Performance of the KAGRA detector during the first joint observation with GEO 600 (O3GK)

KAGRA, the kilometer-scale underground gravitational-wave detector, is located at Kamioka. Japan. In April 2020, an astrophysics observation was performed at the KAGRA detector in combination with the GEO 600 detector; this observation operation is called O3GK. The optical configuration in O3GK is based on a power-recycled Fabry Perot-Michelson interferometer; all the mirrors were set at room temperature. The duty factor of the operation was approximately 53%, and the displacement sensitivity was approximately 1 x 10(-18) m/root Hz at 250 Hz. The binary-neutron-star (BNS) inspiral range was about 0.6 Mpc. The contributions of various noise sources to the sensitivity of O3GK were investigated to understand how the observation range could be improved; this study is called a "noise budget". According to our noise budget, the measured sensitivity could be approximated by adding up the effect of each noise. The sensitivity was dominated by noise from the sensors used for local controls of the vibration isolation systems, acoustic noise, shot noise, and laser frequency noise. Further, other noise sources that did not limit the sensitivity were investigated. This paper provides a detailed account of the KAGRA detector in O3GK, including interferometer configuration, status, and noise budget. In addition, strategies for future sensitivity improvements, such as hardware upgrades, are discussed

Search for continuous gravitational wave emission from the Milky Way center in O3 LIGO-Virgo data

We present a directed search for continuous gravitational wave (CW) signals emitted by spinning neutron stars located in the inner parsecs of the Galactic Center (GC). Compelling evidence for the presence of a numerous population of neutron stars has been reported in the literature, turning this region into a very interesting place to look for CWs. In this search, data from the full O3 LIGO-Virgo run in the detector frequency band [10, 2000] Hz have been used. No significant detection was found and 95% confidence level upper limits on the signal strain amplitude were computed, over the full search band, with the deepest limit of about 7.6 x 10(-26) at similar or equal to 142 Hz. These results are significantly more constraining than those reported in previous searches. We use these limits to put constraints on the fiducial neutron star ellipticity and r-mode amplitude. These limits can be also translated into constraints in the black hole mass-boson mass plane for a hypothetical population of boson clouds around spinning black holes located in the GC

Searches for Gravitational Waves from Known Pulsars at Two Harmonics in the Second and Third LIGO-Virgo Observing Runs

We present a targeted search for continuous gravitational waves (GWs) from 236 pulsars using data from the third observing run of LIGO and Virgo (O3) combined with data from the second observing run (O2). Searches were for emission from the l = m = 2 mass quadrupole mode with a frequency at only twice the pulsar rotation frequency (single harmonic) and the l = 2, m = 1, 2 modes with a frequency of both once and twice the rotation frequency (dual harmonic). No evidence of GWs was found, so we present 95% credible upper limits on the strain amplitudes h (0) for the single-harmonic search along with limits on the pulsars' mass quadrupole moments Q (22) and ellipticities epsilon. Of the pulsars studied, 23 have strain amplitudes that are lower than the limits calculated from their electromagnetically measured spin-down rates. These pulsars include the millisecond pulsars J0437-4715 and J0711-6830, which have spin-down ratios of 0.87 and 0.57, respectively. For nine pulsars, their spin-down limits have been surpassed for the first time. For the Crab and Vela pulsars, our limits are factors of similar to 100 and similar to 20 more constraining than their spin-down limits, respectively. For the dual-harmonic searches, new limits are placed on the strain amplitudes C (21) and C (22). For 23 pulsars, we also present limits on the emission amplitude assuming dipole radiation as predicted by Brans-Dicke theory

First joint observation by the underground gravitational-wave detector KAGRA with GEO 600

We report the results of the first joint observation of the KAGRA detector with GEO600. KAGRA is a cryogenic and underground gravitational-wave detector consisting of a laser interferometer with 3km arms, located in Kamioka, Gifu, Japan. GEO600 is a British-German laser interferometer with 600m arms, located near Hannover, Germany. GEO600 and KAGRA performed a joint observing run from April 7 to 20, 2020. We present the results of the joint analysis of the GEO-KAGRA data for transient gravitational-wave signals, including the coalescence of neutron-star binaries and generic unmodeled transients. We also perform dedicated searches for binary coalescence signals and generic transients associated with gamma-ray burst events observed during the joint run. No gravitational-wave events were identified. We evaluate the minimum detectable amplitude for various types of transient signals and the spacetime volume for which the network is sensitive to binary neutron-star coalescences. We also place lower limits on the distances to the gamma-ray bursts analyzed based on the non-detection of an associated gravitational-wave signal for several signal models, including binary coalescences. These analyses demonstrate the feasibility and utility of KAGRA as a member of the global gravitational-wave detector network

Search for gravitational waves from Scorpius X-1 with a hidden Markov model in O3 LIGO data

Results are presented for a semicoherent search for continuous gravitational waves from the low-mass x-ray binary Scorpius X-1, using a hidden Markov model (HMM) to allow for spin wandering. This search improves on previous HMM-based searches of Laser Interferometer Gravitational-Wave Observatory data by including the orbital period in the search template grid, and by analyzing data from the latest (third) observing run. In the frequency range searched, from 60 to 500 Hz, we find no evidence of gravitational radiation. This is the most sensitive search for Scorpius X-1 using a HMM to date. For the most sensitive subband, starting at 256.06 Hz, we report an upper limit on gravitational wave strain (at 95% confidence) of h(0)(95%) = 6.16 x 10(-26), assuming the orbital inclination angle takes its electromagnetically restricted value. iota = 44 degrees. The upper limits on gravitational wave strain reported here are on average a factor of similar to 3 lower than in the second observing run HMM search. This is the first Scorpius X-1 HMM search with upper limits that reach below the indirect torque-balance limit for certain subbands, assuming iota = 44 degrees

Sources of organizational resilience during the 2012 Korean typhoons: An institutional collective action framework

The objective of this proposed research is to test whether interorganizational collaboration contributes to the ability of an organization to bounce back swiftly from disasters. The research questions are examined from the Institutional Collective Action (ICA) perspective. The general argument of this dissertation is that organizational resilience can be explained by interorganizational collaboration. The ICA framework, specifically, identifies two general network structures to explain strategies that can be adopted to minimize collaboration risks: bonding and bridging structures. This dissertation focuses on how governmental and nongovernmental organizations in South Korea collaborated. The data was collected from the southeastern tip of the Korean Peninsula in August of 2012, and January of 2013. The 2012 Typhoons devastated the area after the first data set was collected in August 2012, causing the loss of estimated US$ 730 million and 29 fatalities. Afterward, the second survey was administrated in January of 2013 to gauge respondents’ views on how organizations responded to the disasters. (Abstract shortened by ProQuest.

Sources of Organizational Resilience for Sustainable Communities: An Institutional Collective Action Perspective

Scholars in the field of sustainability have often argued that the purpose of establishing and maintaining interorganizational collaboration is to overcome internal limitations of organizations and to strengthen organizational capacity. To examine structural effects of inter-organizational collaboration regarding the ability of networked organizations to effectively manage disasters, this study uses an institutional collective action framework to design a critical lens to objectively analyze collective action issues in inter-organizational collaboration networks. Results, based on the Heckman selection model with two stages, provide evidence that networked organizations holding a central position between two other actors perceive a higher level of disaster resilience. The finding implies that local organizations with a bridging strategy can enhance their capacity to recover from a catastrophic event by securing access to critical resources and information through comprehensive emergency preparedness such as joint response and recovery planning

Sources of Organizational Resilience During the 2012 Korean Typhoons: an Institutional Collective Action Framework

The objective of this proposed research is to test whether interorganizational collaboration contributes to the ability of an organization to bounce back swiftly from disasters. The research questions are examined from the Institutional Collective Action (ICA) perspective. The general argument of this dissertation is that organizational resilience can be explained by interorganizational collaboration. The ICA framework, specifically, identifies two general network structures to explain strategies that can be adopted to minimize collaboration risks: bonding and bridging structures. This dissertation focuses on how governmental and nongovernmental organizations in South Korea collaborated. The data was collected from the southeastern tip of the Korean Peninsula in August of 2012, and January of 2013. The 2012 Typhoons devastated the area after the first data set was collected in August 2012, causing the loss of estimated US$ 730 million and 29 fatalities. Afterward, the second survey was administrated in January of 2013 to gauge respondents’ views on how organizations responded to the disasters. This dissertation consists of three essays. The first essay presents a brief overview and assessment of the current research on resilience. The second essay empirically tests the sources of organization resilience. The third essay examines the dynamic nature of interorganizational ties by employing stochastic actor-based models. The findings show how organizations prefer to not coordinate with other organizations even though this could reduce their strains during a disaster. The findings also suggest that organizations that operate in higher risk areas or participate in joint full-scale exercises before a disaster form interorganizational ties afterward

Measuring Efficiency and Effectiveness of Highway Management in Sustainability

This study analyses efficiency and effectiveness of highway management at the state level in the United States. While the current literature on highway management has contributed to understanding infrastructure budget and finance, the relationship between efficiency and effectiveness measurements has not been sufficiently discussed in the context of sustainability. To fill this gap, this study was systemically designed to test the relationship by controlling the states’ political factors, fiscal capacity, median voter, and economic conditions. Data envelopment and principal component analysis with panel data covering 11-year time waves were used to measure both efficiency and effectiveness. The results of the fixed effects model and the spatial autoregressive panel model show a statistically strong relationship between efficiency and effectiveness which are respectively measured by two analysis approaches