The Experts below are selected from a list of 208848 Experts worldwide ranked by ideXlab platform
F Briggs - One of the best experts on this subject based on the ideXlab platform.
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the high time and Frequency Resolution capabilities of the murchison widefield array
Publications of the Astronomical Society of Australia, 2015Co-Authors: S E Tremblay, S M Ord, N D R Bhat, S J Tingay, B Crosse, D Pallot, S I Oronsaye, G Bernardi, Judd D Bowman, F BriggsAbstract:The science cases for incorporating high time Resolution capabilities into modern radio telescopes are as numerous as they are compelling. Science targets range from exotic sources such as pulsars, to our Sun, to recently detected possible extragalactic bursts of radio emission, the so-called fast radio bursts (FRBs). Originally conceived purely as an imaging telescope, the initial design of the Murchison Widefield Array (MWA) did not include the ability to access high time and Frequency Resolution voltage data. However, the flexibility of the MWA’s software correlator allowed an off-the-shelf solution for adding this capability. This paper describes the system that records the 100 μs and 10 kHz Resolution voltage data from the MWA. Example science applications, where this capability is critical, are presented, as well as accompanying commissioning results from this mode to demonstrate verification.
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the high time and Frequency Resolution capabilities of the murchison widefield array
arXiv: Instrumentation and Methods for Astrophysics, 2015Co-Authors: S E Tremblay, S M Ord, N D R Bhat, S J Tingay, B Crosse, D Pallot, S I Oronsaye, G Bernardi, Judd D Bowman, F BriggsAbstract:The science cases for incorporating high time Resolution capabilities into modern radio telescopes are as numerous as they are compelling. Science targets range from exotic sources such as pulsars, to our Sun, to recently detected possible extragalactic bursts of radio emission, the so-called fast radio bursts (FRBs). Originally conceived purely as an imaging telescope, the initial design of the Murchison Widefield Array (MWA) did not include the ability to access high time and Frequency Resolution voltage data. However, the flexibility of the MWA's software correlator allowed an off-the-shelf solution for adding this capability. This paper describes the system that records the 100 micro-second and 10 kHz Resolution voltage data from the MWA. Example science applications, where this capability is critical, are presented, as well as accompanying commissioning results from this mode to demonstrate verification.
N D R Bhat - One of the best experts on this subject based on the ideXlab platform.
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the high time and Frequency Resolution capabilities of the murchison widefield array
Publications of the Astronomical Society of Australia, 2015Co-Authors: S E Tremblay, S M Ord, N D R Bhat, S J Tingay, B Crosse, D Pallot, S I Oronsaye, G Bernardi, Judd D Bowman, F BriggsAbstract:The science cases for incorporating high time Resolution capabilities into modern radio telescopes are as numerous as they are compelling. Science targets range from exotic sources such as pulsars, to our Sun, to recently detected possible extragalactic bursts of radio emission, the so-called fast radio bursts (FRBs). Originally conceived purely as an imaging telescope, the initial design of the Murchison Widefield Array (MWA) did not include the ability to access high time and Frequency Resolution voltage data. However, the flexibility of the MWA’s software correlator allowed an off-the-shelf solution for adding this capability. This paper describes the system that records the 100 μs and 10 kHz Resolution voltage data from the MWA. Example science applications, where this capability is critical, are presented, as well as accompanying commissioning results from this mode to demonstrate verification.
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the high time and Frequency Resolution capabilities of the murchison widefield array
arXiv: Instrumentation and Methods for Astrophysics, 2015Co-Authors: S E Tremblay, S M Ord, N D R Bhat, S J Tingay, B Crosse, D Pallot, S I Oronsaye, G Bernardi, Judd D Bowman, F BriggsAbstract:The science cases for incorporating high time Resolution capabilities into modern radio telescopes are as numerous as they are compelling. Science targets range from exotic sources such as pulsars, to our Sun, to recently detected possible extragalactic bursts of radio emission, the so-called fast radio bursts (FRBs). Originally conceived purely as an imaging telescope, the initial design of the Murchison Widefield Array (MWA) did not include the ability to access high time and Frequency Resolution voltage data. However, the flexibility of the MWA's software correlator allowed an off-the-shelf solution for adding this capability. This paper describes the system that records the 100 micro-second and 10 kHz Resolution voltage data from the MWA. Example science applications, where this capability is critical, are presented, as well as accompanying commissioning results from this mode to demonstrate verification.
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the high time Resolution universe pulsar survey i system configuration and initial discoveries
Monthly Notices of the Royal Astronomical Society, 2010Co-Authors: M J Keith, A Jameson, W Van Straten, M Bailes, S Johnston, M Kramer, A Possenti, S D Bates, N D R BhatAbstract:We have embarked on a survey for pulsars and fast transients using the 13-beam multibeam receiver on the Parkes Radio Telescope. Installation of a digital backend allows us to record 400 MHz of bandwidth for each beam, split into 1024 channels and sampled every 64 μs. Limits of the receiver package restrict us to a 340 MHz observing band centred at 1352 MHz. The factor of 8 improvement in Frequency Resolution over previous multibeam surveys allows us to probe deeper into the Galactic plane for short-duration signals such as the pulses from millisecond pulsars. We plan to survey the entire southern sky in 42 641 pointings, split into low, mid and high Galactic latitude regions, with integration times of 4200, 540 and 270 s, respectively. Simulations suggest that we will discover 400 pulsars, of which 75 will be millisecond pulsars. With ∼30 per cent of the mid-latitude survey complete, we have redetected 223 previously known pulsars and discovered 27 pulsars, five of which are millisecond pulsars. The newly discovered millisecond pulsars tend to have larger dispersion measures than those discovered in previous surveys, as expected from the improved time and Frequency Resolution of our instrument.
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the high time Resolution universe pulsar survey i system configuration and initial discoveries
arXiv: High Energy Astrophysical Phenomena, 2010Co-Authors: M J Keith, N D R Bhat, A Jameson, W Van Straten, M Bailes, S Johnston, M Kramer, A Possenti, S D Bates, M BurgayAbstract:We have embarked on a survey for pulsars and fast transients using the 13-beam Multibeam receiver on the Parkes radio telescope. Installation of a digital backend allows us to record 400 MHz of bandwidth for each beam, split into 1024 channels and sampled every 64 us. Limits of the receiver package restrict us to a 340 MHz observing band centred at 1352 MHz. The factor of eight improvement in Frequency Resolution over previous multibeam surveys allows us to probe deeper into the Galactic plane for short duration signals such as the pulses from millisecond pulsars. We plan to survey the entire southern sky in 42641 pointings, split into low, mid and high Galactic latitude regions, with integration times of 4200, 540 and 270 s respectively. Simulations suggest that we will discover 400 pulsars, of which 75 will be millisecond pulsars. With ~30% of the mid-latitude survey complete, we have re-detected 223 previously known pulsars and discovered 27 pulsars, 5 of which are millisecond pulsars. The newly discovered millisecond pulsars tend to have larger dispersion measures than those discovered in previous surveys, as expected from the improved time and Frequency Resolution of our instrument.
Ayhan Demircan - One of the best experts on this subject based on the ideXlab platform.
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optfrog analytic signal spectrograms with optimized time Frequency Resolution
SoftwareX, 2019Co-Authors: O Melchert, Bernhard Roth, Uwe Morgner, Ayhan DemircanAbstract:Abstract A Python package for the calculation of spectrograms with optimized time and Frequency Resolution for application in the analysis of numerical simulations on ultrashort pulse propagation is presented. Gabor’s uncertainty principle prevents both Resolutions from being optimal simultaneously for a given window function employed in the underlying short-time Fourier analysis. Our aim is to yield a time–Frequency representation of the input signal with marginals that represent the original intensities per unit time and Frequency similarly well. As a use-case, we demonstrate the implemented functionality for the analysis of simulations on ultrashort pulse propagation in a nonlinear waveguide.
S E Tremblay - One of the best experts on this subject based on the ideXlab platform.
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the high time and Frequency Resolution capabilities of the murchison widefield array
Publications of the Astronomical Society of Australia, 2015Co-Authors: S E Tremblay, S M Ord, N D R Bhat, S J Tingay, B Crosse, D Pallot, S I Oronsaye, G Bernardi, Judd D Bowman, F BriggsAbstract:The science cases for incorporating high time Resolution capabilities into modern radio telescopes are as numerous as they are compelling. Science targets range from exotic sources such as pulsars, to our Sun, to recently detected possible extragalactic bursts of radio emission, the so-called fast radio bursts (FRBs). Originally conceived purely as an imaging telescope, the initial design of the Murchison Widefield Array (MWA) did not include the ability to access high time and Frequency Resolution voltage data. However, the flexibility of the MWA’s software correlator allowed an off-the-shelf solution for adding this capability. This paper describes the system that records the 100 μs and 10 kHz Resolution voltage data from the MWA. Example science applications, where this capability is critical, are presented, as well as accompanying commissioning results from this mode to demonstrate verification.
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the high time and Frequency Resolution capabilities of the murchison widefield array
arXiv: Instrumentation and Methods for Astrophysics, 2015Co-Authors: S E Tremblay, S M Ord, N D R Bhat, S J Tingay, B Crosse, D Pallot, S I Oronsaye, G Bernardi, Judd D Bowman, F BriggsAbstract:The science cases for incorporating high time Resolution capabilities into modern radio telescopes are as numerous as they are compelling. Science targets range from exotic sources such as pulsars, to our Sun, to recently detected possible extragalactic bursts of radio emission, the so-called fast radio bursts (FRBs). Originally conceived purely as an imaging telescope, the initial design of the Murchison Widefield Array (MWA) did not include the ability to access high time and Frequency Resolution voltage data. However, the flexibility of the MWA's software correlator allowed an off-the-shelf solution for adding this capability. This paper describes the system that records the 100 micro-second and 10 kHz Resolution voltage data from the MWA. Example science applications, where this capability is critical, are presented, as well as accompanying commissioning results from this mode to demonstrate verification.
Philipp Kukura - One of the best experts on this subject based on the ideXlab platform.
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femtosecond time resolved stimulated raman spectroscopy application to the ultrafast internal conversion in β carotene
Journal of Physical Chemistry A, 2003Co-Authors: David W. Mccamant, Philipp KukuraAbstract:We have developed the technique of femtosecond stimulated Raman spectroscopy (FSRS), which allows the rapid collection of high-Resolution vibrational spectra on the femtosecond time scale. FSRS combines a sub-50 fs actinic pump pulse with a two-pulse stimulated Raman probe to obtain vibrational spectra whose Frequency Resolution limits are uncoupled from the time Resolution. This allows the acquisition of spectra with <100 fs time Resolution and <30 cm-1 Frequency Resolution. Additionally, FSRS is unaffected by background fluorescence, provides rapid (100 ms) acquisition times, and exhibits traditional spontaneous Raman line shapes. FSRS is used here to study the relaxation dynamics of β-carotene. Following optical excitation to S2 (1Bu+) the molecule relaxes in 160 fs to S1 (2Ag-) and then undergoes two distinct stages of intramolecular vibrational energy redistribution (IVR) with 200 and 450 fs time constants. These processes are attributed to rapid (200 fs) distribution of the internal conversion energ...
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femtosecond time resolved stimulated raman spectroscopy application to the ultrafast internal conversion in β carotene
Journal of Physical Chemistry A, 2003Co-Authors: David W. Mccamant, Philipp Kukura, Richard A MathiesAbstract:We have developed the technique of femtosecond stimulated Raman spectroscopy (FSRS), which allows the rapid collection of high-Resolution vibrational spectra on the femtosecond time scale. FSRS combines a sub-50 fs actinic pump pulse with a two-pulse stimulated Raman probe to obtain vibrational spectra whose Frequency Resolution limits are uncoupled from the time Resolution. This allows the acquisition of spectra with <100 fs time Resolution and <30 cm(-1) Frequency Resolution. Additionally, FSRS is unaffected by background fluorescence, provides rapid (100 ms) acquisition times, and exhibits traditional spontaneous Raman line shapes. FSRS is used here to study the relaxation dynamics of beta-carotene. Following optical excitation to S(2) (1B(u) (+)) the molecule relaxes in 160 fs to S(1) (2A(g) (-)) and then undergoes two distinct stages of intramolecular vibrational energy redistribution (IVR) with 200 and 450 fs time constants. These processes are attributed to rapid (200 fs) distribution of the internal conversion energy from the S(1) C=C modes into a restricted bath of anharmonically coupled modes followed by complete IVR in 450 fs. FSRS is a valuable new technique for studying the vibrational structure of chemical reaction intermediates and transition states.
