Diffuse Radiation from the Aquila Rift

TL;DR

This study analyzes the diffuse UV background near the Aquila Rift using GALEX data, revealing its independence from Galactic latitude and IR emission, and estimates dust scattering properties through modeling.

Contribution

It provides new measurements of UV albedo and phase function asymmetry factor in the Aquila Rift region using Monte Carlo modeling.

Findings

UV background level is about 2000 ph cm^-2 s^-1 sr^-1 ^-1

UV emission correlates with distance from star HIP 88149

Derived dust albedo is 0.6-0.7, g is 0.2-0.4

Abstract

We present an analysis of the diffuse ultraviolet (UV) background in a low latitude region near the Aquila Rift based on observations made by the Galaxy Evolution Explorer (GALEX). The UV background is at a level of about 2000 ph cm^-2 s^-1 sr^-1 \AA^-1 with no correlation with either the Galactic latitude or the 100 micron infrared (IR) emission. Rather, the UV emission falls off with distance from the bright B2 star HIP 88149, which is in the centre of the field. We have used a Monte Carlo model to derive an albedo of 0.6 - 0.7 in the UV with a phase function asymmetry factor (g) of 0.2 - 0.4. The value for the albedo is dependent on the dust distribution while g is determined by the extent of the halo.