dc.contributor.author | Garg, Prerak | |
dc.contributor.author | Narayanan, Desika | |
dc.contributor.author | Byler, Nell | |
dc.contributor.author | Sanders, Ryan L. | |
dc.contributor.author | Shapley, Alice E. | |
dc.contributor.author | Strom, Allison L. | |
dc.contributor.author | Davé, Romeel | |
dc.contributor.author | Hirschmann, Michaela | |
dc.contributor.author | Lovell, Christopher C. | |
dc.contributor.author | Otter, Justin | |
dc.contributor.author | Popping, Gergö | |
dc.contributor.author | Privon, George C. | |
dc.date.accessioned | 2022-02-16T09:45:03Z | |
dc.date.available | 2022-02-16T09:45:03Z | |
dc.date.issued | 2022-02-15 | |
dc.identifier.citation | Garg , P , Narayanan , D , Byler , N , Sanders , R L , Shapley , A E , Strom , A L , Davé , R , Hirschmann , M , Lovell , C C , Otter , J , Popping , G & Privon , G C 2022 , ' The BPT Diagram in Cosmological Galaxy Formation Simulations: Understanding the Physics Driving Offsets at High Redshift ' , The Astrophysical Journal , vol. 926 , no. 1 , 80 . https://doi.org/10.3847/1538-4357/ac43b8 | |
dc.identifier.issn | 0004-637X | |
dc.identifier.other | Jisc: 87970 | |
dc.identifier.other | publisher-id: apjac43b8 | |
dc.identifier.other | manuscript: ac43b8 | |
dc.identifier.other | other: aas34759 | |
dc.identifier.uri | http://hdl.handle.net/2299/25379 | |
dc.description | © 2022. The Author(s). Published by the American Astronomical Society This work is licenced under Creative Commons Attribution 4.0 licence. https://creativecommons.org/licenses/by/4.0/ | |
dc.description.abstract | The Baldwin, Philips, & Terlevich diagram of [O iii]/Hβ versus [N ii]/Hα (hereafter N2-BPT) has long been used as a tool for classifying galaxies based on the dominant source of ionizing radiation. Recent observations have demonstrated that galaxies at z ∼ 2 reside offset from local galaxies in the N2-BPT space. In this paper, we conduct a series of controlled numerical experiments to understand the potential physical processes driving this offset. We model nebular line emission in a large sample of galaxies, taken from the simba cosmological hydrodynamic galaxy formation simulation, using the cloudy photoionization code to compute the nebular line luminosities from H ii regions. We find that the observed shift toward higher [O iii]/Hβ and [N ii]/Hα values at high redshift arises from sample selection: when we consider only the most massive galaxies M * ∼ 1010–11 M ⊙, the offset naturally appears, due to their high metallicities. We predict that deeper observations that probe lower-mass galaxies will reveal galaxies that lie on a locus comparable to z ∼ 0 observations. Even when accounting for samples-selection effects, we find that there is a subtle mismatch between simulations and observations. To resolve this discrepancy, we investigate the impact of varying ionization parameters, H ii region densities, gas-phase abundance patterns, and increasing radiation field hardness on N2-BPT diagrams. We find that either decreasing the ionization parameter or increasing the N/O ratio of galaxies at fixed O/H can move galaxies along a self-similar arc in N2-BPT space that is occupied by high-redshift galaxies. | en |
dc.format.extent | 18 | |
dc.format.extent | 4078508 | |
dc.language.iso | eng | |
dc.relation.ispartof | The Astrophysical Journal | |
dc.subject | 310 | |
dc.subject | Galaxies and Cosmology | |
dc.title | The BPT Diagram in Cosmological Galaxy Formation Simulations: Understanding the Physics Driving Offsets at High Redshift | en |
dc.contributor.institution | Department of Physics, Astronomy and Mathematics | |
dc.contributor.institution | School of Physics, Engineering & Computer Science | |
dc.description.status | Peer reviewed | |
rioxxterms.versionofrecord | 10.3847/1538-4357/ac43b8 | |
rioxxterms.type | Journal Article/Review | |
herts.preservation.rarelyaccessed | true | |