Identification of newly discovered radio-emitting X-ray sources: results from spectroscopy |
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Authors: | Wolter Ruscica & Caccianiga |
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Institution: | Osservatorio Astronomico di Brera, Via Brera 28, 20121 Milano, Italy,;Universitàdegli Studi, Via Celoria 16, 20133 Milano, Italy |
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Abstract: | We present optical identifications for a sample of 20 previously unknown X-ray/radio sources that are present both in the source catalogue of ROSAT PSPC pointed observations ( ROSAT SRC) and in the NRAO VLA Sky Survey (NVSS). The optical spectroscopy was carried out with the 2.1-m telescope at San Pedro Martir (Mexico) during 1995 April and September. We have identified 15 active galactic nuclei including 12 broad-emission-line (FWHM >1000 km s−1) objects, one bona fide BL Lac, one BL Lac candidate and one narrow-line (FWHM < 1000 km s−1) radio galaxy] and five radio galaxies. We derive the X-ray fluxes and luminosities by analysing the PSPC exposures, and show the radio morphology from the NVSS maps. We find that the correlation between the monochromatic X-ray luminosity at 2 keV and the core radio luminosity at 5 GHz for the radio galaxies in our sample follows that found for the 3CR radio galaxies, suggesting a possible nuclear origin for the X-ray emission in these sources. This correlation is weaker in the case of broad-line objects, indicating the presence of another (unbeamed) mechanism for the X-ray emission only weakly related to the radio emission. |
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Keywords: | galaxies: active BL Lacertae objects: general quasars: general radio continuum: galaxies X-rays: galaxies |
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