%0 Generic %1 chan2016geometric %A Chan, Brian M. Y. %A Broadhurst, Tom %A Lim, Jeremy %A Diego, Jose M. %A Zitrin, Adi %A Coe, Dan %A Ford, Holland C. %D 2016 %K galaxies high lense redshift %T Geometric Corroboration of the Earliest Lensed Galaxy at z~10.8 from Robust Free-Form Modelling %U http://arxiv.org/abs/1608.06942 %X A multiply-lensed galaxy, MACS0647-JD, with a probable photometric redshift of $z10.7^+0.6_-0.4$ is claimed to constitute one of the very earliest known galaxies, formed well before reionization was completed. However, spectral evidence that MACS0647-JD lies at high redshift has proven infeasible and so here we seek an independent lensing based "geometric redshift" derived from the angles between the three lensed images of MACS0647-JD, using our free-form mass model (WSLAP+) for the lensing cluster MACSJ0647.7+7015 (at $z=0.591$). Our lens model uses the 9 sets of multiple images, including those of MACS0647-JD, identified by the CLASH survey towards this cluster. We convincingly exclude the low redshift regime of $z<3$, for which convoluted critical curves are generated by our method, as the solution bends to accommodate the wide angles of MACS0647-JD for this low redshift. Instead, a best fit to all sets of lensed galaxy positions and redshifts provides a geometric redshift of $z10.8^+0.3_-0.4$ for MACS0647-JD, strongly supporting the higher photometric redshift solution. Importantly, we find a tight linear relation between the relative brightnesses of all 9 sets of multiply lensed images and their relative magnifications as predicted by our model. This agreement provides a benchmark for the quality of the lens model, and establishes the robustness of our free-form lensing method for measuring model-independent geometric source distances and for deriving objective central cluster mass distributions. After correcting for its magnification the luminosity of MACS0647-JD remains relatively high at $M_UV=-19.4$, which is within a factor of a few in flux of some surprisingly luminous $z\simeq 10$--$11$ candidates discovered recently in Hubble black field surveys.

@misc{chan2016geometric, abstract = {A multiply-lensed galaxy, MACS0647-JD, with a probable photometric redshift of $z\simeq 10.7^{+0.6}_{-0.4}$ is claimed to constitute one of the very earliest known galaxies, formed well before reionization was completed. However, spectral evidence that MACS0647-JD lies at high redshift has proven infeasible and so here we seek an independent lensing based "geometric redshift" derived from the angles between the three lensed images of MACS0647-JD, using our free-form mass model (WSLAP+) for the lensing cluster MACSJ0647.7+7015 (at $z=0.591$). Our lens model uses the 9 sets of multiple images, including those of MACS0647-JD, identified by the CLASH survey towards this cluster. We convincingly exclude the low redshift regime of $z<3$, for which convoluted critical curves are generated by our method, as the solution bends to accommodate the wide angles of MACS0647-JD for this low redshift. Instead, a best fit to all sets of lensed galaxy positions and redshifts provides a geometric redshift of $z\simeq 10.8^{+0.3}_{-0.4}$ for MACS0647-JD, strongly supporting the higher photometric redshift solution. Importantly, we find a tight linear relation between the relative brightnesses of all 9 sets of multiply lensed images and their relative magnifications as predicted by our model. This agreement provides a benchmark for the quality of the lens model, and establishes the robustness of our free-form lensing method for measuring model-independent geometric source distances and for deriving objective central cluster mass distributions. After correcting for its magnification the luminosity of MACS0647-JD remains relatively high at $M_{UV}=-19.4$, which is within a factor of a few in flux of some surprisingly luminous $z\simeq 10$--$11$ candidates discovered recently in Hubble black field surveys.}, added-at = {2016-08-26T10:03:21.000+0200}, author = {Chan, Brian M. Y. and Broadhurst, Tom and Lim, Jeremy and Diego, Jose M. and Zitrin, Adi and Coe, Dan and Ford, Holland C.}, biburl = {https://www.bibsonomy.org/bibtex/26b97fc88fbb33d104ab4664f7cbfae87/miki}, description = {[1608.06942] Geometric Corroboration of the Earliest Lensed Galaxy at z~10.8 from Robust Free-Form Modelling}, interhash = {262078bba7873c234d2eb8ff5715e4a4}, intrahash = {6b97fc88fbb33d104ab4664f7cbfae87}, keywords = {galaxies high lense redshift}, note = {cite arxiv:1608.06942Comment: arXiv admin note: text overlap with arXiv:1406.2702}, timestamp = {2016-08-26T10:03:21.000+0200}, title = {Geometric Corroboration of the Earliest Lensed Galaxy at z~10.8 from Robust Free-Form Modelling}, url = {http://arxiv.org/abs/1608.06942}, year = 2016 }