Showing papers by "N. Kijbunchoo published in 2019"
TL;DR: In this paper, auxiliary sensors are used to witness these correlated noise sources, and use them for noise subtraction in the time domain data, which is particularly significant for the LIGO Hanford Observatory.
Abstract: The Advanced LIGO detectors have recently completed their second observation run successfully. The run lasted for approximately 10 months and led to multiple new discoveries. The sensitivity to gravitational waves was partially limited by laser noise. Here, we utilize auxiliary sensors that witness these correlated noise sources, and use them for noise subtraction in the time domain data. This noise and line removal is particularly significant for the LIGO Hanford Observatory, where the improvement in sensitivity is greater than 20%. Consequently, we were also able to improve the astrophysical estimation for the location, masses, spins, and orbital parameters of the gravitational wave progenitors.
89 citations
TL;DR: In this paper, the first and second observing runs of the Advanced LIGO and Virgo detector network were used to obtain the first standard-siren measurement of the Hubble constant.
Abstract: This paper presents the gravitational-wave measurement of the Hubble constant ($H_0$) using the detections from the first and second observing runs of the Advanced LIGO and Virgo detector network. The presence of the transient electromagnetic counterpart of the binary neutron star GW170817 led to the first standard-siren measurement of $H_0$. Here we additionally use binary black hole detections in conjunction with galaxy catalogs and report a joint measurement. Our updated measurement is $H_0 = 69^{+16}_{-8}$ km/s/Mpc (68.3\% of the highest density posterior interval with a flat-in-log prior) which is an improvement by a factor of 1.04 (about 4\%) over the GW170817-only value of $69^{+17}_{-8}$ km/s/Mpc. A significant additional contribution currently comes from GW170814, a loud and well-localized detection from a part of the sky thoroughly covered by the Dark Energy Survey. With numerous detections anticipated over the upcoming years, an exhaustive understanding of other systematic effects are also going to become increasingly important. These results establish the path to cosmology using gravitational-wave observations with and without transient electromagnetic counterparts.
74 citations
TL;DR: In this paper, the authors describe the online identification of gravitational-wave transients and the distribution of gravitationalwave alerts by the LIGO and Virgo collaborations during O2, and also describe the gravitationalwave observables which were sent in the alerts to enable searches for their counterparts.
Abstract: Advanced LIGO's second observing run (O2), conducted from November 30, 2016 to August 25, 2017, combined with Advanced Virgo's first observations in August 2017 witnessed the birth of gravitational-wave multi-messenger astronomy. The first ever gravitational-wave detection from the coalescence of two neutron stars, GW170817, and its gamma-ray counterpart, GRB 170817A, led to an electromagnetic follow-up of the event at an unprecedented scale. Several teams from across the world searched for EM/neutrino counterparts to GW170817, paving the way for the discovery of optical, X-ray, and radio counterparts. In this article, we describe the online identification of gravitational-wave transients and the distribution of gravitational-wave alerts by the LIGO and Virgo collaborations during O2. We also describe the gravitational-wave observables which were sent in the alerts to enable searches for their counterparts. Finally, we give an overview of the online candidate alerts shared with observing partners during O2. Alerts were issued for 14 candidates, six of which have been confirmed as gravitational-wave events associated with the merger of black holes or neutron stars. Eight of the 14 alerts were issued less than an hour after data acquisition.
63 citations
TL;DR: In this paper, phase control for vacuum-squeezed light at a 2-μm wavelength was demonstrated, which is a necessary technology for proposed future gravitational wave observatories.
Abstract: We demonstrate phase control for vacuum-squeezed light at a 2 μm wavelength, which is a necessary technology for proposed future gravitational wave observatories. The control scheme allowed examination of noise behavior at frequencies below 1 kHz and indicated that squeezing below this frequency was limited by dark noise and scattered light. We directly measure 3.9±0.2 dB of squeezing from 2 kHz to 80 kHz and 14.2±0.3 dB of antisqueezing relative to the shot noise level. The observed maximum level of squeezing is currently limited by photodetector quantum efficiency and laser instabilities at this new wavelength for squeezed light. Accounting for all losses, we conclude the generation of 11.3 dB of squeezing at the optical parametric oscillator.
8 citations
TL;DR: In this article, two analysis errors have been identified that affect the results for a handful of the high-value pulsars given in Table 1 of Abbott et al. (2019).
Abstract: Two analysis errors have been identified that affect the results for a handful of the high-value pulsars given in Table 1 of Abbott et al. (2019). One affects the Bayesian analysis for the five pulsars that glitched during the analysis period, and the other affects the 5n-vector analysis for J0711-6830. Updated results after correcting the errors are shown in Table 1, which now supersedes the results given for those pulsars in Table 1 of Abbott et al. (2019). Updated versions of figures can be seen in Figures 1-4. Bayesian analysis.-For the glitching pulsars, the signal phase evolution caused by the glitch was wrongly applied twice and was therefore not consistent with our expected model of the pulsar phase. This error did not affect the F/G-statistic or 5n-vector analysis. Analyses of the five pulsars PSR J0205+6449, PSR J0534+2200, PSR J0835-4510, PSR J1028-5819, and PSR J1718-3825 have been repeated after correcting for the error. There are small quantitative differences in the results, but the changes do not affect the main conclusions of the paper. The largest differences are for PSR J0835-4510 (the Vela pulsar), for which the updated upper limits from the Bayesian method are found to be between 1.1 and 2 times larger than those obtained when the error was present. This appears primarily to be due to the error leading to the decohering of a strong spectral line in the LIGO Livingston detector and thus lowering the amplitude limit. 5n-vector analysis.-An error was also identified in the settings of the 5n-vector analysis, which affected the upper limit computation at the rotation frequency for C21 95% of J0711-6830. Specifically, we found an incorrect choice for the range of amplitudes used to inject simulated signals in the O2 data. The updated upper limit is about 2.5 times worse than that obtained when the error was present. This error did not affect the Bayesian or F/G-statistic results. (Table Presented) (Figure Presented).
6 citations