TY - JOUR
T1 - Exploring effects on magnifications due to line-of-sight galaxies in the Hubble Frontier Fields
AU - Raney, Catie A.
AU - Keeton, Charles R.
AU - Brennan, Sean
N1 - Funding Information:
We acknowledge support from Hubble Frontier Field Lensing Support through contract STScI-49745 from the Space Telescope Science Institute, which is operated by NASA under contract no. NAS5-26555. All version models were obtained via the Mikulski Archive for Space Telescopes (MAST) and the web-based lens model tool. We thank Dan Coe and Keren Sharon for organizing the useful discussions among all modelling teams and contributors.
Publisher Copyright:
© 2019 The Author(s).
PY - 2020/2/1
Y1 - 2020/2/1
N2 - Cluster lensing has become an important tool in the search for high-redshift galaxies through its ability to magnify sources. In order to determine the intrinsic properties of these galaxies, lensing mass models must be constructed to determine the magnification of the images. These models are traditionally 2D, focusing on the mass within the cluster and either ignoring or approximating any contribution from line-of-sight galaxies. In this paper, we present the first full set of 3D mass models of the six Hubble Frontier Fields and use them to test for systematic biases in magnifications due to using the traditional 2D approach. We find that omitting foreground or background galaxies causes image position offsets between 0.1 and 0.4 arcsec, a non-negligible fraction of the typical 0.3-0.7 arcsec residuals of current state-ofthe- art models. We also find that median image magnifications can shift by up to 6 per cent, though it is dependent on the field. This can be alleviated in some cases by approximating the mass in the lensing plane, but a 5 per cent magnification bias still exists in other cases; image position offsets are also improved, but are still present at 0.10 arcsec.
AB - Cluster lensing has become an important tool in the search for high-redshift galaxies through its ability to magnify sources. In order to determine the intrinsic properties of these galaxies, lensing mass models must be constructed to determine the magnification of the images. These models are traditionally 2D, focusing on the mass within the cluster and either ignoring or approximating any contribution from line-of-sight galaxies. In this paper, we present the first full set of 3D mass models of the six Hubble Frontier Fields and use them to test for systematic biases in magnifications due to using the traditional 2D approach. We find that omitting foreground or background galaxies causes image position offsets between 0.1 and 0.4 arcsec, a non-negligible fraction of the typical 0.3-0.7 arcsec residuals of current state-ofthe- art models. We also find that median image magnifications can shift by up to 6 per cent, though it is dependent on the field. This can be alleviated in some cases by approximating the mass in the lensing plane, but a 5 per cent magnification bias still exists in other cases; image position offsets are also improved, but are still present at 0.10 arcsec.
KW - Galaxies: clusters: general
KW - Galaxies: clusters: individual: Abell 2744,MACS J0416.1+2403,MACS J1149.5+2223,MACS J0717.5+3745, Abell S1063, Abell 370
KW - Galaxies: high-redshift
KW - gravitational lensing: strong
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U2 - 10.1093/mnras/stz3116
DO - 10.1093/mnras/stz3116
M3 - Article
AN - SCOPUS:85079455610
SN - 0035-8711
VL - 492
SP - 503
EP - 527
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 1
ER -