Header

UZH-Logo

Maintenance Infos

Bimodality of low-redshift circumgalactic O vi in non-equilibrium eagle zoom simulations


Oppenheimer, Benjamin D; Crain, Robert A; Schaye, Joop; Rahmati, Alireza; Richings, Alexander J; Trayford, James W; Tumlinson, Jason; Bower, Richard G; Schaller, Matthieu; Theuns, Tom (2016). Bimodality of low-redshift circumgalactic O vi in non-equilibrium eagle zoom simulations. Monthly Notices of the Royal Astronomical Society, 460(2):2157-2179.

Abstract

We introduce a series of 20 cosmological hydrodynamical simulations of L* (M200 = 1011.7-1012.3 M⊙) and group-sized (M200 = 1012.7-1013.3 M⊙) haloes run with the model used for the EAGLE project, which additionally includes a non-equilibrium ionization and cooling module that follows 136 ions. The simulations reproduce the observed correlation, revealed by COS-Halos at z ˜ 0.2, between {O {VI}} column density at impact parameters b < 150 kpc and the specific star formation rate (sSFR ≡ SFR/M*) of the central galaxy at z ˜ 0.2. We find that the column density of circumgalactic {O {VI}} is maximal in the haloes associated with L* galaxies, because their virial temperatures are close to the temperature at which the ionization fraction of {O {VI}} peaks (T ˜ 105.5 K). The higher virial temperature of group haloes (>106 K) promotes oxygen to higher ionization states, suppressing the {O {VI}} column density. The observed N_{O {VI}}-sSFR correlation therefore does not imply a causal link, but reflects the changing characteristic ionization state of oxygen as halo mass is increased. In spite of the mass dependence of the oxygen ionization state, the most abundant circumgalactic oxygen ion in both L* and group haloes is {O VII}; {O {VI}} accounts for only 0.1 per cent of the oxygen in group haloes and 0.9-1.3 per cent with L* haloes. Nonetheless, the metals traced by {O {VI}} absorbers represent a fossil record of the feedback history of galaxies over a Hubble time; their characteristic epoch of ejection corresponds to z > 1 and much of the ejected metal mass resides beyond the virial radius of galaxies. For both L* and group galaxies, more of the oxygen produced and released by stars in the circumgalactic medium (within twice the virial radius) than in the stars and interstellar medium of the galaxy.

Abstract

We introduce a series of 20 cosmological hydrodynamical simulations of L* (M200 = 1011.7-1012.3 M⊙) and group-sized (M200 = 1012.7-1013.3 M⊙) haloes run with the model used for the EAGLE project, which additionally includes a non-equilibrium ionization and cooling module that follows 136 ions. The simulations reproduce the observed correlation, revealed by COS-Halos at z ˜ 0.2, between {O {VI}} column density at impact parameters b < 150 kpc and the specific star formation rate (sSFR ≡ SFR/M*) of the central galaxy at z ˜ 0.2. We find that the column density of circumgalactic {O {VI}} is maximal in the haloes associated with L* galaxies, because their virial temperatures are close to the temperature at which the ionization fraction of {O {VI}} peaks (T ˜ 105.5 K). The higher virial temperature of group haloes (>106 K) promotes oxygen to higher ionization states, suppressing the {O {VI}} column density. The observed N_{O {VI}}-sSFR correlation therefore does not imply a causal link, but reflects the changing characteristic ionization state of oxygen as halo mass is increased. In spite of the mass dependence of the oxygen ionization state, the most abundant circumgalactic oxygen ion in both L* and group haloes is {O VII}; {O {VI}} accounts for only 0.1 per cent of the oxygen in group haloes and 0.9-1.3 per cent with L* haloes. Nonetheless, the metals traced by {O {VI}} absorbers represent a fossil record of the feedback history of galaxies over a Hubble time; their characteristic epoch of ejection corresponds to z > 1 and much of the ejected metal mass resides beyond the virial radius of galaxies. For both L* and group galaxies, more of the oxygen produced and released by stars in the circumgalactic medium (within twice the virial radius) than in the stars and interstellar medium of the galaxy.

Statistics

Citations

Altmetrics

Downloads

2 downloads since deposited on 04 Jan 2017
2 downloads since 12 months
Detailed statistics

Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Institute for Computational Science
Dewey Decimal Classification:530 Physics
Language:English
Date:2016
Deposited On:04 Jan 2017 10:00
Last Modified:28 Apr 2017 06:11
Publisher:Oxford University Press
ISSN:0035-8711
Free access at:Publisher DOI. An embargo period may apply.
Publisher DOI:https://doi.org/10.1093/mnras/stw1066

Download

Preview Icon on Download
Preview
Filetype: PDF
Size: 8MB
View at publisher

TrendTerms

TrendTerms displays relevant terms of the abstract of this publication and related documents on a map. The terms and their relations were extracted from ZORA using word statistics. Their timelines are taken from ZORA as well. The bubble size of a term is proportional to the number of documents where the term occurs. Red, orange, yellow and green colors are used for terms that occur in the current document; red indicates high interlinkedness of a term with other terms, orange, yellow and green decreasing interlinkedness. Blue is used for terms that have a relation with the terms in this document, but occur in other documents.
You can navigate and zoom the map. Mouse-hovering a term displays its timeline, clicking it yields the associated documents.

Author Collaborations