phenomenon · claim-type · cross-domain-transfer · mechanism · claim-relation · replication-status · limitation — grounded in the full text| phenomenon | gravitational waves from the inspiral, merger and ringdown of compact binary coalescences, detected by a network of ground-based interferometers— “This network of ground-based interferometric detectors is sensitive to GWs from the inspiral, merger, and ringdown of compact binary coalescences (CBCs), covering a frequency range from about 15 Hz up to a few kilohertz” | |
| claim-type | existence— “In this catalog, we report 11 confident detections of GWs from compact binary mergers as well as a selection of less significant triggers from both observing runs.” | |
| method — evidence | — “The events presented here are obtained from a total of three searches: two matched-filter searches, PyCBC [7,8] and GstLAL [9,10], using relativistic models of GWs from CBCs, as well as one unmodeled search for short-duration transient signals or bursts, coherent WaveBurst (cWB) [11].” | |
| object of study — evidence | — “In this catalog, we report 11 confident detections of GWs from compact binary mergers as well as a selection of less significant triggers from both observing runs.” | |
| research question — evidence | — “To do this identification, we establish an initial threshold on estimated FAR of 1 per 30 days (about 12.2 per year), excluding any event that does not have a FAR less than this threshold in at least one of the two matched-filter analyses (see Sec. III).” | |
| contribution — evidence | — “In this catalog, we announce four previously unpublished BBH mergers observed during O2: GW170729, GW170809, GW170818, and GW170823.” | |
| mechanism | scattered light light scattered inside the interferometer puts excess power at low frequencies, appearing as arch shapes in a spectrogram; where those frequencies reach the analysis band it can produce a significant matched-filter trigger— “Scattered light leads to excess power at low frequencies that appear in time-frequency spectrograms as archlike shapes. In some cases, the frequencies affected are above the minimum frequency used in the analysis. When this happens, scattered light transients can create significant triggers in matched-filter searches [68,92,93].” | mechanisms[0] |
| mechanism | ground motion storms and earthquakes drive high-amplitude ground motion which both destabilises the interferometer and generates the scattering artifacts, so the environmental cause and the data artifact arrive together— “The presence of intense scattering artifacts contribute to the unstable state of the interferometer and could account for the SNR of the marginal trigger.” | mechanisms[1] |
| mechanism | template density why noise triggers pile up at low chirp mass - the template bank is much more densely packed there, so noise has more chances to match something— “The concentration of our marginal triggers at low chirp masses is consistent with expectations for noise triggers, because search template waveforms are much more densely packed at low masses.” | mechanisms[2] |
| mechanism | arrival-time difference sky position is reconstructed from the difference in arrival time across separated detector sites, which is why adding Virgo to the two LIGO sites improves localisation so sharply— “As the sky location is primarily determined by the differences in the times of arrival of the GW signal at the different detector sites, LIGO-Virgo coincident events have a vastly improved sky localization, which is crucial for electromagnetic follow-up campaigns” | mechanisms[3] |
| mechanism | pipeline-specific noise a noise trigger is a function of the pipeline that found it, so the same noise is not expected to appear in both searches - which is why agreement between pipelines carries information and disagreement does not immediately count against a candidate— “As noise triggers are generically a function of the details of the pipeline that identifies a trigger, we do not typically expect to see the same noise triggers in each pipeline.” | mechanisms[4] |
| extends | the individual LIGO-Virgo detection papers for GW150914, GW151226, GW170104, GW170608, GW170814 and GW170817, whose significances and parameter estimates this catalog replaces— “The updated results we report here supersede those previously published.” | claim_relations[0] |
| confirms | an independent catalog by another group which reanalysed the O1 data with the PyCBC pipeline and found the same three events, with identical FAR bounds for two of them— “That catalog also presents search results from the PyCBC pipeline for O1 and also finds GW150914, GW151012, and GW151226 as the only confident gravitational-wave events in O1, with identical bounds on FAR to the PyCBC results in Table I for GW150914 and GW151226.” | claim_relations[1] |
| qualifies | the collaboration's own earlier designation of LVT151012 as a trigger rather than an event, which the improved pipelines overturn— “this event meets the criteria of Sec. IVA for a gravitational-wave event, and we henceforth relabel this event as GW151012.” | claim_relations[2] |
| sense | weakly modeled - THE PAPER COINS THIS ABOUT ITSELF AND SAYS WHY. cWB is introduced as an unmodeled search, but the analysis reported here restricts it to signals that chirp in the time-frequency plane, so it is no longer model-free. The authors change the word rather than keep the stronger one— “In contrast, the cWB search relies on no specific physical models of the source waveform, though in results presented here it does impose a restriction that signals are “chirping” in the time-frequency plane. We therefore refer to it as weakly modeled.” | senses[0] |
| sense | marginal - NEITHER ESTABLISHED NOR EXCLUDED, and the paper holds that line to the end. A marginal trigger passed the false-alarm threshold but was given less than a 50% probability of astrophysical origin by both matched-filter searches. It is not a non-detection and not a weak detection: it is a candidate the collaboration declines to resolve, and it says so in the conclusions as well as the results— “In addition, we list 14 GW candidate events that have an estimated false-alarm rate (FAR) less than 1 per 30 days in either of the two matched-filter analyses but whose astrophysical origin cannot be established nor excluded unambiguously (Sec. VII).” | senses[1] |
| sense | false-alarm rate - AN EMPIRICAL RATE MEASURED AGAINST TIME-SHIFTED DATA, NOT A PROBABILITY THAT THE EVENT IS NOISE. Where a candidate outranks every background trigger the search can only report a BOUND, and the bound depends on how much background time was available - which is why some FARs here are larger than the ones previously published for the same events— “This restriction means, however, the minimum bound on the false-alarm rate of candidates that have a higher ranking statistic than any trigger in the background sample is larger than it would be if longer periods of data are used for the time-shift analysis.” | senses[2] |
| sense | independent, of the three searches - INDEPENDENCE OF METHOD, NOT OF EVIDENCE. The conclusions say `three independent analyses` flatly; what is independent is the pipeline, the ranking statistic and the noise model, while the strain data are the same in all three. The body is more careful than the conclusion, which is worth knowing before the agreement between them is read as three confirmations— “The signals were discovered using three independent analyses: two matched-filter searches [8,9] and one weakly modeled burst search [11].” | senses[3] |
| sense | GW versus marginal - A THRESHOLD CONVENTION, NOT A PROPERTY OF THE UNIVERSE. The boundary is a false-alarm rate ceiling of 1 per 30 days followed by a 50% astrophysical probability, both chosen by the collaboration. An event just under the line and one just over it differ by the convention, and the paper presents the choice as a choice— “we assign the “GW” designation to any event for which the probability of astrophysical origin from either matched-filter search is greater than 50%” | senses[4] |
| sense | detection, in the phrase `no new gravitational-wave events were discovered` - THE O1 REANALYSIS FOUND NOTHING NEW BUT DID CHANGE AN OLD ANSWER. The same data through better pipelines moved LVT151012 across the threshold and it is now GW151012. So the null result is about new events only; the catalog's contents still changed— “These improved FAR measurements for GW151012 are the most salient result of the reanalysis of O1 with the O2 pipelines; no new gravitational-wave events were discovered.” | senses[5] |
| control | significance measured against a background built by repeatedly time-shifting one detector's triggers against the other's and counting the coincidences that result — held— “For an estimation of its statistical significance, each candidate event is ranked against a sample of background triggers obtained by repeating the analysis on time-shifted data, similar to the background estimation in the PyCBC search.” — rules out a chance alignment of independent noise in two detectors being read as a signal - the candidate is ranked against a background of coincidences manufactured from the same data— “For an estimation of its statistical significance, each candidate event is ranked against a sample of background triggers obtained by repeating the analysis on time-shifted data, similar to the background estimation in the PyCBC search.” | controls[0] |
| control | the time shifts are chosen much larger than the light-travel delay between sites — held— “To exclude astrophysical events from the background sample, the time shifts are selected to be much larger than the expected signal delay between the detectors.” — rules out a real astrophysical signal leaking into the background sample and inflating the false-alarm rate it is being measured against— “To exclude astrophysical events from the background sample, the time shifts are selected to be much larger than the expected signal delay between the detectors.” | controls[1] |
| control | GstLAL's noise model built from single-detector triggers that were NOT found in coincidence — held— “is constructed, in part, from single-detector triggers that are not found in coincidence, so as to minimize the possibility of contamination by real signals.” — rules out real signals contaminating the model of what noise looks like - the same concern as the time shifts, met by a different construction— “is constructed, in part, from single-detector triggers that are not found in coincidence, so as to minimize the possibility of contamination by real signals.” | controls[2] |
| control | a veto on the network correlation coefficient, rejecting candidates below 0.7 — held— “Typically, for a GW signal cc ≈ 1, and for instrumental glitches cc ≪ 1. Therefore, candidate events with cc<0.7 are rejected as potential glitches.” — rules out instrumental glitches - the statistic sits near 1 for a real signal and far below it for a glitch, so a floor at 0.7 removes the second without a model of either— “Typically, for a GW signal cc ≈ 1, and for instrumental glitches cc ≪ 1. Therefore, candidate events with cc<0.7 are rejected as potential glitches.” | controls[3] |
| control | a minimum waveform duration of 0.15 s, which sets the high-mass edge of the search — held— “The high-mass boundary of the search space is determined by the requirement that the waveform duration be at least 0.15 s, which reduces the number of false-alarm triggers from short instrumental glitches.” — rules out short instrumental glitches ranking highly against the very short templates a higher mass limit would require— “The high-mass boundary of the search space is determined by the requirement that the waveform duration be at least 0.15 s, which reduces the number of false-alarm triggers from short instrumental glitches.” | controls[4] |
| control | two signal-based vetoes applied to PyCBC single-detector triggers — held— “In order to suppress triggers caused by high-amplitude noise transients (“glitches”), two signal-based vetoes may be calculated [71,72].” — rules out high-amplitude noise transients producing triggers that look like signals to the matched filter— “In order to suppress triggers caused by high-amplitude noise transients (“glitches”), two signal-based vetoes may be calculated [71,72].” | controls[5] |
| control | time shifts restricted to within a single analysis period rather than across the whole run — partial— “This restriction means, however, the minimum bound on the false-alarm rate of candidates that have a higher ranking statistic than any trigger in the background sample is larger than it would be if longer periods of data are used for the time-shift analysis.” — rules out a background averaged over detector states that differ - the noise changes substantially between the start of O1 and the end of O2. IT DOES NOT COME FREE and the authors say so: the reachable lower bound on the false-alarm rate gets larger— “the results here consider only time shifts within a given analysis period, which is done because the noise characteristics of the detector vary significantly from the beginning of O1 through the end of O2, so this restriction more accurately reflects the variation in detector performance.” | controls[6] |
| control | a detector-characterisation investigation of every marginal trigger, using auxiliary sensors alongside the strain data, against two stated metrics — partial— “Of the marginal triggers presented in this catalog, nine have excess power from known sources of noise occurring during times when the matched-filter template that yields the trigger has a GW frequency within the sensitive band of the detectors. For four of these cases, the observed instrumental artifact overlaps the signal region and… — rules out a known instrumental or environmental artifact being the whole explanation of a marginal trigger. PARTIAL BY THE PAPER'S OWN COUNT: nine of the fourteen coincide with known noise and four of those could account for the trigger— “Using auxiliary sensors at each detector, as well as the gravitational-wave strain data, we evaluate the state of the detectors at the time of each marginal trigger, identify and investigate any artifacts in the data due to noise, and test whether any identified artifacts might explain the excess SNR observed in the analysis.” | controls[7] |
| control | glitch subtraction followed by reanalysis of the cleaned data - the counterfactual rather than the correlation — held— “In both cases, the marginal trigger remains with similar significance, suggesting that the observed scattering artifact could not have accounted for the SNR of the marginal trigger.” — rules out scattered light as the cause of the two triggers examined this way - with the artifact subtracted the trigger survives at similar significance, so the artifact was not producing it— “In both cases, the marginal trigger remains with similar significance, suggesting that the observed scattering artifact could not have accounted for the SNR of the marginal trigger.” | controls[8] |
| control | a Poisson calculation on the clustering of five events into August 2017 — held— “The probability that a Poisson process would produce five events or more in at least one of those periods is 5.3%. Thus, seeing five events in one month is statistically consistent with expectations.” — rules out a run of detections in one month being read as an excess over the expected rate - the probability of it happening in at least one of the ten comparable periods is 5.3%— “The probability that a Poisson process would produce five events or more in at least one of those periods is 5.3%. Thus, seeing five events in one month is statistically consistent with expectations.” | controls[9] |
| control | an independent waveform reconstruction using wavelets and the unmodelled search, compared against the template-based reconstruction, both visually and by subtracting the best-fit waveform and reanalysing — held— “Both comparisons agree within expectations from analysis of simulations, and we conclude that there are no detectable discrepancies between the wavelet- and template-based reconstructions” — rules out the inferred signal being an artefact of the relativistic waveform models - which the authors introduce precisely by saying those models may not include all physics— “Quantitative comparisons of the template- and wavelet-based methods include computing overlaps between the reconstructions and reanalyzing the data with the wavelet-based analysis after the best-fit CBC waveform has been subtracted.” | controls[10] |
| control | checking that features appearing in the wavelet reconstruction's 90% band are absent from its 50% band, and reproducing them with simulated signals injected into real data — held— “Analogous features are seen when reconstructing simulated signals added to real data and should not be misinterpreted as evidence for disagreement with the template-based reconstructions.” — rules out apparent extra structure in the reconstruction being read as disagreement with the template model - it is coherent noise, and it appears the same way for signals that are known to be real because they were injected— “We verify that these outliers are absent from the BAYESWAVE 50% credible intervals (not shown here), indicating that they have low significance.” | controls[11] |
| control | the pipeline's response calibrated by recovering injected synthetic signals — held— “The astrophysical probabilities from GstLAL in Table IV are estimated using the pipeline response to injected synthetic signals, where neutron stars are assumed to have masses in the range 1–3 M⊙ and black holes are assumed to have masses of 3 M⊙ or larger.” — rules out the astrophysical probabilities resting on an assumed rather than a measured detection efficiency— “The astrophysical probabilities from GstLAL in Table IV are estimated using the pipeline response to injected synthetic signals, where neutron stars are assumed to have masses in the range 1–3 M⊙ and black holes are assumed to have masses of 3 M⊙ or larger.” | controls[12] |
| control | the unmodelled search's results excluded from the event-selection step — held— “The cWB search results are not used in the event selection process.” — rules out the event list depending on three different ranking statistics with three different noise models - selection rests on the two matched-filter searches only— “The cWB search results are not used in the event selection process.” | controls[13] |
| audit | matched-filter searches —contrasted-with→ unmodeled search — Audit 2026-09-28: DOUBTFUL - read against its full span and kept, but the span lists matched-filter and unmodeled searches side by side; contrasted-with is loose.— “The events presented here are obtained from a total of three searches: two matched-filter searches, PyCBC [7,8] and GstLAL [9,10], using relativistic models of GWs from CBCs, as well as one unmodeled search for short-duration transient signals or bursts, coherent WaveBurst (cWB) [11].” | concept_edges[1] |
| weight | matched-filter searches —contrasted-with→ unmodeled search — 0.95— “The events presented here are obtained from a total of three searches: two matched-filter searches, PyCBC [7,8] and GstLAL [9,10], using relativistic models of GWs from CBCs, as well as one unmodeled search for short-duration transient signals or bursts, coherent WaveBurst (cWB) [11].” | concept_edges[1] |
| note | cWB —is-a→ unmodeled search — and the paper immediately withdraws the word for itself - see the 'weakly modeled' sense. The edge records what cWB is called at first mention, not what it is— “The events presented here are obtained from a total of three searches: two matched-filter searches, PyCBC [7,8] and GstLAL [9,10], using relativistic models of GWs from CBCs, as well as one unmodeled search for short-duration transient signals or bursts, coherent WaveBurst (cWB) [11].” | concept_edges[2] |
| weight | cWB —is-a→ unmodeled search — 0.85— “The events presented here are obtained from a total of three searches: two matched-filter searches, PyCBC [7,8] and GstLAL [9,10], using relativistic models of GWs from CBCs, as well as one unmodeled search for short-duration transient signals or bursts, coherent WaveBurst (cWB) [11].” | concept_edges[2] |
| note | false-alarm rate —operationalised-as→ background triggers — the FAR is the rate of background triggers ranking at least as high as the candidate; the background is manufactured by time shifting, so the measure exists only relative to how much shifted time was analysed— “Each foreground coincident assigned a false-alarm rate (FAR) given by the number of background triggers with an equal or larger ranking, divided by the total time searched for time-shifted coincidences.” | concept_edges[3] |
| weight | false-alarm rate —operationalised-as→ background triggers — 0.95— “Each foreground coincident assigned a false-alarm rate (FAR) given by the number of background triggers with an equal or larger ranking, divided by the total time searched for time-shifted coincidences.” | concept_edges[3] |
| edge | background triggers —operationalised-as→ time-shifted data— “For an estimation of its statistical significance, each candidate event is ranked against a sample of background triggers obtained by repeating the analysis on time-shifted data, similar to the background estimation in the PyCBC search.” | concept_edges[4] |
| audit | scattered light —causes→ triggers — Audit 2026-09-28: DOUBTFUL - read against its span and kept, but scattered light produces excess power seen as arches; 'triggers' is not stated.— “Scattered light leads to excess power at low frequencies that appear in time-frequency spectrograms as archlike shapes. In some cases, the frequencies affected are above the minimum frequency used in the analysis. When this happens, scattered light transients can create significant triggers in matched-filter searches [68,92,93].” | concept_edges[5] |
| effect direction | scattered light —causes→ triggers — increases— “Scattered light leads to excess power at low frequencies that appear in time-frequency spectrograms as archlike shapes. In some cases, the frequencies affected are above the minimum frequency used in the analysis. When this happens, scattered light transients can create significant triggers in matched-filter searches [68,92,93].”— “scattered light transients can create significant triggers in matched-filter searches” | concept_edges[5] |
| weight | scattered light —causes→ triggers — 0.9— “Scattered light leads to excess power at low frequencies that appear in time-frequency spectrograms as archlike shapes. In some cases, the frequencies affected are above the minimum frequency used in the analysis. When this happens, scattered light transients can create significant triggers in matched-filter searches [68,92,93].” | concept_edges[5] |
| effect direction | signal-based vetoes —causes→ triggers — reduces— “In order to suppress triggers caused by high-amplitude noise transients (“glitches”), two signal-based vetoes may be calculated [71,72].”— “In order to suppress triggers caused by high-amplitude noise transients” | concept_edges[7] |
| note | signal-based vetoes —causes→ triggers — the vetoes act on the TRIGGERS, not on the glitches - the noise transients are still in the instrument afterwards. Pointed here in the audit, where the edge had read 'vetoes reduce glitches', which the paper does not say and which is not true— “In order to suppress triggers caused by high-amplitude noise transients (“glitches”), two signal-based vetoes may be calculated [71,72].” | concept_edges[7] |
| weight | signal-based vetoes —causes→ triggers — 0.9— “In order to suppress triggers caused by high-amplitude noise transients (“glitches”), two signal-based vetoes may be calculated [71,72].” | concept_edges[7] |
| outcome | control — held— “For an estimation of its statistical significance, each candidate event is ranked against a sample of background triggers obtained by repeating the analysis on time-shifted data, similar to the background estimation in the PyCBC search.” | controls[0] |
| outcome | control — held— “To exclude astrophysical events from the background sample, the time shifts are selected to be much larger than the expected signal delay between the detectors.” | controls[1] |
| outcome | control — held— “is constructed, in part, from single-detector triggers that are not found in coincidence, so as to minimize the possibility of contamination by real signals.” | controls[2] |
| outcome | control — held— “Typically, for a GW signal cc ≈ 1, and for instrumental glitches cc ≪ 1. Therefore, candidate events with cc<0.7 are rejected as potential glitches.” | controls[3] |
| outcome | control — held— “The high-mass boundary of the search space is determined by the requirement that the waveform duration be at least 0.15 s, which reduces the number of false-alarm triggers from short instrumental glitches.” | controls[4] |
| outcome | control — held— “In order to suppress triggers caused by high-amplitude noise transients (“glitches”), two signal-based vetoes may be calculated [71,72].” | controls[5] |
| outcome | control — partial— “the results here consider only time shifts within a given analysis period, which is done because the noise characteristics of the detector vary significantly from the beginning of O1 through the end of O2, so this restriction more accurately reflects the variation in detector performance.”— “This restriction means, however, the minimum bound on the false-alarm rate of candidates that have a higher ranking statistic than any trigger in the background sample is larger than it would be if longer periods of data are used for the time-shift analysis.” | controls[6] |
| outcome | control — partial— “Using auxiliary sensors at each detector, as well as the gravitational-wave strain data, we evaluate the state of the detectors at the time of each marginal trigger, identify and investigate any artifacts in the data due to noise, and test whether any identified artifacts might explain the excess SNR observed in the analysis.”— “Of the marginal triggers presented in this catalog, nine have excess power from known sources of noise occurring during times when the matched-filter template that yields the trigger has a GW frequency within the sensitive band of the detectors. For four of these cases, the observed instrumental artifact overlaps the signal region and… | controls[7] |
| outcome | control — held— “In both cases, the marginal trigger remains with similar significance, suggesting that the observed scattering artifact could not have accounted for the SNR of the marginal trigger.” | controls[8] |
| outcome | control — held— “The probability that a Poisson process would produce five events or more in at least one of those periods is 5.3%. Thus, seeing five events in one month is statistically consistent with expectations.” | controls[9] |
| outcome | control — held— “Quantitative comparisons of the template- and wavelet-based methods include computing overlaps between the reconstructions and reanalyzing the data with the wavelet-based analysis after the best-fit CBC waveform has been subtracted.”— “Both comparisons agree within expectations from analysis of simulations, and we conclude that there are no detectable discrepancies between the wavelet- and template-based reconstructions” | controls[10] |
| outcome | control — held— “We verify that these outliers are absent from the BAYESWAVE 50% credible intervals (not shown here), indicating that they have low significance.”— “Analogous features are seen when reconstructing simulated signals added to real data and should not be misinterpreted as evidence for disagreement with the template-based reconstructions.” | controls[11] |
| outcome | control — held— “The astrophysical probabilities from GstLAL in Table IV are estimated using the pipeline response to injected synthetic signals, where neutron stars are assumed to have masses in the range 1–3 M⊙ and black holes are assumed to have masses of 3 M⊙ or larger.” | controls[12] |
| outcome | control — held— “The cWB search results are not used in the event selection process.” | controls[13] |
| limitation | the 14 marginal triggers cannot be resolved individually - some may be real and the analysis cannot say which— “Although it may be the case that some of these marginal triggers are of astrophysical origin, we cannot then determine which ones.” | limitations[0] |
| limitation | restated in the conclusions rather than left in the results: the COUNT of marginal events is as expected, and no particular one can be called signal or noise— “The number of observed marginal events is consistent with our expectation given the chosen FAR threshold, but it is not possible to say whether or not a particular marginal trigger is a real GW signal.” | limitations[1] |
| limitation | where a candidate outranks the whole time-shifted background, the false-alarm rate is only a bound, and shortening the time-shift periods made that bound larger than the one previously published for the same events— “This restriction means, however, the minimum bound on the false-alarm rate of candidates that have a higher ranking statistic than any trigger in the background sample is larger than it would be if longer periods of data are used for the time-shift analysis.” | limitations[2] |
| limitation | the source properties rest on relativistic waveform models which the authors say do not necessarily incorporate all physical effects— “Such models, however, do not necessarily incorporate all physical effects.” | limitations[3] |
| limitation | the matched-filter searches assume quasicircular binaries with spins aligned or antialigned to the orbital angular momentum - a restriction on the template bank, though the authors note precessing systems are still often recovered— “The two matched-filter searches assume sources that can be modeled by general relativity and, in particular, quasicircular binaries whose spin angular momenta are either aligned or antialigned with their orbital angular momenta. They are still capable, however, of detecting many systems that exhibit precession [69].” | limitations[4] |
| limitation | individual black hole spins are only weakly constrained— “Similar to previous results, we find that the spins of the individual black holes are only weakly constrained” | limitations[5] |
finding · quantity · variable · definition · key-term — grounded in the full text| finding | 11 confident detections of gravitational waves from compact binary mergers are reported.— “In this catalog, we report 11 confident detections of GWs from compact binary mergers as well as a selection of less significant triggers from both observing runs.” | content_tags.findings[0] |
| finding | four binary black hole mergers announced here for the first time: GW170729, GW170809, GW170818, GW170823— “In this catalog, we announce four previously unpublished BBH mergers observed during O2: GW170729, GW170809, GW170818, and GW170823.” | content_tags.findings[1] |
| finding | No neutron star-black hole merger was detected.— “No neutron star–black hole mergers were detected.” | content_tags.findings[2] |
| finding | NULL RESULT: reanalysing O1 with the improved pipelines discovered no new events at all - but it did raise GW151012's significance enough to relabel it— “These improved FAR measurements for GW151012 are the most salient result of the reanalysis of O1 with the O2 pipelines; no new gravitational-wave events were discovered.” | content_tags.findings[3] |
| finding | NULL RESULT: no binary component has been observed in either putative mass gap - the one between neutron stars and black holes, or the pair-instability gap— “To date, no binary components have been observed in either of the two putative mass gaps [139,140]—one between NSs and BHs and the other one due to pair instability supernovae [136,219].” | content_tags.findings[4] |
| finding | 14 candidates with FAR under 1 per 30 days are listed whose astrophysical origin can be neither established nor excluded.— “In addition, we list 14 GW candidate events that have an estimated false-alarm rate (FAR) less than 1 per 30 days in either of the two matched-filter analyses but whose astrophysical origin cannot be established nor excluded unambiguously (Sec. VII).” | content_tags.findings[5] |
| finding | the two reconstruction methods, one using waveform models and one not, show no detectable discrepancies— “Both comparisons agree within expectations from analysis of simulations, and we conclude that there are no detectable discrepancies between the wavelet- and template-based reconstructions” | content_tags.findings[6] |
| finding | a published false-alarm bound got WORSE: PyCBC's bound for GW150914 and GW151226 is higher here than in the original papers, because shorter time-shift periods were used— “For GW150914 and GW151226, the bound that PyCBC places on the FAR in these updated results is in fact higher than that previously published [1,2,4], because, as noted in Sec. III A, this search elects to use shorter periods of time shifting to better capture the variation in the detectors’ sensitivities” | content_tags.findings[7] |
| quantity | the matched-filter searches analysed 0.46 years of coincident data, in which about six triggers were expected from noise alone at the chosen threshold— “The matched-filter pipelines analyze 0.46 y of coincident data, so, at a false-alarm threshold of once per 30 days, we would expect about six triggers purely from noise.” | content_tags.quantities[0] |
| quantity | PyCBC found three marginal triggers and GstLAL eleven, against about six expected— “Though the probability that 11 triggers could arise only from noise when six are expected is low, it is by itself not sufficiently low to confidently assert that some fraction of these triggers are astrophysical in origin.” | content_tags.quantities[1] |
| quantity | the false-alarm threshold for inclusion: 1 per 30 days, about 12.2 per year, in at least one matched-filter search— “To do this identification, we establish an initial threshold on estimated FAR of 1 per 30 days (about 12.2 per year), excluding any event that does not have a FAR less than this threshold in at least one of the two matched-filter analyses (see Sec. III).” | content_tags.quantities[2] |
| quantity | the detector network is sensitive from about 15 Hz to a few kilohertz; the unmodelled search covers up to 1 kHz and durations of a few seconds— “Designed to operate without a specific waveform model, cWB identifies coincident excess power in the multiresolution time-frequency representations of the detector strain data [85], for signal frequencies up to 1 kHz and durations up to a few seconds.” | content_tags.quantities[3] |
| value source note | quantity — THE DESCRIPTION DRAWS ON THE PAPER BEYOND THIS QUOTE: the 15 Hz and the few kilohertz are the detector network's range, stated in the introduction ('covering a frequency range from about 15 Hz…'). | content_tags.quantities[3] |
| definition | “GW” designation— “we assign the “GW” designation to any event for which the probability of astrophysical origin from either matched-filter search is greater than 50%” | content_tags.definitions[0] |
| definition | marginal events— “For the remaining events in the sample that pass the initial FAR threshold, neither matched-filter search finds a greater than 50% probability of astrophysical origin. These are considered marginal events and are listed in Table II.” | content_tags.definitions[1] |
| definition | background estimation— “For an estimation of its statistical significance, each candidate event is ranked against a sample of background triggers obtained by repeating the analysis on time-shifted data, similar to the background estimation in the PyCBC search.” | content_tags.definitions[3] |
| concept | PyCBC— “The events presented here are obtained from a total of three searches: two matched-filter searches, PyCBC [7,8] and GstLAL [9,10], using relativistic models of GWs from CBCs, as well as one unmodeled search for short-duration transient signals or bursts, coherent WaveBurst (cWB) [11].” | concepts[0] |
| concept | GstLAL— “The events presented here are obtained from a total of three searches: two matched-filter searches, PyCBC [7,8] and GstLAL [9,10], using relativistic models of GWs from CBCs, as well as one unmodeled search for short-duration transient signals or bursts, coherent WaveBurst (cWB) [11].” | concepts[1] |
| concept | cWB— “The events presented here are obtained from a total of three searches: two matched-filter searches, PyCBC [7,8] and GstLAL [9,10], using relativistic models of GWs from CBCs, as well as one unmodeled search for short-duration transient signals or bursts, coherent WaveBurst (cWB) [11].” | concepts[2] |
| concept | matched-filter searches— “The events presented here are obtained from a total of three searches: two matched-filter searches, PyCBC [7,8] and GstLAL [9,10], using relativistic models of GWs from CBCs, as well as one unmodeled search for short-duration transient signals or bursts, coherent WaveBurst (cWB) [11].” | concepts[3] |
| concept | unmodeled search | concepts[4] |
| concept | false-alarm rate | concepts[5] |
| concept | marginal events | concepts[6] |
| concept | background triggers | concepts[7] |
| concept | time-shifted data | concepts[8] |
| concept | glitches | concepts[9] |
| concept | scattered light | concepts[10] |
| concept | compact binary coalescences | concepts[11] |
| concept | GWs | concepts[12] |
| concept | BBH mergers | concepts[13] |
| concept | NSBH Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | concepts[14] |
| concept | sky localization Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | concepts[15] |
| concept | template Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | concepts[16] |
| concept | signal-based vetoes Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | concepts[17] |
| concept | triggers Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | concepts[18] |
| concept | software injections Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | concepts[19] |
| concept | waveform model Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | concepts[20] |
Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.statistics[0] | |
Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.statistics[1] | |
Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.statistics[2] | |
Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | content_tags.statistics[3] |
| claim type | existence — a second reading reaching the same value; recorded: existence Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | alternatives.claim_type |
| method | observational-survey — a second reading DIFFERING from the recorded value; recorded: observational-study Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | alternatives.method |
| phenomenon | gravitational waves from compact binary mergers (binary black hole and binary neutron star coalescence) observed by LIGO and Virgo — a second reading DIFFERING from the recorded value; recorded: gravitational waves from the inspiral, merger and ringdown of compact binary coalescences, detected by a network of grou Quotation withheld — this paper is not ours to reproduce, and the page has already quoted as much of it as the rights layer allows. The tag, its field and its confidence stand; the sentence is at the publisher. | alternatives.phenomenon |
When we have changed our mind. Some entries in the table begin with a word in capitals and the reason for it. EVIDENCE CORRECTED — the finding still stands, but we had quoted the wrong sentence from the paper, and the quotation has been replaced with the right one. RETRACTED — the entry itself was wrong; it stays on the page, marked, with the reason, rather than being deleted. WITHDRAWN AND REPLACED — the entry was wrong, and a corrected version of it appears in the entries below. Each mark carries its own reason, in brackets, because the reasons differ from one entry to the next. An entry we have WITHDRAWN is removed from this page and kept in the record, with its reason. A line reading Audit and a date is a later re-reading of the entry against its whole sentence: DOUBTFUL means it was kept, and the reason says what is loose about it. Quotation marks inside the tagger's sentence. Where a tag is the tagger's own sentence, a phrase in quotation marks inside it is borrowed from the paper — the tagger's wording around it is not. The paper's own sentence is the evidence quote for that row; on this page it is withheld with the article, and the article is at its publisher. Nothing inside quotation marks anywhere on this page is ours: if it is quoted, it is the paper's. Whose words a concept carries. A concept entry records a term the paper itself uses, so the term, the sense given for it, and its evidence are the paper's own words, quoted where the paper fixes them. This is the opposite of a sense entry in the tag table, which is the tagger's sentence about how the paper uses a term. Where a concept entry could not be grounded in the paper's words, the entry says so on its own row.
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