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All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Confinement transition to gravitational waves in the one-flavor $SU(4)$ Hyper Stealth Dark Matter theory

The thermodynamics of the $SU(4)$ gauge theory with a single flavor of fundamental quarks is analyzed on the lattice with dynamical fermion simulations, which is the low-energy sector of a realistic, strongly-interacting dark matter model -- the Hyper Stealth Dark Matter. The gravitational wave spectrum from the first-order confinement transition in the early universe is further calculated, where the effect of the dark sea quarks, which decrease the interface tension in the effective potential of the Polyakov loop, is shown numerically to lower the gravitational wave amplitude.

Ayyar, V. [Boston U.]↗
DOE OSTI2020

GW190814: Gravitational Waves from the Coalescence of a 23 Solar Mass Black Hole with a 2.6 Solar Mass Compact Object

We report the observation of a compact binary coalescence involving a 22.2-24.3 M ⊙ black hole and a compact object with a mass of 2.50-2.67 M ⊙ (all measurements quoted at the 90% credible level). The gravitational-wave signal, GW190814, was observed during LIGO's and Virgo's third observing run on 2019 August 14 at 21:10:39 UTC and has a signal-to-noise ratio of 25 in the three-detector network. The source was localized to 18.5 deg 2 at a distance of 241 +41-41 Mpc; no electromagnetic counterpart has been confirmed to date. The source has the most unequal mass ratio yet measured with gravitational waves , 0.112+0.0090.008, , and its secondary component is either the lightest black hole or the heaviest neutron star ever discovered in a double compact-object system. The dimensionless spin of the primary black hole is tightly constrained to ≤0.07. Tests of general relativity reveal no measurable deviations from the theory, and its prediction of higher-multipole emission is confirmed at high confidence. We estimate a merger rate density of 1-23 Gpc -3 yr -1 for the new class of binary coalescence sources that GW190814 represents. Astrophysical models predict that binaries with mass ratios similar to this event can form through several channels, but are unlikely to have formed in globular clusters. However, the combination of mass ratio, component masses, and the inferred merger rate for this event challenges all current models of the formation and mass distribution of compact-object binaries.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2025

Gravitational Wave Scattering via the Born Series: Scalar Tidal Matching to 𝒪⁡(𝐺 7 ) and Beyond

We introduce a novel method to compute gravitational wave amplitudes within the framework of effective field theory. By reinterpreting the Feynman diagram expansion as a Born series, our method offers several key advantages. It directly yields partial wave amplitudes, streamlining the matching with black hole perturbation theory. Long-distance gravitational interactions are unambiguously factorized from short-distance tidal effects, including dissipation, which are systematically incorporated via an in-in worldline effective action. Crucially, at every order in perturbation theory, integrals are expressed in terms of harmonic polylogarithms, enabling an end-to-end computation scalable to arbitrary orders. We illustrate the method with new predictions for scalar black hole Love numbers and their renormalization group equations to 𝒪⁡(𝐺 7 ).

effective field theory↗
DOE OSTI2022

A Systematic Exploration of Kilonova Candidates from Neutron Star Mergers during the Third Gravitational-wave Observing Run

We present a comprehensive analysis of 653 optical candidate counterparts reported during the third gravitational-wave (GW) observing run. Our sample concentrates on candidates from the 15 events (published in GWTC-2, GWTC-3, or not retracted on GraceDB) that had a >1% chance of including a neutron star in order to assess their viability as true kilonovae. In particular, we leverage tools available in real time, including pre-merger detections and cross-matching with catalogs (i.e., point-source, variable-star, quasar and host-galaxy redshift data sets), to eliminate 65% of candidates in our sample. We further employ spectroscopic classifications, late-time detections, and light-curve behavior analyses and conclude that 66 candidates remain viable kilonovae. These candidates lack sufficient information to determine their classifications, and the majority would require luminosities greater than that of AT 2017gfo. Pre-merger detections in public photometric survey data and comparison of cataloged host-galaxy redshifts with the GW event distances are critical to incorporate into vetting procedures, as these tools eliminated >20% and >30% of candidates, respectively. We expect that such tools that leverage archival information will significantly reduce the strain on spectroscopic and photometric follow-up resources in future observing runs. Finally, we discuss the critical role prompt updates from GW astronomers to the EM community play in reducing the number of candidates requiring vetting.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2024

Limiting Rotation Rate of Neutron Stars from Crust Breaking and Gravitational Waves

Abstract Neutron stars are not observed to spin faster than about half their breakup rate. This limiting rotational frequency may be related to the strength of their crusts. As a star spins up from accretion, centrifugal forces stress the crust. We perform finite-element simulations of rotating neutron stars and find that the crust fails at rotation rates about half the breakup rate. Given uncertainties in microphysics, we have not determined the crust configuration after this failure. Instead, we argue that the crust may fail in an asymmetric way and could produce a configuration with a significant ellipticity (fractional difference in moments of inertia). If the ellipticity is large, a rotating star will radiate gravitational waves that may limit further spin-up. These stars may be promising sources for LIGO/VIRGO and next-generation gravitational-wave detectors.

Morales, J. A.↗
DOE OSTI2022

Searching for dark clumps with gravitational-wave detectors

Dark compact objects (“clumps”) transiting the Solar System exert accelerations on the test masses (TM) in a gravitational-wave (GW) detector. We reexamine the detectability of these clump transits in a variety of current and future GW detectors, operating over a broad range of frequencies. TM accelerations induced by clump transits through the inner Solar System have frequency content around f ~ μ Hz . Some of us [Fedderke et al., Phys. Rev. D 105, 103018 (2022)] recently proposed a GW detection concept with μ Hz sensitivity, based on asteroid-to-asteroid ranging. From the detailed sensitivity projection for this concept, we find both analytically and in simulation that purely gravitational clump–matter interactions would yield one detectable transit every ~ 20 yrs , if clumps with mass m cl ~ 10 14 kg saturate the dark-matter (DM) density. Other (proposed) GW detectors using local TMs and operating in higher frequency bands are sensitive to smaller clump masses and have smaller rates of discoverable signals. We also consider the case of clumps endowed with an additional attractive long-range clump–matter fifth force significantly stronger than gravity (but evading known fifth-force constraints). For the μ Hz detector concept, we use simulations to show that, for example, a clump–matter fifth-force ~ 10 3 times stronger than gravity with a range of ~ AU would boost the rate of detectable transits to a few per year for clumps in the mass range 10 11 kg ≲ m cl ≲ 10 14 kg , even if they are a ~ 1 % subcomponent of the DM. The ability of μ Hz GW detectors to probe asteroid-mass-scale dark objects that may otherwise be undetectable bolsters the science case for their development.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2025

High-frequency gravitational wave detection by the BREAD experiment

The use of experiments searching for light axion dark matter as high-frequency gravitational wave detectors has garnered increasing attention in recent years. We explore the capabilities of the Broadband Reflector Experiment for Axion Detection (BREAD) in probing the GW parameter space and study the directional dependence of its coverage. This detector can investigate frequencies ranging from 0.05 to 200 THz. We find that by employing single photon detectors, BREAD is sensitive to GWs with characteristic strains as low as 10 −21 at 0.1 THz and 10 −25 at 200 THz with a year exposure time, making it competitive with other proposals operating at similar frequencies.

axions↗
DOE OSTI2024

A dark siren measurement of the Hubble constant using gravitational wave events from the first three LIGO/Virgo observing runs and DELVE

The current and next observation seasons will detect hundreds of gravitational waves (GWs) from compact binary systems coalescence at cosmological distances. When combined with independent electromagnetic measurements, the source redshift will be known, and we will be able to obtain precise measurements of the Hubble constant H_0 via the distance–redshift relation. However, most observed mergers are not expected to have electromagnetic counterparts, which prevents a direct redshift measurement. In this scenario, one possibility is to use the dark sirens method that statistically marginalizes over all the potential host galaxies within the GW location volume to provide a probabilistic source redshift. Here we presented H_0 measurements using two new dark sirens compared to previous analyses using DECam data: GW190924|$\_$|021846 and GW200202|$\_$|154313. The photometric redshifts of the possible host galaxies of these two events are acquired from the DECam Local Volume Exploration Survey (DELVE) carried out on the Blanco telescope at Cerro Tololo. The combination of the H_0 posterior from GW190924|$\_$|021846 and GW200202|$\_$|154313 together with the bright siren GW170817 leads to |$H_{0} = 68.84^{+15.51}_{-7.74}\, \rm {km\, s^{-1}\, Mpc^{-1}}$|⁠. Including these two dark sirens improves the 68 per cent confidence interval (CI) by 7 per cent over GW170817 alone. This demonstrates that the addition of well-localized dark sirens in such analysis improves the precision of cosmological measurements. Using a sample containing 10 well-localized dark sirens observed during the third LIGO/Virgo observation run, without the inclusion of GW170817, we determine a measurement of |$H_{0} = 76.00^{+17.64}_{-13.45}\, \rm {km\, s^{-1}\, Mpc^{-1}}$|⁠.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2022

Modified gravitational wave propagation with higher modes and its degeneracies with lensing

Low-energy alternatives to General Relativity (GR) generically modify the phase of gravitational waves (GWs) during their propagation. As detector sensitivities increase, it becomes key to understand how these modifications affect the GW higher modes and to disentangle possible degeneracies with astrophysical phenomena. We apply a general formalism — the WKB approach — for solving analytically wave propagation in the spatial domain with a modified dispersion relation (MDR). We compare this WKB approach to applying a stationary phase approximation (SPA) in the temporal domain with time delays associated to the group or particle velocity. To this end, we extend the SPA to generic signals with higher modes, keeping careful track of reference phases and arrival times. We find that the WKB approach coincides with the SPA using the group velocity, in agreement with the principles of wave propagation. We then explore the degeneracies between a GW propagation with an MDR and a strongly-lensed GW in GR, since the latter can introduce a frequency-independent phase shift which is not degenerate with source parameters in the presence of higher modes. We find that for a particular MDR there is an exact degeneracy for wave propagation, unlike with the SPA for particle propagation. For the other cases, we search for the values of the MDR parameters that minimize the χ 2 and conclude that strongly-lensed GR GWs could be misinterpreted as GWs in modified gravity. As a result, future MDR constraints with higher mode GWs should include the possibility of frequency-independent phase shifts, allowing for the identification of modified gravity and strong lensing distortions at the same time.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2023

Gravitational-wave signature of core-collapse supernovae

Here, we calculate the gravitational-wave (GW) signatures of detailed 3D core-collapse supernova sim ulations spanning a range of massive stars. Most of the simulations are carried out to times late enough to capture more than 95% of the total GW emission. We find that the f/g-mode and f-mode of proto-neutron star oscillations carry away most of the GW power. The f-mode frequency inex orably rises as the proto-neutron star (PNS) core shrinks. We demonstrate that the GW emission is excited mostly by accretion plumes onto the PNS that energize modal oscillations and also high frequency (“haze”) emission correlated with the phase of violent accretion. The duration of the major phase of emission varies with exploding progenitor and there is a strong correlation between the total GW energy radiated and the compactness of the progenitor. Moreover, the total GW emissions vary by as much as three orders of magnitude from star to star. For black-hole formation, the GW signal tapers off slowly and does not manifest the haze seen for the exploding models. For such failed models, we also witness the emergence of a spiral shock motion that modulates the GW emission at a frequency near ~100 Hertz that slowly increases as the stalled shock sinks. We find significant angular anisotropy of both the high- and low-frequency (memory) GW emissions, though the latter have very little power.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2021

Search For Electron-Antineutrinos Associated With 2 Gravitational-Wave Events GW150914, GW151012, GW151226, 3 GW170104, GW170608, GW170814, and GW170817 at Daya Bay

Providing a possible connection between neutrino emission and gravitational-wave (GW) bursts is important to our understanding of the physical processes that occur when black holes or neutron stars merge. In the Daya Bay experiment, using the data collected from December 2011 to August 2017, a search has been performed for electron-antineutrino signals coinciding with detected GW events, including GW150914, GW151012, GW151226, GW170104, GW170608, GW170814, and GW170817. We used three time windows of ±10 s, ±500 s, and ±1000 s relative to the occurrence of the GW events, and a neutrino energy range of 1.8 to 100 MeV to search for correlated neutrino candidates. The detected electron-antineutrino candidates are consistent with the expected background rates for all the three time windows. Assuming monochromatic spectra, we found upper limits (90% confidence level) on electron-antineutrino fluence of (1.13 - 2.44)×1011 cm-2 at 5 MeV to 8.0×107cm-2at 100 MeV for the three timewindows. Under the assumption of a Fermi-Dirac spectrum, the upper limits were found to be (5.4 - 7.0)×109 cm-2 for the three time windows.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2020

Detecting gravitational waves from cosmological phase transitions with LISA: an update

We investigate the potential for observing gravitational waves from cosmological phase transitions with LISA in light of recent theoretical and experimental developments. Our analysis is based on current state-of-the-art simulations of sound waves in the cosmic fluid after the phase transition completes. We discuss the various sources of gravitational radiation, the underlying parameters describing the phase transition and a variety of viable particle physics models in this context, clarifying common misconceptions that appear in the literature and identifying open questions requiring future study. We also present a web-based tool, PTPlot, that allows users to obtain up-to-date detection prospects for a given set of phase transition parameters at LISA.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2021

Detecting the stochastic gravitational wave background from massive gravity with pulsar timing arrays

We explore the potential of pulsar timing arrays (PTAs) such as NANOGrav, EPTA, and PPTA to detect the stochastic gravitational wave background in theories of massive gravity. In general relativity, the function describing the dependence of the correlation between the arrival times of signals from two pulsars on the angle between them is known as the Hellings-Downs curve. We compute the analogous overlap reduction function for massive gravity, including the additional polarization states and the correction due to the mass of the graviton, and compare the result with the Hellings-Downs curve. The primary result is a complete analytical form for the analog Hellings-Downs curve, providing a starting point for future numerical studies aimed at a detailed comparison between PTA data and the predictions of massive gravity. We study both the massless limit and the stationary limit as checks on our calculation, and discuss how our formalism also allows us to study the impact of massive spin-2 dark matter candidates on data from PTAs.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2022

Orbital Decay of Double White Dwarfs: Beyond Gravitational-wave Radiation Effects

The traditional description of the orbital evolution of compact-object binaries, like double white dwarfs (DWDs), assumes that the system is driven only by gravitational-wave (GW) radiation. However, the high magnetic fields with intensities of up to gigagausses measured in WDs alert a potential role of the electromagnetic (EM) emission in the evolution of DWDs. We evaluate the orbital dynamics of DWDs under the effects of GW radiation, tidal synchronization, and EM emission by a unipolar inductor generated by the magnetic primary and the relative motion of the nonmagnetic secondary. We show that the EM emission can affect the orbital dynamics for magnetic fields larger than megagausses. We applied the model to two known DWDs, SDSS J0651+2844 and ZTF J1539+5027, for which the GW radiation alone does not fully account for the measured orbital decay rate. We obtain upper limits to the primary's magnetic field strength, over which the EM emission causes an orbital decay faster than observed. The contribution of tidal locking and the EM emission is comparable, and together they can contribute up to 20% to the measured orbital decay rate. We show that the gravitational waveform for a DWD modeled as purely driven by GWs and including tidal interactions and EM emission can have large relative dephasing detectable in the mHz regime of frequencies relevant for space-based detectors like LISA. Therefore, including physics besides GW radiation in the waveform templates is essential to calibrate the GW detectors using known sources, e.g., ZTF J1539+5027, and to infer binary parameters.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2025

Observing leptogenesis in action with gravitational waves

Leptogenesis is arguably the best motivated theory of baryogenesis given the discovery of finite neutrino masses, yet its experimental test is elusive given its high energy scale. We discuss gravitational waves (GWs) produced via graviton bremsstrahlung in right-handed neutrino decays during leptogenesis. The presence of right-handed neutrinos in the early universe can lead to a period of early matter domination. In this context, the resultant GW spectrum scales quadratically with the right-handed neutrino mass, while its peak frequency scales inversely with the Yukawa coupling. Detecting such a spectrum would provide strong evidence for leptogenesis and the existence of heavy right-handed neutrinos. We also discuss how the GW spectrum emitted from the thermal plasma is altered by an era of early matter domination. We show that it can mimic the effects of additional relativistic degrees of freedom and a higher reheating temperature, and that information from the graviton bremsstrahlung GW spectrum can break this degeneracy.

baryon asymmetry↗
DOE OSTI2026

Gravitational Waves as a Source of Large-Scale White Noise: New Constraints

A stochastic gravitational wave (GW) background sources a shear in the flow of cosmic fluid which, through non-linear mode coupling, generates large-scale white noise (LSWN) in the kurvature density field. Building on the LSWN framework of our previous work, we derive the amplitude of this GW-induced LSWN and translate the observational non-detection of LSWN into bounds on the production redshift and density of gravity waves. In particular, a minimal constraint on gravity waves with $z=0$ density parameter $Ω_\mathrm{GW0}^*$ in frequency band $f_*$ generated at redshift $z_*$ must satisfy ${z_*}^2\,Ω_\mathrm{GW0}^*<5\times10^7\,(f_*/\mathrm{nHz})^{3/2}$. This, for example, precludes the gravity waves recently detected by pulsar timing arrays \cite{NANOGrav:2023hvm} from being present before $z_*\sim10^8$, long after the quark hadron phase transition. While orders of magnitude stronger than other constraints on gravity waves, this is a minimal LSWN constraint as realistic modeling of early universe gravity wave production, including the granularity of the gravity-wave sources and the LSWN produced by the associated acoustic waves would probably tighten this constraint by orders of magnitude.

Barenboim, Gabriela [Valencia U., IFIC; Valencia U↗
DOE OSTI2025

A new probe of μ Hz gravitational waves with FRB timing

We propose Fast Radio Burst (FRB) timing, which uses the precision measurements of the arrival time differences of repeated FRB signals along multiple sightlines, as a new probe of gravitational waves (GWs) around nHz to μHz frequencies, with the highest frequency limited by FRB repeating period. The anticipated experiment requires a sightline separation of tens of AU, achieved by sending radio telescopes to space. We find the signal of arrival time difference induced by GWs depends only on the local GWs in the solar system and we can correlate the measurements from different FRB sources or the same source with different repeaters, which leads to a better sensitivity with a larger number of FRB repeaters detected. Here, the projected sensitivity shows this method is a competitive probe in the nHz to μ Hz frequency range. It can fill the 'μHz gap' between pulsar timing arrays and Laser Interferometer Space Antenna (LISA) and is complementary to other proposals of GW detection in this frequency band.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2023

A Standard Siren Measurement of the Hubble Constant Using Gravitational-wave Events from the First Three LIGO/Virgo Observing Runs and the DESI Legacy Survey

We present a new constraint on the Hubble constant H 0 using a sample of well-localized gravitational-wave (GW) events detected during the first three LIGO/Virgo observing runs as dark standard sirens. In the case of dark standard sirens, a unique host galaxy is not identified, and the redshift information comes from the distribution of potential host galaxies. From the third LIGO/Virgo observing run detections, we add the asymmetric-mass binary black hole GW190412 and the high-confidence GW candidates S191204r, S200129m, and S200311bg to the sample of dark standard sirens analyzed in Palmese et al. Our sample contains the top 20% (based on localization) GW events and candidates to date with significant coverage by the Dark Energy Spectroscopic Instrument Legacy Survey. We combine the H 0 posterior for eight dark siren events, finding H 0 = $79.8^{+19.1}_{-12.8}$ km s -1 Mpc -1 (68% highest density interval) for a prior in H 0 uniform between [20, 140] km s -1 Mpc -1 . This result shows that a combination of eight well-localized dark sirens combined with an appropriate galaxy catalog is able to provide an H 0 constraint that is competitive (~20% versus 18% precision) with a single bright standard siren analysis (i.e., assuming the electromagnetic counterpart) using GW170817. When combining the posterior with that from GW170817, we obtain H 0 = $72.77^{+11.0}_{-7.55}$ km s -1 Mpc -1 . This result is broadly consistent with recent H 0 estimates from both the cosmic microwave background and supernovae.

79 ASTRONOMY AND ASTROPHYSICS↗