10 research outputs found
Measurement of radiation-pressure-induced optomechanical dynamics in a suspended Fabry-Perot cavity
We report on experimental observation of radiation-pressure induced effects
in a high-power optical cavity. These effects play an important role in next
generation gravitational wave (GW) detectors, as well as in quantum
non-demolition (QND) interferometers. We measure the properties of an optical
spring, created by coupling of an intense laser field to the pendulum mode of a
suspended mirror; and also the parametric instability (PI) that arises from the
nonlinear coupling between acoustic modes of the cavity mirrors and the cavity
optical mode. Specifically, we measure an optical rigidity of N/m, and PI value .Comment: 4 pages, 3 figure
Searching for a Stochastic Background of Gravitational Waves with LIGO
The Laser Interferometer Gravitational-wave Observatory (LIGO) has performed
the fourth science run, S4, with significantly improved interferometer
sensitivities with respect to previous runs. Using data acquired during this
science run, we place a limit on the amplitude of a stochastic background of
gravitational waves. For a frequency independent spectrum, the new limit is
. This is currently the most sensitive
result in the frequency range 51-150 Hz, with a factor of 13 improvement over
the previous LIGO result. We discuss complementarity of the new result with
other constraints on a stochastic background of gravitational waves, and we
investigate implications of the new result for different models of this
background.Comment: 37 pages, 16 figure
Design and performance of an ultra-flexible two-photon microscope for in vivo research
We present a cost-effective in vivo two-photon microscope with a highly flexible frontend for in vivo research. Our design ensures fast and reproducible access to the area of interest, including rotation of imaging plane, and maximizes space for auxiliary experimental equipment in the vicinity of the animal. Mechanical flexibility is achieved with large motorized linear stages that move the objective in the X, Y, and Z directions up to 130 mm. 360° rotation of the frontend (rotational freedom for one axis) is achieved with the combination of a motorized high precision bearing and gearing. Additionally, the modular design of the frontend, based on commercially available optomechanical parts, allows straightforward updates to future scanning technologies. The design exceeds the mobility of previous movable microscope designs while maintaining high optical performance
Search of S3 LIGO data for gravitational wave signals from spinning black hole and neutron star binary inspirals
We report on the methods and results of the first dedicated search for
gravitational waves emitted during the inspiral of compact binaries with
spinning component bodies. We analyze 788 hours of data collected during the
third science run (S3) of the LIGO detectors. We searched for binary systems
using a detection template family designed specially to capture the effects of
the spin-induced precession of the orbital plane. We present details of the
techniques developed to enable this search for spin-modulated gravitational
waves, highlighting the differences between this and other recent searches for
binaries with non-spinning components. The template bank we employed was found
to yield high matches with our spin-modulated target waveform for binaries with
masses in the asymmetric range 1.0 Msol < m1 < 3.0 Msol and 12.0 Msol < m2 <
20.0 Msol which is where we would expect the spin of the binary's components to
have significant effect. We find that our search of S3 LIGO data had good
sensitivity to binaries in the Milky Way and to a small fraction of binaries in
M31 and M33 with masses in the range 1.0 Msol < m1, m2 < 20.0 Msol. No
gravitational wave signals were identified during this search. Assuming a
binary population with spinning components and Gaussian distribution of masses
representing a prototypical neutron star - black hole system with m1 ~ 1.35
Msol and m2 ~ 5 Msol, we calculate the 90%-confidence upper limit on the rate
of coalescence of these systems to be 15.9 yr^-1 L_10^-1, where L_10 is 10^10
times the blue light luminosity of the Sun.Comment: 18 pages, 8 figure
Publisher’s Note: First cross-correlation analysis of interferometric and resonant-bar gravitational-wave data for stochastic backgrounds [Phys. Rev. DPRVDAQ0556-2821 76, 022001 (2007)]
This paper was published online on 9 July 2007 with incorrect affiliation numbering in the author list. The affiliations have been corrected as of 23 July 2007. The text is correct in the printed version of the journal
Publisher’s Note: First cross-correlation analysis of interferometric and resonant-bar gravitational-wave data for stochastic backgrounds [Phys. Rev. D 76, 022001 (2007)]
This paper was published online on 9 July 2007 with a formatting error in the fiftieth affiliation in the author list. The affiliation should read as ‘‘University of Western Australia, Crawley, WA 6009, Australia.’’ The affiliation has been corrected as of 4 March 2008. The affiliation is incorrect in the printed version of the journal
Upper limits on gravitational wave emission from 78 radio pulsars
We present upper limits on the gravitational wave emission from 78 radio pulsars based on data from the third and fourth science runs of the LIGO and GEO 600 gravitational wave detectors. The data from both runs have been combined coherently to maximize sensitivity. For the first time, pulsars within binary (or multiple) systems have been included in the search by taking into account the signal modulation due to their orbits. Our upper limits are therefore the first measured for 56 of these pulsars. For the remaining 22, our results improve on previous upper limits by up to a factor of 10. For example, our tightest upper limit on the gravitational strain is 2.6×10-25 for PSR J1603-7202, and the equatorial ellipticity of PSR J2124–3358 is less than 10-6. Furthermore, our strain upper limit for the Crab pulsar is only 2.2 times greater than the fiducial spin-down limit