We use observations of CIV and CII absorption in background quasars to
constrain the parameters of supernova feedback models based on the Illustris
cosmological simulation. We compare our simulations to two CIV absorber surveys
at z=2-4, spanning a column density range $10^12 - 10^15$ cm$^-2$, and an
equivalent width 0.1 - 2 \AA, respectively. We find that reproducing results
from the first survey requires that the energy per unit mass of the supernova
feedback be increased by a factor of two over the Illustris feedback model. We
suggest that winds which deposit a fraction of their energy into heating,
rather than accelerating, the surrounding gas can achieve this without altering
the star formation rate. However, even our most energetic wind models do not
produce enough absorbers with a CIV equivalent width greater than 0.6 Angstrom
to match the results of the second survey. We connect these absorbers to the
most massive haloes present in our simulations, and suggest possible ways to
alleviate the discrepancy, either by further increasing the wind energy per
unit mass, or by modifying the AGN feedback model. We also compare to the
covering fractions and equivalent widths of CIV and CII absorbers around Damped
Lyman-alpha absorbers, showing generally good agreement. Finally, we show that
the CIV in our simulations is predominantly photoionized.
Description
[1512.02221] Simulating the Carbon Footprint of Galactic Halos
%0 Generic
%1 bird2015simulating
%A Bird, Simeon
%A Rubin, Kate H. R.
%A Suresh, Joshua
%A Hernquist, Lars
%D 2015
%K feedback gas metal simulation
%T Simulating the Carbon Footprint of Galactic Halos
%U http://arxiv.org/abs/1512.02221
%X We use observations of CIV and CII absorption in background quasars to
constrain the parameters of supernova feedback models based on the Illustris
cosmological simulation. We compare our simulations to two CIV absorber surveys
at z=2-4, spanning a column density range $10^12 - 10^15$ cm$^-2$, and an
equivalent width 0.1 - 2 \AA, respectively. We find that reproducing results
from the first survey requires that the energy per unit mass of the supernova
feedback be increased by a factor of two over the Illustris feedback model. We
suggest that winds which deposit a fraction of their energy into heating,
rather than accelerating, the surrounding gas can achieve this without altering
the star formation rate. However, even our most energetic wind models do not
produce enough absorbers with a CIV equivalent width greater than 0.6 Angstrom
to match the results of the second survey. We connect these absorbers to the
most massive haloes present in our simulations, and suggest possible ways to
alleviate the discrepancy, either by further increasing the wind energy per
unit mass, or by modifying the AGN feedback model. We also compare to the
covering fractions and equivalent widths of CIV and CII absorbers around Damped
Lyman-alpha absorbers, showing generally good agreement. Finally, we show that
the CIV in our simulations is predominantly photoionized.
@misc{bird2015simulating,
abstract = {We use observations of CIV and CII absorption in background quasars to
constrain the parameters of supernova feedback models based on the Illustris
cosmological simulation. We compare our simulations to two CIV absorber surveys
at z=2-4, spanning a column density range $10^{12} - 10^{15}$ cm$^{-2}$, and an
equivalent width 0.1 - 2 \AA, respectively. We find that reproducing results
from the first survey requires that the energy per unit mass of the supernova
feedback be increased by a factor of two over the Illustris feedback model. We
suggest that winds which deposit a fraction of their energy into heating,
rather than accelerating, the surrounding gas can achieve this without altering
the star formation rate. However, even our most energetic wind models do not
produce enough absorbers with a CIV equivalent width greater than 0.6 Angstrom
to match the results of the second survey. We connect these absorbers to the
most massive haloes present in our simulations, and suggest possible ways to
alleviate the discrepancy, either by further increasing the wind energy per
unit mass, or by modifying the AGN feedback model. We also compare to the
covering fractions and equivalent widths of CIV and CII absorbers around Damped
Lyman-alpha absorbers, showing generally good agreement. Finally, we show that
the CIV in our simulations is predominantly photoionized.},
added-at = {2015-12-09T10:18:38.000+0100},
author = {Bird, Simeon and Rubin, Kate H. R. and Suresh, Joshua and Hernquist, Lars},
biburl = {https://www.bibsonomy.org/bibtex/2b815439e62566d192b058ad7786ef16e/miki},
description = {[1512.02221] Simulating the Carbon Footprint of Galactic Halos},
interhash = {b3ab60657fde89e9ea2ed24d3680a8e5},
intrahash = {b815439e62566d192b058ad7786ef16e},
keywords = {feedback gas metal simulation},
note = {cite arxiv:1512.02221Comment: 13 pages, 10 figures, submitted to MNRAS},
timestamp = {2015-12-09T10:18:38.000+0100},
title = {Simulating the Carbon Footprint of Galactic Halos},
url = {http://arxiv.org/abs/1512.02221},
year = 2015
}