Related papers: Modeling the interstellar aromatic infrared bands …
Polycyclic Aromatic Hydrocarbons (PAHs) are carbon-based molecules resulting from the union of aromatic rings and related species, which are likely responsible for strong infrared emission features (3.3, 6.2, 7.7, 8.6, 11.3 and 12.7…
We present the results of near- to mid-infrared slit spectroscopic observations (2.55--13.4 um) of the diffuse emission toward nine positions in the Large Magellanic Cloud with the Infrared Camera (IRC) on board AKARI. The target positions…
Aims. Infrared (IR) spectroscopy is a powerful tool to study molecules in space. A key issue in such analyses is understanding the effect that temperature and anharmonicity have on different vibrational bands, and thus interpreting the IR…
Herbig Ae/Be stars are a class of young pre-main sequence stellar objects of intermediate mass and are known to have varying amounts of natal cloud material still present in their direct vicinity. We characterise the IR emission bands, due…
The so-called unidentified infrared emission (UIE) features at 3.3, 6.2, 7.7, 8.6, and 11.3 $\mu$m ubiquitously seen in a wide variety of astrophysical regions are generally attributed to polycyclic aromatic hydrocarbon (PAH) molecules.…
Total infrared fluxes are estimated for 99 HII regions around massive stars. The following wavebands have been used for the analysis: 8 and 24 $\mu$m, based on data from Spitzer space telescope (IRAC and MIPS, respectively); 70, 160, 250,…
Context. In the framework of the interstellar polycyclic aromatic hydrocarbons (PAHs) hypothesis, far-IR skeletal bands are expected to be a fingerprint of single species in this class. Aims. We address the question of detectability of low…
Polycyclic aromatic hydrocarbon (PAH) ions are crucial intermediates in interstellar chemistry and may play a key role in the infrared emission features observed in space. Here, we investigate the infrared spectra of the indenyl…
The high interstellar abundances of polycyclic aromatic hydrocarbons (PAHs) and their size distribution are the result of complex chemical processes implying dust, UV radiation, and the main gaseous components (H, C+, and O). These…
We report on the absorption spectra of the polycyclic aromatic hydrocarbon (PAH) molecules anthracene, phenanthrene, and pyrene carrying either an ethynyl (-C2H) or a butadiynyl (-C4H) group. Measurements were carried out in the mid…
Mixtures of polycylic aromatic hydrocarbons (PAHs) have been produced by means of laser pyrolysis. The main fraction of the extracted PAHs were primarily medium-sized, up to a maximum size of 38 carbon atoms per molecule. The use of…
Emission from polycyclic aromatic hydrocarbons (PAHs), a commonly used indicator of star formation activity in galaxies, also has the potential to serve as an effective empirical tracer of molecular gas. We use a sample of 19 nearby…
The 3.3 $\mu$m unidentified infrared emission feature is commonly attributed to C-H stretching band of aromatic molecules. Astronomical observations have shown that this feature is composed of two separate bands at 3.28 and 3.30 $\mu$m and…
Cyano-substituted polycyclic aromatic hydrocarbons (CN-PAHs) may contribute to the emission detected in the 7 - 9 $\mu$m (1430 - 1100 cm$^{-1}$) and 11 - 15 $\mu$m (900 - 670 cm$^{-1}$) regions of astronomical IR spectra. Anharmonic quantum…
It is very important to identify carrier molecules of astronomical interstellar infrared spectrum (IR) to understand chemical evolution step of polycyclic aromatic hydrocarbon (PAH) in the universe. In our previous study, it was suggested…
We present spectra of the 3.3 $\mu$m and 11.2 $\mu$m PAH features of a large number of (extra-) galactic sources, obtained with ISO-SWS. Clear variations are present in the profiles of these features. The sources are classified…
Polycyclic Aromatic Hydrocarbon (PAH) emission features dominate the mid-infrared spectra of star-forming galaxies and can be useful to calibrate star formation rates and diagnose ionized states of grains. However, the PAH 3.3 micron…
PAHs are known to be one of the carriers of the ubiquitous aromatic IR bands. The IR spectra of many objects show IR emission features derived from PAH molecules of different size. Still some of the characteristics of the emitting…
Low spectral resolution (delta lambda/lambda ~ 50) mid-infrared observations with high angular resolution (0.3--0.5'') using the Long Wavelength Spectrometer on the Keck I Telescope are reported of the nuclei of five highly luminous…
We present a study for a sample of galaxies with active nuclei to characterize the main type of PAH molecules present in these objects and the local physical conditions of their irradiating sources, as well as the characteristics of the…