A parallel in-time analysis system for Virgo Amico, P; Alshourbagy, M; Avino, S ...
Journal of Physics: Conference Series,
03/2006, Letnik:
32, Številka:
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The interferometric gravitational wave detector Virgo is currently completing its commissioning phase and it is close to start scientific observations. Among the signals to be searched for, those ...emitted by coalescing binary systems are particularly promising and require a considerable computational effort to optimally search the parameter space. The Virgo collaboration has decided to implement an on-line analysis strategy capable of processing the interferometer data in-time. In this communication we present a component of the analysis pipeline, a parallel computing system based on the Message Passing Interface (MPI). We describe its capabilities, underlining its strength and flexibility, and we illustrate its relation with the other components of the pipeline. The on-line analysis chain, including the presented parallel system, has been run for the first time successfully during the Virgo commissioning run C5 in December 2nd to December 6th 20041.
The Virgo gravitational wave detector is an interferometer (ITF) with 3km
arms located in Pisa, Italy. From July to October 2010, Virgo performed its
third science run (VSR3) in coincidence with the ...LIGO detectors. Despite
several techniques adopted to isolate the interferometer from the environment,
seismic noise remains an important issue for Virgo. Vibrations produced by the
detector infrastructure (such as air conditioning units, water
chillers/heaters, pumps) are found to affect Virgo's sensitivity, with the main
coupling mechanisms being through beam jitter and scattered light processes.
The Advanced Virgo (AdV) design seeks to reduce ITF couplings to environmental
noise by having most vibration-sensitive components suspended and in-vacuum, as
well as muffle and relocate loud machines. During the months of June and July
2010, a Guralp-3TD seismometer was stationed at various locations around the
Virgo site hosting major infrastructure machines. Seismic data were examined
using spectral and coherence analysis with seismic probes close to the
detector. The primary aim of this study was to identify noisy machines which
seismically affect the ITF environment and thus require mitigation attention.
Analyzed machines are located at various distances from the experimental halls,
ranging from 10m to 100m. An attempt is made to measure the attenuation of
emitted noise at the ITF and correlate it to the distance from the source and
to seismic attenuation models in soil.
The Solar System Odyssey mission uses modern-day high-precision experimental techniques to test the laws of fundamental physics which determine dynamics in the solar system. It could lead to major ...discoveries by using demonstrated technologies. The mission proposes to perform a set of precision gravitation experiments from the vicinity of Earth to the outer Solar System. Its scientific objectives can be summarized as follows: i) test of the gravity force law in the Solar System up to and beyond the orbit of Saturn; ii) precise investigation of navigation anomalies at the fly-bys; iii) measurement of Eddington's parameter at occultations; iv) mapping of gravity field in the outer solar system and study of the Kuiper belt. To this aim, the Odyssey mission is built up on a main spacecraft, designed to fly up to 13 AU, with the following components: a) a high-precision accelerometer, with bias-rejection system, measuring the deviation of the trajectory from the geodesics; b) Ka-band transponders, as for Cassini, for a precise range and Doppler measurement up to 13 AU, with additional VLBI equipment; c) optional laser equipment, which would allow one to improve the range and Doppler measurement. In this baseline concept, the main spacecraft is designed to operate beyond the Saturn orbit, up to 13 AU. It experiences multiple planetary fly-bys at Earth, Mars or Venus, and Jupiter. The cruise and fly-by phases allow the mission to achieve its baseline scientific objectives (i) to iii) in the above list). In addition to this baseline concept, the Odyssey mission proposes the release of the Enigma radio-beacon at Saturn, allowing one to extend the deep space gravity test up to at least 50 AU, while achieving the scientific objective of a mapping of gravity field in the outer Solar System.
ESA Spec.Publ. 588 (2005) 3-10 The Pioneer 10 and 11 spacecraft yielded the most precise navigation in deep
space to date. These spacecraft had exceptional acceleration sensitivity.
However, analysis ...of their radio-metric tracking data has consistently
indicated that at heliocentric distances of $\sim 20-70$ astronomical units,
the orbit determinations indicated the presence of a small, anomalous, Doppler
frequency drift. The drift is a blue-shift, uniformly changing with a rate of
$\sim(5.99 \pm 0.01)\times 10^{-9}$ Hz/s, which can be interpreted as a
constant sunward acceleration of each particular spacecraft of $a_P = (8.74 \pm
1.33)\times 10^{-10} {\rm m/s^2}$. This signal has become known as the Pioneer
anomaly. The inability to explain the anomalous behavior of the Pioneers with
conventional physics has contributed to growing discussion about its origin.
There is now an increasing number of proposals that attempt to explain the
anomaly outside conventional physics. This progress emphasizes the need for a
new experiment to explore the detected signal. Furthermore, the recent
extensive efforts led to the conclusion that only a dedicated experiment could
ultimately determine the nature of the found signal. We discuss the Pioneer
anomaly and present the next steps towards an understanding of its origin. We
specifically focus on the development of a mission to explore the Pioneer
Anomaly in a dedicated experiment conducted in deep space.
ESA Spec.Publ. 588 (2005) 11-18 The Laser Astrometric Test Of Relativity (LATOR) is a joint European-U.S.
Michelson-Morley-type experiment designed to test the pure tensor metric nature
of ...gravitation - a fundamental postulate of Einstein's theory of general
relativity. By using a combination of independent time-series of highly
accurate gravitational deflection of light in the immediate proximity to the
Sun, along with measurements of the Shapiro time delay on interplanetary scales
(to a precision respectively better than 0.1 picoradians and 1 cm), LATOR will
significantly improve our knowledge of relativistic gravity. The primary
mission objective is to i) measure the key post-Newtonian Eddington parameter
\gamma with accuracy of a part in 10^9. (1-\gamma) is a direct measure for
presence of a new interaction in gravitational theory, and, in its search,
LATOR goes a factor 30,000 beyond the present best result, Cassini's 2003 test.
The mission will also provide: ii) first measurement of gravity's non-linear
effects on light to ~0.01% accuracy; including both the Eddington \beta
parameter and also the spatial metric's 2nd order potential contribution (never
measured before); iii) direct measurement of the solar quadrupole moment J2
(currently unavailable) to accuracy of a part in 200 of its expected size; iv)
direct measurement of the "frame-dragging" effect on light by the Sun's
gravitomagnetic field, to 1% accuracy. LATOR's primary measurement pushes to
unprecedented accuracy the search for cosmologically relevant scalar-tensor
theories of gravity by looking for a remnant scalar field in today's solar
system. We discuss the mission design of this proposed experiment.
The Laser Astrometric Test Of Relativity (LATOR) is a joint European-U.S. Michelson-Morley-type experiment designed to test the pure tensor metric nature of gravitation - a fundamental postulate of ...Einstein's theory of general relativity. By using a combination of independent time-series of highly accurate gravitational deflection of light in the immediate proximity to the Sun, along with measurements of the Shapiro time delay on interplanetary scales (to a precision respectively better than 0.1 picoradians and 1 cm), LATOR will significantly improve our knowledge of relativistic gravity. The primary mission objective is to i) measure the key post-Newtonian Eddington parameter \gamma with accuracy of a part in 10^9. (1-\gamma) is a direct measure for presence of a new interaction in gravitational theory, and, in its search, LATOR goes a factor 30,000 beyond the present best result, Cassini's 2003 test. The mission will also provide: ii) first measurement of gravity's non-linear effects on light to ~0.01% accuracy; including both the Eddington \beta parameter and also the spatial metric's 2nd order potential contribution (never measured before); iii) direct measurement of the solar quadrupole moment J2 (currently unavailable) to accuracy of a part in 200 of its expected size; iv) direct measurement of the "frame-dragging" effect on light by the Sun's gravitomagnetic field, to 1% accuracy. LATOR's primary measurement pushes to unprecedented accuracy the search for cosmologically relevant scalar-tensor theories of gravity by looking for a remnant scalar field in today's solar system. We discuss the mission design of this proposed experiment.
The Pioneer 10 and 11 spacecraft yielded the most precise navigation in deep space to date. These spacecraft had exceptional acceleration sensitivity. However, analysis of their radio-metric tracking ...data has consistently indicated that at heliocentric distances of \(\sim 20-70\) astronomical units, the orbit determinations indicated the presence of a small, anomalous, Doppler frequency drift. The drift is a blue-shift, uniformly changing with a rate of \(\sim(5.99 \pm 0.01)\times 10^{-9}\) Hz/s, which can be interpreted as a constant sunward acceleration of each particular spacecraft of \(a_P = (8.74 \pm 1.33)\times 10^{-10} {\rm m/s^2}\). This signal has become known as the Pioneer anomaly. The inability to explain the anomalous behavior of the Pioneers with conventional physics has contributed to growing discussion about its origin. There is now an increasing number of proposals that attempt to explain the anomaly outside conventional physics. This progress emphasizes the need for a new experiment to explore the detected signal. Furthermore, the recent extensive efforts led to the conclusion that only a dedicated experiment could ultimately determine the nature of the found signal. We discuss the Pioneer anomaly and present the next steps towards an understanding of its origin. We specifically focus on the development of a mission to explore the Pioneer Anomaly in a dedicated experiment conducted in deep space.
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