Quasar 3C 298: A test-case for meteoritic nanodiamond 3.5 μm emission

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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.

Original languageEnglish
JournalAstronomy and Astrophysics
Volume467
Issue number1
Pages (from-to)L7-L10
ISSN0004-6361
DOIs
Publication statusPublished - 1 May 2007

    Research areas

  • Galaxies: active, Infrared: galaxies, ISM: dust, extinction, Quasars: individual: 3C 298, Ultraviolet: galaxies

ID: 232622504