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arXiv · 1808.01847

CANDELSz7: a large spectroscopic survey of CANDELS galaxies in the reionization epoch

L. Pentericci·E. Vanzella·M. Castellano·A. Fontana·S. De Barros·A. Grazian·F. Marchi·M. Bradac·C. Conselice·S. Cristiani·M. Dickinson·S. Finkelstein·E. Giallongo·L. Guaita·A. Koekemoer·R. Maiolino·P. Santini·V. Tilvi
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Abstract

We present the results of CANDELSz7, an ESO large program aimed at confirming spectroscopically a homogeneous sample of z~6 and z~7 star forming galaxies. The candidates were selected in the GOODS-South, UDS and COSMOS fields using the official CANDELS catalogs based on H160-band detections. Standard color criteria, which were tailored depending on the ancillary multi-wavelength data available for each field, were applied to select more than 160 candidate galaxies at z~6 and z~7. Deep medium resolution FORS2 spectroscopic observations were then conducted with integration times ranging from 12 to 20 hours, to reach a Lyalpha flux limit of approximately 1-3x 10-18 erg/s/cm^2 at 3sigma. For about 40% of the galaxies we could determine a spectroscopic redshift, mainly through the detection of a single emission line that we interpret as Lyalpha emission, or for some of the brightest objects (H160< 25.5) from the presence of faint continuum and sharp drop that we interpret as a Lyman break. In this paper we present the redshifts and main properties of 65 newly confirmed high redshift galaxies. Adding previous proprietary and archival data we assemble a sample of ~260 galaxies that we use to explore the evolution of the Lyalpha fraction in Lyman break galaxies and the change in the shape of the emission line between z~6 and z~7. We also discuss the accuracy of the CANDELS photometric redshifts in this redshift range.

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L. Pentericci, E. Vanzella, M. Castellano, A. Fontana, S. De Barros, A. Grazian, F. Marchi, M. Bradac, C. Conselice, S. Cristiani, M. Dickinson, S. Finkelstein, E. Giallongo, L. Guaita, A. Koekemoer, R. Maiolino, P. Santini, V. Tilvi. 2018-08-06. CANDELSz7: a large spectroscopic survey of CANDELS galaxies in the reionization epoch. https://doi.org/10.1051/0004-6361/201732465

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