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Direct spectroscopic evidence for ionized polycyclic aromatic hydrocarbons in the interstellar medium
G C Sloan1, T L Hayward, L J Allamandola
1School of Physics, Australian Defence Force Academy, Canberra, Australia.
The Astrophysical Journal
|September 7, 2001
Summary
Spectroscopy of the nebula around NGC 1333 SVS 3 reveals unique emission features. These findings provide the first evidence of ionized polycyclic aromatic hydrocarbons (PAHs) in the interstellar medium.
Area of Science:
- Astronomy and Astrophysics
- Astrochemistry
Background:
- Polycyclic Aromatic Hydrocarbons (PAHs) are abundant organic molecules in space.
- PAH emission spectra are crucial for understanding their physical and chemical states.
Purpose of the Study:
- To investigate the spatial variations of emission features in the nebula around NGC 1333 SVS 3.
- To identify the origin of specific emission features, particularly those potentially related to ionized PAHs.
Main Methods:
- Long-slit spectroscopy was performed in the 8-13 micrometer wavelength range.
- Analysis focused on the strength and shape of emission features at different spatial locations within the nebula.
Main Results:
- Spatial variations in emission features attributed to PAHs were observed.
- Unique features near NGC 1333 SVS 3, including an excess at 10.8-11.0 micrometers and a feature at 10 micrometers, were detected.
- These features, absent at larger distances, closely resemble laboratory data of PAH cations.
Conclusions:
- The study presents the first identification of interstellar emission features arising specifically from ionized PAHs.
- The findings enhance our understanding of PAH ionization states and their role in the interstellar medium.
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