Astronomy and Astrophysics – Astronomy
Scientific paper
Jun 2011
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011apj...733...91x&link_type=abstract
The Astrophysical Journal, Volume 733, Issue 2, article id. 91 (2011).
Astronomy and Astrophysics
Astronomy
5
Dust, Extinction, Ism: Lines And Bands, Ism: Molecules
Scientific paper
The diffuse interstellar bands (DIBs) are ubiquitous absorption spectral features arising from the tenuous material in the space between stars—the interstellar medium (ISM). Since their first detection nearly nine decades ago, over 400 DIBs have been observed in the visible and near-infrared wavelength range in both the Milky Way and external galaxies, both nearby and distant. However, the identity of the species responsible for these bands remains as one of the most enigmatic mysteries in astrophysics. An equally mysterious interstellar spectral signature is the 2175 Å extinction bump, the strongest absorption feature observed in the ISM. Its carrier also remains unclear since its first detection 46 years ago. Polycyclic aromatic hydrocarbon (PAH) molecules have long been proposed as a candidate for DIBs as their electronic transitions occur in the wavelength range where DIBs are often found. In recent years, the 2175 Å extinction bump is also often attributed to the π-π* transition in PAHs. If PAHs are indeed responsible for both the 2175 Å extinction feature and DIBs, their strengths may correlate. We perform an extensive literature search for lines of sight for which both the 2175 Å extinction feature and DIBs have been measured. Unfortunately, we found no correlation between the strength of the 2175 Å feature and the equivalent widths of the strongest DIBs. A possible explanation might be that DIBs are produced by small free gas-phase PAH molecules and ions, while the 2175 Å bump is mainly from large PAHs or PAH clusters in condensed phase so that there is no tight correlation between DIBs and the 2175 Å bump.
Li Aigen
Xiang Fu Yuan
Zhong Jian-Xin
No associations
LandOfFree
A Tale of Two Mysteries in Interstellar Astrophysics: The 2175 Å Extinction Bump and Diffuse Interstellar Bands 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 A Tale of Two Mysteries in Interstellar Astrophysics: The 2175 Å Extinction Bump and Diffuse Interstellar Bands, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and A Tale of Two Mysteries in Interstellar Astrophysics: The 2175 Å Extinction Bump and Diffuse Interstellar Bands will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-980773