J. G. Baier
A5027705538- Pulsars and Gravitational Waves Research
- Cosmology and Gravitation Theories
- Gamma-ray bursts and supernovae
- Geophysics and Gravity Measurements
- Astrophysical Phenomena and Observations
- Radio Astronomy Observations and Technology
- High-pressure geophysics and materials
- Seismology and Earthquake Studies
- Dark Matter and Cosmic Phenomena
- Magnetic confinement fusion research
- earthquake and tectonic studies
- Mechanical and Optical Resonators
- Seismic Waves and Analysis
- Superconducting Materials and Applications
- Agriculture and Farm Safety
- Black Holes and Theoretical Physics
- Astronomy and Astrophysical Research
- Digital Image Processing Techniques
- Forest Biomass Utilization and Management
- Astrophysics and Cosmic Phenomena
- CCD and CMOS Imaging Sensors
- Image Processing Techniques and Applications
Kenyon College
2022-2024
Oregon State University
2024
The global network of gravitational-wave observatories now includes five detectors, namely LIGO Hanford, Livingston, Virgo, KAGRA, and GEO 600. These detectors collected data during their third observing run, O3, composed three phases: O3a starting in April 2019 lasting six months, O3b November O3GK 2020 2 weeks. In this paper we describe these various other science products that can be freely accessed through the Gravitational Wave Open Science Center at https://gwosc.org. main dataset,...
Abstract We report the observation of a coalescing compact binary with component masses 2.5–4.5 M ⊙ and 1.2–2.0 (all measurements quoted at 90% credible level). The gravitational-wave signal GW230529_181500 was observed during fourth observing run LIGO–Virgo–KAGRA detector network on 2023 May 29 by LIGO Livingston observatory. primary source has mass less than 5 99% credibility. cannot definitively determine from data alone whether either is neutron star or black hole. However, given...
Abstract Gravitational lensing by massive objects along the line of sight to source causes distortions gravitational wave (GW) signals; such may reveal information about fundamental physics, cosmology, and astrophysics. In this work, we have extended search for signatures all binary black hole events from third observing run LIGO-Virgo network. We repeated signals strong (1) performing targeted searches subthreshold signals, (2) calculating degree overlap among intrinsic parameters sky...
Abstract The NANOGrav 15 yr data provide compelling evidence for a stochastic gravitational-wave (GW) background at nanohertz frequencies. simplest model-independent approach to characterizing the frequency spectrum of this signal consists simple power-law fit involving two parameters: an amplitude A and spectral index γ . In Letter, we consider next logical step beyond minimal model, allowing running (i.e., logarithmic dependence) index, <mml:math...
Abstract Recently we found compelling evidence for a gravitational-wave background with Hellings and Downs (HD) correlations in our 15 yr data set. These describe gravitational waves as predicted by general relativity, which has two transverse polarization modes. However, more metric theories of gravity can have additional modes, produce different interpulsar correlations. In this work, search the NANOGrav set quadrupolar HD scalar-transverse (ST) We find that are best fit to no significant...
Abstract Despite the growing number of binary black hole coalescences confidently observed through gravitational waves so far, astrophysical origin these binaries remains uncertain. Orbital eccentricity is one clearest tracers formation channels. Identifying eccentricity, however, challenging due to limited availability waveforms that include effects eccentricity. Here, we present observational results for a waveform-independent search sensitive eccentric coalescences, covering third...
Abstract The cosmic merger history of supermassive black hole binaries (SMBHBs) is expected to produce a low-frequency gravitational wave background (GWB). Here we investigate how signs the discrete nature this GWB can manifest in pulsar timing arrays (PTAs) through excursions from, and breaks in, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mi>f</mml:mi> </mml:mrow> <mml:mi>GW</mml:mi> <mml:mo>−</mml:mo> <mml:mn>2</mml:mn> <mml:mo...
Gravitational lensing by massive objects along the line of sight to source causes distortions gravitational wave-signals; such may reveal information about fundamental physics, cosmology and astrophysics. In this work, we have extended search for signatures all binary black hole events from third observing run LIGO--Virgo network. We repeated signals strong 1) performing targeted searches subthreshold signals, 2) calculating degree overlap amongst intrinsic parameters sky location pairs 3)...
Abstract We present the results of a model-based search for continuous gravitational waves from low-mass X-ray binary Scorpius X-1 using LIGO detector data third observing run Advanced and Virgo. This is semicoherent that uses details signal model to coherently combine separated by less than specified coherence time, which can be adjusted balance sensitivity with computing cost. The covered range gravitational-wave frequencies 25 1600 Hz, as well ranges in orbital speed, frequency, phase...
Abstract Evidence has emerged for a stochastic signal correlated among 67 pulsars within the 15 yr pulsar-timing data set compiled by NANOGrav collaboration. Similar signals have been found in from European, Indian, Parkes, and Chinese pulsar timing arrays. This interpreted as indicative of presence nanohertz gravitational-wave background (GWB). To explore internal consistency this result, we investigate how recovered strength changes remove one set. We calculate using (noise-marginalized)...
Abstract As pulsar timing arrays (PTAs) transition into the detection era of stochastic gravitational wave background (GWB), it is important for PTA collaborations to review and possibly revise their observing campaigns. The a “single source” would be boon astrophysics, as such source emit waves millions years in frequency band. Here we present generic methods studying effects various observational strategies, taking advantage detector sensitivity curves, i.e., noise-averaged,...
The global network of gravitational-wave observatories now includes five detectors, namely LIGO Hanford, Livingston, Virgo, KAGRA, and GEO 600. These detectors collected data during their third observing run, O3, composed three phases: O3a starting in April 2019 lasting six months, O3b November O3GK 2020 2 weeks. In this paper we describe these various other science products that can be freely accessed through the Gravitational Wave Open Science Center at https://gwosc.org. main dataset,...
Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through measurement of oscillating length changes in arm cavities. In this context, KAGRA has a unique feature due to differing compositions its mirrors, enhancing signal change auxiliary channels. Here we present result search U(1)B−L gauge boson using data from channels during first joint observation run together with GEO600. By applying our pipeline,...
Despite the growing number of confident binary black hole coalescences observed through gravitational waves so far, astrophysical origin these binaries remains uncertain. Orbital eccentricity is one clearest tracers formation channels. Identifying eccentricity, however, challenging due to limited availability waveforms that include effects eccentricity. Here, we present observational results for a waveform-independent search sensitive eccentric coalescences, covering third observing run (O3)...
Abstract The magnetar SGR 1935+2154 is the only known Galactic source of fast radio bursts (FRBs). FRBs from were first detected by Canadian Hydrogen Intensity Mapping Experiment (CHIME)/FRB and Survey for Transient Astronomical Radio Emission 2 in 2020 April, after conclusion LIGO, Virgo, KAGRA Collaborations’ O3 observing run. Here, we analyze four periods gravitational wave (GW) data GEO600 detector coincident with FRB activity CHIME/FRB, as well X-ray glitches NICER NuSTAR close to time...
Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through measurement of oscillating length changes in arm cavities. In this context, KAGRA has a unique feature due to differing compositions its mirrors, enhancing signal change auxiliary channels. Here we present result search $U(1)_{B-L}$ gauge boson using data from channels during first joint observation run together with GEO600. By applying our...
Recently we found compelling evidence for a gravitational wave background with Hellings and Downs (HD) correlations in our 15-year data set. These describe waves as predicted by general relativity, which has two transverse polarization modes. However, more metric theories of gravity can have additional modes produce different interpulsar correlations. In this work search the NANOGrav set quadrupolar Scalar Transverse (ST) We find that HD are best fit to data, no significant favor ST While...
Pulsar-timing-array experiments have reported evidence for a stochastic background of nanohertz gravitational waves consistent with the signal expected from population supermassive--black-hole binaries. Those analyses assume power-law spectra intrinsic pulsar noise and background, as well Hellings--Downs cross-correlation pattern among gravitational-wave--induced residuals across pulsars. These assumptions are idealizations that may not be realized in actuality. We test them NANOGrav 15 yr...
The NANOGrav 15-year data provides compelling evidence for a stochastic gravitational-wave (GW) background at nanohertz frequencies. simplest model-independent approach to characterizing the frequency spectrum of this signal consists in simple power-law fit involving two parameters: an amplitude A and spectral index \gamma. In paper, we consider next logical step beyond minimal model, allowing running (i.e., logarithmic dependence) index, \gamma_run(f) = \gamma + \beta \ln(f/f_ref). We...
As pulsar timing arrays (PTAs) transition into the detection era of stochastic gravitational wave background (GWB), it is important for PTA collaborations to review, and possibly revise, their observing campaigns. The source GWB unknown, may take years pin down its nature. An astrophysical ensemble supermassive binary black holes one very likely GWB. Evidence such a should come in form detectable anisotropies resolvable signals. A ``single source'' would be boon astrophysics, as emit waves...
The detection of a stochastic gravitational wave background by pulsar timing arrays suggests the presence supermassive black hole binary population. Although observed spectrum generally aligns with predictions from orbital evolution driven emission in circular orbits, there is discernible preference for turnover at lowest frequencies. This could indicate significant hardening phase, transitioning early environmental influences to later stages predominantly influenced emission. In vicinity...
Pulsar timing array observations have found evidence for an isotropic gravitational wave background with the Hellings-Downs angular correlations, expected from general relativity. This interpretation hinges on measured shape of which is predominately quadrupolar under Here we explore a more flexible parameterization: expand correlations into sum Legendre polynomials and use Bayesian analysis to constrain their coefficients 15-year pulsar data set collected by North American Nanohertz...
Evidence has emerged for a stochastic signal correlated among 67 pulsars within the 15-year pulsar-timing data set compiled by NANOGrav collaboration. Similar signals have been found in from European, Indian, Parkes, and Chinese PTAs. This interpreted as indicative of presence nanohertz gravitational wave background. To explore internal consistency this result we investigate how recovered strength changes remove one set. We calculate using (noise-marginalized) optimal statistic, frequentist...
Highspeed chains or rotating disks are commonly used to cut and process treesduring forest harvesting operations. Mechanical failure fatigue of these tools can lead toa potentially hazardous situation where fragments chain sawteeth thrown throughthe operator enclosures on machines. Therefore, a test device is needed evaluate theability machine cab resist puncture by objects. This articles details thedevelopment highpressure pneumatic launch system that propels chainfragments at velocities in...