The APOGEE DIB Catalog

(Zasowski et al. 2015)

Left: Density of sightlines included in the catalog.
Middle: Median DIB equivalent width (in mÅ) along each sightline.
Right: Median velocity with respect to the LSR along each sightline.

The phase of the ISM comprising large, carbon-rich molecules (e.g., PAHs and fullerenes) is difficult to trace outside of dense clouds or the immediate vicinity of energetic sources. The Diffuse Interstellar Bands (DIBs), a set of absorption features arising from these types of molecules, offer a window into this ISM component.
Here, we present a catalog of detections of the near-infrared DIB at 1.527 microns, extracted from high resolution H-band spectra.
The absorbers producing this feature have been shown to probe large-scale Galactic structure and dynamics very effectively, and to be very tightly correlated with interstellar dust. This catalog thus contains information useful for mapping the distribution and dynamics of gaseous and dusty ISM across several kiloparsecs of the Milky Way.

The Catalog

APOGEE DIB Catalog, DR11: FITS or ASCII. This is the first release from the APOGEE DIB team, comprising single features along about 50,000 sightlines.

Catalog Columns

Data Description

The APOGEE spectrum observed towards each source is a superposition of the target spectrum and any absorption and emission arising along the line of sight towards the target.
Here, we use synthetic stellar models to remove the stellar contribution to the spectrum. The residual absorption at the position of the 1.527 micron DIB (e.g., Geballe et al. 2011) can be measured in each sightline that has a high quality synthetic model fit.
The Zasowski et al. (2015) paper describes the fitting process and the quality cuts imposed, and should be referenced in any analysis using this catalog.

APOGEE flux residuals (black line) and single Gaussian fits to the DIB absorption (green line). From Zasowski et al. (2015).

Quality Caveats

This catalog includes all sightlines in which a DIB could reasonably have been detected; it is not restricted to well-measured detections only. For many purposes, these noisy sightlines can be used in bulk with proper statistical treatment, but if "good" measurements are required (e.g., for analyses involving velocities or other high-order moments), the sample should be culled using the errors and residual statistics provided.


Please contact G. Zasowski (gail dot zasowski at gmail dot com) with any questions or comments.