Mid-Infrared Extinction and its Variation with Galactic Longitude

MOspace/Manakin Repository

Breadcrumbs Navigation

Mid-Infrared Extinction and its Variation with Galactic Longitude

Please use this identifier to cite or link to this item: http://hdl.handle.net/10355/5135

[+] show full item record


Title: Mid-Infrared Extinction and its Variation with Galactic Longitude
Author: Gao, Jian; Jiang, B. W.; Li, Aigen
Keywords: dust
extinction
galaxy: structure
galaxy: structure
infrared: stars
infrared: ISM
Date: 2009-12-10
Publisher: American Astronomical Society
Citation: The Astrophysical Journal, 707:89-102, 2009 December 10
Abstract: Based on the data obtained from the Spitzer/Galactic Legacy InfraredMidplane Survey Extraordinaire (GLIPMSE) Legacy Program and the Two Micron All Sky Survey (2MASS) project, we derive the extinction in the four IRAC bands, [3.6], [4.5], [5.8], and [8.0]μm, relative to the 2MASS Ks band (at 2.16μm) for 131 GLIPMSE fields along the Galactic plane within |l| 65o, using red giants and red clump giants as tracers. As a whole, themean extinction in the IRAC bands (normalized to the 2MASS Ks band), A[3.6]/AKs ≈ 0.63 ± 0.01, A[4.5]/AKs ≈ 0.57 ± 0.03, A[5.8]/AKs ≈ 0.49 ± 0.03, A[8.0]/AKs ≈ 0.55 ± 0.03, exhibits little variation with wavelength (i.e., the extinction is somewhat flat or gray). This is consistent with previous studies and agrees with that predicted from the standard interstellar grain model for RV = 5.5 by Weingartner & Draine. As far as individual sightline is concerned, however, the wavelength dependence of the mid- infrared interstellar extinction Aλ/AKs varies from one sightline to another, suggesting that there may not exist a “universal” IR extinction law. We, for the first time, demonstrate the existence of systematic variations of extinction with Galactic longitude which appears to correlate with the locations of spiral arms as well as with the variation of the far-infrared luminosity of interstellar dust.
URI: http://hdl.handle.net/10355/5135
ISSN: 1538-4357

This item appears in the following Collection(s)

[+] show full item record