3,834 research outputs found
Detecting Black Hole Occultations by Stars with Space Interferometric Telescopes
We show that the occultation of Sagittarius A* by stars can be detected with
space-based or space-ground very-long-baseline-interferometers (SVLBIs), with
an expected event rate that is high due to relativistic precession. We compute
the tell-tale signal of an occultation event, and describe methods to flag
non-occultation events that can masquerade as the signal.Comment: Matches accepted versio
Detecting Stellar Lensing of Gravitational Waves with Ground-Based Observatories
We investigate the ability of ground based gravitational wave observatories
to detect gravitational wave lensing events caused by stellar mass lenses. We
show that LIGO and Virgo possess the sensitivities required to detect lenses
with masses as small as provided that the gravitational wave
is observed with a signal-to-noise ratio of . Third generation
observatories will allow detection of gravitational wave lenses with masses of
. Finally, we discuss the possibility of lensing by multiple
stars, as is the case if the gravitational radiation is passing through
galactic nucleus or a dense star cluster.Comment: PRD accepte
Bayesian functional linear regression with sparse step functions
The functional linear regression model is a common tool to determine the
relationship between a scalar outcome and a functional predictor seen as a
function of time. This paper focuses on the Bayesian estimation of the support
of the coefficient function. To this aim we propose a parsimonious and adaptive
decomposition of the coefficient function as a step function, and a model
including a prior distribution that we name Bayesian functional Linear
regression with Sparse Step functions (Bliss). The aim of the method is to
recover areas of time which influences the most the outcome. A Bayes estimator
of the support is built with a specific loss function, as well as two Bayes
estimators of the coefficient function, a first one which is smooth and a
second one which is a step function. The performance of the proposed
methodology is analysed on various synthetic datasets and is illustrated on a
black P\'erigord truffle dataset to study the influence of rainfall on the
production
Atmospheric Calorimetry above 10 eV: Shooting Lasers at the Pierre Auger Cosmic-Ray Observatory
The Pierre Auger Cosmic-Ray Observatory uses the earth's atmosphere as a
calorimeter to measure extensive air-showers created by particles of
astrophysical origin. Some of these particles carry joules of energy. At these
extreme energies, test beams are not available in the conventional sense. Yet
understanding the energy response of the observatory is important. For example,
the propagation distance of the highest energy cosmic-rays through the cosmic
microwave background radiation (CMBR) is predicted to be strong function of
energy. This paper will discuss recently reported results from the observatory
and the use of calibrated pulsed UV laser "test-beams" that simulate the
optical signatures of ultra-high energy cosmic rays. The status of the much
larger 200,000 km companion detector planned for the northern hemisphere
will also be outlined.Comment: 6 pages, 11 figures XIII International Conference on Calorimetry in
High Energy Physic
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