Title
A NEW OPTICAL POLARIZATION CATALOG for the SMALL MAGELLANIC CLOUD: The MAGNETIC FIELD STRUCTURE
Date Issued
10 June 2015
Access level
open access
Resource Type
journal article
Author(s)
Publisher(s)
Institute of Physics Publishing
Abstract
We present a new optical polarimetric catalog for the Small Magellanic Cloud (SMC). It contains a total of 7207 stars, located in the northeast (NE) and Wing sections of the SMC and part of the Magellanic Bridge. This new catalog is a significant improvement compared to previous polarimetric catalogs for the SMC. We used it to study the sky-projected interstellar magnetic field structure of the SMC. Three trends were observed for the ordered magnetic field direction at position angles (PAs) of (65° ± 10°), (115° ± 10°), and (150° ± 10°). Our results suggest the existence of an ordered magnetic field aligned with the Magellanic Bridge direction and SMCs Bar in the NE region, which have PAs roughly at 115. 4 and 45°, respectively. However, the overall magnetic field structure is fairly complex. The trends at 115° and 150° may be correlated with the SMCs bimodal structure, observed in Cepheids distances and HI velocities. We derived a value of Bsky = (0.947 ∼0.079) μG for the ordered sky-projected magnetic field, and B = (1.465 ∼0.069) μG for the turbulent magnetic field. This estimate of Bskyis significantly larger (by a factor of ∼10) than the line of sight field derived from Faraday rotation observations, suggesting that most of the ordered field component is on the plane of the sky. A turbulent magnetic field stronger than the ordered field agrees with observed estimates for other irregular and spiral galaxies. For the SMC the BskyB ratio is closer to what is observed for our Galaxy than other irregular dwarf galaxies.
Volume
806
Issue
1
Language
English
OCDE Knowledge area
Termodinámica Astronomía Meteorología y ciencias atmosféricas Física de partículas, Campos de la Física
Scopus EID
2-s2.0-84934941163
Source
Astrophysical Journal
ISSN of the container
0004637X
Sources of information: Directorio de Producción Científica Scopus