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dc.contributor.authorErkal, Denisen
dc.contributor.authorBelokurov, Vasilyen
dc.date.accessioned2015-07-15T11:36:02Z
dc.date.available2015-07-15T11:36:02Z
dc.date.issued2015-04-22en
dc.identifier.citationErkal D, Belokurov V, MNRAS, 2015, 450, 1136-1149, doi:10.1093/mnras/stv655en
dc.identifier.issn0035-8711
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/248977
dc.description.abstractThere is hope to discover dark matter subhaloes free of stars (predicted by the current theory of structure formation) by observing gaps they produce in tidal streams. In fact, this is the most promising technique for dark substructure detection and characterization as such gaps grow with time, magnifying small perturbations into clear signatures observable by ongoing and planned Galaxy surveys. To facilitate such future inference, we develop a comprehensive framework for studies of the growth of the stream density perturbations. Starting with simple assumptions and restricting to streams on circular orbits, we derive analytic formulae that describe the evolution of all gap properties (size, density contrast, etc.) at all times. We uncover complex, previously unnoticed behaviour, with the stream initially forming a density enhancement near the subhalo impact point. Shortly after, a gap forms due to the relative change in period induced by the subhalo's passage. There is an intermediate regime where the gap grows linearly in time. At late times, the particles in the stream overtake each other, forming caustics, and the gap grows like √t. In addition to the secular growth, we find that the gap oscillates as it grows due to epicyclic motion. We compare this analytic model to N-body simulations and find an impressive level of agreement. Importantly, when analysing the observation of a single gap we find a large degeneracy between the subhalo mass, the impact geometry and kinematics, the host potential, and the time since flyby.
dc.description.sponsorshipThe research leading to these results has received funding from the European Research Council under the European Union's Seventh Framework Programme (FP/2007–2013)/ERC Grant Agreement No. 308024.
dc.languageEnglishen
dc.language.isoenen
dc.publisherOxford University Press
dc.subjectgalaxies: haloesen
dc.subjectgalaxies: kinematics and dynamicsen
dc.subjectgalaxies: structureen
dc.subjectcosmology: theoryen
dc.subjectdark matteren
dc.titleForensics of subhalo–stream encounters: the three phases of gap growthen
dc.typeArticle
dc.description.versionThis is the final published version of the article. It was originally published in the Monthly Notices of the Royal Astronomical Society (Erkal D, Belokurov V, MNRAS, 2015, 450, 1136-1149, doi:10.1093/mnras/stv655). The final version is available at http://dx.doi.org/10.1093/mnras/stv655 This article has been accepted for publication in the Monthly Notices of the Royal Astronomical Society ©: 2015 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.en
prism.endingPage1149
prism.publicationDate2015en
prism.publicationNameMonthly Notices of the Royal Astronomical Societyen
prism.startingPage1136
prism.volume450en
dc.rioxxterms.funderERC
dc.rioxxterms.projectid308024
rioxxterms.versionofrecord10.1093/mnras/stv655en
rioxxterms.licenseref.urihttp://www.rioxx.net/licenses/all-rights-reserveden
rioxxterms.licenseref.startdate2015-04-22en
dc.contributor.orcidBelokurov, Vasily [0000-0002-0038-9584]
dc.identifier.eissn1365-2966
rioxxterms.typeJournal Article/Reviewen


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