Abundances of PAHs in the ISM: Confronting Observations with Experimental Results

Details Abundances of PAHs in the ISM: Confronting Observations with Experimental Results Abundances of PAHs in the ISM: Confronting Observations with Experimental Results

2011-02-18

arxiv.org/abs/1102.3775v1

Astronomy and Astrophysics

Astrophysics

Galaxy Astrophysics

18 pages, 14 figures, paper accepted by A&A

Scientific paper

We present recent UV laboratory spectra of various polycyclic aromatic hydrocarbons (PAHs) and explore the potential of these molecules as carriers of the DIBs. From a detailed comparison of gas-phase and Ne-matrix absorption spectra of anthracene, phenanthrene, pyrene, 2,3-benzofluorene, benzo[ghi]perylene, and hexabenzocoronene with new interstellar spectra, we infer upper limits in the abundance of these PAHs in the interstellar medium. Upper limits in the column densities of anthracene of $0.8 - 2.8 \times 10^{12}$\ cm$^{-2}$ and of pyrene and 2,3-benzofluorene ranging from $2 - 8 \times 10^{12}$\ cm$^{-2}$ are inferred. Upper limits in the column densities of benzo[ghi]perylene are $0.9 - 2.4 \times 10^{13}$ and $10^{14}$ cm$^{-2}$ for phenanthrene. The measurements indicate fractional abundances of anthracene, pyrene, and 2,3-benzofluorene of a few times $10^{-10}$. Upper limits in the fractional abundance of benzo[ghi]perylene of a few times $10^{-9}$ and of phenanthrene of few times $10^{-8}$ are inferred. {Toward CPD $-32^\circ 1734$, we found near 3584 {\AA} an absorption line of OH$^+$, which was discovered in the interstellar medium only very recently. The fractional abundances of PAHs inferred here are up to two orders of magnitude lower than estimated total PAH abundances in the interstellar medium. This indicates that either neutral PAHs are not abundant in translucent molecular clouds, or that a PAH population with a large variety of molecules is present.

Affiliated with

Also associated with

No associations

Rating

Abundances of PAHs in the ISM: Confronting Observations with Experimental Results does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Abundances of PAHs in the ISM: Confronting Observations with Experimental Results, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Abundances of PAHs in the ISM: Confronting Observations with Experimental Results will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-211638