Star Formation at z~6: i-dropouts in the ACS GTO fields

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dc.creatorBouwens, R. J.
dc.creatorIllingworth, G. D.
dc.creatorRosati, P.
dc.creatorLidman, C.
dc.creatorBroadhurst, T.
dc.creatorFranx, M.
dc.creatorFord, H. C.
dc.creatorMagee, D.
dc.creatorBenitez, N.
dc.creatorBlakeslee, J. P.
dc.creatorMeurer, G. R.
dc.creatorClampin, M.
dc.creatorHartig, G. F.
dc.creatorArdila, D. R.
dc.creatorBartko, F.
dc.creatorBrown, R. A.
dc.creatorBurrows, C. J.
dc.creatorCheng, E. S.
dc.creatorCross, N. J. G.
dc.creatorFeldman, P. D.
dc.creatorGolimowski, D. A.
dc.creatorGronwall, C.
dc.creatorInfante, L.
dc.creatorKimble, R. A.
dc.creatorKrist, J. E.
dc.creatorLesser, M. P.
dc.creatorMartel, A. R.
dc.creatorMenanteau, F.
dc.creatorMiley, G. K.
dc.creatorPostman, M.
dc.creatorSirianni, M.
dc.creatorSparks, W. B.
dc.creatorTran, H. D.
dc.creatorTsvetanov, Z. I.
dc.creatorWhite, R. L.
dc.creatorZheng, W.
dc.date2003-06-11
dc.date.accessioned2026-07-07T10:47:38Z
dc.date.available2026-07-07T10:47:38Z
dc.descriptionUsing an i-z dropout criterion, we determine the space density of z~6 galaxies from two deep ACS GTO fields with deep optical-IR imaging. A total of 23 objects are found over 46 arcmin^2, or ~0.5 objects/arcmin^2 down to z~27.3 (6 sigma; all AB mag) (including one probable z~6 AGN). Combining deep ISAAC data for our RDCS1252-2927 field (J~25.7 and Ks~25.0 (5 sigma)) and NICMOS data for the HDF North (JH~27.3 (5 sigma)), we verify that these dropouts have flat spectral slopes. i-dropouts in our sample range in luminosity from ~1.5 L* (z~25.6) to ~0.3 L* (z~27.3) with the exception of one very bright candidate at z~24.2. The half-light radii vary from 0.09" to 0.29", or 0.5 kpc to 1.7 kpc. We derive the z~6 rest-frame UV luminosity density using three different procedures, each utilizing simulations based on a CDF South V dropout sample. First, we compare our findings with a no-evolution projection of this V-dropout sample. We find 23+/-25% more i-dropouts than we predict. Adopting previous results to z~5, this works out to a 20+/-29% drop in the luminosity density from z~3 to z~6. Second, we use these same V-dropout simulations to derive a selection function for our i-dropout sample and compute the UV-luminosity density (7.2+/-2.5 x 10^25 ergs/s/Hz/Mpc^3 down to z~27). We find a 39+/-21% drop over the same redshift range. This is our preferred value and suggests a star formation rate of 0.0090+/-0.0031 M_sol/yr/Mpc^3 to z~27, or ~0.036+/- 0.012 M_sol/yr/Mpc^3 extrapolating the LF to the faint limit. Third, we follow a very similar procedure, but assume no incompleteness, finding a luminosity density which is ~2-3X lower. This final estimate constitutes a lower limit. All three estimates are within the canonical range of luminosity densities necessary for reionization of the universe at this epoch. (abridged)
dc.description36 pages, 13 figures, 2 tables, accepted for publication in ApJ, postscript version with high-resolution figures can be downloaded at http://www.ucolick.org/~bouwens/idropout.ps
dc.identifierhttps://arxiv.org/abs/astro-ph/0306215
dc.identifierhttp://arxiv.org/abs/astro-ph/0306215
dc.identifierAstrophys.J.595:589-602,2003
dc.identifierdoi:10.1086/377477
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/183601
dc.subjectAstrophysics
dc.titleStar Formation at z~6: i-dropouts in the ACS GTO fields
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