limit; and the new parameter has the meaning of a characteristic diffusion speed at which relativistic effects become important and lead to a much softer asymptotic behavior, i.e., fat tails, giving rise to volatility smiles. We argue that a nonlocal stochastic description of such (Lévy) processes is inadequate and discuss a local description from physics. The presentation is intended to be pedagogical.
Double Relativistic Electron Accelerating Mirror
Saltanat Sadykova
2013-02-01
Full Text Available In the present paper, the possibility of generation of thin dense relativistic electron layers is shown using the analytical and numerical modeling of laser pulse interaction with ultra-thin layers. It was shown that the maximum electron energy can be gained by optimal tuning between the target width, intensity and laser pulse duration. The optimal parameters were obtained from a self-consistent system of Maxwell equations and the equation of motion of electron layer. For thin relativistic electron layers, the gaining of maximum electron energies requires a second additional overdense plasma layer, thus cutting the laser radiation off the plasma screen at the instant of gaining the maximum energy (DREAM-schema.
Relativistic stars in bigravity theory
Aoki, Katsuki; Tanabe, Makoto
2016-01-01
Assuming static and spherically symmetric spacetimes in the ghost-free bigravity theory, we find a relativistic star solution, which is very close to that in general relativity. The coupling constants are classified into two classes: Class [I] and Class [II]. Although the Vainshtein screening mechanism is found in the weak gravitational field for both classes, we find that there is no regular solution beyond the critical value of the compactness in Class [I]. This implies that the maximum mass of a neutron star in Class [I] becomes much smaller than that in GR. On the other hand, for the solution in Class [II], the Vainshtein screening mechanism works well even in a relativistic star and the result in GR is recovered.
Relativistic Hydrodynamics on Graphic Cards
Gerhard, Jochen; Bleicher, Marcus
2012-01-01
We show how to accelerate relativistic hydrodynamics simulations using graphic cards (graphic processing units, GPUs). These improvements are of highest relevance e.g. to the field of high-energetic nucleus-nucleus collisions at RHIC and LHC where (ideal and dissipative) relativistic hydrodynamics is used to calculate the evolution of hot and dense QCD matter. The results reported here are based on the Sharp And Smooth Transport Algorithm (SHASTA), which is employed in many hydrodynamical models and hybrid simulation packages, e.g. the Ultrarelativistic Quantum Molecular Dynamics model (UrQMD). We have redesigned the SHASTA using the OpenCL computing framework to work on accelerators like graphic processing units (GPUs) as well as on multi-core processors. With the redesign of the algorithm the hydrodynamic calculations have been accelerated by a factor 160 allowing for event-by-event calculations and better statistics in hybrid calculations.
A relativistic symmetry in nuclei
Ginocchio, J N [MS B283, Theoretical Division, Los Alamos National Laboratory Los Alamos, New Mexico 87545 (Mexico)
2007-11-15
We review some of the empirical and theoretical evidence supporting pseudospin symmetry in nuclei as a relativistic symmetry. We review the case that the eigenfunctions of realistic relativistic nuclear mean fields approximately conserve pseudospin symmetry in nuclei. We discuss the implications of pseudospin symmetry for magnetic dipole transitions and Gamow-Teller transitions between states in pseudospin doublets. We explore a more fundamental rationale for pseudospin symmetry in terms of quantum chromodynamics (QCD), the basic theory of the strong interactions. We show that pseudospin symmetry in nuclei implies spin symmetry for an anti-nucleon in a nuclear environment. We also discuss the future and what role pseudospin symmetry may be expected to play in an effective field theory of nucleons.
Fluctuations in Relativistic Causal Hydrodynamics
Kumar, Avdhesh; Mishra, Ananta P
2013-01-01
The formalism to calculate the hydrodynamics fluctuation using the quasi-stationary fluctuation theory of Onsager to the relativistic Navier-Stokes hydrodynamics is already known. In this work we calculate hydrodynamic fluctuations in relativistic causal theory of Muller, Israel and Stewart and other related causal hydrodynamic theories. We show that expressions for the Onsager coefficients and the correlation functions have form similar to the ones obtained by using Navier-Stokes equation. However, temporal evolution of the correlation functions obtained using MIS and the other causal theories can be significantly different than the correlation functions obtained using the Navier-Stokes equation. Finally, as an illustrative example, we explicitly plot the correlation functions obtained using the causal-hydrodynamics theories and compare them with correlation functions obtained by earlier authors using the expanding boost-invariant (Bjorken) flows.
Thermodynamic and relativistic uncertainty relations
Artamonov, A. A.; Plotnikov, E. M.
2017-01-01
Thermodynamic uncertainty relation (UR) was verified experimentally. The experiments have shown the validity of the quantum analogue of the zeroth law of stochastic thermodynamics in the form of the saturated Schrödinger UR. We have also proposed a new type of UR for the relativistic mechanics. These relations allow us to consider macroscopic phenomena within the limits of the ratio of the uncertainty relations for different physical quantities.
Pythagoras Theorem and Relativistic Kinematics
Mulaj, Zenun; Dhoqina, Polikron
2010-01-01
In two inertial frames that move in a particular direction, may be registered a light signal that propagates in an angle with this direction. Applying Pythagoras theorem and principles of STR in both systems, we can derive all relativistic kinematics relations like the relativity of simultaneity of events, of the time interval, of the length of objects, of the velocity of the material point, Lorentz transformations, Doppler effect and stellar aberration.
Geodetic Control Points, Published in 2008, 1:4800 (1in=400ft) scale, Sauk County.
NSGIC GIS Inventory (aka Ramona) — This Geodetic Control Points dataset, published at 1:4800 (1in=400ft) scale, was produced all or in part from Field Survey/GPS information as of 2008. Data by this...
Geosat Geodetic Mission Waveform Data Records (WDR) for May, 1985 (NODC Accession 0002365)
National Oceanic and Atmospheric Administration, Department of Commerce — This accession contains one month of waveform data records (WDRs) from the GEOSAT Geodetic Mission (GM) and(or) Exact Repeat Mission (ERM) for the time period of...
Geosat Geodetic Mission Sensor Data Records (SDR) for December, 1985 (NODC Accession 0002541)
National Oceanic and Atmospheric Administration, Department of Commerce — This accession contains one month of sensor data records (SDRs) from the GEOSAT Geodetic Mission (GM) for the time period of December 01, 1985 to December 31, 1985....
Geosat Geodetic Mission Sensor Data Records (SDR) for March 1986 (NODC Accession 0002544)
National Oceanic and Atmospheric Administration, Department of Commerce — This accession contains one month of sensor data records (SDRs) from the GEOSAT Geodetic Mission (GM) for the time period of March 01, 1986 to March 31, 1986....
Geosat Geodetic Mission Sensor Data Records (SDR) for November, 1985 (NODC Accession 0002540)
National Oceanic and Atmospheric Administration, Department of Commerce — This accession contains one month of sensor data records (SDRs) from the GEOSAT Geodetic Mission (GM) for the time period of November 01, 1985 to November 30, 1985....
Geosat Geodetic Mission Sensor Data Records (SDR) for May, 1986 (NODC Accession 0002546)
National Oceanic and Atmospheric Administration, Department of Commerce — This accession contains one month of sensor data records (SDRs) from the GEOSAT Geodetic Mission (GM) for the time period of May 01, 1986 to May 31, 1986....
Geosat Geodetic Mission Sensor Data Records (SDR) for June, 1985 (NODC Accession 0002359)
National Oceanic and Atmospheric Administration, Department of Commerce — This accession contains one month of sensor data records (SDRs) from the GEOSAT Geodetic Mission (GM) for the time period of June 01, 1985 to June 30, 1985....
Geodetic Control Points, Wisconsin HARN, Published in 1993, Not Applicable scale, Dunn County, WI.
NSGIC GIS Inventory (aka Ramona) — This Geodetic Control Points dataset, published at Not Applicable scale, was produced all or in part from Field Survey/GPS information as of 1993. It is described as...
Geosat Geodetic Mission Waveform Data Records (WDR) for June, 1985 (NODC Accession 0002551)
National Oceanic and Atmospheric Administration, Department of Commerce — This accession contains one month of waveform data records (WDRs) from the GEOSAT Geodetic Mission (GM) and(or) Exact Repeat Mission (ERM) for the time period of...
Geosat Geodetic Mission Sensor Data Records (SDR) for April, 1985 (NODC Accession 0002350)
National Oceanic and Atmospheric Administration, Department of Commerce — This accession contains one month of sensor data records (SDRs) from the GEOSAT Geodetic Mission (GM) for the time period of April 01, 1985 to April 30, 1985....
Geodetic Markers at Pipe Spring National Monument, Arizona (pisp_geomrkrs)
National Park Service, Department of the Interior — This is an Arc/Info coverage consisting of 7 points representing known coordinates on the earth's surface at Pipe Spring National Monument, Arizona. One geodetic...
Geosat Geodetic Mission Waveform Data Records (WDR) for April, 1986 (NODC Accession 0002561)
National Oceanic and Atmospheric Administration, Department of Commerce — This accession contains one month of waveform data records (WDRs) from the GEOSAT Geodetic Mission (GM) and(or) Exact Repeat Mission (ERM) for the time period of...
Geosat Geodetic Mission Sensor Data Records (SDR) for July, 1986 (NODC Accession 0002548)
National Oceanic and Atmospheric Administration, Department of Commerce — This accession contains one month of sensor data records (SDRs) from the GEOSAT Geodetic Mission (GM) for the time period of July 01, 1986 to July 31, 1986....
Geodetic Control Points, Published in 2003, 1:1200 (1in=100ft) scale, Greenwood County.
NSGIC GIS Inventory (aka Ramona) — This Geodetic Control Points dataset, published at 1:1200 (1in=100ft) scale, was produced all or in part from Field Survey/GPS information as of 2003. Data by this...
Geosat Geodetic Mission Sensor Data Records (SDR) for September, 1986 (NODC Accession 0002550)
National Oceanic and Atmospheric Administration, Department of Commerce — This accession contains one month of sensor data records (SDRs) from the GEOSAT Geodetic Mission (GM) for the time period of September 01, 1986 to Setpember 30,...
Geosat Geodetic Mission Sensor Data Records (SDR) for August, 1986 (NODC Accession 0002549)
National Oceanic and Atmospheric Administration, Department of Commerce — This accession contains one month of sensor data records (SDRs) from the GEOSAT Geodetic Mission (GM) for the time period of August 01, 1986 to August 31, 1986....
Geosat Geodetic Mission Sensor Data Records (SDR) for September, 1985 (NODC Accession 0002538)
National Oceanic and Atmospheric Administration, Department of Commerce — This accession contains one month of sensor data records (SDRs) from the GEOSAT Geodetic Mission (GM) for the time period of September 01, 1985 to September 30,...
Geosat Geodetic Mission Waveform Data Records (WDR) for August, 1986 (NODC Accession 0002565)
National Oceanic and Atmospheric Administration, Department of Commerce — This accession contains one month of waveform data records (WDRs) from the GEOSAT Geodetic Mission (GM) and(or) Exact Repeat Mission (ERM) for the time period of...
Geosat Geodetic Mission Waveform Data Records (WDR) for January, 1986 (NODC Accession 0002558)
National Oceanic and Atmospheric Administration, Department of Commerce — This accession contains one month of waveform data records (WDRs) from the GEOSAT Geodetic Mission (GM) and(or) Exact Repeat Mission (ERM) for the time period of...
Geosat Geodetic Mission Sensor Data Records (SDR) for May, 1985 (NODC Accession 0002351)
National Oceanic and Atmospheric Administration, Department of Commerce — This accession contains one month of sensor data records (SDRs) from the GEOSAT Geodetic Mission (GM) for the time period of May 01, 1985 to May 31, 1985. Parameters...
Geosat Geodetic Mission Waveform Data Records (WDR) for October, 1985 (NODC Accession 0002555)
National Oceanic and Atmospheric Administration, Department of Commerce — This accession contains one month of waveform data records (WDRs) from the GEOSAT Geodetic Mission (GM) and(or) Exact Repeat Mission (ERM) for the time period of...
Geosat Geodetic Mission Waveform Data Records (WDR) for September, 1985 (NODC Accession 0002554)
National Oceanic and Atmospheric Administration, Department of Commerce — This accession contains one month of waveform data records (WDRs) from the GEOSAT Geodetic Mission (GM) and(or) Exact Repeat Mission (ERM) for the time period of...
Geosat Geodetic Mission Waveform Data Records (WDR) for November, 1985 (NODC Accession 0002556)
National Oceanic and Atmospheric Administration, Department of Commerce — This accession contains one month of waveform data records (WDRs) from the GEOSAT Geodetic Mission (GM) and(or) Exact Repeat Mission (ERM) for the time period of...
Geosat Geodetic Mission Waveform Data Records (WDR) for August, 1985 (NODC Accession 0002553)
National Oceanic and Atmospheric Administration, Department of Commerce — his accession contains one month of waveform data records (WDRs) from the GEOSAT Geodetic Mission (GM) and(or) Exact Repeat Mission (ERM) for the time period of...
Geosat Geodetic Mission Waveform Data Records (WDR) for July, 1985 (NODC Accession 0002552)
National Oceanic and Atmospheric Administration, Department of Commerce — This accession contains one month of waveform data records (WDRs) from the GEOSAT Geodetic Mission (GM) and(or) Exact Repeat Mission (ERM) for the time period of...
Geosat Geodetic Mission Waveform Data Records (WDR) for April, 1985 (NODC Accession 0002364)
National Oceanic and Atmospheric Administration, Department of Commerce — This accession contains one month of waveform data records (WDRs) from the GEOSAT Geodetic Mission (GM) and(or) Exact Repeat Mission (ERM) for the time period of...
Geosat Geodetic Mission Waveform Data Records (WDR) for February, 1986 (NODC Accession 0002559)
National Oceanic and Atmospheric Administration, Department of Commerce — This accession contains one month of waveform data records (WDRs) from the GEOSAT Geodetic Mission (GM) and(or) Exact Repeat Mission (ERM) for the time period of...
Geosat Geodetic Mission Sensor Data Records (SDR) for October, 1985 (NODC Accession 0002539)
National Oceanic and Atmospheric Administration, Department of Commerce — This accession contains one month of sensor data records (SDRs) from the GEOSAT Geodetic Mission (GM) for the time period of October 01, 1985 to October 31, 1985....
Geodetic Control Points, Published in 2006, 1:600 (1in=50ft) scale, Washoe County.
NSGIC GIS Inventory (aka Ramona) — This Geodetic Control Points dataset, published at 1:600 (1in=50ft) scale, was produced all or in part from Field Survey/GPS information as of 2006. Data by this...
Geodetic and geophysical observations in Antarctica an overview in the IPY perspective
Capra, Alessandro
2008-01-01
This book is a collection of papers on various aspects of the geodetic and geophysical investigation and observation techniques. It includes material from the Arctic and Antarctica, as well as covering work from both temporary and permanent observatories.
Geosat Geodetic Mission Sensor Data Records (SDR) for July, 1985 (NODC Accession 0002536)
National Oceanic and Atmospheric Administration, Department of Commerce — This accession contains one month of sensor data records (SDRs) from the GEOSAT Geodetic Mission (GM) for the time period of July 01, 1985 to July 31, 1985....
Geosat Geodetic Mission Waveform Data Records (WDR) for July, 1986 (NODC Accession 0002564)
National Oceanic and Atmospheric Administration, Department of Commerce — This accession contains one month of waveform data records (WDRs) from the GEOSAT Geodetic Mission (GM) and(or) Exact Repeat Mission (ERM) for the time period of...
Geosat Geodetic Mission Sensor Data Records (SDR) for August, 1985 (NODC Accession 0002537)
National Oceanic and Atmospheric Administration, Department of Commerce — This accession contains one month of sensor data records (SDRs) from the GEOSAT Geodetic Mission (GM) for the time period of August 01, 1985 to August 31, 1985....
Geosat Geodetic Mission Waveform Data Records (WDR) for March, 1985 (NODC Accession 0002363)
National Oceanic and Atmospheric Administration, Department of Commerce — This accession contains one month of waveform data records (WDRs) from the GEOSAT Geodetic Mission (GM) and(or) Exact Repeat Mission (ERM) for the time period of...
Geosat Geodetic Mission Sensor Data Records (SDR) for January, 1986 (NODC Accession 0002542)
National Oceanic and Atmospheric Administration, Department of Commerce — This accession contains one month of sensor data records (SDRs) from the GEOSAT Geodetic Mission (GM) for the time period of January 01, 1986 to January 31, 1986....
Relativistic Binaries in Globular Clusters
Benacquista Matthew J.
2006-02-01
Full Text Available The galactic population of globular clusters are old, dense star systems, with a typical cluster containing 10^4 - 10^7 stars. As an old population of stars, globular clusters contain many collapsed and degenerate objects. As a dense population of stars, globular clusters are the scene of many interesting close dynamical interactions between stars. These dynamical interactions can alter the evolution of individual stars and can produce tight binary systems containing one or two compact objects. In this review, we discuss the theoretical models of globular cluster evolution and binary evolution, techniques for simulating this evolution which lead to relativistic binaries, and current and possible future observational evidence for this population. Globular cluster evolution will focus on the properties that boost the production of hard binary systems and on the tidal interactions of the galaxy with the cluster, which tend to alter the structure of the globular cluster with time. The interaction of the components of hard binary systems alters the evolution of both bodies and can lead to exotic objects. Direct N-body integrations and Fokker-Planck simulations of the evolution of globular clusters that incorporate tidal interactions and lead to predictions of relativistic binary populations are also discussed. We discuss the current observational evidence for cataclysmic variables, millisecond pulsars, and low-mass X-ray binaries as well as possible future detection of relativistic binaries with gravitational radiation.
Relativistic Binaries in Globular Clusters
Benacquista Matthew
2002-01-01
Full Text Available The galactic population of globular clusters are old, dense star systems, with a typical cluster containing $10^4 - 10^6$ stars. As an old population of stars, globular clusters contain many collapsed and degenerate objects. As a dense population of stars, globular clusters are the scene of many interesting close dynamical interactions between stars. These dynamical interactions can alter the evolution of individual stars and can produce tight binary systems containing one or two compact objects. In this review, we discuss the theoretical models of globular cluster evolution and binary evolution, techniques for simulating this evolution which lead to relativistic binaries, and current and possible future observational evidence for this population. Globular cluster evolution will focus on the properties that boost the production of hard binary systems and on the tidal interactions of the galaxy with the cluster, which tend to alter the structure of the globular cluster with time. The interaction of the components of hard binary systems alters the evolution of both bodies and can lead to exotic objects. Direct $N$-body integrations and Fokker--Planck simulations of the evolution of globular clusters that incorporate tidal interactions and lead to predictions of relativistic binary populations are also discussed. We discuss the current observational evidence for cataclysmic variables, millisecond pulsars, and low-mass X-ray binaries as well as possible future detection of relativistic binaries with gravitational radiation.
Relativistic Binaries in Globular Clusters
Matthew J. Benacquista
2013-03-01
Full Text Available Galactic globular clusters are old, dense star systems typically containing 10^4 – 10^6 stars. As an old population of stars, globular clusters contain many collapsed and degenerate objects. As a dense population of stars, globular clusters are the scene of many interesting close dynamical interactions between stars. These dynamical interactions can alter the evolution of individual stars and can produce tight binary systems containing one or two compact objects. In this review, we discuss theoretical models of globular cluster evolution and binary evolution, techniques for simulating this evolution that leads to relativistic binaries, and current and possible future observational evidence for this population. Our discussion of globular cluster evolution will focus on the processes that boost the production of tight binary systems and the subsequent interaction of these binaries that can alter the properties of both bodies and can lead to exotic objects. Direct N-body integrations and Fokker–Planck simulations of the evolution of globular clusters that incorporate tidal interactions and lead to predictions of relativistic binary populations are also discussed. We discuss the current observational evidence for cataclysmic variables, millisecond pulsars, and low-mass X-ray binaries as well as possible future detection of relativistic binaries with gravitational radiation.
Relativistic Tennis Using Flying Mirror
Pirozhkov, A. S.; Kando, M.; Esirkepov, T. Zh.; Ma, J.; Fukuda, Y.; Chen, L.-M.; Daito, I.; Ogura, K.; Homma, T.; Hayashi, Y.; Kotaki, H.; Sagisaka, A.; Mori, M.; Koga, J. K.; Kawachi, T.; Daido, H.; Bulanov, S. V.; Kimura, T.; Kato, Y.; Tajima, T.
2008-06-01
Upon reflection from a relativistic mirror, the electromagnetic pulse frequency is upshifted and the duration is shortened by the factor proportional to the relativistic gamma-factor squared due to the double Doppler effect. We present the results of the proof-of-principle experiment for frequency upshifting of the laser pulse reflected from the relativistic "flying mirror", which is a wake wave near the breaking threshold created by a strong driver pulse propagating in underdense plasma. Experimentally, the wake wave is created by a 2 TW, 76 fs Ti:S laser pulse from the JLITE-X laser system in helium plasma with the electron density of ≈4-6×1019 cm-3. The reflected signal is observed with a grazing-incidence spectrograph in 24 shots. The wavelength of the reflected radiation ranges from 7 to 14 nm, the corresponding frequency upshifting factors are ˜55-115, and the gamma-factors are y = 4-6. The reflected signal contains at least 3×107 photons/sr. This effect can be used to generate coherent high-frequency ultrashort pulses that inherit temporal shape and polarization from the original (low-frequency) ones. Apart from this, the reflected radiation contains important information about the wake wave itself, e.g. location, size, phase velocity, etc.
Magnetohydrodynamics of Chiral Relativistic Fluids
Boyarsky, Alexey; Ruchayskiy, Oleg
2015-01-01
We study the dynamics of a plasma of charged relativistic fermions at very high temperature $T\\gg m$, where $m$ is the fermion mass, coupled to the electromagnetic field. In particular, we derive a magneto-hydrodynamical description of the evolution of such a plasma. We show that, as compared to conventional MHD for a plasma of non-relativistic particles, the hydrodynamical description of the relativistic plasma involves new degrees of freedom described by a pseudo-scalar field originating in a local asymmetry in the densities of left-handed and right-handed fermions. This field can be interpreted as an effective axion field. Taking into account the chiral anomaly we present dynamical equations for the evolution of this field, as well as of other fields appearing in the MHD description of the plasma. Due to its non-linear coupling to helical magnetic fields, the axion field significantly affects the dynamics of a magnetized plasma and can give rise to a novel type of inverse cascade.
Trials for better precision of seafloor geodetic observation system
Mochizuki, M.; Sato, M.; Fujita, M.; Yoshida, Z.; Yabuki, T.; Asada, A.
2002-12-01
Institute of Industrial Science, University of Tokyo, and Hydrographic Department, Japan, have been developing seafloor geodetic observation system and conducting observations using the system. Precise acoustic ranging and kinematic GPS positioning techniques are combined into the system. Seafloor reference station which consists of four mirror type transponders is deployed on the seafloor and measures its position in reference to GPS stations on land and ship. Fourteen seafloor geodetic reference stations have been distributed on the forearc areas of Japan island arc. Subsea crustal deformation due to subducting two oceanic plates of the Pacific and the Philippine sea can be monitored by using the seafloor reference stations. Although we obtained satisfactory results with the already existing system, we come up with possible improvements of the system as we accumulate the experience of the observations using the system. Trials to improve the system are always done. In this poster, we will present two of such trials. 1. To improve the stability of the rigid pole connecting the GPS antenna and the ship-board transducer. The bending of the GPS pole was found by examining the offsets in the acoustic ranging residuals. Acoustic ranging is made with condition that the ship drifts over sea surface. Drag force generated between surface current and the pole makes the pole itself bend. The pole was replaced by new, more rigid pole to overcome the problem. Also, we monitor amount of bending of the pole, that is, the offset between the GPS antenna and the transducer, using tiltmeter through the observation. 2. To reduce the acoustic ranging error due to shape of the transducer. Coded sinusoidal acoustic wave with 15cm wave length is used as the ranging signal. This wave length is comparable to the dimension of the cylindrical transducers employed both on the ship-board system and on the seafloor transponder. Transducer can not be regarded as a point considering the wave
Geodetic Imaging of Glacio-Seismotectonic Processes in Southern Alaska
Sauber, J.; Bruhn, R.; Forster, R.; Hofton, M.
2008-12-01
Across southern Alaska the northwest directed motion of the Pacific plate is accompanied by migration and collision of the Yakutat terrane. The Yakutat terrane is a fragment of the North American plate margin that is partly subducted beneath and partly accreted to the continental margin. Over the last couple of decades the rate of ongoing deformation associated with subduction and a locked main thrust zone has been estimated by geodetic measurements. In the last five years more extensive geodetic measurements, structural and tectonic field studies, thermochronolgy, and high-resolution lidar have been acquired and analyzed as part of the STEEP project [Pavlis et al., 2006]. The nature and magnitude of accretion and translation on upper crustal faults and folds remains uncertain, however, due to complex variations in the style of tectonic deformation, pervasive and changing glaciation, and the logistical challenges of conducting field studies in formidable topography. In this study, we analyze new high-resolution lidar data to extract locations, geometry, and heights of seismogenic faults and zones of active folding across the Malaspina-Seward-Bagley region of the southern Alaska plate boundary that is hypothesized to accommodate upper crustal shortening and right-lateral slip. Airborne Topographic Mapper (ATM) lidar swath data acquired by Krabill et al. in the summer of 2005 and ICESat data (1993-present) cross a number of proposed faults and folds partially masked by glaciation, including the Malaspina thrust, Esker Creek, Chugach-St.Elias thrust, and Contact. Focal mechanisms from this region indicate mostly shallow (0-30 km) thrust and oblique strike-slip faulting. Similarly, rupture in the 1979 St. Elias earthquake (M=7.4) started as a shallow, north-dipping thrust that later changed to more steeply NE dipping with a large right-lateral strike-slip component. Additionally, we are using the morphology and dynamics of glaciers derived from L-Band SAR ice
Geodetic Monitoring System Operating On Neapolitan Volcanic Area (southern Italy)
Pingue, F.; Ov-Geodesy Team
volcanic high risk, is monitored also by dense geodetic networks using different methods: levelling, GPS, tiltmeter, tide-gauge, gravimetry, INSAR. Each of the collected data contributes to volcanic sources modelling, thus to the eruptive scenarios definition and the risk mitigation. Here the geodetic surveillance system in the Neapolitan area is described in detail and the main results obtained in the last years are shown and discussed.
Analysis and interpretation of geodetic landslide monitoring data based on fuzzy systems
M. Haberler-Weber
2005-01-01
Full Text Available To place high precision geotechnical sensors exactly at the boundaries between blocks with different directions and rates of movement in a sliding area, it is important to detect these boundaries in a preceding step. An automated algorithm for the block detection based on fuzzy systems is presented. Combining objective geodetic indicators with fuzzy systems gives a powerful tool for the assessment of geodetic landslide monitoring data. The example of a landsliding area shows the applicability of the algorithm.
The ambiguity of the results of the strict adjustment of horizontal geodetic networks
Preweda, Edward; Jasi?ska, El?bieta; Butryn, Krzysztof
2016-01-01
The algorithm of the strict adjustment of horizontal geodetic networks using least square adjustment method is well known and widely described in the literature. Referring to the Regulation of the minister of administration and digitization of 14 February 2012 on geodetic, gravimetric and magnetic control networks, which is in force in Poland, the authors draw attention to the important provision contained in this Ordinance: Observa-tions should be adjusted using a rigorous adjustment, based ...
Xu, Peng
2015-01-01
With continuous advances in technology, future satellite gradiometry missions will be capable of performing precision relativistic experiments and imposing constraints on modern gravity theories. To this end, the full first-order post-Newtonian tidal tensor under inertially guided and Earth-pointing local frames along post-Newtonian orbits is worked out. The physical picture behind the "Mashhoon-Theiss anomaly" is explained at the post-Newtonian level. The relativistic precession of the local frame with respect to the sidereal frame will produce modulations of Newtonian tidal forces along certain bases, which gives rise to two different kinds of secular tidal tensors. The measurements of the secular tidal force from the frame-dragging effect is also discussed.
Relativistic effects in Lyman-alpha forest
Iršič, Vid; Viel, Matteo
2015-01-01
We present the calculation of the Lyman-alpha (Lyman-$\\alpha$) transmitted flux fluctuations with full relativistic corrections to the first order. Even though several studies exist on relativistic effects in galaxy clustering, this is the first study to extend the formalism to a different tracer of underlying matter at unique redshift range ($z = 2 - 5$). Furthermore, we show a comprehensive application of our calculations to the Quasar- Lyman-$\\alpha$ cross-correlation function. Our results indicate that the signal of relativistic effects can be as large as 30% at Baryonic Acoustic Oscillation (BAO) scale, which is much larger than anticipated and mainly due to the large differences in density bias factors of our tracers. We construct an observable, the anti-symmetric part of the cross- correlation function, that is dominated by the relativistic signal and offers a new way to measure the relativistic terms at relatively small scales. The analysis shows that relativistic effects are important when considerin...
Transverse relativistic effects in paraxial wave interference
Bliokh, Konstantin Y; Nori, Franco
2013-01-01
We consider relativistic deformations of interfering paraxial waves moving in the transverse direction. Owing to superluminal transverse phase velocities, noticeable deformations of the interference patterns arise when the waves move with respect to each other with non-relativistic velocities. Similar distortions also appear on a mutual tilt of the interfering waves, which causes a phase delay analogous to the relativistic time delay. We illustrate these observations by the interference between a vortex wave beam and a plane wave, which exhibits a pronounced deformation of the radial fringes into a fork-like pattern (relativistic Hall effect). Furthermore, we describe an additional relativistic motion of the interference fringes (a counter-rotation in the vortex case), which become noticeable at the same non-relativistic velocities.
Entropy current for non-relativistic fluid
Banerjee, Nabamita; Jain, Akash; Roychowdhury, Dibakar
2014-01-01
We study transport properties of a parity-odd, non-relativistic charged fluid in presence of background electric and magnetic fields. To obtain stress tensor and charged current for the non-relativistic system we start with the most generic relativistic fluid, living in one higher dimension and reduce the constituent equations along the light-cone direction. We also reduce the equation satisfied by the entropy current of the relativistic theory and obtain a consistent entropy current for the non-relativistic system (we call it "canonical form" of the entropy current). Demanding that the non-relativistic fluid satisfies the second law of thermodynamics we impose constraints on various first order transport coefficients. For parity even fluid, this is straight forward; it tells us positive definiteness of different transport coefficients like viscosity, thermal conductivity, electric conductivity etc. However for parity-odd fluid, canonical form of the entropy current fails to confirm the second law of thermody...
Non-Relativistic Spacetimes with Cosmological Constant
Aldrovandi, R.; Barbosa, A. L.; Crispino, L.C.B.; Pereira, J. G.
1998-01-01
Recent data on supernovae favor high values of the cosmological constant. Spacetimes with a cosmological constant have non-relativistic kinematics quite different from Galilean kinematics. De Sitter spacetimes, vacuum solutions of Einstein's equations with a cosmological constant, reduce in the non-relativistic limit to Newton-Hooke spacetimes, which are non-metric homogeneous spacetimes with non-vanishing curvature. The whole non-relativistic kinematics would then be modified, with possible ...
Relativistic non-equilibrium thermodynamics revisited
García-Colin, L S
2006-01-01
Relativistic irreversible thermodynamics is reformulated following the conventional approach proposed by Meixner in the non-relativistic case. Clear separation between mechanical and non-mechanical energy fluxes is made. The resulting equations for the entropy production and the local internal energy have the same structure as the non-relativistic ones. Assuming linear constitutive laws, it is shown that consistency is obtained both with the laws of thermodynamics and causality.
Analogy betwen dislocation creep and relativistic cosmology
J.A. Montemayor-Aldrete; J.D. Muñoz-Andrade; Mendoza-Allende, A.; Montemayor-Varela, A.
2005-01-01
A formal, physical analogy between plastic deformation, mainly dislocation creep, and Relativistic Cosmology is presented. The physical analogy between eight expressions for dislocation creep and Relativistic Cosmology have been obtained. By comparing the mathematical expressions and by using a physical analysis, two new equations have been obtained for dislocation creep. Also, four new expressions have been obtained for Relativistic Cosmology. From these four new equations, one may determine...
A relativistic correction to semiclassical charmonium
Weiss, J.
1995-09-01
It is shown that the relativistic linear potentials, introduced by the author within the particle à la Wheeler-Feynman direct-interaction (AAD) theory, applied to the semiclassically quantized charmonium, yield energy spectrum comparable to that of some known models. Using the expansion of the relativistic linear AAD potentials in powers ofc -1, the charmonium spectrum, given as a rule by Bohr-Sommerfeld quantization of circular orbits, is extended up to the second order of relativistic corrections.
Data-adaptive detection of transient deformation in geodetic networks
Walwer, Damian; Calais, Eric; Ghil, Michael
2016-03-01
The recent development of dense and continuously operating Global Navigation Satellite System (GNSS) networks worldwide has led to a significant increase in geodetic data sets that sometimes capture transient-deformation signals. It is challenging, however, to extract such transients of geophysical origin from the background noise inherent to GNSS time series and, even more so, to separate them from other signals, such as seasonal redistributions of geophysical fluid mass loads. In addition, because of the very large number of continuously recording GNSS stations now available, it has become impossible to systematically inspect each time series and visually compare them at all neighboring sites. Here we show that Multichannel Singular Spectrum Analysis (M-SSA), a method derived from the analysis of dynamical systems, can be used to extract transient deformations, seasonal oscillations, and background noise present in GNSS time series. M-SSA is a multivariate, nonparametric, statistical method that simultaneously exploits the spatial and temporal correlations of geophysical fields. The method allows for the extraction of common modes of variability, such as trends with nonconstant slopes and oscillations shared across time series, without a priori hypotheses about their spatiotemporal structure or their noise characteristics. We illustrate this method using synthetic examples and show applications to actual GPS data from Alaska to detect seasonal signals and microdeformation at the Akutan active volcano. The geophysically coherent spatiotemporal patterns of uplift and subsidence thus detected are compared to the results of an idealized model of such processes in the presence of a magma chamber source.
Geodetic Observations of Ongoing Unrest at Santorini Caldera, Greece
Newman, A. V.; Stiros, S. C.; Moschas, F.; Saltogianni, V.; Feng, L.; Psimoulis, P.; Jiang, Y.; Karakas, O.; Polster, S.
2012-12-01
After approximately 60 years of seismic quiescence within Santorini caldera, in January 2011 the volcano reawakened with a significant seismic swarm and rapidly expanding near-radial deformation. Using a combination of 10 continuous and 22 campaign GPS stations with observations beginning in 2006, we've captured the onset, and 3D shape of surface deformation. Deformation primarily radiates from inside the northern half of the caldera, with episodic growth periods lasting several months at a time. As of this writing, the caldera has expanded laterally about 185 mm, and uplifted at least 80 mm (with the maximum uplift likely occurring under the submerged caldera floor—unobservable by GPS). We will discuss the current geodetic evolution including continuous and 4 GPS campaigns during the period of unrest, exploring new numerical models to address the accompanying stress evolution of the system. We recognize that only anelastic inflation models including volumetric addition and viscoelastic relaxation or discrete dislocation will allow such growth to occur without a long-term stress increase. While observations of the current deformation sequence are unprecedented at Santorini, it is not certain that they mark the early stages of a process leading to an eruption given that other similar calderas have experienced comparable activity without eruption.
Dynamic testing of railway metal culvert using geodetic methods
Beben Damian
2017-01-01
Full Text Available The objective of the study was to compare and assess suitability of two methods of geodetic measurements (tachymetry i interferometry used to determine changes of the geometric condition of building and engineering structures. The paper presents the selected results of experimental tests under dynamic loads that were conducted on a railway metal culvert. The dynamic loads were caused by the passages of various trains. The measurements were made for all trains which had been running over the culvert during a 24 hour period. Advantages and disadvantages of both applied methods were characterized. The disadvantage of the tachymetry method is the discreteness of measurements and the lack of the possibility of verifying the results after finishing the field works. The tachymetry measurements were conducted using precise tachymetry manufactured by Leica TC2002. The IBIS microwave coherent radar was used in the interferometry method. Moreover, a special microwave horns IBIS-H23 type with a maximum gain of 23 dBi were used as the interferometer antennas (transmitting and receiving. Conclusions drawn from the tests can be helpful in the measurements of such culverts.
Generalized One-Dimensional Point Interaction in Relativistic and Non-relativistic Quantum Mechanics
Shigehara, T; Mishima, T; Cheon, T; Cheon, Taksu
1999-01-01
We first give the solution for the local approximation of a four parameter family of generalized one-dimensional point interactions within the framework of non-relativistic model with three neighboring $\\delta$ functions. We also discuss the problem within relativistic (Dirac) framework and give the solution for a three parameter family. It gives a physical interpretation for so-called high energy substantially differ between non-relativistic and relativistic cases.
Relativistic ponderomotive Hamiltonian of a Dirac particle in a vacuum laser field
Ruiz, D. E.; Ellison, C. L.; Dodin, I. Y.
2015-12-01
We report a point-particle ponderomotive model of a Dirac electron oscillating in a high-frequency field. Starting from the Dirac Lagrangian density, we derive a reduced phase-space Lagrangian that describes the relativistic time-averaged dynamics of such a particle in a geometrical-optics laser pulse propagating in vacuum. The pulse is allowed to have an arbitrarily large amplitude provided that radiation damping and pair production are negligible. The model captures the Bargmann-Michel-Telegdi (BMT) spin dynamics, the Stern-Gerlach spin-orbital coupling, the conventional ponderomotive forces, and the interaction with large-scale background fields (if any). Agreement with the BMT spin precession equation is shown numerically. The commonly known theory in which ponderomotive effects are incorporated in the particle effective mass is reproduced as a special case when the spin-orbital coupling is negligible. This model could be useful for studying laser-plasma interactions in relativistic spin-1 /2 plasmas.
Velocity operator and velocity field for spinning particles in (non-relativistic) quantum mechanics
Recami, E. [Bergamo Univ. (Italy). Facolta` di Ingegneria]|[INFN, Milan (Italy)]|[Campinas State Univ., SP (Brazil). Dept. of Applied Math.; Salesi, G. [Catania Univ. (Italy). Dip. di Fisica
1995-06-01
Starting from the formal expressions of the hydrodynamical (or local) quantities employed in the applications of Clifford Algebras to quantum mechanics, the paper introduces - in terms of the ordinary tensorial framework - a new definition for the field of a generic quantity. By translating from Clifford into tensor algebra, a new (non-relativistic) velocity operator for a spin 1/2 particle is also proposed. This operator is the sum of the ordinary part p/m describing the mean motion (the motion of the center-of-mass), and of a second part associated with the so-called Zitterbewegung, which is the spin internal motion observed in the center-of- mass frame. This spin component of the velocity operator is non-zero not only in the Pauli theoretical framework, i.e. in presence of external magnetic fields and spin precession, but also in the Schroedinger case, when the wave-function is a spin eigenstate. In the latter case, one gets a decomposition of the velocity field for the Madelueng fluid into two distinct parts: which the constitutes the non-relativistic analogue of the Gordon decomposition for the Dirac current.
Turbulence driven by precession in spherical and slightly elongated spheroidal cavities
Goto, Susumu, E-mail: goto@me.es.osaka-u.ac.jp [Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531 (Japan); Matsunaga, Arihiro; Tsuda, Shinya [Department of Mechanical Engineering and Science, Kyoto University, Yoshida-Honmachi, Sakyo, Kyoto 606-8501 (Japan); Fujiwara, Masahiro; Yamato, Masahiro [Department of Mechanical Engineering, Okayama University 3-1-1, Tsushima-naka, Kita, Okayama 700-8530 (Japan); Nishioka, Michio [Department of Aerospace Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Sakai, Osaka 599-8531 (Japan); Kida, Shigeo [Organization for Advanced Research and Education, Doshisha University, 1-3, Tatara-miyakodani, Kyotanabe 610-0394 (Japan)
2014-05-15
Motivated by the fascinating fact that strong turbulence can be sustained in a weakly precessing container, we conducted a series of laboratory experiments on the flow in a precessing spherical cavity, and in a slightly elongated prolate spheroidal cavity with a minor-to-major axis ratio of 0.9. In order to determine the conditions required to sustain turbulence in these cavities, and to investigate the statistics of the sustained turbulence, we developed an experimental technique to conduct high-quality flow visualizations as well as measurements via particle image velocimetry on a turntable and by using an intense laser. In general, flows in a precessing cavity are controlled by two non-dimensional parameters: the Reynolds number Re (or its reciprocal, the Ekman number) which is defined by the cavity size, spin angular velocity, and the kinematic viscosity of the confined fluid, and the Poincaré number Po, which is defined by the ratio of the magnitude of the precession angular velocity to that of the spin angular velocity. However, our experiments show that the global flow statistics, such as the mean velocity field and the spatial distribution of the intensity of the turbulence, are almost independent of Re, and they are determined predominantly by Po, whereas the instability of these global flow structures is governed by Re. It is also shown that the turbulence statistics are most likely similar in the two cavities due to the slight difference between their shapes. However, the condition to sustain the unsteady flows, and therefore the turbulence, differs drastically depending on the cavity shape. Interestingly, the asymmetric cavity, i.e., the spheroid, requires a much stronger precession than a sphere to sustain such unsteady flows. The most developed turbulence for a given Re is generated in these cavities when 0.04 ≲ Po ≲ 0.1. In such cases, the sustained turbulence is always accompanied by vigorous large-scale vortical structures, and shearing
Relativistic Cyclotron Instability in Anisotropic Plasmas
López, Rodrigo A.; Moya, Pablo S.; Navarro, Roberto E.; Araneda, Jaime A.; Muñoz, Víctor; Viñas, Adolfo F.; Alejandro Valdivia, J.
2016-11-01
A sufficiently large temperature anisotropy can sometimes drive various types of electromagnetic plasma micro-instabilities, which can play an important role in the dynamics of relativistic pair plasmas in space, astrophysics, and laboratory environments. Here, we provide a detailed description of the cyclotron instability of parallel propagating electromagnetic waves in relativistic pair plasmas on the basis of a relativistic anisotropic distribution function. Using plasma kinetic theory and particle-in-cell simulations, we study the influence of the relativistic temperature and the temperature anisotropy on the collective and noncollective modes of these plasmas. Growth rates and dispersion curves from the linear theory show a good agreement with simulations results.
Do non-relativistic neutrinos oscillate?
Akhmedov, Evgeny
2017-07-01
We study the question of whether oscillations between non-relativistic neutrinos or between relativistic and non-relativistic neutrinos are possible. The issues of neutrino production and propagation coherence and their impact on the above question are discussed in detail. It is demonstrated that no neutrino oscillations can occur when neutrinos that are non-relativistic in the laboratory frame are involved, except in a strongly mass-degenerate case. We also discuss how this analysis depends on the choice of the Lorentz frame. Our results are for the most part in agreement with Hinchliffe's rule.
Geometric Models of the Relativistic Harmonic Oscillator
Cotaescu, I I
1997-01-01
A family of relativistic geometric models is defined as a generalization of the actual anti-de Sitter (1+1) model of the relativistic harmonic oscillator. It is shown that all these models lead to the usual harmonic oscillator in the non-relativistic limit, even though their relativistic behavior is quite different. Among quantum models we find a set of models with countable energy spectra, and another one having only a finite number of energy levels and in addition a continuous spectrum.
Relativistic and non-relativistic solitons in plasmas
Barman, Satyendra Nath
This thesis entitled as "Relativistic and Non-relativistic Solitons in Plasmas" is the embodiment of a number of investigations related to the formation of ion-acoustic solitary waves in plasmas under various physical situations. The whole work of the thesis is devoted to the studies of solitary waves in cold and warm collisionless magnetized or unmagnetized plasmas with or without relativistic effect. To analyze the formation of solitary waves in all our models of plasmas, we have employed two established methods namely - reductive perturbation method to deduce the Korteweg-de Vries (KdV) equation, the solutions of which represent the important but near exact characteristic concepts of soliton-physics. Next, the pseudopotential method to deduce the energy integral with total nonlinearity in the coupling process for exact characteristic results of solitons has been incorporated. In Chapter 1, a brief description of plasma in nature and laboratory and its generation are outlined elegantly. The nonlinear differential equations to characterize solitary waves and the relevant but important methods of solutions have been mentioned in this chapter. The formation of solitary waves in unmagnetized and magnetized plasmas, and in relativistic plasmas has been described through mathematical entity. Applications of plasmas in different fields are also put forwarded briefly showing its importance. The study of plasmas as they naturally occur in the universe encompasses number of topics including sun's corona, solar wind, planetary magnetospheres, ionospheres, auroras, cosmic rays and radiation. The study of space weather to understand the universe, communications and the activities of weather satellites are some useful areas of space plasma physics. The surface cleaning, sterilization of food and medical appliances, killing of bacteria on various surfaces, destroying of viruses, fungi, spores and plasma coating in industrial instruments ( like computers) are some of the fields
Palano, M.; Cannavò, F.; Ferranti, L.; Mattia, M.; Mazzella, M. E.
2011-12-01
We present an improved evaluation of the current strain and stress fields in the Southern Apennines (Italy) obtained through a careful analysis of geodetic, seismological and borehole data. In particular, our analysis provides an updated comparison between the accrued strain recorded by geodetic data, and the strain released by seismic activity in a region hit by destructive historical earthquakes. To this end, we have used nine years of GPS observations (2001-2010) from a dense network of permanent stations, a data set of 73 well-constrained stress indicators (borehole breakouts and focal mechanisms of moderate-to-large earthquakes) and published estimations of the geological strain accommodated by active faults in the region. Although geodetic data are generally consistent with seismic and geological information, previously unknown features of the current deformation in southern Italy emerge from this analysis. The newly obtained GPS velocity field supports the well-established notion of a dominant NE-SW-oriented extension concentrated in a ˜50-km-wide belt along the topographic relief of the Apennines, as outlined by the distribution of seismogenic normal faults. Geodetic deformation is, however, non-uniform along the belt, with two patches of higher strain-rate and shear-stress accumulation in the north (Matese Mountains) and in the south (Irpinia area). Low geodetic strain-rates are found in the Bradano basin and Apulia plateau to the east. Along the Ionian Sea margin of southern Italy, in southern Apulia and eastern Basilicata and Calabria, geodetic velocities indicate NW-SE extension that is consistent with active shallow-crustal gravitational motion documented by geological studies. In the west, along the Tyrrhenian margin of the Campania region, the tectonic geodetic field is disturbed by volcanic processes. Comparison between the magnitude of the geodetic and the seismic strain rates (computed using a long historical seismicity catalogue) allow detecting
Relativistic Corrections to the Bohr Model of the Atom
Kraft, David W.
1974-01-01
Presents a simple means for extending the Bohr model to include relativistic corrections using a derivation similar to that for the non-relativistic case, except that the relativistic expressions for mass and kinetic energy are employed. (Author/GS)
Magnetogenesis through Relativistic Velocity Shear
Miller, Evan
Magnetic fields at all scales are prevalent in our universe. However, current cosmological models predict that initially the universe was bereft of large-scale fields. Standard magnetohydrodynamics (MHD) does not permit magnetogenesis; in the MHD Faraday's law, the change in magnetic field B depends on B itself. Thus if B is initially zero, it will remain zero for all time. A more accurate physical model is needed to explain the origins of the galactic-scale magnetic fields observed today. In this thesis, I explore two velocity-driven mechanisms for magnetogenesis in 2-fluid plasma. The first is a novel kinematic 'battery' arising from convection of vorticity. A coupling between thermal and plasma oscillations, this non-relativistic mechanism can operate in flows that are incompressible, quasi-neutral and barotropic. The second mechanism results from inclusion of thermal effects in relativistic shear flow instabilities. In such flows, parallel perturbations are ubiquitously unstable at small scales, with growth rates of order with the plasma frequency over a defined range of parameter-space. Of these two processes, instabilities seem far more likely to account for galactic magnetic fields. Stable kinematic effects will, at best, be comparable to an ideal Biermann battery, which is suspected to be orders of magnitude too weak to produce the observed galactic fields. On the other hand, instabilities grow until saturation is reached, a topic that has yet to be explored in detail on cosmological scales. In addition to investigating these magnetogenesis sources, I derive a general dispersion relation for three dimensional, warm, two species plasma with discontinuous shear flow. The mathematics of relativistic plasma, sheared-flow instability and the Biermann battery are also discussed.
Theory of director precession and nonlinear waves in nematic liquid crystals under elliptical shear.
Krekhov, A P; Kramer, L
2005-09-01
We study theoretically the slow director precession and nonlinear waves observed in homeotropically oriented nematic liquid crystals subjected to circular or elliptical Couette and Poiseuille flow and an electric field. From a linear analysis of the nematodynamic equations it is found that in the presence of the flow the electric bend Fréedericksz transition is transformed into a Hopf-type bifurcation. In the framework of an approximate weakly nonlinear analysis we have calculated the coefficients of the modified complex Ginzburg-Landau equation, which slightly above onset describes nonlinear waves with strong nonlinear dispersion. We also derive the equation describing the precession and waves well above the Fréedericksz transition and for small flow amplitudes. Then the nonlinear waves are of diffusive nature. The results are compared with full numerical simulations and with experimental data.
Random magnetic fields inducing solar neutrino spin-flavor precession in a three generation context
Guzzo, M M; Peres, O L G
2005-01-01
We study the effect of random magnetic fields in the spin-flavor precession of solar neutrinos in a three generation context, when a non-vanishing transition magnetic moment is assumed. While this kind of precession is strongly constrained when the magnetic moment involves the first family, such constraints do not apply if we suppose a transition magnetic moment between the second and third families. In this scenario we can have a large non-electron anti-neutrino flux arriving on Earth, which can lead to some interesting phenomenological consequences, as, for instance, the suppression of day-night asymmetry. We have analyzed the high energy solar neutrino data and the KamLAND experiment to constrain the solar mixing angle, and solar mass difference, and we have found a larger shift of allowed values.
An Apparent Precessing Helical Outflow from a Massive Evolved Star: Evidence for Binary Interaction
Lau, Ryan M; Herter, Terry L; Morris, Mark R; Mills, Elisabeth A C; Ressler, Michael E
2015-01-01
Massive, evolved stars play a crucial role in the metal-enrichment, dust budget, and energetics of the interstellar medium; however, the details of their evolution are uncertain because of their rarity and short lifetimes before exploding as supernovae. Discrepancies between theoretical predictions from single-star evolutionary models and observations of massive stars have evoked a shifting paradigm that implicates the importance of binary interaction. We present mid- to far-infrared observations from the Stratospheric Observatory for Infrared Astronomy (SOFIA) of a conical ``helix'' of warm dust ($\\sim180$ K) that appears to extend from the Wolf-Rayet star WR102c. Our interpretation of the helix is a precessing, collimated outflow that emerged from WR102c during a previous evolutionary phase as a rapidly rotating luminous blue variable. We attribute the precession of WR102c to gravitational interactions with an unseen compact binary companion whose orbital period can be constrained to $800\\,\\mathrm{d}
Non-equilibrium effects in a Josephson junction coupled to a precessing spin
Fogelstroem, Mikael [Department of Microtechnology and Nanoscience, Chalmers University of Technology, 42196 Goeteborg (Sweden)
2015-07-01
I will discuss a theoretical study of s-wave superconductors coupled to a classical spin. When an external magnetic field is applied, the classical spin can be driven to precess with the Larmor frequency. This results in a time-dependent boundary condition for the superconducting quasiparticles, with different tunnelling amplitudes for spin-up and spin-down quasiparticles and where the precession produces spin-flip scattering processes. Andreev states develop at the interface with a non-equilibrium population which depend on how the spin is driven. The Andreev states carry a steady-state Josephson current whose current-phase relation could be used for characterising the spin. In addition to the charge transport, a spin current is also generated. This spin current will induce a torque and couple back to the dynamics of the classical spin.
Obliquity of Mercury: Influence of the precession of the pericenter and of tides
Baland, Rose-Marie; Yseboodt, Marie; Rivoldini, Attilio; Van Hoolst, Tim
2017-07-01
Mercury is expected to deviate from the classical Cassini state since this state is defined for a uniformly precessing rigid planet. We develop an extended Cassini state model that includes the variations (or nutations) in obliquity and deviation induced by the slow precession of the pericenter. The model also describes the constant shift over time in mean obliquity and deviation associated with the short-periodic tidal deformations of Mercury, characterized by the tidal love number k2 and by the ratio k2/Q of the tidal Love number over the tidal quality factor, respectively. This model is then used to interpret Mercury's orientation, including the deviation from the classical Cassini state, in terms of parameters of Mercury's interior.
Jet precession in the active nucleus of M81. Ongoing VLBI monitoring
Marti-Vidal, I; Alberdi, A; Brunthaler, A
2013-01-01
In a recent publication, we reported results of a multi-frequency VLBI campaign of observations of the Active Galactic Nucleus (AGN) in galaxy M\\,81, phase-referenced to the supernova SN\\,1993J. We were able to extract precise information on the relative astrometry of the AGN radio emission at different epochs and frequencies. We found strong evidence of precession in the AGN jet (i.e., a systematic evolution in the jet inclination at each frequency) coupled to changes in the overall flux density at the different frequencies. In these proceedings, we summarise the main contents of our previous publication and we report on (preliminary) new results from our follow-up VLBI observations, now phase-referenced to the young supernova SN2008iz. We also briefly discuss how these results match the picture of our previously-reported precession model.
Hannam, Mark
2013-01-01
The inspiral and merger of two orbiting black holes is among the most promising sources for the first (hopefully imminent) direct detection of gravitational waves (GWs), and measurements of these signals could provide a wealth of information about astrophysics, fundamental physics and cosmology. Detection and measurement require a theoretical description of the GW signals from all possible black-hole-binary configurations, which can include complicated precession effects due to the black-hole spins. Modelling the GW signal from generic precessing binaries is therefore one of the most urgent theoretical challenges facing GW astronomy. This article briefly reviews the phenomenology of generic-binary dynamics and waveforms, and recent advances in modelling them.
Relativistic Plasma Polarizer: Impact of Temperature Anisotropy on Relativistic Transparency
Hazeltine, R. D.; Stark, David J.; Bhattacharjee, Chinmoy; Arefiev, Alexey V.; Toncian, Toma; Mahajan, S. M.
2015-11-01
3D particle-in-cell simulations demonstrate that the enhanced transparency of a relativistically hot plasma is sensitive to how the energy is partitioned between different degrees of freedom. We consider here the simplest problem: the propagation of a low amplitude pulse through a preformed relativistically hot anisotropic electron plasma to explore its intrinsic dielectric properties. We find that: 1) the critical density for propagation depends strongly on the pulse polarization, 2) two plasmas with the same density and average energy per electron can exhibit profoundly different responses to electromagnetic pulses, 3) the anisotropy-driven Weibel instability develops as expected; the timescales of the growth and back reaction (on anisotropy), however, are long enough that sufficient anisotropy persists for the entire duration of the simulation. This plasma can then function as a polarizer or a wave plate to dramatically alter the pulse polarization. This work was supported by the U.S. DOE Contract Nos. DE-FG02-04ER54742 and DE-AC05-06OR23100 (D. J. S.) and NNSA Contract No. DE-FC52-08NA28512.
On the relativistic anisotropic configurations
Shojai, F. [University of Tehran, Department of Physics, Tehran (Iran, Islamic Republic of); Institute for Research in Fundamental Sciences (IPM), Foundations of Physics Group, School of Physics, Tehran (Iran, Islamic Republic of); Kohandel, M. [Alzahra University, Department of Physics and Chemistry, Tehran (Iran, Islamic Republic of); Stepanian, A. [University of Tehran, Department of Physics, Tehran (Iran, Islamic Republic of)
2016-06-15
In this paper we study anisotropic spherical polytropes within the framework of general relativity. Using the anisotropic Tolman-Oppenheimer-Volkov equations, we explore the relativistic anisotropic Lane-Emden equations. We find how the anisotropic pressure affects the boundary conditions of these equations. Also we argue that the behavior of physical quantities near the center of star changes in the presence of anisotropy. For constant density, a class of exact solution is derived with the aid of a new ansatz and its physical properties are discussed. (orig.)
Simple waves in relativistic fluids.
Lyutikov, Maxim
2010-11-01
We consider the Riemann problem for relativistic flows of polytropic fluids and find relations for the flow characteristics. Evolution of physical quantities takes especially simple form for the case of cold magnetized plasmas. We find exact explicit analytical solutions for one-dimensional expansion of magnetized plasma into vacuum, valid for arbitrary magnetization. We also consider expansion into cold unmagnetized external medium both for stationary initial conditions and for initially moving plasma, as well as reflection of rarefaction wave from a wall. We also find self-similar structure of three-dimensional magnetized outflows into vacuum, valid close to the plasma-vacuum interface.
Observation of relativistic antihydrogen atoms
Blanford, Glenn Delfosse, Jr.
1997-09-01
An observation of relativistic antihydrogen atoms is reported in this dissertation. Experiment 862 at Fermi National Accelerator Laboratory observed antihydrogen atoms produced by the interaction of a circulating beam of high momentum (3 production is outlined within. The cross section corresponds to the process where a high momentum antiproton causes e+e/sp- pair creation near a nucleus with the e+ being captured by the antiproton. Antihydrogen is the first atom made exclusively of antimatter to be detected. The observation experiment's results are the first step towards an antihydrogen spectroscopy experiment which would measure the n = 2 Lamb shift and fine structure.
Einstein Toolkit for Relativistic Astrophysics
Collaborative Effort
2011-02-01
The Einstein Toolkit is a collection of software components and tools for simulating and analyzing general relativistic astrophysical systems. Such systems include gravitational wave space-times, collisions of compact objects such as black holes or neutron stars, accretion onto compact objects, core collapse supernovae and Gamma-Ray Bursts. The Einstein Toolkit builds on numerous software efforts in the numerical relativity community including CactusEinstein, Whisky, and Carpet. The Einstein Toolkit currently uses the Cactus Framework as the underlying computational infrastructure that provides large-scale parallelization, general computational components, and a model for collaborative, portable code development.
Density perturbations with relativistic thermodynamics
Maartens, R
1997-01-01
We investigate cosmological density perturbations in a covariant and gauge- invariant formalism, incorporating relativistic causal thermodynamics to give a self-consistent description. The gradient of density inhomogeneities splits covariantly into a scalar part, a rotational vector part that is determined by the vorticity, and a tensor part that describes the shape. We give the evolution equations for these parts in the general dissipative case. Causal thermodynamics gives evolution equations for viswcous stress and heat flux, which are coupled to the density perturbation equation and to the entropy and temperature perturbation equations. We give the full coupled system in the general dissipative case, and simplify the system in certain cases.
Thermodynamics of polarized relativistic matter
Kovtun, Pavel
2016-07-01
We give the free energy of equilibrium relativistic matter subject to external gravitational and electromagnetic fields, to one-derivative order in the gradients of the external fields. The free energy allows for a straightforward derivation of bound currents and bound momenta in equilibrium. At leading order, the energy-momentum tensor admits a simple expression in terms of the polarization tensor. Beyond the leading order, electric and magnetic polarization vectors are intrinsically ambiguous. The physical effects of polarization, such as the correlation between the magneto-vortically induced surface charge and the electro-vortically induced surface current, are not ambiguous.
Thermodynamics of polarized relativistic matter
Kovtun, Pavel
2016-01-01
We give the free energy of equilibrium relativistic matter subject to external gravitational and electromagnetic fields, to one-derivative order in the gradients of the external fields. The free energy allows for a straightforward derivation of bound currents and bound momenta in equilibrium. At leading order, the energy-momentum tensor admits a simple expression in terms of the polarization tensor. Beyond the leading order, electric and magnetic polarization vectors are intrinsically ambiguous. The physical effects of polarization, such as the correlation between the magneto-vortically induced surface charge and the electro-vortically induced surface current, are not ambiguous.
Relativistic solitons and superluminal signals
Maccari, Attilio [Technical Institute ' G. Cardano' , Piazza della Resistenza 1, Monterotondo, Rome 00015 (Italy)]. E-mail: solitone@yahoo.it
2005-02-01
Envelope solitons in the weakly nonlinear Klein-Gordon equation in 1 + 1 dimensions are investigated by the asymptotic perturbation (AP) method. Two different types of solitons are possible according to the properties of the dispersion relation. In the first case, solitons propagate with the group velocity (less than the light speed) of the carrier wave, on the contrary in the second case solitons always move with the group velocity of the carrier wave, but now this velocity is greater than the light speed. Superluminal signals are then possible in classical relativistic nonlinear field equations.
Magnetohydrodynamic instabilities in rotating and precessing sheared flows: an asymptotic analysis.
Salhi, A; Lehner, T; Cambon, C
2010-07-01
Linear magnetohydrodynamic instabilities are studied analytically in the case of unbounded inviscid and electrically conducting flows that are submitted to both rotation and precession with shear in an external magnetic field. For given rotation and precession the possible configurations of the shear and of the magnetic field and their interplay are imposed by the "admissibility" condition (i.e., the base flow must be a solution of the magnetohydrodynamic Euler equations): we show that an "admissible" basic magnetic field must align with the basic absolute vorticity. For these flows with elliptical streamlines due to precession we undertake an analytical stability analysis for the corresponding Floquet system, by using an asymptotic expansion into the small parameter ε (ratio of precession to rotation frequencies) by a method first developed in the magnetoelliptical instabilities study by Lebovitz and Zweibel [Astrophys. J. 609, 301 (2004)]10.1086/420972. The present stability analysis is performed into a suitable frame that is obtained by a systematic change of variables guided by symmetry and the existence of invariants of motion. The obtained Floquet system depends on three parameters: ε , η (ratio of the cyclotron frequency to the rotation frequency) and χ=cos α, with α being a characteristic angle which, for circular streamlines, ε=0, identifies with the angle between the wave vector and the axis of the solid body rotation. We look at the various (centrifugal or precessional) resonant couplings between the three present modes: hydrodynamical (inertial), magnetic (Alfvén), and mixed (magnetoinertial) modes by computing analytically to leading order in ε the instabilities by estimating their threshold, growth rate, and maximum growth rate and their bandwidths as functions of ε, η, and χ. We show that the subharmonic "magnetic" mode appears only for η>square root of 5/2 and at large η (>1) the maximal growth rate of both the "hydrodynamic" and
1974-01-01
The survey of negative pion absorption reactions on light and medium nuclei was continued. Muon spin precession was studied using an iron target. An impulse approximation model of the pion absorption process implied that the ion will absorb almost exclusively on nucleon pairs, single nucleon absorption being suppressed by energy and momentum conservation requirements. For measurements on both paramagnetic and ferromagnetic iron, the external magnetic field was supplied by a large C-type electromagnet carrying a current of about 100 amperes.
Current status of the EPOS WG4 - GNSS and Other Geodetic Data
Fernandes, Rui; Bastos, Luísa; Bruyninx, Carine; D'Agostino, Nicola; Dousa, Jan; Ganas, Athanassios; Lidberg, Martin; Nocquet, Jean-Mathieu
2013-04-01
WG4 - "EPOS Geodetic Data and Other Geodetic Data" is the Working Group of the EPOS project in charge of defining and preparing the integration of the existing Pan-European Geodetic Infrastructures that will support the European Geosciences, which is the ultimate goal of the EPOS project. The WG4 is formed by representatives of the participating EPOS countries (23) but it is also open to the entire geodetic community. In fact, WG4 also includes members from countries that formally are not part of the current phase of EPOS. In an ongoing effort, the majority of existing GNSS Research Infrastructures in Europe were identified. The current database, available at http://epos-couch.cloudant.com/epos-couch/_design/epos-couch/, lists a total of 50 Research Infrastructures managing a total of 1534 GNSS CORS sites. This presentation intends to detail the work being produced within the working group WG4 related with the definition of strategies towards the implementation of the best solutions that will permit to the end-users, and in particular geo-scientists, to access the geodetic data, derived solutions, and associated metadata using transparent and uniform processes. The first step toward the design of an implementation and business plan is the definition of the core services for geodetic data within EPOS. In this talk, we will present the current status of the discussion about the content of core services. Three levels of core services could be distinguished, for which their content need to be defined. The 3 levels are: (1) the core services associated to data (diffusion, archive, long-term preservation, quality check, rapid analysis) (2) core services associated to geodetic products (analysis, products definition like position time series, velocity field and Zenithal Total Delay) (3) User oriented services (reference frames, real-time solutions for early warning systems, strain rate maps, meteorology, space weather, …). Current propositions and remaining open
GeoSEA: Geodetic Earthquake Observatory on the Seafloor
Kopp, Heidrun; Lange, Dietrich; Flueh, Ernst R.; Petersen, Florian; Behrmann, Jan-Hinrich; Devey, Colin
2014-05-01
Space geodetic observations of crustal deformation have contributed greatly to our understanding of plate tectonic processes in general, and plate subduction in particular. Measurements of interseismic strain have documented the active accumulation of strain, and subsequent strain release during earthquakes. However, techniques such as GPS cannot be applied below the water surface because the electromagnetic energy is strongly attenuated in the water column. Evidence suggests that much of the elastic strain build up and release (and particularly that responsible for both tsunami generation and giant earthquakes) occurs offshore. To quantify strain accumulation and assess the resultant hazard potential we urgently need systems to resolve seafloor crustal deformation. Here we report on first results of sea trials of a newly implemented seafloor geodesy array. The GeoSEA (Geodetic Earthquake Observatory on the Seafloor) array consists of a seafloor transponder network comprising 35 units and a wave glider acting as a surface unit (GeoSURF) to ensure satellite correspondence, data transfer and monitor system health. Seafloor displacement occurs in the horizontal (x,y) and vertical direction (z). The vertical displacement is measured by monitoring pressure variations at the seafloor. Horizontal seafloor displacement can be measured either using an acoustic/GPS combination to provide absolute positioning (requiring a suitably equipped vessel to perform repeated cruises to provide the GPS fixes) or by long-term acoustic telemetry between different beacons fixed on the seafloor to determine relative distances by using the travel time observations to each other, which is the technique tested during our short sea trials. For horizontal direct path measurements, the system utilizes acoustic ranging techniques with a ranging precision better than 15 mm and long term stability over 2 km distances. Vertical motion is obtained from pressure gauges. Integrated inclinometers
A Strategic Independent Geodetic VLBI Network for Europe
Dale, Denise; Combrinck, Ludwig; de Witt, Alet
2014-12-01
Irregularities of the rotation of the Earth in space are described by the Earth Orientation Parameters (EOPs). An independent EOP network, applying the Very Long Baseline Interferometry (VLBI) technique and using the Vienna VLBI Software (VieVS), are strategically essential for Europe to minimize its reliance on foreign global support in terms of required infrastructure for the realization of such a network. The generation of independent EOPs is already achievable by countries such as the USA, the People's Republic of China, and the Russian Federation due to their large extent of land mass that allows for long baselines in both the North-South and East-West directions and thus allows for accurate determination of all EOPs. These three countries need not rely on foreign partnerships to generate EOPs, as they all have independent geodetic VLBI networks capable of determining EOPs for precise positioning, navigation, and satellite launch/orbital purposes. They also have or are developing independent Global Navigation Satellite Systems (GNSS) constellations; so does the European Union (EU). Accurate EOPs are essential for long-term orbital maintenance of GNSS constellations, leaving the EU GALILEO GNSS vulnerable and reliant on the three superpowers. Generation of accurate EOPs by Europe is not possible due to its much smaller land mass and thus smaller achievable baselines. Even though there are many radio telescopes spread across Europe, these are separated by relatively short distances. The proposed stations that will be used to investigate this independent EOP network for Europe are the WETTZELL radio telescope in Germany, two German owned radio telescopes, TIGOCONC in Concepción, Chile, and OHIGGINS in Antarctica, as well as the HartRAO radio telescope in South Africa.
Finite element method for solving geodetic boundary value problems
Fašková, Zuzana; Čunderlík, Róbert; Mikula, Karol
2010-02-01
The goal of this paper is to present the finite element scheme for solving the Earth potential problems in 3D domains above the Earth surface. To that goal we formulate the boundary-value problem (BVP) consisting of the Laplace equation outside the Earth accompanied by the Neumann as well as the Dirichlet boundary conditions (BC). The 3D computational domain consists of the bottom boundary in the form of a spherical approximation or real triangulation of the Earth’s surface on which surface gravity disturbances are given. We introduce additional upper (spherical) and side (planar and conical) boundaries where the Dirichlet BC is given. Solution of such elliptic BVP is understood in a weak sense, it always exists and is unique and can be efficiently found by the finite element method (FEM). We briefly present derivation of FEM for such type of problems including main discretization ideas. This method leads to a solution of the sparse symmetric linear systems which give the Earth’s potential solution in every discrete node of the 3D computational domain. In this point our method differs from other numerical approaches, e.g. boundary element method (BEM) where the potential is sought on a hypersurface only. We apply and test FEM in various situations. First, we compare the FEM solution with the known exact solution in case of homogeneous sphere. Then, we solve the geodetic BVP in continental scale using the DNSC08 data. We compare the results with the EGM2008 geopotential model. Finally, we study the precision of our solution by the GPS/levelling test in Slovakia where we use terrestrial gravimetric measurements as input data. All tests show qualitative and quantitative agreement with the given solutions.