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Title: Investigating Ionization in the Intergalactic Medium
Abstract The intergalactic medium (IGM) contains >50% of the baryonic mass of the Universe, yet the mechanisms responsible for keeping the IGM ionized have not been fully explained. Hence, we investigate ion abundances from the largest blind QSO absorption catalog for clouds that show Civ, Nv, and Ovisimultaneously. The wavelength range of present UV spectrographs, however, makes it possible to probe Civand Ovionly over a small range of redshift (z≈ 0.12–0.15). As a result, we only have five IGM absorbing clouds, yet these provide a powerful and representative tool to probe the IGM ionization state. We found one cloud to be in collisional ionization equilibrium while three of the five showed signs of being produced by nonequilibrium processes, specifically conductive interfaces and turbulent mixing layers. None of the models we explore here were able to reproduce the ionization state of the remaining system. Energetic processes, such as galactic feedback from star formation and active galactic nucleus winds, would be excellent candidates that can cause such widespread ionization.  more » « less
Award ID(s):
2108159
PAR ID:
10528221
Author(s) / Creator(s):
; ;
Corporate Creator(s):
Editor(s):
NA
Publisher / Repository:
Astrophysical Journal
Date Published:
Journal Name:
The Astrophysical Journal
Edition / Version:
1
Volume:
965
Issue:
2
ISSN:
0004-637X
Page Range / eLocation ID:
142
Subject(s) / Keyword(s):
CGm, IGM, non-equilibrium
Format(s):
Medium: X Size: 1MB Other: pdf
Size(s):
1MB
Sponsoring Org:
National Science Foundation
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