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Showing papers by "Leibniz University of Hanover published in 2019"


Journal ArticleDOI
TL;DR: The authors show the double-slit interference effect in the strong-field ionization of neon dimers by employing COLTRIMS method to record the momentum distribution of the photoelectrons in the molecular frame.
Abstract: Wave-particle duality is an inherent peculiarity of the quantum world. The double-slit experiment has been frequently used for understanding different aspects of this fundamental concept. The occurrence of interference rests on the lack of which-way information and on the absence of decoherence mechanisms, which could scramble the wave fronts. Here, we report on the observation of two-center interference in the molecular-frame photoelectron momentum distribution upon ionization of the neon dimer by a strong laser field. Postselection of ions, which are measured in coincidence with electrons, allows choosing the symmetry of the residual ion, leading to observation of both, gerade and ungerade, types of interference.

7,160 citations


Journal ArticleDOI
B. P. Abbott1, Richard J. Abbott2, T. D. Abbott, Fausto Acernese3  +1157 moreInstitutions (70)
TL;DR: In this paper, the authors improved initial estimates of the binary's properties, including component masses, spins, and tidal parameters, using the known source location, improved modeling, and recalibrated Virgo data.
Abstract: On August 17, 2017, the Advanced LIGO and Advanced Virgo gravitational-wave detectors observed a low-mass compact binary inspiral. The initial sky localization of the source of the gravitational-wave signal, GW170817, allowed electromagnetic observatories to identify NGC 4993 as the host galaxy. In this work, we improve initial estimates of the binary's properties, including component masses, spins, and tidal parameters, using the known source location, improved modeling, and recalibrated Virgo data. We extend the range of gravitational-wave frequencies considered down to 23 Hz, compared to 30 Hz in the initial analysis. We also compare results inferred using several signal models, which are more accurate and incorporate additional physical effects as compared to the initial analysis. We improve the localization of the gravitational-wave source to a 90% credible region of 16 deg2. We find tighter constraints on the masses, spins, and tidal parameters, and continue to find no evidence for nonzero component spins. The component masses are inferred to lie between 1.00 and 1.89 M when allowing for large component spins, and to lie between 1.16 and 1.60 M (with a total mass 2.73-0.01+0.04 M) when the spins are restricted to be within the range observed in Galactic binary neutron stars. Using a precessing model and allowing for large component spins, we constrain the dimensionless spins of the components to be less than 0.50 for the primary and 0.61 for the secondary. Under minimal assumptions about the nature of the compact objects, our constraints for the tidal deformability parameter Λ are (0,630) when we allow for large component spins, and 300-230+420 (using a 90% highest posterior density interval) when restricting the magnitude of the component spins, ruling out several equation-of-state models at the 90% credible level. Finally, with LIGO and GEO600 data, we use a Bayesian analysis to place upper limits on the amplitude and spectral energy density of a possible postmerger signal.

715 citations


Journal ArticleDOI
B. P. Abbott1, Richard J. Abbott1, T. D. Abbott2, Sheelu Abraham3  +1215 moreInstitutions (134)
TL;DR: In this paper, the mass, spin, and redshift distributions of binary black hole (BBH) mergers with LIGO and Advanced Virgo observations were analyzed using phenomenological population models.
Abstract: We present results on the mass, spin, and redshift distributions with phenomenological population models using the 10 binary black hole (BBH) mergers detected in the first and second observing runs completed by Advanced LIGO and Advanced Virgo. We constrain properties of the BBH mass spectrum using models with a range of parameterizations of the BBH mass and spin distributions. We find that the mass distribution of the more massive BH in such binaries is well approximated by models with no more than 1% of BHs more massive than 45 M and a power-law index of (90% credibility). We also show that BBHs are unlikely to be composed of BHs with large spins aligned to the orbital angular momentum. Modeling the evolution of the BBH merger rate with redshift, we show that it is flat or increasing with redshift with 93% probability. Marginalizing over uncertainties in the BBH population, we find robust estimates of the BBH merger rate density of R= (90% credibility). As the BBH catalog grows in future observing runs, we expect that uncertainties in the population model parameters will shrink, potentially providing insights into the formation of BHs via supernovae, binary interactions of massive stars, stellar cluster dynamics, and the formation history of BHs across cosmic time.

464 citations



Journal ArticleDOI
B. P. Abbott1, Richard J. Abbott1, T. D. Abbott2, Fausto Acernese3  +1237 moreInstitutions (131)
TL;DR: In this paper, the authors place constraints on the dipole radiation and possible deviations from GR in the post-Newtonian coefficients that govern the inspiral regime of a binary neutron star inspiral.
Abstract: The recent discovery by Advanced LIGO and Advanced Virgo of a gravitational wave signal from a binary neutron star inspiral has enabled tests of general relativity (GR) with this new type of source. This source, for the first time, permits tests of strong-field dynamics of compact binaries in the presence of matter. In this Letter, we place constraints on the dipole radiation and possible deviations from GR in the post-Newtonian coefficients that govern the inspiral regime. Bounds on modified dispersion of gravitational waves are obtained; in combination with information from the observed electromagnetic counterpart we can also constrain effects due to large extra dimensions. Finally, the polarization content of the gravitational wave signal is studied. The results of all tests performed here show good agreement with GR.

430 citations


Journal ArticleDOI
Maggie Tse1, Haocun Yu1, N. Kijbunchoo2, A. Fernandez-Galiana1  +207 moreInstitutions (34)
TL;DR: During the ongoing O3 observation run, squeezed states are improving the sensitivity of the LIGO interferometers to signals above 50 Hz by up to 3 dB, thereby increasing the expected detection rate by 40% and 50% respectively.
Abstract: The Laser Interferometer Gravitational Wave Observatory (LIGO) has been directly detecting gravitational waves from compact binary mergers since 2015. We report on the first use of squeezed vacuum states in the direct measurement of gravitational waves with the Advanced LIGO H1 and L1 detectors. This achievement is the culmination of decades of research to implement squeezed states in gravitational-wave detectors. During the ongoing O3 observation run, squeezed states are improving the sensitivity of the LIGO interferometers to signals above 50 Hz by up to 3 dB, thereby increasing the expected detection rate by 40% (H1) and 50% (L1).

422 citations


Book
21 Oct 2019
TL;DR: This chapter brings together the concepts from Chaps.
Abstract: In this chapter, we give the definition of Mordell–Weil lattice (in Sect. 6.5). First, we bring together the concepts from Chaps. 4 and 5 in order to gain a better understanding of the Neron–Severi lattice of an elliptic surface. This will lead to the announced notion of Mordell–Weil lattice which will be studied in detail in this chapter, but also throughout the remainder of this book.

359 citations


Journal ArticleDOI
TL;DR: In this paper, the authors present the analytic techniques for monitoring the fate of charge carriers at each elementary photocatalytic step, including charge carrier generation, trapping and recombination inside the photocatalyst, as well as the interfacial charge transfer.

315 citations


Journal ArticleDOI
TL;DR: In a combined experimental and theoretical analysis, this work determines the parameter regime for the formation of coherent stripes, whose lifetime of a few tens of milliseconds is limited by the eventual destruction of the stripe pattern due to three-body losses.
Abstract: The competition of dipole-dipole and contact interactions leads to exciting new physics in dipolar gases, well illustrated by the recent observation of quantum droplets and rotons in dipolar condensates. We show that the combination of the roton instability and quantum stabilization leads under proper conditions to a novel regime that presents supersolid properties due to the coexistence of stripe modulation and phase coherence. In a combined experimental and theoretical analysis, we determine the parameter regime for the formation of coherent stripes, whose lifetime of a few tens of milliseconds is limited by the eventual destruction of the stripe pattern due to three-body losses. Our results open intriguing prospects for the development of long-lived dipolar supersolids.

310 citations


Journal ArticleDOI
Fausto Acernese1, M. Agathos2, Lloyd Paul Aiello, A. Allocca  +354 moreInstitutions (24)
TL;DR: The squeezing injection was fully automated and over the first 5 months of the third joint LIGO-Virgo observation run O3 squeezing was applied for more than 99% of the science time, and several gravitational-wave candidates have been recorded.
Abstract: Current interferometric gravitational-wave detectors are limited by quantum noise over a wide range of their measurement bandwidth. One method to overcome the quantum limit is the injection of squeezed vacuum states of light into the interferometer’s dark port. Here, we report on the successful application of this quantum technology to improve the shot noise limited sensitivity of the Advanced Virgo gravitational-wave detector. A sensitivity enhancement of up to 3.2±0.1 dB beyond the shot noise limit is achieved. This nonclassical improvement corresponds to a 5%–8% increase of the binary neutron star horizon. The squeezing injection was fully automated and over the first 5 months of the third joint LIGO-Virgo observation run O3 squeezing was applied for more than 99% of the science time. During this period several gravitational-wave candidates have been recorded.

286 citations


Journal ArticleDOI
TL;DR: The authors show that Anak Krakatau exhibited an elevated state of activity several months prior to the collapse, including precursory thermal anomalies, an increase in the island’s surface area, and a gradual seaward motion of the southwestern flank.
Abstract: Flank instability and sector collapses, which pose major threats, are common on volcanic islands. On 22 Dec 2018, a sector collapse event occurred at Anak Krakatau volcano in the Sunda Strait, triggering a deadly tsunami. Here we use multiparametric ground-based and space-borne data to show that prior to its collapse, the volcano exhibited an elevated state of activity, including precursory thermal anomalies, an increase in the island’s surface area, and a gradual seaward motion of its southwestern flank on a dipping decollement. Two minutes after a small earthquake, seismic signals characterize the collapse of the volcano’s flank at 13:55 UTC. This sector collapse decapitated the cone-shaped edifice and triggered a tsunami that caused 430 fatalities. We discuss the nature of the precursor processes underpinning the collapse that culminated in a complex hazard cascade with important implications for the early detection of potential flank instability at other volcanoes. On 22 December 2018, the western flank of Anak Krakatau collapsed into the sea of the Sunda Strait triggering a tsunami which killed approximately 430 people and displaced 33,000. Here, the authors show that Anak Krakatau exhibited an elevated state of activity several months prior to the collapse, including precursory thermal anomalies, an increase in the island’s surface area, and a gradual seaward motion of the southwestern flank.

Proceedings ArticleDOI
26 Feb 2019
TL;DR: RepNet as discussed by the authors proposes a reprojection network to reproject the estimated 3D pose back to 2D, which results in a loss function that can be used for weakly supervised training.
Abstract: This paper addresses the problem of 3D human pose estimation from single images. While for a long time human skeletons were parameterized and fitted to the observation by satisfying a reprojection error, nowadays researchers directly use neural networks to infer the 3D pose from the observations. However, most of these approaches ignore the fact that a reprojection constraint has to be satisfied and are sensitive to overfitting. We tackle the overfitting problem by ignoring 2D to 3D correspondences. This efficiently avoids a simple memorization of the training data and allows for a weakly supervised training. One part of the proposed reprojection network (RepNet) learns a mapping from a distribution of 2D poses to a distribution of 3D poses using an adversarial training approach. Another part of the network estimates the camera. This allows for the definition of a network layer that performs the reprojection of the estimated 3D pose back to 2D which results in a reprojection loss function. Our experiments show that RepNet generalizes well to unknown data and outperforms state-of-the-art methods when applied to unseen data. Moreover, our implementation runs in real-time on a standard desktop PC.

Journal ArticleDOI
TL;DR: In this paper, a phase field model (PFM) is presented for simulating complex crack patterns including crack propagation, branching and coalescence in rock, based on the strain decomposition for the elastic energy, which drives the evolution of the phase field.
Abstract: We present a phase field model (PFM) for simulating complex crack patterns including crack propagation, branching and coalescence in rock. The phase field model is implemented in COMSOL and is based on the strain decomposition for the elastic energy, which drives the evolution of the phase field. Then, numerical simulations of notched semi-circular bend (NSCB) tests and Brazil splitting tests are performed. Subsequently, crack propagation and coalescence in rock plates with multiple echelon flaws and twenty parallel flaws are studied. Finally, complex crack patterns are presented for a plate subjected to increasing internal pressure, the (3D) Pertersson beam and a 3D NSCB test. All results are in good agreement with previous experimental and numerical results.

Journal ArticleDOI
28 Oct 2019
TL;DR: In this paper, the authors discuss the associated scientific and technological challenges and highlights recent advances of atom interferometry in metrology, geophysics, space, civil engineering, oil and minerals exploration, and navigation.
Abstract: Since the first proof-of-principle experiments over 25 years ago, atom interferometry has matured to a versatile tool that can be used in fundamental research in particle physics, general relativity and cosmology. At the same time, atom interferometers are currently moving out of the laboratory to be used as ultraprecise quantum sensors in metrology, geophysics, space, civil engineering, oil and minerals exploration, and navigation. This Perspective discusses the associated scientific and technological challenges and highlights recent advances. Quantum sensors based on atom interferometry are moving from fundamental research towards commercial applications in metrology, geophysics, space, civil engineering, oil and minerals exploration, and navigation, but a number of challenges need to be overcome.

Journal ArticleDOI
TL;DR: The results demonstrate that rapid detoxification of potentially detrimental amino acids such as Lys is a priority during the initial stress recovery period and support a tight relationship between amino acid metabolism and stress responses.
Abstract: Plant responses to abiotic stress include various modifications in amino acid metabolism. By using a hydroponic culture system, we systematically investigate modification in amino acid profiles and the proteome of Arabidopsis thaliana leaves during initial recovery from low water potential or high salinity. Both treatments elicited oxidative stress leading to a biphasic stress response during recovery. Degradation of highly abundant proteins such as subunits of photosystems and ribosomes contributed to an accumulation of free amino acids. Catabolic pathways for several low abundant amino acids were induced indicating their usage as an alternative respiratory substrate to compensate for the decreased photosynthesis. Our results demonstrate that rapid detoxification of potentially detrimental amino acids such as Lys is a priority during the initial stress recovery period. The content of Pro, which acts as a compatible osmolyte during stress, was adjusted by balancing its synthesis and catabolism both of which were induced both during and after stress treatments. The production of amino acid derived secondary metabolites was up-regulated specifically during the recovery period, and our dataset also indicates increased synthesis rates of the precursor amino acids. Overall, our results support a tight relationship between amino acid metabolism and stress responses.

Journal ArticleDOI
TL;DR: In this paper, a nonlocal operator theory based on the variational principle is proposed for the solution of partial differential equations, which allows assembling of the tangent stiffness matrix with ease and simplicity, which is necessary for the eigenvalue analysis such as the waveguide problem.
Abstract: A novel nonlocal operator theory based on the variational principle is proposed for the solution of partial differential equations. Common differential operators as well as the variational forms are defined within the context of nonlocal operators. The present nonlocal formulation allows the assembling of the tangent stiffness matrix with ease and simplicity, which is necessary for the eigenvalue analysis such as the waveguide problem. The present formulation is applied to solve the differential electromagnetic vector wave equations based on electric fields. The governing equations are converted into nonlocal integral form. An hourglass energy functional is introduced for the elimination of zeroenergy modes. Finally, the proposed method is validated by testing three classical benchmark problems.

Journal ArticleDOI
TL;DR: Novel wrinkled 3D microspherical MOF@rGO composites with both superhydrophobic and superoleophilic properties were developed by embedding MOF nanoparticles between graphene oxide (GO) nanosheets, followed by high-temperature reduction self-assembly.
Abstract: Graphene/MOF-based composite materials in three-dimensional (3D) architectures are promising for the treatment of oil-containing wastewater by absorption owing to their intrinsic properties of graphene and metal-organic frameworks (MOFs), such as high porosity, ultralow density, and facilely tailored superwettability. In this study, novel wrinkled 3D microspherical MOF@rGO composites with both superhydrophobic and superoleophilic properties were developed by embedding MOF nanoparticles between graphene oxide (GO) nanosheets, followed by high-temperature reduction self-assembly. The microspherical composites feature a unique micro/nano hierarchy consisting of crumpled reduced GO (rGO) nanosheets intercalated with well-dispersed MOF nanoparticles. Combined with the superwettability and abundant meso/microporosity, the peculiar architectures of wrinkled ZIF-8@rGO microspheres show very fast absorption rates and high sorption selectivity for organic solvents and oils from water.

Journal ArticleDOI
TL;DR: In this paper, the authors investigate the impact of uncertainty in the metallicity-specific star formation rate over cosmic time on predictions of the rates and masses of double compact object mergers observable through gravitational waves.
Abstract: We investigate the impact of uncertainty in the metallicity-specific star formation rate over cosmic time on predictions of the rates and masses of double compact object mergers observable through gravitational waves. We find that this uncertainty can change the predicted detectable merger rate by more than an order of magnitude, comparable to contributions from uncertain physical assumptions regarding binary evolution, such as mass transfer efficiency or supernova kicks. We statistically compare the results produced by the COMPAS population synthesis suite against a catalogue of gravitational-wave detections from the first two Advanced LIGO and Virgo observing runs. We find that the rate and chirp mass of observed binary black hole mergers can be well matched under our default evolutionary model with a star formation metallicity spread of 0.39 dex around a mean metallicity 〈Z〉 that scales with redshift z as 〈Z〉 = 0.035 × 10−0.23z, assuming a star formation rate of 0.01×(1+z)2.77/(1+((1+z)/2.9)4.7)M⊙ Mpc−3 yr−1. Intriguingly, this default model predicts that 80 per cent of the approximately one binary black hole merger per day that will be detectable at design sensitivity will have formed through isolated binary evolution with only dynamically stable mass transfer, i.e. without experiencing a common-envelope event.

Journal ArticleDOI
TL;DR: In this paper, a new class of high entropy materials for energy storage applications is introduced, which are prepared by facile mechanochemistry using a recently designed multi-cationic transition-metal-based high entropy oxide as the precursor and LiF or NaCl as the reactant, leading to formation of lithiated or sodiated materials.
Abstract: In the present work, a new class of high entropy materials for energy storage applications is introduced. Multi-anionic and -cationic compounds are prepared by facile mechanochemistry using a recently designed multi-cationic transition-metal-based high entropy oxide as the precursor and LiF or NaCl as the reactant, leading to formation of lithiated or sodiated materials. Notably, the Li-containing entropy-stabilized oxyfluoride described herein (Lix(Co0.2Cu0.2Mg0.2Ni0.2Zn0.2)OFx) exhibits a working potential of 3.4 V vs. Li+/Li, enabling its use as a cathode active material. Unlike conventional (non-entropy-stabilized) oxyfluorides, this new material shows enhanced Li storage properties due to entropy stabilization, which, in general, facilitates tailoring the cycling performance by varying the constituent elements in yet unprecedented ways. In addition, we demonstrate that the concept of entropy stabilization is also applicable to Na-containing oxychlorides with a rock-salt structure, thus paving the way toward development of (next-generation) post-Li battery technologies.

Journal ArticleDOI
TL;DR: The Zif-722 -8 membrane shows significantly sharpened molecular sieving for CO2 /CH4 with a separation factor above 25, which soared tenfold compared with other unmodified ZIF-8 membranes.
Abstract: ZIF-8 membrane has the potential for CO2 /CH4 separation based on size exclusion. But if traditionally prepared by solvothermal methods, it shows only negligible selectivity due to the linker mobility. Here, ≈500 nm-thin hybrid ZIF-7x -8 membranes with suppressed linker mobility and narrowed window aperture are prepared by a fast current-driven synthesis (FCDS) within 20 min. The in situ electric field during FCDS allows the formation of stiffened ZIF-8_Cm as parent skeleton and the mixed-linker strategy is applied to narrow the aperture size simultaneously. The ZIF-722 -8 membrane shows significantly sharpened molecular sieving for CO2 /CH4 with a separation factor above 25, which soared tenfold compared with other unmodified ZIF-8 membranes. Additionally, the membrane shows exceptional separation performance for H2 /CH4 and CO2 /N2 , with separation factors of 71 and 20, respectively. After 180 h temperature swing operation, it still maintains the excellent separation performance.

Journal ArticleDOI
TL;DR: In this article, a phase field model for fluid-driven dynamic crack propagation in poroelastic media is proposed and verified through three classical benchmark problems which are compared to analytical solutions for dynamic consolidation and pressure distribution in a single crack and in a specimen with two sets of joints.

Journal ArticleDOI
TL;DR: In this paper, an explicit phase field model for dynamic brittle fracture is proposed, where the mechanical field is integrated with a Verlet-velocity scheme, while the phase field is incremented with sub-steps at each step.

Journal ArticleDOI
TL;DR: Traditional migratory rangeland management was sustainable over millennia, and possibly still offers the best strategy to conserve and possibly increase C stocks in the Kobresia turf.

Journal ArticleDOI
TL;DR: In this article, a numerical relativity (NR) based approximation for the tidal part of the phasing was proposed for nonprecessing and precessing binary black hole systems, as implemented in the LSC Algorithm Library Suite.
Abstract: The combined observation of gravitational and electromagnetic waves from the coalescence of two neutron stars marks the beginning of multimessenger astronomy with gravitational waves (GWs). The development of accurate gravitational waveform models is a crucial prerequisite to extract information about the properties of the binary system that generated a detected GW signal. In binary neutron star systems (BNS), tidal effects also need to be incorporated in the modeling for an accurate waveform representation. Building on previous work [Phys. Rev. D 96, 121501 (2017)], we explore the performance of inspiral-merger waveform models that are obtained by adding a numerical relativity (NR) based approximant for the tidal part of the phasing ($\mathrm{NRTidal}$) to existing models for nonprecessing and precessing binary black hole systems, as implemented in the LSC Algorithm Library Suite. The resulting BNS waveforms are compared and contrasted to a set of target waveforms which we obtain by hybridizing NR waveforms (covering the last $\ensuremath{\sim}10$ orbits up to the merger and extending through the postmerger phase) with inspiral waveforms calculated from 30 Hz obtained with a state-of-the-art effective-one-body waveform model. While due to the construction procedure of the target waveforms, there is no error budget available over the full frequency range accessible by advanced GW detectors, the waveform set presents only an approximation of the real signal. We probe that the combination of the self-spin terms and of the $\mathrm{NRTidal}$ description is necessary to obtain minimal mismatches ($\ensuremath{\lesssim}0.01$) and phase differences ($\ensuremath{\lesssim}1\text{ }\text{ }\mathrm{rad}$) with respect to the target waveforms. We also discuss possible improvements and drawbacks of the $\mathrm{NRTidal}$ approximant in its current form.

Journal ArticleDOI
TL;DR: In this paper, the effects of two independent spins in the precession dynamics of binary black holes were modeled using a single-spin frequency-dependent post-Newtonian rotation to describe precession effects and a double-spin rotation that is based on recent developments in the description of precessional dynamics.
Abstract: The properties of compact binaries, such as masses and spins, are imprinted in the gravitational waves (GWs) they emit and can be measured using parametrized waveform models. Accurately and efficiently describing the complicated precessional dynamics of the various angular momenta of the system in these waveform models is the object of active investigation. One of the key models extensively used in the analysis of LIGO and Virgo data is the single-precessing-spin waveform model IMRPhenomPv2. In this article we present a new model IMRPhenomPv3, which includes the effects of two independent spins in the precession dynamics. Whereas IMRPhenomPv2 utilizes a single-spin frequency-dependent post-Newtonian rotation to describe precession effects, the improved model, IMRPhenomPv3, employs a double-spin rotation that is based on recent developments in the description of precessional dynamics. Besides double-spin precession, the improved model benefits from a more accurate description of precessional effects. We validate our new model against a large set of precessing numerical-relativity simulations. We find that IMRPhenomPv3 has better agreement with the inspiral portion of precessing binary-black-hole simulations and is more robust across a larger region of the parameter space than IMRPhenomPv2. As a first application we analyze the gravitational-wave event GW151226 with an efficient frequency-domain waveform model that describes two-spin precession. Within statistical uncertainty our results are consistent with published results. IMRPhenomPv3 will allow studies of the measurability of individual spins of binary black holes using GWs and can be used as a foundation upon which to build further improvements, such as modeling precession through merger, extending to higher multipoles, and including tidal effects.

Journal ArticleDOI
TL;DR: In this article, a new phase field model that can simulate well compressive-shear fractures in rock-like materials was proposed, where only the compressive part of the strain is used in the new driving force with consideration of the influence of cohesion and internal friction angle.

Journal ArticleDOI
Marcelle Soares-Santos1, Antonella Palmese2, W. G. Hartley3, J. Annis2  +1285 moreInstitutions (156)
TL;DR: In this article, a multi-messenger measurement of the Hubble constant H 0 using the binary-black-hole merger GW170814 as a standard siren, combined with a photometric redshift catalog from the Dark Energy Survey (DES), is presented.
Abstract: We present a multi-messenger measurement of the Hubble constant H 0 using the binary–black-hole merger GW170814 as a standard siren, combined with a photometric redshift catalog from the Dark Energy Survey (DES). The luminosity distance is obtained from the gravitational wave signal detected by the Laser Interferometer Gravitational-Wave Observatory (LIGO)/Virgo Collaboration (LVC) on 2017 August 14, and the redshift information is provided by the DES Year 3 data. Black hole mergers such as GW170814 are expected to lack bright electromagnetic emission to uniquely identify their host galaxies and build an object-by-object Hubble diagram. However, they are suitable for a statistical measurement, provided that a galaxy catalog of adequate depth and redshift completion is available. Here we present the first Hubble parameter measurement using a black hole merger. Our analysis results in ${H}_{0}={75}_{-32}^{+40}\,\mathrm{km}\,{{\rm{s}}}^{-1}\,{\mathrm{Mpc}}^{-1}$, which is consistent with both SN Ia and cosmic microwave background measurements of the Hubble constant. The quoted 68% credible region comprises 60% of the uniform prior range [20, 140] km s−1 Mpc−1, and it depends on the assumed prior range. If we take a broader prior of [10, 220] km s−1 Mpc−1, we find ${H}_{0}={78}_{-24}^{+96}\,\mathrm{km}\,{{\rm{s}}}^{-1}\,{\mathrm{Mpc}}^{-1}$ (57% of the prior range). Although a weak constraint on the Hubble constant from a single event is expected using the dark siren method, a multifold increase in the LVC event rate is anticipated in the coming years and combinations of many sirens will lead to improved constraints on H 0.

Proceedings ArticleDOI
23 Sep 2019
TL;DR: In this article, the authors present the first steps towards a knowledge graph based infrastructure that acquires scholarly knowledge in machine actionable form thus enabling new possibilities for scholarly knowledge curation, publication and processing.
Abstract: Despite improved digital access to scholarly knowledge in recent decades, scholarly communication remains exclusively document-based. In this form, scholarly knowledge is hard to process automatically. We present the first steps towards a knowledge graph based infrastructure that acquires scholarly knowledge in machine actionable form thus enabling new possibilities for scholarly knowledge curation, publication and processing. The primary contribution is to present, evaluate and discuss multi-modal scholarly knowledge acquisition, combining crowdsourced and automated techniques. We present the results of the first user evaluation of the infrastructure with the participants of a recent international conference. Results suggest that users were intrigued by the novelty of the proposed infrastructure and by the possibilities for innovative scholarly knowledge processing it could enable.

Journal ArticleDOI
TL;DR: The Laser Ranging Interferometer (LRI) instrument on the GRACE Follow-On mission has provided the first laser interferometric range measurements between remote spacecraft, separated by approximately 220 km.
Abstract: The Laser Ranging Interferometer (LRI) instrument on the Gravity Recovery and Climate Experiment (GRACE) Follow-On mission has provided the first laser interferometric range measurements between remote spacecraft, separated by approximately 220 km. Autonomous controls that lock the laser frequency to a cavity reference and establish the 5 degrees of freedom two-way laser link between remote spacecraft succeeded on the first attempt. Active beam pointing based on differential wave front sensing compensates spacecraft attitude fluctuations. The LRI has operated continuously without breaks in phase tracking for more than 50 days, and has shown biased range measurements similar to the primary ranging instrument based on microwaves, but with much less noise at a level of 1 nm/sqrt[Hz] at Fourier frequencies above 100 mHz.

Journal ArticleDOI
TL;DR: In this paper, the authors explore how landscape planning and governance research can contribute to the identification, design and implementation of nature-based solutions (NBS) in river landscapes, such as restoring floodplains, can not only decrease flood risks for downstream communities but also provide co-benefits in terms of habitat creation for numerous species and enhanced delivery of diverse ecosystem services.