{
  "id": "1602.05199",
  "version": "v1",
  "published": "2016-02-16T21:00:05.000Z",
  "updated": "2016-02-16T21:00:05.000Z",
  "title": "The z = 9-10 galaxy population in the Hubble Frontier Fields and CLASH surveys: The z=9 LF and further evidence for a smooth decline in UV luminosity at z >= 8",
  "authors": [
    "D. J. McLeod",
    "R. J. McLure",
    "J. S. Dunlop"
  ],
  "comment": "Submitted to MNRAS, 13 pages, 11 figures",
  "categories": [
    "astro-ph.GA"
  ],
  "abstract": "We present the results of a search for z=9-10 galaxies within the first 8 pointings of the Hubble Frontier Fields (HFF) (4 clusters plus 4 parallel fields) and 20 cluster fields from the CLASH survey. Combined with our previous analysis of the Hubble Ultra-Deep field (HUDF), we have now completed a search for z=9-10 galaxies over ~130 sq. arcmin, across 29 HST WFC3/IR pointings. As in our recent study of the first two HFF fields, we confine our primary search for high-redshift candidates in the HFF imaging to the uniformly deep (i.e. sigma_160>30 AB mag in 0.5-arcsec diameter apertures), relatively low magnification regions. In the CLASH fields our search was confined to uniformly deep regions where sigma_160>28.8 AB mag. Our SED fitting analysis unveils a sample of 33 galaxy candidates at z_phot>=8.4, five of which have primary photometric redshift solutions in the range 9.6<z_phot<11.2. By calculating a de-lensed effective volume for each candidate, the improved statistics and reduced cosmic variance provided by our new sample allows a more accurate determination of the UV-selected galaxy luminosity function (LF) at z~9. Our new results strengthen our previous conclusion that the LF appears to evolve smoothly from z=8 to z=9, an evolution which can be equally well modelled by a factor of ~2 drop in density, or a dimming of ~0.5 mag in M*. Moreover, based on our new sample, we are able to place initial constraints on the z=10 LF, finding that the number density at M_1500 ~ -19.7 is log(phi) = -4.1 (+0.2,-0.3), a factor of ~2 lower than at z=9. Finally, we use our new results to re-visit the issue of the decline in UV luminosity density at z>=8. We conclude that the data continue to support a smooth decline in rho_UV over the redshift interval 6<z<10, in agreement with simple models of early galaxy evolution driven by the growth in the underlying dark matter halo mass function.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2016-02-16T21:00:05.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "hubble frontier fields",
      "clash survey",
      "smooth decline",
      "uv luminosity",
      "galaxy population"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 13,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "adsabs": "2016arXiv160205199M"
    }
  }
}