A Census of Star-forming Galaxies in the Z ∼ 9-10 Universe Based on Hst+spitzer Observations Over 19 Clash Clusters: Three Candidate Z ∼ 9-10 Galaxies and Improved Constraints on the Star Formation Rate Density at Z ∼ 9.2
Year: 2014
Type: article
Abstract: We utilize a two-color Lyman-break selection criterion to search for z ∼ 9–10 galaxies over the first 19 clusters in the CLASH program. A systematic search yields three z ∼ 9–10 candidates. While we have already reported the most robust of these candidates, MACS1149-JD, two additional z ∼ 9 candidates are also found and have H 160 -band magnitudes of ∼26.2–26.9. A careful assessment of various sources of contamination suggests ≲1 contaminants for our z ∼ 9–10 selection. To determine the implications of these search results for the luminosity function (LF) and star formation rate density at z ∼ 9, we introduce a new differential approach to deriving these quantities in lensing fields. Our procedure is to derive the evolution by comparing the number of z ∼ 9–10 galaxy candidates found in CLASH with the number of galaxies in a slightly lower-redshift sample (after correcting for the differences in selection volumes), here taken to be z ∼ 8. This procedure takes advantage of the fact that the relative volumes available for the z ∼ 8 and z ∼ 9–10 selections behind lensing clusters are not greatly dependent on the details of the lensing models. We find that the normalization of the UV LF at z ∼ 9 is just that at z ∼ 8, which is ∼1.4 × lower than extrapolating z ∼ 4–8 LF results. While consistent with the evolution in the UV LF seen at z ∼ 4–8, these results marginally favor a more rapid evolution at z > 8. Compared to similar evolutionary findings from the HUDF, our result is less insensitive to large-scale structure uncertainties, given our many independent sightlines on the high-redshift universe.
Source: The Astrophysical Journal
Authors: R. J. Bouwens, L. Bradley, A. Zitrin, D. Coe, M. Franx, W. Zheng, R. Smit, O. Host, M. Postman, L. Moustakas, I. Labbé, M. Carrasco, A. Molino, M. Donahue, D.D. Kelson, M. Meneghetti, N. Benítez, D. Lemze, K. Umetsu, T. Broadhurst, J. Moustakas, P. Rosati, S. Jouvel, M. Bartelmann, H. Ford, G. Graves, C. Grillo, L. Infante, Y. Jimenez-Teja, O. Lahav, D. Maoz, E. Medezinski, P. Melchior, J. Merten, M. Nonino, S. Ogaz, S. Seitz
Institutions: Leiden University, University of California, Santa Cruz, Leiden Observatory, Space Telescope Science Institute, Heidelberg University, Johns Hopkins University, University of Copenhagen, California Institute of Technology, Jet Propulsion Laboratory, Pontificia Universidad Católica de Chile, Instituto de Astrofísica de Andalucía, Michigan State University, Carnegie Institution for Science, Carnegie Observatories, Osservatorio astronomico di Bologna, National Institute for Astrophysics, Institute of Astronomy and Astrophysics, Academia Sinica, Academia Sinica, University of the Basque Country, Siena College, European Southern Observatory, Institute of Space Sciences, Consejo Superior de Investigaciones Científicas, University of California, Berkeley, University College London, Tel Aviv University, The Ohio State University, Trieste Astronomical Observatory
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
Awards: G58316358, G767601387
OpenAlex ID: W2039781173