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Centro de Astrofísica da Universidade do Porto
"PowellSnakes", a fast Bayesian detection method of compact objects. The extraction of Planck's nominal SZ clusters of galaxies catalogue

Pedro Carvalho
Kavli Institute for Cosmology, Cambridge

"PowellSnakes" (PwS) is a fast Bayesian algorithm designed for detecting compact objects immersed in a diffuse background. PwS was selected and successfully employed by the Planck consortium in the production of its first public deliverable: the Early Release Compact Source Catalogue (ERCSC) and later as an extraction/characterisation tool of Planck's nominal mission Sunyaev–Zel’dovich (SZ) clusters of galaxies catalogue. We present the reasons why Planck's SZ catalogue needed a Bayesian method and why a simple naïve implementation was not practical. An emphasis is placed on the necessity of a multi-frequency, multi-model detection algorithm in order to achieve optimality.

19 April 2013, 13:30

Centro de Astrofísica
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Institute of Astrophysics and Space Sciences

Institute of Astrophysics and Space Sciences (IA) is a new but long anticipated research infrastructure with a national dimension. It embodies a bold but feasible vision for the development of Astronomy, Astrophysics and Space Sciences in Portugal, taking full advantage and fully realizing the potential created by the national membership of the European Space Agency (ESA) and the European Southern Observatory (ESO). IA resulted from the merging the two most prominent research units in the field in Portugal: the Centre for Astrophysics of the University of Porto (CAUP) and the Center for Astronomy and Astrophysics of the University of Lisbon (CAAUL). It currently hosts more than two-thirds of all active researchers working in Space Sciences in Portugal, and is responsible for an even greater fraction of the national productivity in international ISI journals in the area of Space Sciences. This is the scientific area with the highest relative impact factor (1.65 times above the international average) and the field with the highest average number of citations per article for Portugal.

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