Dipolar modulation in the size of galaxies: the effect of Doppler magnification

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dc.contributor.authorBull, Philip
dc.date.accessioned2021-10-08T07:08:24Z
dc.date.available2021-10-08T07:08:24Z
dc.date.issued2017
dc.description.abstractObjects falling into an overdensity appear larger on its near side and smaller on its far side than other objects at the same redshift. This produces a dipolar pattern of magnification, primarily as a consequence of the Doppler effect. At low redshift this Doppler magnification completely dominates the usual integrated gravitational lensing contribution to the lensing magnification. We show that one can optimally observe this pattern by extracting the dipole in the cross-correlation of number counts and galaxy sizes. This dipole allows us to almost completely remove the contribution from gravitational lensing up to redshift ≲0.5 ≲0.5 , and even at high redshift z ≃ 1 the dipole picks up the Doppler magnification predominantly. Doppler magnification should be easily detectable in current and upcoming optical and radio surveys; by forecasting for telescopes such as the SKA, we show that this technique is competitive with using peculiar velocities via redshift-space distortions to constrain dark energy. It produces similar yet complementary constraints on the cosmological model to those found using measurements of the cosmic shear.
dc.identifier.apacitationBull, P. (2017). Dipolar modulation in the size of galaxies: the effect of Doppler magnification. <i>Monthly Notices of the Royal Astronomical Society</i>, 472(4), 3936 - 3951. http://hdl.handle.net/11427/34573en_ZA
dc.identifier.chicagocitationBull, Philip "Dipolar modulation in the size of galaxies: the effect of Doppler magnification." <i>Monthly Notices of the Royal Astronomical Society</i> 472, 4. (2017): 3936 - 3951. http://hdl.handle.net/11427/34573en_ZA
dc.identifier.citationBull, P. 2017. Dipolar modulation in the size of galaxies: the effect of Doppler magnification. <i>Monthly Notices of the Royal Astronomical Society.</i> 472(4):3936 - 3951. http://hdl.handle.net/11427/34573en_ZA
dc.identifier.issn0035-8711
dc.identifier.issn1365-2966
dc.identifier.ris TY - Journal Article AU - Bull, Philip AB - Objects falling into an overdensity appear larger on its near side and smaller on its far side than other objects at the same redshift. This produces a dipolar pattern of magnification, primarily as a consequence of the Doppler effect. At low redshift this Doppler magnification completely dominates the usual integrated gravitational lensing contribution to the lensing magnification. We show that one can optimally observe this pattern by extracting the dipole in the cross-correlation of number counts and galaxy sizes. This dipole allows us to almost completely remove the contribution from gravitational lensing up to redshift ≲0.5 ≲0.5 , and even at high redshift z ≃ 1 the dipole picks up the Doppler magnification predominantly. Doppler magnification should be easily detectable in current and upcoming optical and radio surveys; by forecasting for telescopes such as the SKA, we show that this technique is competitive with using peculiar velocities via redshift-space distortions to constrain dark energy. It produces similar yet complementary constraints on the cosmological model to those found using measurements of the cosmic shear. DA - 2017 DB - OpenUCT DP - University of Cape Town IS - 4 J1 - Monthly Notices of the Royal Astronomical Society LK - https://open.uct.ac.za PY - 2017 SM - 0035-8711 SM - 1365-2966 T1 - Dipolar modulation in the size of galaxies: the effect of Doppler magnification TI - Dipolar modulation in the size of galaxies: the effect of Doppler magnification UR - http://hdl.handle.net/11427/34573 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/34573
dc.identifier.vancouvercitationBull P. Dipolar modulation in the size of galaxies: the effect of Doppler magnification. Monthly Notices of the Royal Astronomical Society. 2017;472(4):3936 - 3951. http://hdl.handle.net/11427/34573.en_ZA
dc.language.isoeng
dc.publisher.departmentDepartment of Mathematics and Applied Mathematics
dc.publisher.facultyFaculty of Science
dc.sourceMonthly Notices of the Royal Astronomical Society
dc.source.journalissue4
dc.source.journalvolume472
dc.source.pagination3936 - 3951
dc.source.urihttps://dx.doi.org/10.1093/mnras/stx2049
dc.subject.otherastro-ph.CO
dc.subject.otherRCUK
dc.subject.otherSTFC
dc.subject.otherST/K00090X/1
dc.titleDipolar modulation in the size of galaxies: the effect of Doppler magnification
dc.typeJournal Article
uct.type.publicationResearch
uct.type.resourceJournal Article
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