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Gabriela González

Publications and source records attributed to Gabriela González.

13 recordsLinked to original sources
arXiv2026

SGNAX: a unified matched-filter and excess-power pipeline for gravitational-wave detector characterization

We present SGNAX, an open-source pipeline for gravitational-wave detector characterization that delivers matched-filter and excess-power transient triggers from a single streaming dataflow graph. Built on the Stream Graph Navigator (sgn) framework, SGNAX unifies the multi-rate sine-Gaussian matched-filter search of snax and the multi-resolution Q-transform search of omicron in one Python-native package. Auxiliary channels from an interferometer are analyzed as parallel branches sharing data-read and whitening stages, reducing per-channel processing cost as channels are added. A full day of 16 kHz strain is analyzed in 14 minutes, and Q-transform processing is 2.8 times more efficient per channel at 32 channels than at one. Matched-filter correlations use PyTorch and run on CPU or GPU. Data sources include offline frame caches, shared-memory buffers, and the arrakis distribution service, with the same configuration supporting offline and online operation. The matched filter delivers triggers at about five seconds end-to-end latency, while the Q-transform operates at latencies of tens of seconds. Injection campaigns recover 99.4% of recoverable sine-Gaussian injections with parameters within the expected template mismatch and show broadband white-noise-burst recovery consistent with established event-trigger generators. On 24 hours of archival LIGO strain, SGNAX reproduces the omicron trigger population at 10--100 Hz, with trigger rates and SNRs agreeing to a few percent. On production auxiliary channels, it recovers the snax loud-feature population with 80% per-bin coincidence. The injection-calibrated reimplementation also reveals a multiband amplitude error in production snax that inflates reported SNRs below 25.6 Hz by factors of $\sqrt{2}$--2, for which we identify the mechanism and correction.

astro-ph.IM↗
arXiv2026

Scattered light noise at LIGO Livingston Observatory during O4

Scattered light is one of the most common sources of noise in the LIGO gravitational wave detectors. Light scattering is a highly non-linear process through which motion at low frequencies gets up-converted and creates noise in a higher frequency band in the detector data. From the beginning of the fourth observation run, many glitches appeared in the data of LIGO Livingston detector in the frequency range 10-40 Hz, and the morphology of these glitches suggested that they were produced by scattered light. From our analysis, we identified two different populations of scattered light glitches, one group having higher SNR than the other. The glitches of the high- SNR group were solely modulated by microseismic ground motion (ground motion in 0.1-1.0 Hz) and in this paper, we present models of possible coupling mechanisms for these glitches. We also present results of a statistical correlation analysis based on our models, which indicates that the microseismic ground motion at the corner station along the X direction is the one most correlated with the noise which create these high SNR glitches. After installing baffles very close to the test mass mirrors, we have noticed a significant reduction in the rate and SNR of these glitches. The low-SNR glitches were primarily modulated by high frequency (10-30 Hz) vertical ground motion at the corner station, and this motion was coupling through a specific vacuum chamber at the corner station. After installing an additional seismic isolation platform in that vacuum chamber, these glitches have disappeared.

astro-ph.IM↗
arXiv2025

An Analysis of LIGO Glitches Using t-SNE During the First Part of the Fourth LIGO-Virgo-KAGRA Observing Run

This paper presents an analysis of noise transients observed in LIGO data during the first part of the fourth observing run, using the unsupervised machine learning technique t-distributed Stochastic Neighbor Embedding (t-SNE) to examine the behavior of glitch groups. Based on the t-SNE output, we apply Agglomerative Clustering in combination with the Silhouette Score to determine the optimal number of groups. We then track these groups over time and investigate correlations between their occurrence and environmental or instrumental conditions. At the Livingston observatory, the most common glitches during O4a were seasonal and associated with ground motion, whereas at Hanford, the most prevalent glitches were related to instrumental conditions.

astro-ph.IM↗
arXiv2025

PINCH: Pipeline-Informed Noise Characterization in LIGO's Third Observing Run

We present a method to identify and categorize gravitational wave candidate triggers identified by matched filtering gravitational wave searches (pipelines) caused by transient noise (glitches) in gravitational wave detectors using Support Vector Machine (SVM) classifiers. Our approach involves training SVM models on pipeline triggers which occur outside periods of excess noise to distinguish between triggers caused by random noise and those induced by glitches. This method is applied independently to the triggers produced by the GstLAL search pipeline on data from the LIGO Hanford and Livingston observatories during the second half of the O3 observing run. The trained SVM models assign scores to ambiguous triggers, quantifying their similarity to triggers caused by random fluctuations, with triggers with scores above a defined threshold being classified as glitch-induced. Analysis of these triggers reveals the distinct impact of different glitch classes on the search pipeline, including their distribution in relevant parameter spaces. We use metrics such as the Bhattacharyya coefficient and an over-representation ratio to quantify the consistency and prevalence of glitch impacts over time and across parameter spaces. Our findings indicate that some glitch types consistently produce triggers in specific regions of the parameter space, while others generate triggers that are more widely distributed. We observe that Scattered Light glitches appear differently in the search pipeline before and after a commissioning change, demonstrating how such detector changes appear in the pipeline's response to certain glitch classes. This method provides a framework for understanding and mitigating the influence of non-Gaussian transients on gravitational wave search pipelines, with implications for improving detection sensitivity and better understanding noise populations.

gr-qc↗
arXiv2025

Using t-SNE for characterizing glitches in LIGO detectors

Glitches are non-Gaussian noise transients originating from environmental and instrumental sources that contaminate data from gravitational wave detectors. Some glitches can even mimic gravitational wave signals from compact object mergers, which are the primary targets of terrestrial observatories. In this study, we present a method to analyze noise transients from the LIGO observatories using Q-transform information combined with t-Distributed Stochastic Neighbor Embedding (t-SNE). We implement classification techniques, examine the influence of parameters on glitch classification, and conduct a week-long daily analysis to track outlier transients over time.

astro-ph.IM↗
arXiv2023

Modeling and Reduction of High Frequency Scatter Noise at LIGO Livingston

The sensitivity of aLIGO detectors is adversely affected by the presence of noise caused by light scattering. Low frequency seismic disturbances can create higher frequency scattering noise adversely impacting the frequency band in which we detect gravitational waves. In this paper, we analyze instances of a type of scattered light noise we call "Fast Scatter" that is produced by motion at frequencies greater than 1 Hz, to locate surfaces in the detector that may be responsible for the noise. We model the phase noise to better understand the relationship between increases in seismic noise near the site and the resulting Fast Scatter observed. We find that mechanical damping of the Arm Cavity Baffles (ACBs) led to a significant reduction of this noise in recent data. For a similar degree of seismic motion in the 1-3 Hz range, the rate of noise transients is reduced by a factor of ~ 50.

astro-ph.IM↗
arXiv2023

Noise in the LIGO Livingston Gravitational Wave Observatory due to Trains

Environmental seismic disturbances limit the sensitivity of LIGO gravitational wave detectors. Trains near the LIGO Livingston detector produce low frequency (0.5-10 Hz) ground noise that couples into the gravitational wave sensitive frequency band (10-100 Hz) 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 Hz, 1.7-1.9 Hz, 1.8-2.0 Hz, and 2.3-2.5 Hz in the LIGO Livingston corner station.

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arXiv2021

An Exploration of Possible Governance Models for the Future Global Gravitational-Wave Observatory Network

The construction of a global network of detectors is the cornerstone to scientific success for 3rd generation gravitational wave astronomy. If carried out with a vision to the future, the third generation implementation, in its infrastructure, technology base and governance can provide the point of departure for subsequent developments beyond the third generation, a path to the long and revolutionary future of gravitational wave astrophysics. The goal of this document is to lay out considerations that influence the optimal choice of governance and to lay out a possible path that can lead the community to an optimal governance model. This report is the six in a six part series of reports by the GWIC 3G Subcommittee: i) Expanding the Reach of Gravitational Wave Observatories to the Edge of the Universe, ii) The Next Generation Global Gravitational Wave Observatory: The Science Book, iii) 3G R&D: R&D for the Next Generation of Ground-based Gravitational Wave Detectors, iv) Gravitational Wave Data Analysis: Computing Challenges in the 3G Era, v) Future Ground-based Gravitational-wave Observatories: Synergies with Other Scientific Communities, and vi) An Exploration of Possible Governance Models for the Future Global Gravitational-Wave Observatory Network (this report).

gr-qc↗
arXiv2021

3G R&D: R&D for the Next Generation of Ground-based Gravitational-wave Detectors

To deliver on the promise of next generation gravitational-wave observatories, a sustained and coordinated detector research and development program is required. This report examines in detail the wide range of nearer- and longer-term detector R&D programs needed for next generation GW detectors commensurate with the key science targets presented in "The Next Generation Global Gravitational Wave Observatory: The Science Book", including considerations of site selection and large-scale vacuum infrastructure. The report makes a series of detailed recommendations on the needed advances in detector technology and the timescales needed to achieve those advances. It also identifies areas where larger-scale globally coordinated R&D efforts will be critical to ensuring success while minimizing costs. This report is the third in a six part series of reports by the GWIC 3G Subcommittee: i) Expanding the Reach of Gravitational Wave Observatories to the Edge of the Universe, ii) The Next Generation Global Gravitational Wave Observatory: The Science Book, iii) 3G R&D: R&D for the Next Generation of Ground-based Gravitational Wave Detectors (this report), iv) Gravitational Wave Data Analysis: Computing Challenges in the 3G Era, v) Future Ground-based Gravitational-wave Observatories: Synergies with Other Scientific Communities, and vi) An Exploration of Possible Governance Models for the Future Global Gravitational-Wave Observatory Network.

gr-qc↗
arXiv2021

Gwadaptive_scattering: an automated pipeline for scattered light noise characterization

Scattered light noise affects the sensitivity of gravitational waves detectors. The characterization of such noise is needed to mitigate it. The time-varying filter empirical mode decomposition algorithm is suitable for identifying signals with time-dependent frequency such as scattered light noise (or scattering). We present a fully automated pipeline based on the pytvfemd library, a python implementation of the tvf-EMD algorithm, to identify objects inducing scattering in the gravitational-wave channel with their motion. The pipeline application to LIGO Livingston O3 data shows that most scattering noise is due to the penultimate mass at the end of the X-arm of the detector (EXPUM) and with a motion in the micro-seismic frequency range.

astro-ph.IM↗
arXiv2004

Vetoes for Inspiral Triggers in LIGO Data

Presented is a summary of studies by the LIGO Scientific Collaboration's Inspiral Analysis Group on the development of possible vetoes to be used in evaluation of data from the first two LIGO science data runs. Numerous environmental monitor signals and interferometer control channels have been analyzed in order to characterize the interferometers' performance. The results of studies on selected data segments are provided in this paper. The vetoes used in the compact binary inspiral analyses of LIGO's S1 and S2 science data runs are presented and discussed.

gr-qc↗
arXiv2000

Suspensions Thermal Noise in the LIGO Gravitational Wave Detector

We present a calculation of the maximum sensitivity achievable by the LIGO Gravitational wave detector in construction, due to limiting thermal noise of its suspensions. We present a method to calculate thermal noise that allows the prediction of the suspension thermal noise in all its 6 degrees of freedom, from the energy dissipation due to the elasticity of the suspension wires. We show how this approach encompasses and explains previous ways to approximate the thermal noise limit in gravitational waver detectors. We show how this approach can be extended to more complicated suspensions to be used in future LIGO detectors.

gr-qc↗