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

Abstract

We analyse an all-sky compilation of thirteen data sources with optical interstellar linear polarisation for 3871 Gaia DR2 and 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.

Gaia DR2 giants in the Galactic dust – II. Application of the reddening maps and models

“…• 0.91 for GM20 versus G12, • 0.86 for G17 versus LVV19, • 0.84 for LVV19 versus GSF19, • 0.83 for GM20 versus G17, • 0.82 for G17 versus GSF19. Similar tight correlations have been found by Gontcharov & Mosenkov (2019) between G17, G12, AGG92, on the one hand, and a previous (albeit rather similar) version LVV14 of LVV19, on the other hand. This means that, at least, the independent reddening estimates from G17, LVV19, and GSF19 can be basically described as some linear combinations of each other (this is also evident from Fig.…”

“…3 from the first to the third Galactic quadrant. It is the well-known Local interstellar tunnel, or the Great tunnel (Welsh 1991;Gontcharov 2012;Gontcharov & Mosenkov 2019). Its appearance in Fig.…”

Extreme starlight polarization in a region with highly polarized dust emission

“…However, as discussed in Section 3.1, the determination of p V /E(B − V) is limited in large part by accurate determination of interstellar reddening. For instance, Gontcharov & Mosenkov (2019) find that the same sample of nearby stars may reject the classical [p V /E(B − V)] max limit or not, depending on the choice of reddening map. Through polarimetry of many stars in a single region of high submillimeter polarization, we have shown that the mean p V /E(B−V) in the region is inconsistent with an upper limit of 9% mag −1 regardless of which reddening map is used.…”

Isochrone fitting of Galactic globular clusters – I. NGC 5904

“…For example, Meisner & Finkbeiner (2015), Schlafly & Finkbeiner (2011), Drimmel, Cabrera-Lavers & López-Corredoira (2003, and Lallement et al (2018) have similar reddening zero points by use of the same data from SFD or by use of SFD as the prior for a poor dataset at such a high latitude (b ≈ 47 • ). More details on this topic are presented by Gontcharov & Mosenkov (2017b, 2019.…”