Volume 593, September 2016
|Number of page(s)||7|
|Section||Interstellar and circumstellar matter|
|Published online||04 October 2016|
Constraining dust extinction properties via the VVV survey
1 Mount Saint Vincent University, Halifax, NS B3M 2J6, Canada
2 Department of Astronomy & Physics, Saint Mary’s University, Halifax, NS B3H 3C3, Canada
3 Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Mönchhofstr. 12-14, 69120 Heidelberg, Germany
4 The Millennium Institute of Astrophysics (MAS), 36- D Santiago, Chile
5 Departamento de Ciencias Físicas, Universidad Andrés Bello, Campus La Casona, Fernández Concha 700, Santiago, Chile
6 Vatican Observatory, V 00120 Vatican City State, Italy
7 Universidad de Concepción, Departamento de Astronomía, Casilla 160-C, Concepción, Chile
Received: 21 April 2016
Accepted: 28 July 2016
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 BVJHKs(3.4 → 22) μm data for classical Cepheids and O stars occupying the broader Galaxy. The apparent optical color-excess ratios vary significantly with Galactic longitude (ℓ), whereas the near-infrared results are comparatively constant with ℓ and Galactocentric distance (). The results derived imply that classical Cepheids and O stars display separate optical trends (RV,BV) with ℓ, 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 ⟨AJ/E(J−Ks)⟩ = ⟨RJ,JKs⟩ = 1.49 ± 0.05 (⟨AKs/AJ⟩ = 0.33 ± 0.02), whereas the O stars are expectedly impacted by emission beyond 3.6 μm. The mean optical ratios characterizing classical Cepheids and O stars are approximately ⟨RV,BV⟩ ~ 3.1 and ⟨RV,BV⟩ ~ 3.3, respectively.
Key words: dust, extinction
© ESO, 2016
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.