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

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

2003-06-11

arxiv.org/abs/astro-ph/0306215v1

Astrophys.J.595:589-602,2003

Astronomy and Astrophysics

Astrophysics

36 pages, 13 figures, 2 tables, accepted for publication in ApJ, postscript version with high-resolution figures can be downlo

Scientific paper

10.1086/377477

Using 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)

Affiliated with

Also associated with

No associations

Rating

Star Formation at z~6: i-dropouts in the ACS GTO fields does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Star Formation at z~6: i-dropouts in the ACS GTO fields, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Star Formation at z~6: i-dropouts in the ACS GTO fields will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-458874