dc.contributor.author Penoyre, Z en dc.contributor.author Moster, Benjamin en dc.contributor.author Sijacki, D en dc.contributor.author Genel, S en dc.date.accessioned 2017-06-29T11:19:51Z dc.date.available 2017-06-29T11:19:51Z dc.date.issued 2017-07 en dc.identifier.issn 0035-8711 dc.identifier.uri https://www.repository.cam.ac.uk/handle/1810/265086 dc.description.abstract Using the Illustris simulation, we follow thousands of elliptical galaxies back in time to identify how the dichotomy between fast and slow rotating ellipticals (FRs and SRs) develops. Comparing to the $\textrm{ATLAS}^\textrm{3D}$ survey, we show that Illustris reproduces similar elliptical galaxy rotation properties, quantified by the degree of ordered rotation, $\lambda_\textrm{R}$. There is a clear segregation between low-mass ($M_{\rm *} < 10^{11} M_{\rm \odot}$) ellipticals, which form a smooth distribution of FRs, and high-mass galaxies ($M_{\rm *} > 10^{11.5} M_{\rm \odot}$), which are mostly SRs, in agreement with observations. We find that SRs are very gas poor, metal rich and red in colour, while FRs are generally more gas rich and still star forming. We suggest that ellipticals begin naturally as FRs and, as they grow in mass, lose their spin and become SRs. While at $z = 1$, the progenitors of SRs and FRs are nearly indistinguishable, their merger and star formation histories differ thereafter. We find that major mergers tend to disrupt galaxy spin, though in rare cases can lead to a spin-up. No major difference is found between the effects of gas-rich and gas-poor mergers and the amount of minor mergers seem to have little correlation with galaxy spin. In between major mergers, lower-mass ellipticals, which are mostly gas-rich, tend to recover their spin by accreting gas and stars. For galaxies with $M_{\rm *}$ above $\sim 10^{11} M_{\rm \odot}$, this trend reverses; galaxies only retain or steadily lose their spin. More frequent mergers, accompanied by an inability to regain spin, lead massive ellipticals to lose most of ordered rotation and transition from FRs to SRs. dc.description.sponsorship BPM acknowledges support from the Kavli Foundation and the German Science Foundation (DFG) for an Emmy Noether grant. The Flatiron Institute is supported by the Simons Foundation. DS acknowledges support by the STFC and the ERC Starting Grant 638707 ‘Black holes and their host galaxies: co-evolution across cosmic time’. dc.language.iso en en dc.publisher Oxford University Press dc.subject methods: numerical en dc.subject galaxies: elliptical and lenticular, cD en dc.subject galaxies: evolution en dc.subject galaxies: kinematics and dynamics en dc.subject galaxies: structure en dc.title The Origin and Evolution of Fast and Slow Rotators in the Illustris Simulation en dc.type Article prism.endingPage 3906 prism.issueIdentifier 4 en prism.publicationDate 2017 en prism.publicationName Monthly Notices of the Royal Astronomical Society en prism.startingPage 3883 prism.volume 468 en dc.identifier.doi 10.17863/CAM.10998 dcterms.dateAccepted 2017-03-24 en rioxxterms.versionofrecord 10.1093/mnras/stx762 en rioxxterms.version VoR en rioxxterms.licenseref.uri http://www.rioxx.net/licenses/all-rights-reserved en rioxxterms.licenseref.startdate 2017-07 en dc.identifier.eissn 1365-2966 dc.publisher.url http://dx.doi.org/10.1093/mnras/stx762 en rioxxterms.type Journal Article/Review en pubs.funder-project-id SCIENCE & TECHNOLOGY FACILITIES COUNCIL (ST/N000927/1) pubs.funder-project-id ECH2020 EUROPEAN RESEARCH COUNCIL (ERC) (638707) cam.issuedOnline 2017-03-29 en dc.identifier.url http://dx.doi.org/10.1093/mnras/stx762 en
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