Institution
University of Hamburg
Education•Hamburg, Germany•
About: University of Hamburg is a education organization based out in Hamburg, Germany. It is known for research contribution in the topics: Population & Laser. The organization has 45564 authors who have published 89286 publications receiving 2850161 citations. The organization is also known as: Hamburg University.
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TL;DR: In this paper, the authors used the observed time delay of $(+1.74\pm 0.05)\,{\rm{s}}$ between GRB 170817A and GW170817 to constrain the difference between the speed of gravity and speed of light to be between $-3
Abstract: On 2017 August 17, the gravitational-wave event GW170817 was observed by the Advanced LIGO and Virgo detectors, and the gamma-ray burst (GRB) GRB 170817A was observed independently by the Fermi Gamma-ray Burst Monitor, and the Anti-Coincidence Shield for the Spectrometer for the International Gamma-Ray Astrophysics Laboratory. The probability of the near-simultaneous temporal and spatial observation of GRB 170817A and GW170817 occurring by chance is $5.0\times {10}^{-8}$. We therefore confirm binary neutron star mergers as a progenitor of short GRBs. The association of GW170817 and GRB 170817A provides new insight into fundamental physics and the origin of short GRBs. We use the observed time delay of $(+1.74\pm 0.05)\,{\rm{s}}$ between GRB 170817A and GW170817 to: (i) constrain the difference between the speed of gravity and the speed of light to be between $-3\times {10}^{-15}$ and $+7\times {10}^{-16}$ times the speed of light, (ii) place new bounds on the violation of Lorentz invariance, (iii) present a new test of the equivalence principle by constraining the Shapiro delay between gravitational and electromagnetic radiation. We also use the time delay to constrain the size and bulk Lorentz factor of the region emitting the gamma-rays. GRB 170817A is the closest short GRB with a known distance, but is between 2 and 6 orders of magnitude less energetic than other bursts with measured redshift. A new generation of gamma-ray detectors, and subthreshold searches in existing detectors, will be essential to detect similar short bursts at greater distances. Finally, we predict a joint detection rate for the Fermi Gamma-ray Burst Monitor and the Advanced LIGO and Virgo detectors of 0.1–1.4 per year during the 2018–2019 observing run and 0.3–1.7 per year at design sensitivity.
2,633 citations
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TL;DR: It is shown that this approach can reprogram multiple human cell types to pluripotency with efficiencies that greatly surpass established protocols and represents a safe, efficient strategy for somatic cell reprogramming and directing cell fate that has broad applicability for basic research, disease modeling, and regenerative medicine.
2,627 citations
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TL;DR: The magnitude of modifications to the gravitational-wave dispersion relation is constrain, the graviton mass is bound to m_{g}≤7.7×10^{-23} eV/c^{2} and null tests of general relativity are performed, finding that GW170104 is consistent with general relativity.
Abstract: We describe the observation of GW170104, a gravitational-wave signal produced by the coalescence of a pair of stellar-mass black holes. The signal was measured on January 4, 2017 at 10∶11:58.6 UTC by the twin advanced detectors of the Laser Interferometer Gravitational-Wave Observatory during their second observing run, with a network signal-to-noise ratio of 13 and a false alarm rate less than 1 in 70 000 years. The inferred component black hole masses are 31.2^(8.4) _(−6.0)M_⊙ and 19.4^(5.3)_( −5.9)M_⊙ (at the 90% credible level). The black hole spins are best constrained through measurement of the effective inspiral spin parameter, a mass-weighted combination of the spin components perpendicular to the orbital plane, χ_(eff) = −0.12^(0.21)_( −0.30). This result implies that spin configurations with both component spins positively aligned with the orbital angular momentum are disfavored. The source luminosity distance is 880^(450)_(−390) Mpc corresponding to a redshift of z = 0.18^(0.08)_( −0.07) . We constrain the magnitude of modifications to the gravitational-wave dispersion relation and perform null tests of general relativity. Assuming that gravitons are dispersed in vacuum like massive particles, we bound the graviton mass to m_g ≤ 7.7 × 10^(−23) eV/c^2. In all cases, we find that GW170104 is consistent with general relativity.
2,569 citations
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TL;DR: An overview of the state of the art for transcranial direct current stimulation (tDCS) is offered, which suggests that it can induce beneficial effects in brain disorders and facilitate and standardize future tDCS studies.
2,539 citations
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TL;DR: A wealth of recent research on negative emotions in animals and humans is examined, and it is concluded that, contrary to the traditional dichotomy, both subdivisions make key contributions to emotional processing.
2,484 citations
Authors
Showing all 46072 results
Name | H-index | Papers | Citations |
---|---|---|---|
Rudolf Jaenisch | 206 | 606 | 178436 |
Bruce M. Psaty | 181 | 1205 | 138244 |
Stefan Schreiber | 178 | 1233 | 138528 |
Chris Sander | 178 | 713 | 233287 |
Dennis J. Selkoe | 177 | 607 | 145825 |
Daniel R. Weinberger | 177 | 879 | 128450 |
Ramachandran S. Vasan | 172 | 1100 | 138108 |
Bradley Cox | 169 | 2150 | 156200 |
Anders Björklund | 165 | 769 | 84268 |
J. S. Lange | 160 | 2083 | 145919 |
Hannes Jung | 159 | 2069 | 125069 |
Andrew D. Hamilton | 151 | 1334 | 105439 |
Jongmin Lee | 150 | 2257 | 134772 |
Teresa Lenz | 150 | 1718 | 114725 |
Stefanie Dimmeler | 147 | 574 | 81658 |