English

Modeling the Cosmic Ultraviolet Background at the North Galactic Pole

Instrumentation and Methods for Astrophysics 2025-07-08 v1

Abstract

I explore models of the dust-scattered component of the Cosmic Ultraviolet Background (CUVB) at the North Galactic Pole (NGP) in order to develop a framework for calculating the dust-scattered light as a function of the optical depths. As expected, I find that the dust-scattered emission scales linearly with reddening up to E(BV)0.1E(B-V) \approx 0.1\ mag and derive a parametric model for this dependence. I have applied these models to fit the far-ultraviolet (1350--1800 \AA) observations from the \textit{Galaxy Evolution Explorer (GALEX)} finding that the optical constants of the interstellar dust grains -- albedo (aa) and phase function asymmetry factor (gg) -- are consistent with predictions from the Astrodust model (a=0.33a = 0.33, g=0.68g = 0.68). I detect an isotropic offset of 267±7267 \pm 7 ph cm2^{-2} s1^{-1} sr1^{-1} \AA1^{-1}, half of which remains unaccounted for by known Galactic or extragalactic sources. I will now extend my analysis to wider sky regions with the goal of generating high-resolution extinction maps.

Keywords

Cite

@article{arxiv.2507.03322,
  title  = {Modeling the Cosmic Ultraviolet Background at the North Galactic Pole},
  author = {Jayant Murthy},
  journal= {arXiv preprint arXiv:2507.03322},
  year   = {2025}
}

Comments

7 pages, 4 figures, accepted in Journal of Astrophysics and Astronomy

R2 v1 2026-07-01T03:46:18.237Z