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

Journal Article · Fri Mar 10 04:00:00 EST 2017 · Astrophysical Journal

DOI:https://doi.org/10.3847/1538-4357/AA62A7· OSTI ID:22869213

Santos, Fabio P.; Ashton, Peter; Fissel, Laura M.; Matthews, Tristan G.; Novak, Giles ^[1]; Ade, Peter A. R. ^[2]; Angilè, Francesco E.; Devlin, Mark J.; Dober, Bradley; Galitzki, Nicholas; Klein, Jeffrey ^[3]; Benton, Steven J.; Netterfield, Calvin B. ^[4]; Fukui, Yasuo ^[5]; Gandilo, Natalie N. ^[6]; Korotkov, Andrei L. ^[7]; Li, Zhi-Yun ^[8]; Martin, Peter G. ^[9]; Moncelsi, Lorenzo ^[10]; Nakamura, Fumitaka ^[11] ; others, and

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1. Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) and Department of Physics and Astronomy,Northwestern University, 2145 Sheridan Road, Evanston, IL 60208 (United States)
2. Cardiff University, School of Physics and Astronomy, Queens Buildings, The Parade, Cardiff CF24 3AA (United Kingdom)
3. Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104 (United States)
4. Department of Physics, University of Toronto, 60 St. George Street Toronto, ON M5S 1A7 (Canada)
5. Department of Physics and Astrophysics, Nagoya University, Nagoya 464-8602 (Japan)
6. Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4 (Canada)
7. Department of Physics, Brown University, 182 Hope Street, Providence, RI 02912 (United States)
8. Department of Astronomy, University of Virginia, 530 McCormick Road, Charlottesville, VA 22904 (United States)
9. CITA, University of Toronto, 60 St. George St., Toronto, ON M5S 3H8 (Canada)
10. California Institute of Technology, 1200 E. California Boulevard, Pasadena, CA 91125 (United States)
11. National Astronomical Observatory, Mitaka, Tokyo 181-8588 (Japan)

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{sub eff}), a quantity that is expected to depend only on grain-intrinsic physical properties. It is defined as p{sub 500}/(p{sub I}/τ{sub V}), where p {sub 500} and p {sub I} are polarization fractions at 500 μm and the I band, respectively, and τ{sub 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{sub 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{sub eff} appears to be relatively flat as a function of the cloud depth for the range of visual extinctions probed.

• OSTI ID: 22869213
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 837; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
APERTURES
COMPARATIVE EVALUATIONS
COSMIC DUST
COSMIC GASES
DENSITY
DETECTION
EFFICIENCY
EMISSION
FORECASTING
MAGNETIC FIELDS
MOLECULES
POLARIMETRY
POLARIZATION
STARS
TELESCOPES
WAVELENGTHS