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Comparing Submillimeter Polarized Emission with Near-infrared Polarization of Background Stars for the Vela C Molecular Cloud

Santos, Fábio P. and Moncelsi, Lorenzo (2017) Comparing Submillimeter Polarized Emission with Near-infrared Polarization of Background Stars for the Vela C Molecular Cloud. Astrophysical Journal, 837 (2). Art. No. 161. ISSN 1538-4357. doi:10.3847/1538-4357/aa62a7.

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We present a large-scale combination of near-infrared (near-IR) interstellar polarization data from background starlight with polarized emission data at submillimeter wavelengths for the Vela C molecular cloud. The near-IR data consist of more than 6700 detections probing a range of visual extinctions between 2 and 20 mag in and around the cloud. The submillimeter data were collected in Antarctica by the Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry. This is the first direct combination of near-IR and submillimeter polarization data for a molecular cloud aimed at measuring the "polarization efficiency ratio" R_(eff), a quantity that is expected to depend only on grain-intrinsic physical properties. It is defined as p_(500)/(pt_TV), where p 500 and p I are polarization fractions at 500 µm and the I band, respectively, and t_V is the optical depth. To ensure that the same column density of material is producing both polarization from emission and from extinction, we conducted a careful selection of near-background stars using 2MASS, Herschel, and Planck data. This selection excludes objects contaminated by the Galactic diffuse background material as well as objects located in the foreground. Accounting for statistical and systematic uncertainties, we estimate an average R_(eff) value of 2.4 ± 0.8, which can be used to test the predictions of dust grain models designed for molecular clouds when such predictions become available. The ratio R_(eff) appears to be relatively flat as a function of the cloud depth for the range of visual extinctions probed.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Santos, Fábio P.0000-0002-9650-3619
Moncelsi, Lorenzo0000-0002-4242-3015
Additional Information:© 2017 American Astronomical Society. Received 2016 May 27. Accepted 2017 February 21. Published 2017 March 15. We are grateful to the anonymous referee for the valuable suggestions and comments. The BLASTPol collaboration acknowledges support from NASA (through grant numbers NAG5-12785, NAG5-13301, NNGO-6GI11G, NNX0-9AB98G, and the Illinois Space Grant Consortium), the Canadian Space Agency (CSA), the Leverhulme Trust through the Research Project Grant F/00 407/BN, Canada's Natural Sciences and Engineering Research Council (NSERC), the Canada Foundation for Innovation, the Ontario Innovation Trust, and the US National Science Foundation Office of Polar Programs. C. B. Netterfield also acknowledges support from the Canadian Institute for Advanced Research. F.P.S. was supported by the CAPES grant 2397/13-7. We thank the Columbia Scientific Balloon Facility (CSBF) staff for their outstanding work. F.P. thanks the European Commission under the Marie Sklodowska-Curie Actions within the H2020 program, Grant Agreement number: 658499—PolAME—H2020-MSCA-IF-2014. We thank the staff of OPD/LNA (Brazil) for their invaluable help during our observing runs. This investigation made extensive use of data products from the Two Micron All Sky Survey (2MASS), which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation. We are grateful to Drs. A. M. Magalhães and A. Pereyra for providing the polarimeter and software used for the near-IR data reduction. Facilities: BLASTPol, LNA: 1.6 m, LNA: 0.6 m.
Funding AgencyGrant Number
Canadian Space Agency (CSA)UNSPECIFIED
Leverhulme TrustF/00 407/BN
Natural Sciences and Engineering Research Council of Canada (NSERC)UNSPECIFIED
Canada Foundation for InnovationUNSPECIFIED
Ontario Innovation TrustUNSPECIFIED
Canadian Institute for Advanced Research (CIFAR)UNSPECIFIED
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)2397/13-7
Marie Curie Fellowship658499
European Research Council (ERC)H2020-MSCA-IF-2014
Subject Keywords:dust, extinction; ISM: magnetic fields; ISM: individual objects (Vela C molecular cloud) ; techniques: polarimetric
Issue or Number:2
Record Number:CaltechAUTHORS:20170320-071918564
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Official Citation:Fabio P. Santos et al 2017 ApJ 837 161
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:75224
Deposited By: Ruth Sustaita
Deposited On:20 Mar 2017 15:52
Last Modified:15 Nov 2021 16:31

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