ALMA observations of lensed Herschel sources: testing the dark matter halo paradigm

Amvrosiadis, A. and Eales, S.A. and Negrello, M. and Marchetti, L. and Smith, M.W.L. and Bourne, N. and Clements, D.L. and De Zotti, G. and Dunne, L. and Dye, S. and Furlanetto, C. and Ivison, R.J. and Maddox, S.J. and Valiante, E. and Baes, M. and Baker, A.J. and Cooray, A. and Crawford, S.M. and Frayer, D. and Harris, A. and Michałowski, M.J. and Nayyeri, H. and Oliver, S. and Riechers, D.A. and Serjeant, S. and Vaccari, M. (2018) ALMA observations of lensed Herschel sources: testing the dark matter halo paradigm. Monthly Notices of the Royal Astronomical Society, 475 (4). pp. 4939-4952. ISSN 1365-2966

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With the advent of wide-area submillimetre surveys, a large number of high-redshift gravitationally lensed dusty star-forming galaxies have been revealed. Because of the simplicity of the selection criteria for candidate lensed sources in such surveys, identified as those with S500 μm > 100 mJy, uncertainties associated with the modelling of the selection function are expunged. The combination of these attributes makes submillimetre surveys ideal for the study of strong lens statistics. We carried out a pilot study of the lensing statistics of submillimetre-selected sources by making observations with the Atacama Large Millimeter Array (ALMA) of a sample of strongly lensed sources selected from surveys carried out with the Herschel Space Observatory. We attempted to reproduce the distribution of image separations for the lensed sources using a halo mass function taken from a numerical simulation that contains both dark matter and baryons. We used three different density distributions, one based on analytical fits to the haloes formed in the EAGLE simulation and two density distributions [Singular Isothermal Sphere (SIS) and SISSA] that have been used before in lensing studies. We found that we could reproduce the observed distribution with all three density distributions, as long as we imposed an upper mass transition of ∼1013 M⊙ for the SIS and SISSA models, above which we assumed that the density distribution could be represented by a Navarro–Frenk–White profile. We show that we would need a sample of ∼500 lensed sources to distinguish between the density distributions, which is practical given the predicted number of lensed sources in the Herschel surveys.

Item Type: Article
Additional Information: This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2018 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
Keywords: gravitational lensing: strong, galaxies: high-redshift, submillimetre: galaxies
Schools/Departments: University of Nottingham, UK > Faculty of Science > School of Physics and Astronomy
Identification Number: 10.1093/mnras/sty138
Depositing User: Eprints, Support
Date Deposited: 07 Mar 2018 14:11
Last Modified: 08 Mar 2018 05:35

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