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Environmental seismic disturbances limit the sensitivity of LIGO gravitational wave detectors. Trains near the LIGO Livingston detector produce low frequency (0.5–$10\mathrm{H}\mathrm{z}$) ground noise that couples into the gravitational wave sensitive frequency band (10–$100\mathrm{H}\mathrm{z}$) through light reflected in mirrors and other surfaces. We investigate the effect of trains during the Advanced LIGO third observing run, and propose a method to search for narrow band seismic frequencies responsible for contributing to increases in scattered light. Through the use of the linear regression tool Lasso (least absolute shrinkage and selection operator) and glitch correlations, we identify the most common seismic frequencies that correlate with increases in detector noise as 0.6–$0.8\mathrm{H}\mathrm{z}$, 1.7–$1.9\mathrm{H}\mathrm{z}$, 1.8–$2.0\mathrm{H}\mathrm{z}$, and 2.3–$2.5\mathrm{H}\mathrm{z}$in the LIGO Livingston corner station.

 

Understanding the noise in gravitational-wave detectors is central to detecting and interpreting gravitational-wave signals. Glitches are transient, non-Gaussian noise features that can have a range of environmental and instrumental origins. The Gravity Spy project uses a machine-learning algorithm to classify glitches based upon their time–frequency morphology. The resulting set of classified glitches can be used as input to detector-characterisation investigations of how to mitigate glitches, or data-analysis studies of how to ameliorate the impact of glitches. Here we present the results of the Gravity Spy analysis of data up to the end of the third observing run of advanced laser interferometric gravitational-wave observatory (LIGO). We classify 233981 glitches from LIGO Hanford and 379805 glitches from LIGO Livingston into morphological classes. We find that the distribution of glitches differs between the two LIGO sites. This highlights the potential need for studies of data quality to be individually tailored to each gravitational-wave observatory.

 

Previous work demonstrated an accelerated in vitro and in vivo wound healing response when insulinoma cells were used to deliver insulin to scratches in keratinocyte mono- layers and chronic diabetic excise wounds in mice, respectively. When combined with mesenchymal stem cells (MSCs), the response was amplified (healing in 14 vs. 35+ days). To isolate the role of insulin in the response and exclude any potential contribution of an unknown cancer moiety released by the insulinoma cells, the effect on wound healing of multiple lines derived from the same insulinoma was examined. 

Previous work demonstrated an accelerated in vitro and in vivo wound healing response when insulinoma cells were used to deliver insulin to scratches in keratinocyte mono- layers and chronic diabetic excise wounds in mice, respectively. When combined with mesenchymal stem cells (MSCs), the response was amplified (healing in 14 vs. 35+ days). To isolate the role of insulin in the response and exclude any potential contribution of an un known cancer moiety released by the insulinoma cells, the effect on wound healing of multiple lines derived from the same insulinoma was examined. 

Gravitational lensing by massive objects along the line of sight to the source causes distortions to gravitational wave (GW) signals; such distortions may reveal information about fundamental physics, cosmology, and astrophysics. In this work, we have extended the search for lensing signatures to all binary black hole events from the third observing run of the LIGO-Virgo network. We search for repeated signals from strong lensing by (1) performing targeted searches for subthreshold signals, (2) calculating the degree of overlap among the intrinsic parameters and sky location of pairs of signals, (3) comparing the similarities of the spectrograms among pairs of signals, and (4) performing dual-signal Bayesian analysis that takes into account selection effects and astrophysical knowledge. We also search for distortions to the gravitational waveform caused by (1) frequency-independent phase shifts in strongly lensed images, and (2) frequency-dependent modulation of the amplitude and phase due to point masses. None of these searches yields significant evidence for lensing. Finally, we use the nondetection of GW lensing to constrain the lensing rate based on the latest merger-rate estimates and the fraction of dark matter composed of compact objects.