Bibcode
Zasowski, G.; Ménard, Brice; Bizyaev, Dmitry; Garcia-Hernandez, D.; García Pérez, Ana; Hayden, Michael R.; Hearty, Fred; Holtzman, Jon A.; Johnson, Jennifer; Kinemuchi, Karen; Majewski, Steven R.; Nidever, David L.; Sellgren, Kristen; Shetrone, Matthew D.; Whelan, David G.; Wilson, John C.
Referencia bibliográfica
American Astronomical Society, AAS Meeting #225, #319.03
Advertised on:
1
2015
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Descripción
Astronomers have studied the set of interstellar absorption features
known as the diffuse interstellar bands (DIBs) for nearly a century,
characterizing them into families and using them as probes of local
interstellar medium (ISM) conditions even while trying to understand
their origin. Though most DIB studies have focused on the optical
features, recent DIB identifications at infrared (IR) wavelengths --
where extinction by interstellar dust is significantly decreased --
provide us with tracers of ISM along heavily extincted, previously
inaccessible sightlines. This talk will briefly summarize results from a
project using the strongest of these IR DIBs (detected in more than
60,000 sightlines towards cool, distant giant stars observed as part of
the SDSS-III/APOGEE survey) to characterize the large-scale distribution
and properties of the Galactic ISM, including in the heavily reddened
bulge and inner disk. The DIB absorption's tight correlation with
foreground reddening makes it a powerful, independent probe of
line-of-sight dust extinction. For the first time, we map the velocity
field of a DIB on large scales and find that it displays the signature
of the rotating Galactic disk. Three-dimensional modeling of the carrier
distribution reveals not only large-scale gradients consistent with
other ISM components, but also substructures that coincide with
particular Galactic bulge and disk features. Finally, we find that
features that are outliers in the distribution of DIB profile shapes may
have an origin in circumstellar, rather than interstellar, environments
along these particular sightlines, and the properties of these atypical
features may contain clues towards identifying the currently-unknown
carrier molecule of this DIB.