CaltechAUTHORS
  A Caltech Library Service

Gaia GraL: Gaia DR2 gravitational lens systems. IV. Keck/LRIS spectroscopic confirmation of GRAL 113100−441959 and model prediction of time delays

Wertz, O. and Stern, D. and Krone-Martins, A. and Delchambre, L. and Ducourant, C. and Jørgensen, U. Gråe and Dominik, M. and Burgdorf, M. and Surdej, J. and Mignard, F. and Teixeira, R. and Galluccio, L. and Klüter, J. and Djorgovski, S. G. and Graham, M. J. and Bastian, U. and Wambsganss, J. and Boehm, C. and LeCampion, J.-F. and Slezak, E. (2019) Gaia GraL: Gaia DR2 gravitational lens systems. IV. Keck/LRIS spectroscopic confirmation of GRAL 113100−441959 and model prediction of time delays. Astronomy and Astrophysics, 628 . Art. No. A17. ISSN 0004-6361. https://resolver.caltech.edu/CaltechAUTHORS:20190809-104904061

[img] PDF - Published Version
See Usage Policy.

5Mb
[img] PDF - Submitted Version
See Usage Policy.

4Mb

Use this Persistent URL to link to this item: https://resolver.caltech.edu/CaltechAUTHORS:20190809-104904061

Abstract

We report the spectroscopic confirmation and modeling of the quadruply imaged quasar GRAL 113100–441959, the first gravitational lens (GL) to be discovered from a machine learning technique that only relies on the relative positions and fluxes of the observed images without considering colour informations. Follow-up spectra obtained with Keck/LRIS reveal the lensing nature of this quadruply imaged quasar with redshift z_s = 1.090 ± 0.002, but show no evidence of the central lens galaxy. Using the image positions and G-band flux ratios provided by Gaia Data Release 2 as constraints, we modeled the system with a singular power-law elliptical mass distribution (SPEMD) plus external shear, to different levels of complexity. We show that relaxing the isothermal constraint of the SPEMD does not lead to statistically significant different results in terms of fitting the lensing data. We thus simplified the SPEMD to a singular isothermal ellipsoid to estimate the Einstein radius of the main lens galaxy θ_E = 0.″851, the intensity and position angle of the external shear (γ,θ_γ) = (0.044, 11.°5), and we predict the lensing galaxy position to be (θ_(gal,1), θ_(gal,2)) = (−0.″424, −0.″744) with respect to image A. We provide time delay predictions for pairs of images, assuming a plausible range of lens redshift values z_l between 0.5 and 0.9. Finally, we examine the impact on time delays of the so-called source position transformation, a family of degeneracies existing between different mass density profiles that reproduce most of the lensing observables equally well. We show that this effect contributes significantly to the time delay error budget and cannot be ignored during the modeling. This has implications for robust cosmography applications of lensed systems. GRAL 113100–441959 is the first in a series of seven new spectroscopically confirmed GLs discovered from Gaia Data Release 2.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1051/0004-6361/201834573DOIArticle
https://arxiv.org/abs/1810.02624arXivDiscussion Paper
ORCID:
AuthorORCID
Wertz, O.0000-0003-3849-2285
Stern, D.0000-0003-2686-9241
Ducourant, C.0000-0003-4843-8979
Dominik, M.0000-0002-3202-0343
Surdej, J.0000-0002-7005-1976
Djorgovski, S. G.0000-0002-0603-3087
Graham, M. J.0000-0002-3168-0139
Additional Information:© 2019 ESO. Article published by EDP Sciences. Received 5 November 2018; Accepted 23 January 2019; Published online 29 July 2019. The authors would like to thank Paul Schechter for valuable discussions. OW is supported by the Humboldt Research Fellowship for Postdoctoral Researchers. The work of DS was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA. AKM acknowledges the support from the Portuguese Fundação para a Ciência e a Tecnologia (FCT) through grants SFRH/BPD/74697/2010, PTDC/FIS-AST/31546/2017, from the Portuguese Strategic Program UID/FIS/00099/2013 for CENTRA, from the ESA contract AO/1-7836/14/NL/HB and from the Caltech Division of Physics, Mathematics and Astronomy for hosting a research leave during 2017–2018, when this paper was partially prepared. AKM additionally acknowledges that this research was partially supported by the Munich Institute for Astro- and Particle Physics (MIAPP) of the DFG cluster of excellence “Origin and Structure of the Universe”. LD and JS acknowledge support from the ESA PRODEX Program “Gaia-DPAC QSOs” and from the Belgian Federal Science Policy Office. SGD and MJG acknowledge a partial support from the NSF grants AST-1413600 and AST-1518308, and the NASA grant 16-ADAP16-0232. We acknowledge partial support from “Actions sur projet INSU-PNGRAM”, and from the Brazil-France exchange programs Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) – Comité Français d’Évaluation de la Coopération Universitaire et Scientifique avec le Brésil (COFECUB). This work has made use of the computing facilities of the Laboratory of Astroinformatics (IAG/USP, NAT/Unicsul), whose purchase was made possible by the Brazilian agency FAPESP (grant 2009/54006-4) and the INCT-A, and we thank the entire LAi team, specially Carlos Paladini, Ulisses Manzo Castello, Luis Ricardo Manrique and Alex Carciofi for the support. This work has made use of results from the ESA space mission Gaia, the data from which were processed by the Gaia Data Processing and Analysis Consortium (DPAC). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. The Gaia mission website is: http://www.cosmos.esa.int/gaia. Some of the authors are members of the Gaia Data Processing and Analysis Consortium (DPAC).
Funders:
Funding AgencyGrant Number
Alexander von Humboldt FoundationUNSPECIFIED
NASA/JPL/CaltechUNSPECIFIED
Fundação para a Ciência e a Tecnologia (FCT)SFRH/BPD/74697/2010
Fundação para a Ciência e a Tecnologia (FCT)PTDC/FIS-AST/31546/2017
Fundação para a Ciência e a Tecnologia (FCT)UID/FIS/00099/2013
European Space Agency (ESA)AO/1-7836/14/NL/HB
Caltech Division of Physics, Mathematics and AstronomyUNSPECIFIED
Munich Institute for Astro- and Particle Physics (MIAPP)UNSPECIFIED
Deutsche Forschungsgemeinschaft (DFG)UNSPECIFIED
Belgian Federal Science Policy Office (BELSPO)UNSPECIFIED
NSFAST-1413600
NSFAST-1518308
NASA16-ADAP16-0232
Institut national des sciences de l'Univers (INSU)UNSPECIFIED
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)2009/54006-4
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)UNSPECIFIED
Comité Français d’Évaluation de la Coopération Universitaire et Scientifique avec le Brésil (COFECUB)UNSPECIFIED
Gaia Multilateral AgreementUNSPECIFIED
Subject Keywords:gravitational lensing: strong – quasars: general – astrometry
Record Number:CaltechAUTHORS:20190809-104904061
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20190809-104904061
Official Citation:Gaia GraL: Gaia DR2 gravitational lens systems - IV. Keck/LRIS spectroscopic confirmation of GRAL 113100−441959 and model prediction of time delays. O. Wertz, D. Stern, A. Krone-Martins, L. Delchambre, C. Ducourant, U. Gråe Jørgensen, M. Dominik, M. Burgdorf, J. Surdej, F. Mignard, R. Teixeira, L. Galluccio, J. Klüter, S. G. Djorgovski, M. J. Graham, U. Bastian, J. Wambsganss, C. Boehm, J.-F. LeCampion and E. Slezak. A&A, 628 (2019) A17. DOI: https://doi.org/10.1051/0004-6361/201834573
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:97721
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:09 Aug 2019 18:04
Last Modified:09 Mar 2020 13:18

Repository Staff Only: item control page