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arXiv · 1510.07084

Young Galaxy Candidates in the Hubble Frontier Fields. II. MACS,J0416-2403

Leopoldo Infante·Wei Zheng·Nicolas Laporte·Paulina Troncoso·Alberto Molino·Jose M. Diego·Franz E. Bauer·Adi Zitrin·John Moustakas·Xingxing Huang·Xinwen Shu·David Bina·Gabriel B. Brammer·Tom Broadhurst·Holland C. Ford·Stefano Garcia·Sam Kim
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Abstract

We searched for z > 7 Lyman-break galaxies (LBGs) in the optical-to-mid-infrared Hubble Frontier Field and associated parallel field observations of the strong-lensing cluster MACS J0416-2403. We discovered 22 candidates, of which six lie at z > 9 and one lies at z > 10. Based on the Hubble and Spitzer photometry, all have secure photometric redshifts and a negligible probability of being at lower redshifts, according to their peak probability ratios, R. This substantial increase in the number of known high-redshift galaxies allows a solid determination of the luminosity function at z > 8. The number of high-z candidates in the parallel field is considerably higher than that in the Abell 2744 parallel field. Our candidates have median stellar masses of log(M_*) ~ 8.40^{+0.55}_{-0.31}~Msun, SFRs of ~ 1.6^{+0.5}_{-0.4} Msun yr^-1, and SFR-weighted ages of < 310^{+70}_{-140} Myr. Finally, we are able to put strong constraints on the z = 7,8,9 and 10 luminosity functions. One of the objects in the cluster field is a z ~ 10 candidate, with a magnification of mu ~ 20 +- 13. This object is likely the faintest z ~ 10 object known to date, allowing a first look into the extreme faint-end (L ~ 0.04L*) of the z ~ 10 luminosity function.

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Leopoldo Infante, Wei Zheng, Nicolas Laporte, Paulina Troncoso, Alberto Molino, Jose M. Diego, Franz E. Bauer, Adi Zitrin, John Moustakas, Xingxing Huang, Xinwen Shu, David Bina, Gabriel B. Brammer, Tom Broadhurst, Holland C. Ford, Stefano Garcia, Sam Kim. 2015-10-23. Young Galaxy Candidates in the Hubble Frontier Fields. II. MACS,J0416-2403. https://doi.org/10.1088/0004-637x%2F815%2F1%2F18

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