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arXiv · 1308.6280

CLASH: z ~ 6 young galaxy candidate quintuply lensed by the frontier field cluster RXC J2248.7-4431

A. Monna·S. Seitz·N. Greisel·T. Eichner·N. Drory·M. Postman·A. Zitrin·D. Coe·A. Halkola·S. H. Suyu·C. Grillo·P. Rosati·D. Lemze·I. Balestra·J. Snigula·L. Bradley·K. Umetsu·A. Koekemoer·U. Kuchner·L. Moustakas·M. Bartelmann·N. Benitez·R. Bouwens·T. Broadhurst·M. Donahue·H. Ford·O. Host·L. Infante·Y. Jimenez-Teja·S. Jouvel·D. Kelson·O. Lahav·E. Medezinski·P. Melchior·M. Meneghetti·J. Merten·A. Molino·J. Moustakas·M. Nonino·W. Zheng
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Abstract

We present a quintuply lensed z ~ 6 candidate discovered in the field of the galaxy cluster RXC J2248.7-4431 (z ~ 0.348) targeted within the Cluster Lensing and Supernova survey with Hubble (CLASH) and selected in the deep HST Frontier Fields survey. Thanks to the CLASH 16-band HST imaging, we identify the quintuply lensed z ~ 6 candidate as an optical dropout in the inner region of the cluster, the brightest image having magAB=24.81+-0.02 in the f105w filter. We perform a detailed photometric analysis to verify its high-z and lensed nature. We get as photometric redshift z_phot ~ 5.9, and given the extended nature and NIR colours of the lensed images, we rule out low-z early type and galactic star contaminants. We perform a strong lensing analysis of the cluster, using 13 families of multiple lensed images identified in the HST images. Our final best model predicts the high-z quintuply lensed system with a position accuracy of 0.8''. The magnifications of the five images are between 2.2 and 8.3, which leads to a delensed UV luminosity of L_1600 ~ 0.5L*_1600 at z=6. We also estimate the UV slope from the observed NIR colours, finding a steep beta=-2.89+-0.38. We use singular and composite stellar population SEDs to fit the photometry of the hiz candidate, and we conclude that it is a young (age <300 Myr) galaxy with mass of M ~ 10^8Msol, subsolar metallicity (Z<0.2Zsol) and low dust content (AV ~ 0.2-0.4).

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A. Monna, S. Seitz, N. Greisel, T. Eichner, N. Drory, M. Postman, A. Zitrin, D. Coe, A. Halkola, S. H. Suyu, C. Grillo, P. Rosati, D. Lemze, I. Balestra, J. Snigula, L. Bradley, K. Umetsu, A. Koekemoer, U. Kuchner, L. Moustakas, M. Bartelmann, N. Benitez, R. Bouwens, T. Broadhurst, M. Donahue, H. Ford, O. Host, L. Infante, Y. Jimenez-Teja, S. Jouvel, D. Kelson, O. Lahav, E. Medezinski, P. Melchior, M. Meneghetti, J. Merten, A. Molino, J. Moustakas, M. Nonino, W. Zheng. 2013-08-28. CLASH: z ~ 6 young galaxy candidate quintuply lensed by the frontier field cluster RXC J2248.7-4431. https://doi.org/10.1093/mnras%2Fstt2284

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