Evidence
Same model and position · retrieved passages supplied · first output
Continuous gravitational waves are expected to be emitted by rapidly rotating, non-axisymmetric neutron stars, and their detection would provide direct information on the internal structure and equation of state of these compact objects.
Passages supplied to the Evidence version
Card 1 · Prospects for observing and localizing gravitational-wave transients with Advanced LIGO, Advanced Virgo and KAGRA
We present our current best estimate of the plausible observing scenarios for the Advanced LIGO, Advanced Virgo and KAGRA gravitational-wave detectors over the next several years, with the intention of providing information to facilitate planning for multi-messenger astronomy with gravitational wave…
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We present our current best estimate of the plausible observing scenarios for the Advanced LIGO, Advanced Virgo and KAGRA gravitational-wave detectors over the next several years, with the intention of providing information to facilitate planning for multi-messenger astronomy with gravitational waves. We estimate the sensitivity of the network to transient gravitational-wave signals for the third (O3), fourth (O4) and fifth observing (O5) runs, including the planned upgrades of the Advanced LIGO and Advanced Virgo detectors. We study the capability of the network to determine the sky location of the source for gravitational-wave signals from the inspiral of binary systems of compact objects, that is binary neutron star, neutron star–black hole, and binary black hole systems. The ability to localize the sources is given as a sky-area probability, luminosity distance, and comoving volume. The median sky localization area (90% credible region) is expected to be a few hundreds of square de …
Card 2 · Narrowband Searches for Continuous and Long-duration Transient Gravitational Waves from Known Pulsars in the LIGO-Virgo Third Observing Run
Abstract Isolated neutron stars that are asymmetric with respect to their spin axis are possible sources of detectable continuous gravitational waves. This paper presents a fully coherent search for such signals from eighteen pulsars in data from LIGO and Virgo’s third observing run (O3). For known…
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Abstract Isolated neutron stars that are asymmetric with respect to their spin axis are possible sources of detectable continuous gravitational waves. This paper presents a fully coherent search for such signals from eighteen pulsars in data from LIGO and Virgo’s third observing run (O3). For known pulsars, efficient and sensitive matched-filter searches can be carried out if one assumes the gravitational radiation is phase-locked to the electromagnetic emission. In the search presented here, we relax this assumption and allow both the frequency and the time derivative of the frequency of the gravitational waves to vary in a small range around those inferred from electromagnetic observations. We find no evidence for continuous gravitational waves, and set upper limits on the strain amplitude for each target. These limits are more constraining for seven of the targets than the spin-down limit defined by ascribing all rotational energy loss to gravitational radiation. In an additional se …
Card 3 · All-sky search for continuous gravitational waves from isolated neutron stars using Advanced LIGO and Advanced Virgo O3 data
We present results of an all-sky search for continuous gravitational waves which can be produced by spinning neutron stars with an asymmetry around their rotation axis, using data from the third observing run of the Advanced LIGO and Advanced Virgo detectors. Four different analysis methods are used…
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We present results of an all-sky search for continuous gravitational waves which can be produced by spinning neutron stars with an asymmetry around their rotation axis, using data from the third observing run of the Advanced LIGO and Advanced Virgo detectors. Four different analysis methods are used to search in a gravitational-wave frequency band from 10 to 2048 Hz and a first frequency derivative from $\ensuremath{-}{10}^{\ensuremath{-}8}$ to ${10}^{\ensuremath{-}9}\text{ }\text{ }\mathrm{Hz}/\mathrm{s}$. No statistically significant periodic gravitational-wave signal is observed by any of the four searches. As a result, upper limits on the gravitational-wave strain amplitude ${h}_{0}$ are calculated. The best upper limits are obtained in the frequency range of 100 to 200 Hz and they are $\ensuremath{\sim}1.1\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}25}$ at 95% confidence level. The minimum upper limit of $1.10\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}25}$ is …
Card 4 · Probing gravitational wave polarizations with Advanced LIGO, Advanced Virgo, and KAGRA
Assuming that, for a given source of gravitational waves (GWs), we know its sky position, as is the case for GW events with an electromagnetic counterpart such as GW170817, we discuss a null stream method to probe GW polarizations including spin-0 (scalar) GW modes and spin-1 (vector) modes, especia…
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Assuming that, for a given source of gravitational waves (GWs), we know its sky position, as is the case for GW events with an electromagnetic counterpart such as GW170817, we discuss a null stream method to probe GW polarizations including spin-0 (scalar) GW modes and spin-1 (vector) modes, especially with an expected network of Advanced LIGO, Advanced Virgo, and KAGRA. For two independent null streams for four noncoaligned GW detectors, we study a location on the sky, exactly at which the spin-0 modes of GWs vanish in any null stream for the GW detector network, though the strain output at a detector may contain the spin-0 modes. Our numerical calculations show that there exist 70 sky positions that satisfy this condition of killing the spin-0 modes in the null streams. If a GW source with an electromagnetic counterpart is found in one of the 70 sky positions, the spin-1 modes will be testable separately from the spin-0 modes by the null stream method. In addition, we study a superpo …
Card 5 · All-sky search for continuous gravitational waves from isolated neutron stars in the early O3 LIGO data
We report on an all-sky search for continuous gravitational waves in the frequency band 20--2000 Hz and with a frequency time derivative in the range of $[\ensuremath{-}1.0,+0.1]\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}8}\text{ }\text{ }\mathrm{Hz}/\mathrm{s}$. Such a signal could be pr…
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We report on an all-sky search for continuous gravitational waves in the frequency band 20--2000 Hz and with a frequency time derivative in the range of $[\ensuremath{-}1.0,+0.1]\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}8}\text{ }\text{ }\mathrm{Hz}/\mathrm{s}$. Such a signal could be produced by a nearby, spinning and slightly nonaxisymmetric isolated neutron star in our Galaxy. This search uses the LIGO data from the first six months of Advanced LIGO's and Advanced Virgo's third observational run, O3. No periodic gravitational wave signals are observed, and 95% confidence-level (C.L.) frequentist upper limits are placed on their strengths. The lowest upper limits on worst-case (linearly polarized) strain amplitude ${h}_{0}$ are $\ensuremath{\sim}1.7\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}25}$ near 200 Hz. For a circularly polarized source (most favorable orientation), the lowest upper limits are $\ensuremath{\sim}6.3\ifmmode\times\else\texttimes\fi{}{10}^{\e …
Model-reported card use
Card 2 · fact
Affected output: Continuous gravitational waves are expected to be emitted by rapidly rotating, non-axisymmetric neutron stars
Model explanation: This row supplied the source premise that non-axisymmetric spinning neutron stars are candidate continuous-wave emitters, which the Draft had not yet stated explicitly.
Card 3 · terminology
Affected output: non-axisymmetric neutron stars
Model explanation: This row provided the field-native phrasing for the neutron-star asymmetry that generates continuous waves.