Search Publications
Probing the size and charge of polycyclic aromatic hydrocarbons
Peeters, E.; Maragkoudakis, A.; Ricca, A.
We present a new method to accurately describe the ionization fraction and the size distribution of polycyclic aromatic hydrocarbons (PAHs) within astrophysical sources. To this purpose, we have computed the mid-infrared emission spectra of 308 PAH molecules of varying sizes, symmetries, and compactness, generated in a range of radiation fields. W…
Crystalline silicate absorption at 11.1 µm: ubiquitous and abundant in embedded YSOs and the interstellar medium
Wright, Christopher M.; Fujiyoshi, Takuya; Siebenmorgen, Ralf +5 more
Utilizing several instruments on 4-8 m telescopes, we have observed a large sample of objects in the mid-infrared (8-13 µm). These comprise a few evolved stars, multiple envelopes of embedded young stellar objects (YSOs) or compact H-II regions, and several sightlines through the interstellar medium (ISM). The latter is where dust resides - …
Eta carinae and the homunculus: far infrared/submillimetre spectral lines detected with the Herschel Space Observatory
Gull, T. R.; Nielsen, K. E.; Morris, P. W. +4 more
The evolved massive binary star η Carinae underwent eruptive mass-loss events that formed the complex bi-polar 'Homunculus' nebula harbouring tens of solar masses of unusually nitrogen-rich gas and dust. Despite expectations for the presence of a significant molecular component to the gas, detections have been observationally challenged by limited…
Infrared properties of planetary nebulae with [WR] and wels central stars
Parthasarathy, M.; Muthumariappan, C.
We report the infrared (IR) properties of planetary nebulae (PNe) with Wolf-Rayet (WR) type and wels central stars known to date and compare them with the IR properties of a sample of PNe with H-rich central stars. We use near-, mid-, and far-IR photometric data from archives to derive the IR properties of PNe. We have constructed IR colour-colour…
Exploiting morphological data from Pulsar Wind Nebulae via a spatiotemporal leptonic transport code
Venter, C.; Seyffert, A. S.; van Rensburg, C. +1 more
The next era of ground-based Cherenkov telescope development will see a great increase in both quantity and quality of γ-ray morphological data. This initiated the development of a spatiotemporal leptonic transport code to model pulsar wind nebulae. We present results from this code that predicts the evolution of the leptonic particle spectrum and…
Integrated approach to the PDR/H II complex by the application of carbon radio recombination lines in the millimetre range and fine-structure lines of C II and O I
Siddiqui, S. A.; Khan, Shafiqullah; Qaiyum, A.
We have performed self-consistent calculations to estimate the physical parameters of photodissociation regions (PDRs) associated with objects, namely, NGC 2024, Orion A and W3, using far-infrared continuum emission, fine-structure lines of C II and O I, and radio recombination lines of carbon. Typically, PDRs separate H II regions from the molecu…