Examinando por Autor "Lin H."

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    STRIDES: Spectroscopic and photometric characterization of the environment and effects of mass along the line of sight to the gravitational lenses des J0408-5354 and WGD 2038-4008
    (Oxford University Press, 2020-11-01) Buckley-Geer E.J.; Lin H.; Rusu C.E.; Poh J.; Palmese A.; Agnello A.; Christensen L.; Frieman J.; Shajib A.J.; Treu T.; Collett T.; Birrer S.; Anguita T.; Fassnacht C.D.; Meylan G.; Mukherjee S.; Wong K.C.; Aguena M.; Allam S.; Avila S.; Bertin E.; Bhargava S.; Brooks D.; Carnero Rosell A.; Carrasco Kind M.; Carretero J.; Castander F.J.; Costanzi M.; Da Costa L.N.; De Vicente J.; Desai S.; Diehl H.T.; Doel P.; Eifler T.F.; Everett S.; Flaugher B.; Fosalba P.; Garciá-Bellido J.; Gaztanaga E.; Gruen D.; Gruendl R.A.; Gschwend J.; Gutierrez G.; Hinton S.R.; Honscheid K.; James D.J.; Kuehn K.; Kuropatkin N.; Maia M.A.G.; Marshall J.L.; Melchior P.; Menanteau F.; Miquel R.; Ogando R.L.C.; Paz-Chinchón F.; Plazas A.A.; Sanchez E.; Scarpine V.; Schubnell M.
    In time-delay cosmography, three of the key ingredients are (1) determining the velocity dispersion of the lensing galaxy, (2) identifying galaxies and groups along the line of sight with sufficient proximity and mass to be included in the mass model, and (3) estimating the external convergence κext from less massive structures that are not included in the mass model. We present results on all three of these ingredients for two time-delay lensed quad quasar systems, DES J0408-5354 and WGD 2038-4008. We use the Gemini, Magellan, and VLT telescopes to obtain spectra to both measure the stellar velocity dispersions of the main lensing galaxies and to identify the line-of-sight galaxies in these systems. Next, we identify 10 groups in DES J0408-5354 and two groups in WGD 2038-4008 using a group-finding algorithm. We then identify the most significant galaxy and galaxy-group perturbers using the 'flexion shift' criterion. We determine the probability distribution function of the external convergence κext for both of these systems based on our spectroscopy and on the DES-only multiband wide-field observations. Using weighted galaxy counts, calibrated based on the Millennium Simulation, we find that DES J0408-5354 is located in a significantly underdense environment, leading to a tight (width ∼ 3%), negative-value κext distribution. On the other hand, WGD 2038-4008 is located in an environment of close to unit density, and its low source redshift results in a much tighter κext of ~1%, as long as no external shear constraints are imposed.
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    The STRong lensing Insights into the Dark Energy Survey (STRIDES) 2016 follow-up campaign - II. New quasar lenses from double component fitting
    (Oxford University Press, 2018-11) Anguita T.; Schechter P.L.; Kuropatkin N.; Morgan N.D.; Ostrovski F.; Abramson L.E.; Agnello A.; Apostolovski Y.; Fassnacht C.D.; Hsueh J.W.; Motta V.; Rojas K.; Rusu C.E.; Treu T.; Williams P.; Auger M.; Buckley-Geer E.; Lin H.; McMahon R.; Abbott T.M.C.; Allam S.; Annis J.; Bernstein R.A.; Bertin E.; Brooks D.; Burke D.L.; Carnero Rosell A.; Carrasco-Kind M.; Carretero J.; Cunha C.E.; D'Andrea C.B.; De Vicente J.; Depoy D.L.; Desai S.; DIehl H.T.; Doel P.; Flaugher B.; García-Bellido J.; Gerdes D.W.; Gschwend J.; Hartley W.G.; Hollowood D.L.; Honscheid K.; James D.J.; Kuehn K.; Lima M.; Maia M.A.G.; Miquel R.; Plazas A.A.; Sanchez E.; Scarpine V.; Smith M.; Soares-Santos M.; Sobreira F.; Suchyta E.; Tarle G.; Walker A.R.; Gruent, D.
    We report upon the follow-up of 34 candidate lensed quasars found in the Dark Energy Survey using NTT EFOSC, Magellan-IMACS, KECK-ESI, and SOAR-SAMI. These candidates were selected by a combination of double component fitting, morphological assessment, and colour analysis. Most systems followed up are indeed composed of at least one quasar image and 13 with two or more quasar images: two lenses, four projected binaries, and seven nearly identical quasar pairs (NIQs). The two systems confirmed as genuine gravitationally lensed quasars are one quadruple at $z$s = 1.713 and one double at $z$s = 1.515. Lens modelling of these two systems reveals that both systems require very little contribution from the environment to reproduce the image configuration. Nevertheless, small flux anomalies can be observed in one of the images of the quad. Further observations of nine inconclusive systems (including seven NIQs) will allow to confirm (or not) their gravitational lens nature. © 2018 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society.