Examinando por Autor "Sluse, D."
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Ítem Double dark matter vision: Twice the number of compact-source lenses with narrow-line lensing and the WFC3 grism(Oxford University Press, 2020) Nierenberg, A.; Gilman, D.; Treu, T.; Brammer, G.; Birrer, S.; Moustakas, L.; Agnello, A.; Anguita, T.; Fassnacht, C.; Motta, V.; Peter, A.; Sluse, D.The magnifications of compact-source lenses are extremely sensitive to the presence of lowmass darkmatter haloes along the entire sightline from the source to the observer. Traditionally, the study of darkmatter structure in compact-source strong gravitational lenses has been limited to radio-loud systems, as the radio emission is extended and thus unaffected by microlensing which can mimic the signal of dark matter structure. An alternate approach is to measure quasar nuclear-narrow-line emission, which is free from microlensing and present in virtually all quasar lenses. In this paper, we double the number of systems which can be used for gravitational lensing analyses by presenting measurements of narrow-line emission from a sample of eight quadruply imaged quasar lens systems, WGD J0405-3308, HS 0810+2554, RX J0911+0551, SDSS J1330+1810, PS J1606-2333, WFI 2026-4536, WFI 2033-4723, and WGD J2038-4008. We describe our updated grism spectral modelling pipeline, which we use to measure narrow-line fluxes with uncertainties of 2-10 per cent, presented here. We fit the lensed image positions with smooth mass models and demonstrate that these models fail to produce the observed distribution of image fluxes over the entire sample of lenses. Furthermore, typical deviations are larger than those expected from macromodel uncertainties. This discrepancy indicates the presence of perturbations caused by small-scale dark matter structure. The interpretation of this result in terms of dark matter models is presented in a companion paper.Ítem Evidence for two spatially separated UV continuum emitting regions in the Cloverleaf broad absorption line quasar(EDP Sciences, 2015-10) Sluse, D.; Hutsemekers, D.; Anguita, T.; Braibant, L.; Riaud, P.Testing the standard Shakura-Sunyaev model of accretion is a challenging task because the central region of quasars where accretion takes place is unresolved with telescopes. The analysis of microlensing in gravitationally lensed quasars is one of the few techniques that can test this model, yielding to the measurement of the size and of temperature profile of the accretion disc. We present spectroscopic observations of the gravitationally lensed broad absorption line quasar H1413+117, which reveal partial microlensing of the continuum emission that appears to originate from two separated regions: a microlensed region, corresponding the compact accretion disc; and a non-microlensed region, more extended and contributing to at least 30% of the total UV-continuum flux. Because this extended continuum is occulted by the broad absorption line clouds, it is not associated with the host galaxy, but rather with light scattered in the neighbourhood of the central engine. We measure the amplitude of microlensing of the compact continuum over the rest-frame wavelength range 1000-7000 Å. Following a Bayesian scheme, we confront our measurements to microlensing simulations of an accretion disc with a temperature varying as T ∝ R-1/ν. We find a most likely source half-light radius of R1/2 = 0.61 × 1016cm (i.e., 0.002 pc) at 0.18μm, and a most-likely index of ν = 0.4. The standard disc (ν = 4/3) model is not ruled out by our data, and is found within the 95% confidence interval associated with our measurements. We demonstrate that, for H1413+117, the existence of an extended continuum in addition to the disc emission only has a small impact on the inferred disc parameters, and is unlikely to solve the tension between the microlensing source size and standard disc sizes, as previously reported in the literature. © 2015 ESO.Ítem Polarization microlensing in the quadruply imaged broad absorption line quasar H1413+117(EDP Sciences, 2015-12) Hutsemékers, D.; Sluse, D.; Braibant, L.; Anguita, T.We have obtained spectropolarimetric observations of the four images of the gravitationally lensed broad absorption line quasar H1413+117. The polarization of the microlensed image D is significantly different, both in the continuum and in the broad lines, from the polarization of image A, which is essentially unaffected by microlensing. The observations suggest that the continuum is scattered off two regions, spatially separated, and producing roughly perpendicular polarizations. These results are compatible with a model in which the microlensed polarized continuum comes from a compact region located in the equatorial plane close to the accretion disk and the non-microlensed continuum from an extended region located along the polar axis. © ESO, 2015.