de Diego, J. A. and Binette, L. and Ogle, P. and Andersen, A. C. and Haro-Corzo, S. and Wold, M. (2007) Quasar 3C 298: a test-case for meteoritic nanodiamond 3.5 µm emission. Astronomy and Astrophysics, 467 (1). L7-L10. ISSN 0004-6361 http://resolver.caltech.edu/CaltechAUTHORS:20100427-143440116
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Aims. We calculate the dust emission expected at 3.43 and 3.53 µm if meteoritic (i.e. hydrogenated) nanodiamonds are responsible for most of the far-UV break observed in quasars. Methods. We integrate the UV flux that hydrogenated nanodiamonds must absorb to reproduce the far-UV break. Based on laboratory spectra of H-terminated diamond surfaces, we analyse the radiative energy budget and derive theoretically the IR emission profiles expected for possible C-H surface stretch modes of the diamonds. Results. Using as test case a spectrum of 3C 298 provided by the Spitzer Observatory, we do not find evidence of these emission bands. Conclusions. While diamonds without surface adsorbates remain a viable candidate for explaining the far-UV break observed in quasars, hydrogenated nanodiamonds appear to be ruled out, as they would give rise to IR emission bands, which have not been observed so far.
|Additional Information:||© ESO 2007. Received 11 January 2007. Accepted 1 March 2007. This work was funded by the CONACyT grant J-50296 and the UNAM PAPIIT grant IN118601. It is partly based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under NASA contract 1407. The Dark Cosmology Centre is funded by the Danish National Research Foundation. We thank Diethild Starkmeth and Dominique Binette for help with proofreading.|
|Subject Keywords:||galaxies: active – ISM: dust, extinction – infrared: galaxies – ultraviolet: galaxies – quasars: individual: 3C 298|
|Official Citation:||J. A. de Diego, L. Binette, P. Ogle, A. C. Andersen, S. Haro-Corzo and M. Wold A&A 467 (1) L7-L10 (2007) DOI: 10.1051/0004-6361:20077081|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Tony Diaz|
|Deposited On:||12 May 2010 16:30|
|Last Modified:||26 Dec 2012 11:59|
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