Positron Annihilation on Polycyclic Aromatic Hydrocarbon molecules in the Interstellar Medium

Abstract

We examine the annihilation of positrons on polycyclic aromatic hydrocarbon (PAH) molecules in interstellar medium conditions. We estimate the annihilation rates of positrons on PAHs by a semi-empirical approach. We show that PAHs can play a significant role in the overall galactic positron annihilation picture and use the annihilation rates and INTEGRAL galactic emission measurements to constrain the amount of PAHs present in the ISM. We find an upper limit of 4.6 x 10^-7 for the PAH abundance.

Accepted in MNRAS, 10 pages, 5 figures

References in corpus (6)

• The sky distribution of positronium annihilation continuum emission measured with SPI/INTEGRAL
• The mixed chemistry phenomenon in Galactic Bulge PNe
• Microquasars as sources of positron annihilation radiation
• Search for corannulene (C20H10) in the Red Rectangle
• [SiPAH]+ pi-Complexes in the Interstellar Medium
• The Mid-Infrared Colours of Galactic Bulge, Disk and Magellanic Planetary Nebulae

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• Vibrational Feshbach Resonances Mediated by Nondipole Positron-Molecule Interactions
• The effect of positron-alkali metal atom interactions in the diffuse ISM
• A Search for Annihilating Dark Matter in 47 Tucanae and Omega Centauri