19 research outputs found
Detecting a stochastic gravitational wave background with the Laser Interferometer Space Antenna
The random superposition of many weak sources will produce a stochastic
background of gravitational waves that may dominate the response of the LISA
(Laser Interferometer Space Antenna) gravitational wave observatory. Unless
something can be done to distinguish between a stochastic background and
detector noise, the two will combine to form an effective noise floor for the
detector. Two methods have been proposed to solve this problem. The first is to
cross-correlate the output of two independent interferometers. The second is an
ingenious scheme for monitoring the instrument noise by operating LISA as a
Sagnac interferometer. Here we derive the optimal orbital alignment for
cross-correlating a pair of LISA detectors, and provide the first analytic
derivation of the Sagnac sensitivity curve.Comment: 9 pages, 11 figures. Significant changes to the noise estimate
The IceCube Data Acquisition System: Signal Capture, Digitization, and Timestamping
IceCube is a km-scale neutrino observatory under construction at the South
Pole with sensors both in the deep ice (InIce) and on the surface (IceTop). The
sensors, called Digital Optical Modules (DOMs), detect, digitize and timestamp
the signals from optical Cherenkov-radiation photons. The DOM Main Board (MB)
data acquisition subsystem is connected to the central DAQ in the IceCube
Laboratory (ICL) by a single twisted copper wire-pair and transmits packetized
data on demand. Time calibration is maintained throughout the array by regular
transmission to the DOMs of precisely timed analog signals, synchronized to a
central GPS-disciplined clock. The design goals and consequent features,
functional capabilities, and initial performance of the DOM MB, and the
operation of a combined array of DOMs as a system, are described here.
Experience with the first InIce strings and the IceTop stations indicates that
the system design and performance goals have been achieved.Comment: 42 pages, 20 figures, submitted to Nuclear Instruments and Methods
Search for dark matter from the galactic halo with the IceCube Neutrino Telescope
Self-annihilating or decaying dark matter in the Galactic halo might produce high energy neutrinos detectable with neutrino telescopes. We have conducted a search for such a signal using 276 days of data from the IceCube 22-string configuration detector acquired during 2007 and 2008. The effect of halo model choice in the extracted limit is reduced by performing a search that considers the outer halo region and not the Galactic Center. We constrain any large-scale neutrino anisotropy and are able to set a limit on the dark matter self-annihilation cross section of h similar or equal to 10(-22) cm(3) s(-1) for weakly interacting massive particle masses above 1 TeV, assuming a monochromatic neutrino line spectrum
Limits on a muon flux from neutralino annihilations in the Sun with the IceCube 22-string detector.
A search for muon neutrinos from neutralino annihilations in the Sun has been
performed with the IceCube 22-string neutrino detector using data collected in
104.3 days of live-time in 2007. No excess over the expected atmospheric
background has been observed. Upper limits have been obtained on the
annihilation rate of captured neutralinos in the Sun and converted to limits on
the WIMP-proton cross-sections for WIMP masses in the range 250 - 5000 GeV.
These results are the most stringent limits to date on neutralino annihilation
in the Sun.Comment: 5 pages, 4 figures. Accepted for publication in Phys. Rev. Let