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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…

Instrumentation and Methods for Astrophysics · Physics 2011-01-24 M. Steglich , C. Jäger , G. Rouillé , F. Huisken , H. Mutschke , Th. Henning

Machine learning feature importance calculations are used to determine the molecular substructures that are responsible for mid and far-infrared (IR) emission features of neutral polycyclic aromatic hydrocarbons (PAHs). Using the…

Astrophysics of Galaxies · Physics 2023-07-18 Zhisen Meng , Yong Zhang , Enwei Liang , Zhao Wang

We study the polarized infrared emission by Polycyclic Aromatic Hydrocarbons (PAHs), when anisotropically illuminated by UV photons. PAH molecules are modeled as planar disks with in-plane and out-of-plane vibrational dipoles. As first…

Astrophysics of Galaxies · Physics 2011-02-11 Lorenzo Sironi , Bruce T. Draine

We present a sample of low-resolution 5-38um Spitzer IRS spectra of the inner few square kiloparsecs of 59 nearby galaxies spanning a large range of star formation properties. A robust method for decomposing mid-infrared galaxy spectra is…

We present a new model of interstellar dust in which large grains are a single composite material, ``astrodust,'' and nanoparticle-sized grains come in distinct varieties including polycyclic aromatic hydrocarbons (PAHs). We argue that a…

Astrophysics of Galaxies · Physics 2023-06-07 Brandon S. Hensley , B. T. Draine

We present 5-20 micron spectral maps of the reflection nebula NGC2023 obtained with the Infrared Spectrograph SL and SH modes on board the Spitzer Space Telescope which reveal emission from polycyclic aromatic hydrocarbons (PAHs), C60, and…

The 11.2 $\mu$m emission band belongs to the family of the `Unidentified' Infrared (UIR) emission bands seen in many astronomical environments. In this work we present a theoretical interpretation of the band characteristics and profile…

Astrophysics of Galaxies · Physics 2015-03-10 A. Candian , P. J. Sarre

Using an AKARI multi-wavelength mid-infrared (IR) survey, we identify luminous starburst galaxies at z> 0.5 based on the PAH luminosity, and investigate the nature of these PAH-selected starbursts. An extragalactic survey with AKARI towards…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 T. Takagi , Y. Ohyama , T. Goto , H. Matsuhara , S. Oyabu , T. Wada , C. P. Pearson , H. M. Lee , M. Im , M. G. Lee , H. Shim , H. Hanami , T. Ishigaki , K. Imai , G. J. White , S. Serjeant , M. Malkan

We examine polycyclic aromatic hydrocarbon (PAH), dust and atomic/molecular emission toward the Galactic bulge using Spitzer Space Telescope observations of four fields: C32, C35, OGLE and NGC 6522. These fields are approximately centered…

Astrophysics of Galaxies · Physics 2018-03-21 Matthew J. Shannon , Els Peeters , Jan Cami , Joris A. D. L. Blommaert

Measurements of the star formation activity on cloud scales are fundamental to uncovering the physics of the molecular cloud, star formation, and stellar feedback cycle in galaxies. Infrared (IR) emission from small dust grains and…

Long-slit 8-13 um spectroscopy of the nebula around NGC 1333 SVS reveals spatial variations in the strength and shape of emission features which are probably produced by polycyclic aromatic hydrocarbons (PAHs). Close to SVS 3, the 11.2 um…

Astrophysics · Physics 2009-10-31 G. C. Sloan , T. L. Hayward , L. J. Allamandola , J. D. Bregman , B. DeVito , D. M. Hudgins

Context: PAHs are thought to be a ubiquitous and important dust component of the interstellar medium. However, the effects of their immersion in a hot (post-shock) gas have never before been fully investigated. Aims: We study the effects of…

Astrophysics of Galaxies · Physics 2015-05-14 E. R. Micelotta , A. P. Jones , A. G. G. M. Tielens

Polycyclic aromatic hydrocarbons (PAHs) are key dust components in galaxies and play a fundamental role in the physics of the interstellar medium (ISM), yet their response to AGN feedback remains debated. We present a spatially resolved…

Superhydrogenated polycyclic aromatic hydrocarbons (PAHs) may be present in H-rich and ultraviolet-poor benign regions. The addition of excess H atoms to PAHs converts the aromatic bonds into aliphatic bonds, the strongest of which falls…

Astrophysics of Galaxies · Physics 2020-03-04 X. J. Yang , Aigen Li , R. Glaser

Interstellar Polycyclic Aromatic Hydrocarbon (PAH) molecules exist in diverse forms depending on the local physical environment. Formation of ionized PAHs (anions and cations) is favourable in the extreme conditions of the ISM. Besides in…

Astrophysics of Galaxies · Physics 2017-12-27 Mridusmita Buragohain , Amit Pathak , Peter Sarre , Nand Kishor Gour

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…

We report new correlations between ratios of band intensities of the 15-20 {\mu}m emission bands of polycyclic aromatic hydrocarbons (PAHs) in a sample of fifty-seven sources observed with Spitzer/IRS. This sample includes Large Magellanic…

Astrophysics of Galaxies · Physics 2015-10-14 M. J. Shannon , D. J. Stock , E. Peeters

Polycyclic aromatic hydrocarbons (PAHs) are of great astrochemical and astrobiological interest due to their potential to form prebiotic molecules. We analyse the 7.7 and 8.6 ${\mu}$m PAH bands in 126 predominantly starburst-dominated…

We investigate in the mid-IR the spatial properties of the PAHs emission in the disk of HD179218. We obtained mid-IR images in the PAH1, PAH2 and Si6 filters at 8.6, 11.3 and 12.5 mu, and N band low-resolution spectra using CanariCam on the…

Our aim is to determine the presence and location of the emission from polycyclic aromatic hydrocarbons (PAHs) towards low and intermediate mass young stars with disks using large aperture telescopes. VLT-VISIR N-band spectra and VLT-ISAAC…