NASA/IPAC EXTRAGALACTIC DATABASE
Date and Time of the Query: 2018-12-13 T09:31:13 PST
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For refcode 2009ApJ...703.1778S:
Retrieve 1376 NED objects in this reference.
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NED Abstract

Copyright by American Astronomical Society. Reproduced by permission
2009ApJ...703.1778S Spectroscopic Identifications of Spitzer Sources in the SWIRE/XMM-Newton/ELAIS-S1 Field: A Large Fraction of Active Galactic Nucleus with High F(24 micron)/F(R) Ratio Sacchi, N.; La Franca, F.; Feruglio, C.; Fiore, F.; Puccetti, S.; Cocchia, F.; Berta, S.; Brusa, M.; Cimatti, A.; Comastri, A.; Franceschini, A.; Gruppioni, C.; Maiolino, R.; Matute, I.; Polletta, M.; Pozzetti, L.; Pozzi, F.; Vignali, C.; Zamorani, G.; Oliver, S.; Rowan-Robinson, M.; Smith, G.; Lonsdale, C. Abstract. We present a catalog of optical spectroscopic identifications of sources detected by Spitzer at 3.6 or 24 micron down to ~10 and ~280 muJy, respectively, in the SWIRE/XMM-Newton/ELAIS-S1 field and classified via line width analysis and diagnostic diagrams. A total of 1376 sources down to R ~ 24.2 mag have been identified (1362 detected at 3.6 micron, 419 at 24 micron, and 405 at both) by low-resolution optical spectroscopy carried out with FORS2, VIMOS, and EFOSC2 at the Very Large Telescope and 3.6 m ESO telescope. The spectroscopic campaigns have been carried out over the central 0.6 deg^2^ area of ELAIS-S1 which, in particular, has also been observed by XMM-Newton and Chandra. We find the first direct optical spectroscopic evidence that the fraction of active galactic nuclei (AGNs; mostly AGN2) increases with increasing F(24 micron)/F(R) ratio, reaching values of 70(+/-20)% in the range 316 < F(24 micron)/F(R) < 1000. We present an Infrared Array Camera-Multiband Imaging Photometer color-color diagram able to separate AGN1 from obscured AGN2 candidates. After having corrected for the spectroscopic incompleteness of our sample, the result is that the AGN fraction at F(24 micron) ~0.8 mJy is ~22(+/-7)% and decreases slowly to ~19(+/-5)% down to F(24 micron) ~ 0.3 mJy. Key words: galaxies: active, infrared: galaxies, surveys
Retrieve 1376 NED objects in this reference.
Please click here for ADS abstract

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