I propose to use as a window the dark core of an optical vortex to examine a weak background signal hidden in the glare of a bright coherent source. Applications such as the detection of an astronomical object, forward-scattered radiation, and incoherent light are described whereby signal enhancements of at least 7 orders of magnitude may be achieved.

ABSTRACT Standard sirens (SS) are the gravitational wave analogue of astronomical standard candles, and can provide powerful information about dynamics Universe up to very high z values. In this work, we generate three mock SS catalogues based on merger massive black hole binaries which expected be observed in LISA operating frequency band. Then, perform an analysis test modifications general r...

Opening public sector information has recently become a trend in many countries around the world. Online government data catalogues with national, regional or local scope act as one-stop data portals providing descriptions of available government datasets. These catalogues though remain isolated. Potential benefits from federating geographically overlapping or thematically complementary catalog...

[Context and motivation] To remedy the lack of security expertise, industrial security risk assessment methods come with catalogues of threats and security controls. [Question/problem] We investigate in both qualitative and quantitative terms whether the use of catalogues of threats and security controls has an effect on the actual and perceived effectiveness of a security risk assessment metho...

This paper surveys card-image public access catalogues (CIPACs) – online library catalogues based on databases of digitized catalogue cards and more or less sophisticated mechanisms for browsing or searching. Solutions of this kind have been implemented by a number of libraries in various countries since the mid-1990s, mainly as inexpensive alternatives to a full retrospective conversion of the...

The accuracy in position and flux density of 19 large radio continuum source catalogues has been determined using SPECFIND, a new tool recently made available through the CDS. The ∼ 67 000 radio continuum spectra with three or more frequencies produced by SPECFIND were used to cross-correlate sources from different catalogues and to calculate offsets in right ascension and declination in the va...

This article identifies and discusses the issues and problems that need to be considered in the process of planning and implementing card-image public access catalogues (CIPACs). CIPACs are online library catalogues based on databases of digitised catalogue cards with more or less sophisticated mechanisms for browsing or searching. Solutions of this kind have been implemented by a number of lib...

We present a comprehensive set of mock 2dF and SDSS galaxy redshift surveys constructed from a set of large, high-resolution cosmological N -body simulations. The radial selection functions and geometrical limits of the catalogues mimic those of the genuine surveys. The catalogues span a wide range of cosmologies, including both open and flat universes. In all the models the galaxy distribution...