A Principal component analysis of the diffuse interstellar bands

Abstract

We present a principal component analysis of 23 line of sight parameters (including the strengths of 16 diffuse interstellar bands, DIBs) for a well-chosen sample of single-cloud sightlines representing a broad range of environmental conditions. Our analysis indicates that the majority ($\sim$93\%) of the variations in the measurements can be captured by only four parameters The main driver (i.e., the first principal component) is the amount of DIB-producing material in the line of sight, a quantity that is extremely well traced by the equivalent width of the $\lambda$5797 DIB. The second principal component is the amount of UV radiation, which correlates well with the $\lambda$5797/$\lambda$5780 DIB strength ratio. The remaining two principal components are more difficult to interpret, but are likely related to the properties of dust in the line of sight (e.g., the gas-to-dust ratio). With our PCA results, the DIBs can then be used to estimate these line of sight parameters.

29 pages, 17 figures; accepted for publication in The Astrophysical Journal

References in corpus (13)

• A Unified Representation of Gas-Phase Element Depletions in the Interstellar Medium
• Molecfit: A general tool for telluric absorption correction. I. Method and application to ESO instruments
• An Analysis of the Shapes of Interstellar Extinction Curves. V. The IR-Through-UV Curve Morphology
• Molecfit: A general tool for telluric absorption correction II. Quantitative evaluation on ESO-VLT X-Shooter spectra
• A Catalog of Diffuse Interstellar Bands in the Spectrum of HD 204827
• The Diffuse Interstellar Bands: A Major Problem in Astronomical Spectroscopy
• The Fundamental Properties of Galaxies and a New Galaxy Classification System
• Studies of the Diffuse Interstellar Bands. III. HD 183143
• Abundances and Behavior of 12CO, 13CO, and C2 in Translucent Sight Lines
• VLT/UVES Observations of Interstellar Molecules and Diffuse Bands in the Magellanic Clouds
• Observational Constraints on Interstellar Grain Alignment
• Dusting off the diffuse interstellar bands: DIBs and dust in extragalactic SDSS spectra
• Reliable Eigenspectra for New Generation Surveys

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