Interstellar polarisation and extinction in the Local Bubble and the Gould Belt

George A. Gontcharov; Aleksandr V. Mosenkov

doi:10.1093/mnras/sty2978

paper

Interstellar polarisation and extinction in the Local Bubble and the Gould Belt

arXiv:1811.01411 · doi:10.1093/mnras/sty2978

Abstract

We analyse an all-sky compilation of thirteen data sources with optical interstellar linear polarisation for 3871 {\it Gaia} DR2 and {\it Hipparcos} stars within 500 pc, which do not exhibit a considerable intrinsic polarisation. These data are analysed together with five 3D maps and models of the reddening $E (B - V)$ . We consider variations of the polarisation degree $P$ , position angle $θ$ , and polarisation efficiency $P / E (B - V)$ with Galactic coordinates, distance $R$ , and dereddened colour. $P$ shows a maximum at the Gould Belt mid-plane. $P / R$ drops in the Local Bubble by several times defining a boundary of the Bubble at $P = 0.1$ per cent. All the data sources of the reddening, except Lallement et al., show a drop of $P / E (B - V)$ in the Bubble. A significant number of stars with a too high $P / E (B - V)$ , where the reddening is taken from Arenou et al., Drimmel et al. or Lallement et al., either reject the Serkowski's limit $P / E (B - V) < 9.3$ per cent per mag or manifest a systematic underestimation of the reddening by these data sources. The spatial and colour dependent variations of $P$ and $E (B - V)$ outside the Bubble compensate each other, resulting in a nearly constant $P / E (B - V)$ . A giant envelope of aligned dust dominates at middle and high latitudes outside the Bubble. The Markkanen's cloud, the North Polar Spur, and some other filaments are parts of this envelope.

19 pages, 16 figures, published in Monthly Notices of the Royal Astronomical Society

Interstellar polarisation and extinction in the Local Bubble and the Gould Belt

Abstract

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