Variations in the 6.2 μm emission profile in starburst-dominated galaxies: a signature of polycyclic aromatic nitrogen heterocycles (PANHs)?
| Autor: | Carla M. Canelo, Miriani Griselda Pastoriza, Dinalva A. Sales, Amâncio C. S. Friaça, D. Ruschel-Dutra |
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| Rok vydání: | 2018 |
| Předmět: |
Physics
Luminous infrared galaxy chemistry.chemical_classification Astrochemistry 010504 meteorology & atmospheric sciences Polycyclic aromatic hydrocarbon chemistry.chemical_element Astronomy and Astrophysics Aromaticity Astrophysics ASTROQUÍMICA Astrophysics - Astrophysics of Galaxies 01 natural sciences Nitrogen Galaxy Spectral line Interstellar medium chemistry Space and Planetary Science 0103 physical sciences 010303 astronomy & astrophysics 0105 earth and related environmental sciences |
| Zdroj: | Repositório Institucional da USP (Biblioteca Digital da Produção Intelectual) Universidade de São Paulo (USP) instacron:USP |
| Popis: | Analyses of the polycyclic aromatic hydrocarbon (PAH) feature profiles, especially the 6.2 $\mu$m feature, could indicate the presence of nitrogen incorporated in their aromatic rings. In this work, 155 predominantly starburst-dominated galaxies (including HII regions and Seyferts, for example), extracted from the Spitzer/IRS ATLAS project (Hern\'an-Caballero & Hatziminaoglou 2011), have their 6.2 $\mu$m profiles fitted allowing their separation into the Peeters' A, B and C classes (Peeters et al. 2002). 67% of these galaxies were classified as class A, 31% were as class B and 2% as class C. Currently class A sources, corresponding to a central wavelength near 6.22 $\mu$m, seem only to be explained by polycyclic aromatic nitrogen heterocycles (PANH, Hudgins et al. 2005), whereas class B may represent a mix between PAHs and PANHs emissions or different PANH structures or ionization states. Therefore, these spectra suggest a significant presence of PANHs in the interstellar medium (ISM) of these galaxies that could be related to their starburst-dominated emission. These results also suggest that PANHs constitute another reservoir of nitrogen in the Universe, in addition to the nitrogen in the gas phase and ices of the ISM. |
| Databáze: | OpenAIRE |
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