The abundance of HOC+ in diffuse clouds

Abstract

We used the Plateau de Bure Interferometer to search for $\lambda$3mm absorption lines of HOC+ from local diffuse and translucent clouds occulting compact extragalactic mm-wave continuum sources. We detected HOC+ in three directions with column densities only 70-120 times below those of the HCO+ isomer, a factor 5-50 higher than typically found in dense dark gas but comparable to recent observations of dense photon-dominated regions. The observed amounts of HOC+, N(HOC+)/N(\HH) $=3-6\times 10^{-11}$, can be made in quiescent diffuse gas at thermal gas-kinetic rates if the {\HH O}/OH ratio is of order unity, in mild violation of extant observational limits. %

Accepted for publication in Astronomy and Astrophysics 23/08/2004

References in corpus (8)

• Maps of Dust IR Emission for Use in Estimation of Reddening and CMBR Foregrounds
• Enhanced cosmic-ray flux toward zeta Persei inferred from laboratory study of H3+ - e- recombination rate
• Detection of C${}_3$ in Diffuse Interstellar Clouds
• Comparative Chemistry of Diffuse Clouds II: CN, HCN, HNC, CH3CN & N2H+
• Carbon budget and carbon chemistry in Photon Dominated Regions
• Comparative chemistry of diffuse clouds III: sulfur-bearing molecules
• Comparative Chemistry of Diffuse Clouds IV: CH
• Gas-phase recombination, grain neutralization and cosmic-ray ionization in diffuse gas

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