More Like this

1. Seismic Cloaking for LIGO

   Nathaniel, Kaila; Kamai, Brittany; Adhikari, Rana (July 2018, LIGO Laboratory Summer 2018 Undergraduate Research)

   We investigate the feasibility of using trees as a seismic meta-material that could shield the LIGO detectors from seismic activity. This seismic cloak would reflect low frequency surface waves away from the detector, thereby increasing the sensitivity of the detectors. This study models the energy transfer from surface waves as they pass through the bandgap filters designed from trees in different arrangements. The attenuation and rejection will hopefully serve to cloak the LIGO detectors from seismic activity. This work could have future impact on high sensitivity detectors, leading to more detections of merger events. 

   more » « less
2. Outlook for detecting the gravitational-wave displacement and spin memory effects with current and future gravitational-wave detectors

   https://doi.org/10.1103/PhysRevD.107.064056  

   Grant, Alexander M.; Nichols, David A. (March 2023, Physical Review D)

   Gravitational-wave memory effects arise from nonoscillatory components of gravitational-wave signals, and they are predictions of general relativity in the nonlinear regime that have close connections to the asymptotic properties of isolated gravitating systems. There are many types of memory effects that have been studied in the literature. In this paper we focus on the “displacement” and “spin” memories, which are expected to be the largest of these effects from sources such as the binary black hole mergers which have already been detected by LIGO and Virgo. The displacement memory is a change in the relative separation of two initially comoving observers due to a burst of gravitational waves, whereas the spin memory is a portion of the change in relative separation of observers with initial relative velocity. As both of these effects are small, LIGO, Virgo, and KAGRA can only detect memory effects from individual events that are much louder (and thus rarer) than those that have been detected so far. By combining data from multiple events, however, these effects could be detected in a population of binary mergers. In this paper, we present new forecasts for how long current and future detectors will need to operate in order to measure these effects from populations of binary black hole systems that are consistent with the populations inferred from the detections from LIGO and Virgo’s first three observing runs. We find that a second-generation detector network of LIGO, Virgo, and KAGRA operating at the O4 (“design”) sensitivity for 1.5 years and then operating at the O5 (“plus”) sensitivity for an additional 1.5 years can detect the displacement memory. For Cosmic Explorer, we find that displacement memory could be detected for individual loud events, and that the spin memory could be detected in a population after 5 years of observation time. 

   more » « less
3. Open Data from the Third Observing Run of LIGO, Virgo, KAGRA, and GEO

   https://doi.org/10.3847/1538-4365/acdc9f  

   Abbott, R.; Abe, H.; Acernese, F.; Ackley, K.; Adhicary, S.; Adhikari, N.; Adhikari, R. X.; Adkins, V. K.; Adya, V. B.; Affeldt, C.; et al (July 2023, The Astrophysical Journal Supplement Series)

   Abstract The global network of gravitational-wave observatories now includes five detectors, namely LIGO Hanford, LIGO Livingston, Virgo, KAGRA, and GEO 600. These detectors collected data during their third observing run, O3, composed of three phases: O3a starting in 2019 April and lasting six months, O3b starting in 2019 November and lasting five months, and O3GK starting in 2020 April and lasting two weeks. In this paper we describe these data and various other science products that can be freely accessed through the Gravitational Wave Open Science Center at https://gwosc.org . The main data set, consisting of the gravitational-wave strain time series that contains the astrophysical signals, is released together with supporting data useful for their analysis and documentation, tutorials, as well as analysis software packages. 

   more » « less
4. Measuring neutron star radius with second and third generation gravitational wave detector networks

   https://doi.org/10.1088/1361-6382/ad828a  

   Bandopadhyay, Ananya; Kacanja, Keisi; Somasundaram, Rahul; Nitz, Alexander H; Brown, Duncan A (October 2024, Classical and Quantum Gravity)

   Abstract The next generation of ground-based interferometric gravitational wave detectors will observe mergers of black holes and neutron stars throughout cosmic time. A large number of the binary neutron star merger events will be observed with extreme high fidelity, and will provide stringent constraints on the equation of state of nuclear matter. In this paper, we investigate the systematic improvement in the measurability of the equation of state with increase in detector sensitivity by combining constraints obtained on the radius of a $1.4{\mathrm{M}}_{\odot }$neutron star from a simulated source population. Since the measurability of the equation of state depends on its stiffness, we consider a range of realistic equations of state that span the current observational constraints. We show that a single 40 km Cosmic Explorer detector can pin down the neutron star radius for a soft, medium and stiff equation of state with a precision of 10 m within a decade, whereas the current generation of ground-based detectors like the Advanced LIGO-Virgo network would take $O\left({10}^5\right)$years to do so for a soft equation of state. 

   more » « less
5. Too small to fail: characterizing sub-solar mass black hole mergers with gravitational waves

   https://doi.org/10.1088/1475-7516/2023/11/039  

   Wolfe, Noah E; Vitale, Salvatore; Talbot, Colm (November 2023, Journal of Cosmology and Astroparticle Physics)

   Abstract The detection of a sub-solar mass black hole could yield dramatic new insights into the nature of dark matter and early-Universe physics, as such objects lack a traditional astrophysical formation mechanism. Gravitational waves allow for the direct measurement of compact object masses during binary mergers, and we expect the gravitational-wave signal from a low-mass coalescence to remain within the LIGO frequency band for thousands of seconds. However, it is unclear whether one can confidently measure the properties of a sub-solar mass compact object and distinguish between a sub-solar mass black hole or other exotic objects. To this end, we perform Bayesian parameter estimation on simulated gravitational-wave signals from sub-solar mass black hole mergers to explore the measurability of their source properties. We find that the LIGO/Virgo detectors during the O4 observing run would be able to confidently identify sub-solar component masses at the threshold of detectability; these events would also be well-localized on the sky and may reveal some information on their binary spin geometry. Further, next-generation detectors such as Cosmic Explorer and the Einstein Telescope will allow for precision measurement of the properties of sub-solar mass mergers and tighter constraints on their compact-object nature. 

   more » « less