Dust Scattered Radiation in the Galactic Poles

TL;DR

This study models the diffuse ultraviolet background at the Galactic Poles, estimating dust properties and extragalactic light contributions using a single-scattering dust model.

Contribution

It provides new estimates of dust albedo and background offsets in the FUV and NUV at the Galactic Poles, highlighting regional variations.

Findings

Dust albedo varies between Galactic Poles and wavelengths.

Offsets at zero-reddening are quantified for FUV and NUV.

Differences in albedo may indicate changes in dust-to-gas ratio.

Abstract

We have modeled the diffuse background at the Galactic Poles in the far-ultraviolet (FUV: 1536 \AA) and the near-ultraviolet (NUV: 2316 \AA). The background is well-fit using a single-scattering dust model with an offset representing the extragalactic light plus any other contribution to the diffuse background. We have found a dust albedo of 0.35 -- 0.40 (FUV) and 0.11 -- 0.19 in the NGP ($b > 70^{\circ}$) and 0.46 -- 0.56 (FUV) and 0.31 -- 0.33 (NUV) in the SGP ($b < 70^{\circ}$. The differences in the albedo may reflect changes in the dust-to-gas ratio over the sky or in the dust distribution. We find offsets at zero-reddening of 273 -- 286 and 553 -- 581 photons cm$^{-2}$ s$^{-1}$ sr$^{-1}$ \AA$^{-1}$ in the FUV and NUV, respectively, in the NGP with similar values in the SGP.