659 research outputs found
Principles of wide bandwidth acoustic detectors and the single-mass DUAL detector
We apply the standard theory of the elastic body to obtain a set of equations
describing the behavior of an acoustic Gravitational Wave detector, fully
taking into account the 3-dimensional properties of the mass, the readout and
the signal. We show that the advantages given by a Dual detector made by two
nested oscillators can also be obtained by monitoring two different acoustic
modes of the same oscillator, thus easing the detector realization. We apply
these concepts and by means of an optimization process we derive the main
figures of such a single-mass Dual detector designed specifically for the
frequency interval 2-5kHz. Finally we calculate the SQL sensitivity of this
detector.Comment: 29 pages, 10 figure
Regression of Environmental Noise in LIGO Data
We address the problem of noise regression in the output of
gravitational-wave (GW) interferometers, using data from the physical
environmental monitors (PEM). The objective of the regression analysis is to
predict environmental noise in the gravitational-wave channel from the PEM
measurements. One of the most promising regression method is based on the
construction of Wiener-Kolmogorov filters. Using this method, the seismic noise
cancellation from the LIGO GW channel has already been performed. In the
presented approach the Wiener-Kolmogorov method has been extended,
incorporating banks of Wiener filters in the time-frequency domain,
multi-channel analysis and regulation schemes, which greatly enhance the
versatility of the regression analysis. Also we presents the first results on
regression of the bi-coherent noise in the LIGO data
Prospects for detecting and localizing short-duration transient gravitational waves from glitching neutron stars without electromagnetic counterparts
Neutron stars are known to show accelerated spin-up of their rotational
frequency called a glitch. Highly magnetized rotating neutron stars (pulsars)
are frequently observed by radio telescopes (and in other frequencies), where
the glitch is observed as irregular arrival times of pulses which are otherwise
very regular. A glitch in an isolated neutron star can excite the fundamental
(f)-mode oscillations which can lead to gravitational wave generation.
Electromagnetic observations of pulsars (and hence pulsar glitches) require the
pulsar to be oriented so that the jet is pointed toward the detector, but this
is not a requirement for gravitational wave emission which is more isotropic
and not jetlike. Hence, gravitational wave observations have the potential to
uncover nearby neutron stars where the jet is not pointed towards the Earth. In
this work, we study the prospects of finding glitching neutron stars using a
generic all-sky search for short-duration gravitational wave transients. The
analysis covers the high-frequency range from kHz of LIGO-Virgo detectors
for signals up to a few seconds. We set upper limits for the third observing
run of the LIGO-Virgo detectors and present the prospects for upcoming
observing runs of LIGO, Virgo, KAGRA, and LIGO India. We find the detectable
glitch size will be around Hz for the fifth observing run for pulsars
with spin frequencies and distances comparable to the Vela pulsar. We also
present the prospects of localizing the direction in the sky of these sources
with gravitational waves alone, which can facilitate electromagnetic follow-up.
We find that for the five detector configuration, the localization capability
for a glitch size of Hz is around at
confidence for of events with distance and spin frequency as
that of Vela
A Proposed Search for the Detection of Gravitational Waves from Eccentric Binary Black Holes
Most of compact binary systems are expected to circularize before the
frequency of emitted gravitational waves (GWs) enters the sensitivity band of
the ground based interferometric detectors. However, several mechanisms have
been proposed for the formation of binary systems, which retain eccentricity
throughout their lifetimes. Since no matched-filtering algorithm has been
developed to extract continuous GW signals from compact binaries on orbits with
low to moderate values of eccentricity, and available algorithms to detect
binaries on quasi-circular orbits are sub-optimal to recover these events, in
this paper we propose a search method for detection of gravitational waves
produced from the coalescences of eccentric binary black holes (eBBH). We study
the search sensitivity and the false alarm rates on a segment of data from the
second joint science run of LIGO and Virgo detectors, and discuss the
implications of the eccentric binary search for the advanced GW detectors
The cosmic web of dwarf galaxies in a warm versus cold dark matter universe: mock galaxies in CDM and WDM simulations
Using cosmological simulations, we show that the cosmic web of dwarf galaxies in a warm dark matter (WDM) universe, wherein low mass halo formation is heavily suppressed, is nearly indistinguishable to that of a cold dark matter (CDM) universe whose low mass halos are not seen because galaxy formation is suppressed below some threshold mass. Low mass warm dark matter halos are suppressed nearly equally in all environments. For example, WDM voids in the galaxy distribution are neither larger nor emptier than CDM voids, once normalized to the same total galaxy number density and assuming galaxy luminosity scales with halo mass. It is thus a challenge to find hints about the dark matter particle in the cosmic web of galaxies. However, if the scatter between dwarf galaxy luminosity and halo properties is large, low mass CDM halos would sometimes host bright galaxies thereby populating voids that would be empty in WDM. Future surveys that will capture the small scale clustering in the local volume could thus help determine whether the CDM problem of the over-abundance of small halos with respect to the number density of observed dwarf galaxies has a cosmological solution or an astrophysical solution
Probing deformed commutators with macroscopic harmonic oscillators
A minimal observable length is a common feature of theories that aim to merge
quantum physics and gravity. Quantum mechanically, this concept is associated
to a nonzero minimal uncertainty in position measurements, which is encoded in
deformed commutation relations. In spite of increasing theoretical interest,
the subject suffers from the complete lack of dedicated experiments and bounds
to the deformation parameters are roughly extrapolated from indirect
measurements. As recently proposed, low-energy mechanical oscillators could
allow to reveal the effect of a modified commutator. Here we analyze the free
evolution of high quality factor micro- and nano-oscillators, spanning a wide
range of masses around the Planck mass (), and compare it with a model of deformed dynamics.
Previous limits to the parameters quantifying the commutator deformation are
substantially lowered.Comment: 11 pages, 3 figures, reference adde
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