An analysis of the evolving comoving number density of galaxies in hydrodynamical simulations
We present an analysis of the evolving comoving cumulative number density of galaxy populations found in the Illustris simulation. Cumulative number density is commonly used to link galaxy populations across different epochs by assuming that galaxies preserve their number density in time. Our analys...
| Main Authors: | , , , , , , , , , , , , |
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| Format: | Article |
| Language: | en_US |
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Oxford University Press
2017
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| Online Access: | http://hdl.handle.net/1721.1/108494 https://orcid.org/0000-0002-5653-0786 https://orcid.org/0000-0001-8745-5830 https://orcid.org/0000-0001-9018-1180 https://orcid.org/0000-0001-8593-7692 |
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| author | Wellons, Sarah Nelson, Dylan Rodriguez-Gomez, Vicente McKinnon, Ryan Pillepich, Annalisa Ma, Chung-Pei Springel, Volker Hernquist, Lars Torrey, Paul A. Leal Machado, Francisco Griffen, Brendan F. McKinnon, Ryan Michael Vogelsberger, Mark |
| author2 | MIT Kavli Institute for Astrophysics and Space Research |
| author_facet | MIT Kavli Institute for Astrophysics and Space Research Wellons, Sarah Nelson, Dylan Rodriguez-Gomez, Vicente McKinnon, Ryan Pillepich, Annalisa Ma, Chung-Pei Springel, Volker Hernquist, Lars Torrey, Paul A. Leal Machado, Francisco Griffen, Brendan F. McKinnon, Ryan Michael Vogelsberger, Mark |
| author_sort | Wellons, Sarah |
| collection | MIT |
| description | We present an analysis of the evolving comoving cumulative number density of galaxy populations found in the Illustris simulation. Cumulative number density is commonly used to link galaxy populations across different epochs by assuming that galaxies preserve their number density in time. Our analysis allows us to examine the extent to which this assumption holds in the presence of galaxy mergers or when rank ordering is broken owing to variable stellar growth rates. Our primary results are as follows: (1) the inferred average stellar mass evolution obtained via a constant comoving number density assumption is systematically biased compared to the merger tree results at the factor of ∼2(4) level when tracking galaxies from redshift z = 0 to 2(3); (2) the median number density evolution for galaxy populations tracked forward in time is shallower than for galaxy populations tracked backward; (3) a similar evolution in the median number density of tracked galaxy populations is found regardless of whether number density is assigned via stellar mass, stellar velocity dispersion, or halo mass; (4) explicit tracking reveals a large diversity in the stellar and dark matter assembly histories that cannot be captured by constant number density analyses; (5) the significant scatter in galaxy linking methods is only marginally reduced (∼20 per cent) by considering additional physical galaxy properties. We provide fits for the median evolution in number density for use with observational data and discuss the implications of our analysis for interpreting multi-epoch galaxy property observations. |
| first_indexed | 2024-09-23T10:43:03Z |
| format | Article |
| id | mit-1721.1/108494 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T10:43:03Z |
| publishDate | 2017 |
| publisher | Oxford University Press |
| record_format | dspace |
| spelling | mit-1721.1/1084942022-09-27T14:29:45Z An analysis of the evolving comoving number density of galaxies in hydrodynamical simulations Wellons, Sarah Nelson, Dylan Rodriguez-Gomez, Vicente McKinnon, Ryan Pillepich, Annalisa Ma, Chung-Pei Springel, Volker Hernquist, Lars Torrey, Paul A. Leal Machado, Francisco Griffen, Brendan F. McKinnon, Ryan Michael Vogelsberger, Mark MIT Kavli Institute for Astrophysics and Space Research Torrey, Paul A. Leal Machado, Francisco Griffen, Brendan F. McKinnon, Ryan Michael Vogelsberger, Mark We present an analysis of the evolving comoving cumulative number density of galaxy populations found in the Illustris simulation. Cumulative number density is commonly used to link galaxy populations across different epochs by assuming that galaxies preserve their number density in time. Our analysis allows us to examine the extent to which this assumption holds in the presence of galaxy mergers or when rank ordering is broken owing to variable stellar growth rates. Our primary results are as follows: (1) the inferred average stellar mass evolution obtained via a constant comoving number density assumption is systematically biased compared to the merger tree results at the factor of ∼2(4) level when tracking galaxies from redshift z = 0 to 2(3); (2) the median number density evolution for galaxy populations tracked forward in time is shallower than for galaxy populations tracked backward; (3) a similar evolution in the median number density of tracked galaxy populations is found regardless of whether number density is assigned via stellar mass, stellar velocity dispersion, or halo mass; (4) explicit tracking reveals a large diversity in the stellar and dark matter assembly histories that cannot be captured by constant number density analyses; (5) the significant scatter in galaxy linking methods is only marginally reduced (∼20 per cent) by considering additional physical galaxy properties. We provide fits for the median evolution in number density for use with observational data and discuss the implications of our analysis for interpreting multi-epoch galaxy property observations. National Science Foundation (U.S.) (DGE1144152) United States. Department of Energy (DE-FG02-97ER25308) United States. National Aeronautics and Space Administration (NNX12AC67G) National Science Foundation (U.S.) (AST-1312095) 2017-04-28T17:19:16Z 2017-04-28T17:19:16Z 2015-10 2015-08 Article http://purl.org/eprint/type/JournalArticle 0035-8711 1365-2966 http://hdl.handle.net/1721.1/108494 orrey, Paul; Wellons, Sarah; Machado, Francisco; Griffen, Brendan; Nelson, Dylan; Rodriguez-Gomez, Vicente; McKinnon, Ryan, et al. “An Analysis of the Evolving Comoving Number Density of Galaxies in Hydrodynamical Simulations.” Monthly Notices of the Royal Astronomical Society 454, no. 3 (October 14, 2015): 2770–2786. https://orcid.org/0000-0002-5653-0786 https://orcid.org/0000-0001-8745-5830 https://orcid.org/0000-0001-9018-1180 https://orcid.org/0000-0001-8593-7692 en_US http://dx.doi.org/10.1093/mnras/stv1986 Monthly Notices of the Royal Astronomical Society Creative Commons Attribution-Noncommercial-Share Alike http://creativecommons.org/licenses/by-nc-sa/4.0/ application/pdf Oxford University Press arXiv |
| spellingShingle | Wellons, Sarah Nelson, Dylan Rodriguez-Gomez, Vicente McKinnon, Ryan Pillepich, Annalisa Ma, Chung-Pei Springel, Volker Hernquist, Lars Torrey, Paul A. Leal Machado, Francisco Griffen, Brendan F. McKinnon, Ryan Michael Vogelsberger, Mark An analysis of the evolving comoving number density of galaxies in hydrodynamical simulations |
| title | An analysis of the evolving comoving number density of galaxies in hydrodynamical simulations |
| title_full | An analysis of the evolving comoving number density of galaxies in hydrodynamical simulations |
| title_fullStr | An analysis of the evolving comoving number density of galaxies in hydrodynamical simulations |
| title_full_unstemmed | An analysis of the evolving comoving number density of galaxies in hydrodynamical simulations |
| title_short | An analysis of the evolving comoving number density of galaxies in hydrodynamical simulations |
| title_sort | analysis of the evolving comoving number density of galaxies in hydrodynamical simulations |
| url | http://hdl.handle.net/1721.1/108494 https://orcid.org/0000-0002-5653-0786 https://orcid.org/0000-0001-8745-5830 https://orcid.org/0000-0001-9018-1180 https://orcid.org/0000-0001-8593-7692 |
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