Fakultäten » Mathematisch-naturwissenschaftliche Fakultät » Physik-Institut » Prof. Dr. Philippe Jetzer » Chieregato

Completed research project

Title / Titel Blank field sources in the ROSAT HRI Brera multiscale wavelet catalog
PDF Abstract (PDF, 14 KB)
Summary / Zusammenfassung The search for Blank Field Sources (BFS), i.e. X-ray sources without optical counterparts, paves the way to identification of unusual objects in the X-ray sky. Here we present four BFS detected in the Brera Multiscale Wavelet catalog of ROSAT HRI observations. This sample was selected on the basis of source brightness, distance from possible counterparts at other wavelengths, point-like shape and a good estimate of the X-ray flux ( f (X) ). The observed f (X) and the limiting magnitude of the optical catalogs fix a lower limit for our BFS on {f (X) /f (opt) }~ 40. This value puts them well beyond the 90% threshold for usual source classes once the HRI energy band and proper spectral shape are taken into account, leaving room for speculation on their nature. Three BFS also show evidence of transient behaviour.
Publications / Publikationen Astronomy and Astrophysics, Volume 444, Issue 1,
December II 2005, pp.69-77
Keywords / Suchbegriffe X-rays: general, stars: neutron, X-rays: galaxies:, clusters, galaxies: BL Lacertae objects: general,, galaxies: quasars: general
Project leadership and contacts /
Projektleitung und Kontakte
M. Chieregato (Project Leader)  
Prof Dr. Philippe Jetzer  
Funding source(s) /
Unterstützt durch
Universität Zürich (position pursuing an academic career), Others
Duration of Project / Projektdauer Dec 2004 to Dec 2005