Constraining dust extinction properties via the VVV survey
Near-infrared color-excess and extinction ratios are essential for establishing the cosmic distance scale and probing the Galaxy, particularly when analyzing targets attenuated by significant dust. A robust determination of those ratios followed from leveraging new infrared observations from the VVV...
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| Main Authors: | , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
04 October 2016
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| In: |
Astronomy and astrophysics
Year: 2016, Volume: 593 |
| ISSN: | 1432-0746 |
| DOI: | 10.1051/0004-6361/201628763 |
| Online Access: | Verlag, kostenfrei, Volltext: http://dx.doi.org/10.1051/0004-6361/201628763
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| Author Notes: | D. Majaess, D. Turner, I. Dékány, D. Minniti, and W. Gieren |
| Summary: | Near-infrared color-excess and extinction ratios are essential for establishing the cosmic distance scale and probing the Galaxy, particularly when analyzing targets attenuated by significant dust. A robust determination of those ratios followed from leveraging new infrared observations from the VVV survey, wherein numerous bulge RR Lyrae and Type II Cepheids were discovered, in addition to <i>BVJH<i/><i>K<i/><sub>s<sub/>(3.4 → 22) <i>μ<i/>m data for classical Cepheids and O stars occupying the broader Galaxy. The apparent optical color-excess ratios vary significantly with Galactic longitude (<i>ℓ<i/>), whereas the near-infrared results are comparatively constant with <i>ℓ<i/> and Galactocentric distance (\hbox{$\langle E(J-\overline{3.5~\mu {\rm m}})/E(J-K_{\rm s}) \rangle =1.28\,\pm\,0.03$}). The results derived imply that classical Cepheids and O stars display separate optical trends (<i>R<i/><sub><i>V,BV<i/><sub/>) with <i>ℓ<i/>, which appear to disfavor theories advocating a strict and marked decrease in dust size with increasing Galactocentric distance. The classical Cepheid, Type II Cepheid, and RR Lyrae variables are characterized by ⟨<i>A<i/><sub><i>J<i/><sub/>/<i>E<i/>(<i>J<i/>−<i>K<i/><sub>s<sub/>)⟩ = ⟨<i>R<i/><sub><i>J,J<i/><i>K<i/><sub>s<sub/><sub/>⟩ = 1.49 ± 0.05 (⟨<i>A<i/><sub><i>K<i/><sub>s<sub/><sub/>/<i>A<i/><sub><i>J<i/><sub/>⟩ = 0.33 ± 0.02), whereas the O stars are expectedly impacted by emission beyond 3.6 <i>μ<i/>m. The mean optical ratios characterizing classical Cepheids and O stars are approximately ⟨<i>R<i/><sub><i>V,BV<i/><sub/>⟩ ~ 3.1 and ⟨<i>R<i/><sub><i>V,BV<i/><sub/>⟩ ~ 3.3, respectively. |
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| Item Description: | Gesehen am 30.10.2017 |
| Physical Description: | Online Resource |
| ISSN: | 1432-0746 |
| DOI: | 10.1051/0004-6361/201628763 |