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Probing the z > 6 Universe with the First Hubble Frontier Fields Cluster A2744

Atek, H.; Richard, J.; Kneib, J.-P.; Clément, B.; Egami, E.; Ebeling, H.; Jauzac, M.; Jullo, E.; Laporte, N.; Limousin, M.; Natarajan, P.

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H. Atek

J. Richard

J.-P. Kneib

B. Clément

E. Egami

H. Ebeling

E. Jullo

N. Laporte

M. Limousin

P. Natarajan


The Hubble Frontier Fields program combines the capabilities of the Hubble Space Telescope (HST) with the gravitational lensing of massive galaxy clusters to probe the distant universe to an unprecedented depth. Here, we present the results of the first combined HST and Spitzer observations of the cluster A-2744. We combine the full near-infrared data with ancillary optical images to search for gravitationally lensed high-redshift (z gsim 6) galaxies. We report the detection of 15 I 814 dropout candidates at z ~ 6-7 and one Y 105 dropout at z ~ 8 in a total survey area of 1.43 arcmin2 in the source plane. The predictions of our lens model also allow us to identify five multiply imaged systems lying at redshifts between z ~ 6 and z ~ 8. Thanks to constraints from the mass distribution in the cluster, we were able to estimate the effective survey volume corrected for completeness and magnification effects. This was in turn used to estimate the rest-frame ultraviolet luminosity function (LF) at z ~ 6-8. Our LF results are generally in agreement with the most recent blank field estimates, confirming the feasibility of surveys through lensing clusters. Although based on a shallower observations than what will be achieved in the final data set including the full Advanced Camera for Survey observations, the LF presented here goes down to M UV ~–18.5, corresponding to 0.2L sstarf at z ~ 7 with one identified object at M UV ~–15 thanks to the highly magnified survey areas. This early study forecasts the power of using massive galaxy clusters as cosmic telescopes and its complementarity to blank fields.


Atek, H., Richard, J., Kneib, J., Clément, B., Egami, E., Ebeling, H., …Natarajan, P. (2014). Probing the z > 6 Universe with the First Hubble Frontier Fields Cluster A2744. Astrophysical Journal, 786(1),

Journal Article Type Article
Acceptance Date Mar 13, 2014
Online Publication Date Apr 16, 2014
Publication Date May 1, 2014
Deposit Date Nov 5, 2015
Publicly Available Date Nov 5, 2015
Journal Astrophysical Journal
Print ISSN 0004-637X
Electronic ISSN 1538-4357
Publisher American Astronomical Society
Peer Reviewed Peer Reviewed
Volume 786
Issue 1
Keywords Galaxies: high-redshift, Gravitational lensing: strong, Surveys.


Published Journal Article (1.4 Mb)

Copyright Statement
© 2014. The American Astronomical Society. All rights reserved.

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