ORCID Profile
0000-0001-6586-9901
Current Organisation
Vrije Universiteit Amsterdam
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Publisher: American Physical Society (APS)
Date: 12-05-2005
Publisher: American Physical Society (APS)
Date: 30-04-2004
Publisher: IOP Publishing
Date: 05-01-2016
Publisher: American Astronomical Society
Date: 18-12-2017
Publisher: Springer Science and Business Media LLC
Date: 11-09-2011
DOI: 10.1038/NPHYS2083
Publisher: Springer Science and Business Media LLC
Date: 16-10-2017
DOI: 10.1038/NATURE24471
Abstract: On 17 August 2017, the Advanced LIGO and Virgo detectors observed the gravitational-wave event GW170817-a strong signal from the merger of a binary neutron-star system. Less than two seconds after the merger, a γ-ray burst (GRB 170817A) was detected within a region of the sky consistent with the LIGO-Virgo-derived location of the gravitational-wave source. This sky region was subsequently observed by optical astronomy facilities, resulting in the identification of an optical transient signal within about ten arcseconds of the galaxy NGC 4993. This detection of GW170817 in both gravitational waves and electromagnetic waves represents the first 'multi-messenger' astronomical observation. Such observations enable GW170817 to be used as a 'standard siren' (meaning that the absolute distance to the source can be determined directly from the gravitational-wave measurements) to measure the Hubble constant. This quantity represents the local expansion rate of the Universe, sets the overall scale of the Universe and is of fundamental importance to cosmology. Here we report a measurement of the Hubble constant that combines the distance to the source inferred purely from the gravitational-wave signal with the recession velocity inferred from measurements of the redshift using the electromagnetic data. In contrast to previous measurements, ours does not require the use of a cosmic 'distance ladder': the gravitational-wave analysis can be used to estimate the luminosity distance out to cosmological scales directly, without the use of intermediate astronomical distance measurements. We determine the Hubble constant to be about 70 kilometres per second per megaparsec. This value is consistent with existing measurements, while being completely independent of them. Additional standard siren measurements from future gravitational-wave sources will enable the Hubble constant to be constrained to high precision.
Publisher: American Physical Society (APS)
Date: 12-08-2005
Publisher: IOP Publishing
Date: 11-08-2003
Publisher: American Physical Society (APS)
Date: 26-05-2022
Publisher: IOP Publishing
Date: 29-07-2020
Publisher: IOP Publishing
Date: 29-09-2004
Publisher: American Astronomical Society
Date: 16-10-2017
Publisher: IOP Publishing
Date: 21-04-2005
Publisher: IOP Publishing
Date: 19-12-2019
Publisher: Optica Publishing Group
Date: 15-10-2020
DOI: 10.1364/OL.403802
Abstract: This Letter derives explicit factors linking mode-mismatch-induced power losses in Hermite–Gauss optical modes to the losses of the fundamental spatial mode. Higher-order modes are found to be more sensitive to beam parameter mismatches. This is particularly relevant for gravitational-wave detectors, where lasers employing higher-order optical modes have been proposed to mitigate thermal noise, and quantum-enhanced detectors are very susceptible to losses. This work should inform mode matching and squeezing requirements for Advanced+ and third generation detectors.
Publisher: American Physical Society (APS)
Date: 03-03-2021
Publisher: American Physical Society (APS)
Date: 13-07-2017
Publisher: American Physical Society (APS)
Date: 25-06-2020
Publisher: IOP Publishing
Date: 12-03-2002
Publisher: SPIE
Date: 21-02-2003
DOI: 10.1117/12.459095
Publisher: American Physical Society (APS)
Date: 31-03-2014
Publisher: Elsevier BV
Date: 2004
Publisher: American Physical Society (APS)
Date: 05-01-2021
Publisher: American Physical Society (APS)
Date: 14-09-2017
Publisher: American Physical Society (APS)
Date: 28-11-2005
Publisher: Optica Publishing Group
Date: 24-03-2020
DOI: 10.1364/OE.389081
Abstract: An accurate readout of low-power optical higher-order spatial modes is of increasing importance to the precision metrology community. Mode sensors are used to prevent mode mismatches from degrading quantum and thermal noise mitigation strategies. Direct mode analysis sensors (MODAN) are a promising technology for real-time monitoring of arbitrary higher-order modes. We demonstrate MODAN with photo-diode readout to mitigate the typically low dynamic range of CCDs. We look for asymmetries in the response of our sensor to break degeneracies in the relative alignment of the MODAN and photo-diode and consequently improve the dynamic range of the mode sensor. We provide a tolerance analysis and show methodology that can be applied for sensors beyond first order spatial modes.
Publisher: American Physical Society (APS)
Date: 08-09-2005
Publisher: IOP Publishing
Date: 29-03-2006
Publisher: AIP Publishing
Date: 23-07-2003
DOI: 10.1063/1.1589160
Abstract: The British–German interferometric gravitational-wave detector GEO600 uses two high-finesse triangular ring cavities of 8 m optical pathlength each, as an optical mode-cleaning system. The modecleaner system is housed in an ultrahigh-vacuum environment to avoid contamination of the optics and to minimize both the influence of refractive index variations of the air and acoustic coupling to the optics. To isolate the cavities from seismic noise, all optical components are suspended as double pendulums. These pendulums are d ed at their resonance frequencies at the upper pendulum stage with magnet-coil actuators. A suspended reaction mass supports three coils matching magnets bonded onto the surface of one mirror of each cavity, allowing length control of the modecleaner cavities to maintain resonance with the laser light. A fully automated control system stabilizes the frequency of the slave laser to that of the master laser, the frequency of the master laser to the length of the first modecleaner and the length of the first to the length of the second modecleaner. The control system uses the Pound–Drever–Hall sideband technique and operates autonomously over long time periods with only infrequent human interaction. The duty cycle of the system was measured to be 99.7% during an 18 day period. The throughput of the whole modecleaner system is about 50%. In this article, we give an overview of the mechanical and optical setup and the achieved performance of the double modecleaner system.
Publisher: Wiley
Date: 04-10-2016
Publisher: IOP Publishing
Date: 18-05-2017
Publisher: IOP Publishing
Date: 06-2012
Publisher: Springer Science and Business Media LLC
Date: 19-07-2014
Publisher: American Physical Society (APS)
Date: 07-05-2004
Publisher: American Astronomical Society
Date: 07-04-2017
Publisher: American Physical Society (APS)
Date: 10-03-2008
Publisher: American Physical Society (APS)
Date: 10-03-2008
Publisher: American Physical Society (APS)
Date: 06-2004
Publisher: American Physical Society (APS)
Date: 10-03-2008
Publisher: American Physical Society (APS)
Date: 10-03-2008
Publisher: Springer Science and Business Media LLC
Date: 26-04-2018
DOI: 10.1007/S41114-018-0012-9
Abstract: We present possible observing scenarios for the Advanced LIGO, Advanced Virgo and KAGRA gravitational-wave detectors over the next decade, with the intention of providing information to the astronomy community to facilitate planning for multi-messenger astronomy with gravitational waves. We estimate the sensitivity of the network to transient gravitational-wave signals, and study the capability of the network to determine the sky location of the source. We report our findings for gravitational-wave transients, with particular focus on gravitational-wave signals from the inspiral of binary neutron star systems, which are the most promising targets for multi-messenger astronomy. The ability to localize the sources of the detected signals depends on the geographical distribution of the detectors and their relative sensitivity, and $$90\\%$$ 90 % credible regions can be as large as thousands of square degrees when only two sensitive detectors are operational. Determining the sky position of a significant fraction of detected signals to areas of 5– $$20~\\mathrm {deg}^2$$ 20 deg 2 requires at least three detectors of sensitivity within a factor of $$\\sim 2$$ ∼ 2 of each other and with a broad frequency bandwidth. When all detectors, including KAGRA and the third LIGO detector in India, reach design sensitivity, a significant fraction of gravitational-wave signals will be localized to a few square degrees by gravitational-wave observations alone.
Publisher: American Astronomical Society
Date: 06-11-2009
Publisher: IOP Publishing
Date: 12-04-2017
Publisher: American Physical Society (APS)
Date: 25-10-2005
Publisher: American Physical Society (APS)
Date: 25-10-2005
Publisher: IOP Publishing
Date: 24-10-2007
Publisher: American Physical Society (APS)
Date: 02-06-2004
Publisher: IOP Publishing
Date: 09-02-2004
Publisher: IOP Publishing
Date: 26-09-2017
Publisher: IOP Publishing
Date: 03-02-2004
Publisher: American Physical Society (APS)
Date: 07-03-2006
Publisher: American Physical Society (APS)
Date: 23-12-2009
Publisher: IOP Publishing
Date: 07-08-2003
Publisher: IOP Publishing
Date: 24-03-2006
Publisher: World Scientific Publishing Company
Date: 02-2006
Publisher: American Physical Society (APS)
Date: 30-07-2007
Publisher: American Physical Society (APS)
Date: 08-11-2017
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Andreas Freise.