High resolution imaging of the anomalous flux-ratio gravitational lens system CLASS B2045+265: Dark or luminous satellites?

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dc.creatorMcKean, J. P.
dc.creatorKoopmans, L. V. E.
dc.creatorFlack, C. E.
dc.creatorFassnacht, C. D.
dc.creatorThompson, D.
dc.creatorMatthews, K.
dc.creatorBlandford, R. D.
dc.creatorReadhead, A. C. S.
dc.creatorSoifer, B. T.
dc.date2006-11-07
dc.date2007-03-16
dc.date.accessioned2026-07-07T11:00:08Z
dc.date.available2026-07-07T11:00:08Z
dc.descriptionThe existence of flux-ratio anomalies between fold and cusp images in galaxy-scale strong-lens systems has led to an interpretation based on the presence of a high mass-fraction of cold-dark-matter (CDM) substructures around galaxies, as predicted by numerical N-body simulations. The flux-ratio anomaly is particularly evident in the radio-loud quadruple gravitational lens system CLASS B2045+265. In this paper, new high-resolution radio, optical, and infrared imaging of B2045+265 is presented which sheds more light on this anomaly and its possible causes. First, deep Very Long Baseline Array observations show very compact images, possibly with a hint of a jet, but with no evidence for differential scattering or scatter broadening. Second, optical and infrared observations with the Hubble Space Telescope and through Adaptive-Optics imaging with the W. M. Keck Telescope, show a previously undiscovered object -- interpreted as a (tidally disrupted) dwarf satellite based on its colours and slight extension -- between the main lens galaxy and the three anomalous flux-ratio images. Third, colour variations in the early-type lens galaxy indicate recent star-formation, possibly the result of secondary infall of gas-rich satellites. A population of such galaxies around the lens system could explain the previously discovered strong [O II] emission. However, spiral structure and/or normal star formation in the lens galaxy cannot be excluded. In light of these new data, we propose a lens model for the system, including the observed dwarf satellite, which reproduces all positional and flux-ratio constraints, without the need for additional CDM substructure. [abridged]
dc.description10 pages, 6 figures, accepted for publication in MNRAS
dc.identifierhttps://arxiv.org/abs/astro-ph/0611215
dc.identifierhttp://arxiv.org/abs/astro-ph/0611215
dc.identifierMon.Not.Roy.Astron.Soc.378:109-118,2007
dc.identifierdoi:10.1111/j.1365-2966.2007.11744.x
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/187621
dc.subjectAstrophysics
dc.titleHigh resolution imaging of the anomalous flux-ratio gravitational lens system CLASS B2045+265: Dark or luminous satellites?
dc.typetext

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