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Title: The Formation and Physical Origin of Highly Ionized Cooling Gas

Abstract

We present a simple model that explains the origin of warm, diffuse gas seen primarily as highly ionized absorption-line systems in the spectra of background sources. We predict the observed column densities of several highly ionized transitions such as O vi, O vii, Ne viii, N v, and Mg x, and we present a unified comparison of the model predictions with absorption lines seen in the Milky Way disk, Milky Way halo, starburst galaxies, the circumgalactic medium, and the intergalactic medium at low and high redshifts. We show that diffuse gas seen in such diverse environments can be simultaneously explained by a simple model of radiatively cooling gas. We show that most such absorption-line systems are consistent with being collisionally ionized, and we estimate the maximum-likelihood temperature of the gas in each observation. This model satisfactorily explains why O vi is regularly observed around star-forming low- z L* galaxies, and why N v is rarely seen around the same galaxies. We further present some consequences of this model in quantifying the dynamics of the cooling gas around galaxies and predict the shock velocities associated with such flows. A unique strength of this model is that while it has only onemore » free (but physically well-constrained) parameter, it nevertheless successfully reproduces the available data on O vi absorbers in the interstellar, circumgalactic, intragroup, and intergalactic media, as well as the available data on other absorption lines from highly ionized species.« less

Authors:
 [1];  [2]; ;  [3]
  1. MIT-Kavli Center for Astrophysics and Space Research, 77 Massachusetts Avenue, Cambridge, MA, 02139 (United States)
  2. University of Tsukuba, Center for Computational Sciences, Tennodai 1-1-1, Tsukuba, Ibaraki (Japan)
  3. Department of Physics and Astronomy, John Hopkins University, 21218, Baltimore, MD (United States)
Publication Date:
OSTI Identifier:
22679732
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 848; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABSORPTION SPECTRA; COMPARATIVE EVALUATIONS; DENSITY; ELEMENT ABUNDANCE; FORECASTING; MAXIMUM-LIKELIHOOD FIT; MILKY WAY; QUASARS; RADIATIVE COOLING; RED SHIFT; SPECTRA; STAR EVOLUTION; STARS; VELOCITY

Citation Formats

Bordoloi, Rongmon, Wagner, Alexander Y., Heckman, Timothy M., and Norman, Colin A., E-mail: bordoloi@mit.edu, E-mail: bordoloi@mit.edu. The Formation and Physical Origin of Highly Ionized Cooling Gas. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA8E9C.
Bordoloi, Rongmon, Wagner, Alexander Y., Heckman, Timothy M., & Norman, Colin A., E-mail: bordoloi@mit.edu, E-mail: bordoloi@mit.edu. The Formation and Physical Origin of Highly Ionized Cooling Gas. United States. doi:10.3847/1538-4357/AA8E9C.
Bordoloi, Rongmon, Wagner, Alexander Y., Heckman, Timothy M., and Norman, Colin A., E-mail: bordoloi@mit.edu, E-mail: bordoloi@mit.edu. Fri . "The Formation and Physical Origin of Highly Ionized Cooling Gas". United States. doi:10.3847/1538-4357/AA8E9C.
@article{osti_22679732,
title = {The Formation and Physical Origin of Highly Ionized Cooling Gas},
author = {Bordoloi, Rongmon and Wagner, Alexander Y. and Heckman, Timothy M. and Norman, Colin A., E-mail: bordoloi@mit.edu, E-mail: bordoloi@mit.edu},
abstractNote = {We present a simple model that explains the origin of warm, diffuse gas seen primarily as highly ionized absorption-line systems in the spectra of background sources. We predict the observed column densities of several highly ionized transitions such as O vi, O vii, Ne viii, N v, and Mg x, and we present a unified comparison of the model predictions with absorption lines seen in the Milky Way disk, Milky Way halo, starburst galaxies, the circumgalactic medium, and the intergalactic medium at low and high redshifts. We show that diffuse gas seen in such diverse environments can be simultaneously explained by a simple model of radiatively cooling gas. We show that most such absorption-line systems are consistent with being collisionally ionized, and we estimate the maximum-likelihood temperature of the gas in each observation. This model satisfactorily explains why O vi is regularly observed around star-forming low- z L* galaxies, and why N v is rarely seen around the same galaxies. We further present some consequences of this model in quantifying the dynamics of the cooling gas around galaxies and predict the shock velocities associated with such flows. A unique strength of this model is that while it has only one free (but physically well-constrained) parameter, it nevertheless successfully reproduces the available data on O vi absorbers in the interstellar, circumgalactic, intragroup, and intergalactic media, as well as the available data on other absorption lines from highly ionized species.},
doi = {10.3847/1538-4357/AA8E9C},
journal = {Astrophysical Journal},
number = 2,
volume = 848,
place = {United States},
year = {Fri Oct 20 00:00:00 EDT 2017},
month = {Fri Oct 20 00:00:00 EDT 2017}
}