English

The ionic composition of the local absorber towards 3C 273

Astrophysics of Galaxies 2020-01-29 v1

Abstract

Hot ionized gas is observed in the local vicinity of our galaxy through spectral absorption features. The most common hypothesis is that this gas forms a halo surrounding our Milky-Way (MW), in collisional ionization equilibrium. In this paper we investigate the elemental abundance of this hot and ionized local gas. We use a 2.4 Ms stacked X-ray spectrum of the bright blazar 3C 273 and probe the local absorption features. Using ion-by-ion fitting of the X-ray absorption lines we derive the column density of each ionization species. Based on the column densities we reconstruct the Absorption measure distribution (AMD), namely the hydrogenic column density as a function of temperature. We report the elemental abundances of C, N, Ne, and Fe relative to solar O. Previous measurements of local X-ray emission lines in conjunction with the present column densities indicate a scale height of 1801-80 kpc and hydrogen number density of 10410310^{-4}-10^{-3}cm3^{-3} for the hot ionized gas. Additionally, we detect He-like O lines from the quasar broad line region with velocities of 6400±\pm1500 km s1^{-1}

Keywords

Cite

@article{arxiv.2001.06815,
  title  = {The ionic composition of the local absorber towards 3C 273},
  author = {Itay Gissis and Uria Peretz and Ehud Behar},
  journal= {arXiv preprint arXiv:2001.06815},
  year   = {2020}
}