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Date and Time of the Query: 2019-06-24 T16:37:32 PDT
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For refcode 2011MNRAS.414.1455L:
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NED Abstract

Copyright by Royal Astronomical Society. 2011MNRAS.414.1455L Star-forming galaxies at z~ 8-9 from Hubble Space Telescope/WFC3: implications for reionization Lorenzoni, Silvio; Bunker, Andrew J.; Wilkins, Stephen M.; Stanway, Elizabeth R.; Jarvis, Matt J.; Caruana, Joseph Abstract. We present a search for galaxies at 7.6 < z < 9.8 using the latest Hubble Space Telescope/Wide Field Camera 3 (WFC3) near-infrared data, based on the Lyman-break technique. We search for galaxies which have large (Y-J) colours (the 'Y-drops') on account of the Lyman {alpha} forest absorption, and with (J-H) colours inconsistent with being low-redshift contaminants. We identify 24 candidates at redshift z~ 8-9 (15 are robust and a further nine more marginal but consistent with being high redshift) over an area of ~50 arcmin^2^. Previous searches for Y-drops with WFC3 have focused only on the Hubble Ultra Deep Field, and our larger survey (involving two other nearby deep fields and a wider area survey) has trebled the number of robust Y-drop candidates. For the first time, we have sufficient z~ 8-9 galaxies to fit both {phi}* and M* of the UV Schechter luminosity function. There is evidence for evolution in this luminosity function from z= 6-7 to z= 8-9, in the sense that there are fewer UV-bright galaxies at z~ 8-9, consistent with an evolution mainly in M*. The candidate z~ 8-9 galaxies we detect have insufficient ionizing flux to reionize the Universe, and it is probable that galaxies below our detection limit provide a significant UV contribution. The faint-end slope, {alpha}, is not well constrained. However, adopting a similar faint-end slope to that determined at z= 3-6 ({alpha}=-1.7) and a Salpeter initial mass function (IMF), then the ionizing photon budget still falls short if f_esc_ < 0.5, even integrating down to M_UV_=-8. A steeper faint-end slope or a low-metallicity population (or a top-heavy IMF) might still provide sufficient photons for star-forming galaxies to reionize the Universe, but confirmation of this might have to await the James Webb Space Telescope. Key words: galaxies: evolution, galaxies: formation, galaxies: high-redshift, galaxies: starburst, ultraviolet: galaxies
Retrieve 24 NED objects in this reference.
Please click here for ADS abstract

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