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dc.contributor.authorGao, Jianeng
dc.contributor.authorJiang, B. W.eng
dc.contributor.authorLi, Aigeneng
dc.date.issued2009eng
dc.description.abstractBased 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.eng
dc.identifier.citationThe Astrophysical Journal, 707:89-102, 2009 December 10eng
dc.identifier.issn1538-4357eng
dc.identifier.urihttp://hdl.handle.net/10355/5135eng
dc.languageEnglisheng
dc.publisherAmerican Astronomical Societyeng
dc.relation.ispartofcollectionUniversity of Missouri--Columbia. College of Arts and Sciences. Department of Physics and Astronomy. Physics and Astronomy publicationseng
dc.source.urihttp://www.iop.org/EJ/article/-search=68901184.9/0004-637X/707/1/89/apj_707_1_89.pdf?request-id=0d3cbb8b-6fe1-4b68-a566-76b5cd489683eng
dc.subjectdusteng
dc.subjectextinctioneng
dc.subjectgalaxy: structureeng
dc.subjectgalaxy: structureeng
dc.subjectinfrared: starseng
dc.subjectinfrared: ISMeng
dc.subject.lcshCosmic dusteng
dc.subject.lcshGalaxies -- Evolutioneng
dc.subject.lcshInterstellar reddeningeng
dc.subject.lcshStars -- Initial mass functioneng
dc.titleMid-Infrared Extinction and its Variation with Galactic Longitudeeng
dc.typeArticleeng


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