Sign on

SAO/NASA ADS Astronomy Abstract Service

· Find Similar Abstracts (with default settings below)
· Full Refereed Journal Article (PDF/Postscript)
· Full Refereed Scanned Article (GIF)
· arXiv e-print (arXiv:astro-ph/0403223)
· On-line Data
· References in the article
· Citations to the Article (226) (Citation History)
· Refereed Citations to the Article
· SIMBAD Objects (61)
· NED Objects (56)
· Also-Read Articles (Reads History)
·
· Translate This Page
Title:
The star formation rate of the Universe at z~ 6 from the Hubble Ultra-Deep Field
Authors:
Bunker, Andrew J.; Stanway, Elizabeth R.; Ellis, Richard S.; McMahon, Richard G.
Affiliation:
AA(School of Physics, University of Exeter, Stocker Road, Exeter, EX4 4QL; Institute of Astrophysics, University of Cambridge, Madingley Road, Cambridge, CB30HA), AB(Institute of Astrophysics, University of Cambridge, Madingley Road, Cambridge, CB30HA), AC(California Institute of Technology, Mail Stop 169-327, Pasadena, CA 91109, USA), AD(Institute of Astrophysics, University of Cambridge, Madingley Road, Cambridge, CB30HA)
Publication:
Monthly Notices of the Royal Astronomical Society, Volume 355, Issue 2, pp. 374-384. (MNRAS Homepage)
Publication Date:
12/2004
Origin:
MNRAS
Astronomy Keywords:
galaxies: evolution, galaxies: formation, galaxies: high-redshift, galaxies: individual: SBM03#1, galaxies: starburst, ultraviolet: galaxies
DOI:
10.1111/j.1365-2966.2004.08326.x
Bibliographic Code:
2004MNRAS.355..374B

Abstract

We determine the abundance of i'-band dropouts in the recently released HST/ACS Hubble Ultra-Deep Field (UDF). Because the majority of these sources are likely to be z~ 6 galaxies whose flux decrement between the F775W i'-band and F850LP z'-band arises from Lyman-alpha absorption, the number of detected candidates provides a valuable upper limit to the unextincted star formation rate at this redshift. We demonstrate that the increased depth of UDF enables us to reach an 8sigma limiting magnitude of z'AB= 28.5 (equivalent to 1.5h-270Msolaryr-1 at z= 6.1, or 0.1L*UV for the z~ 3U-drop population), permitting us to address earlier ambiguities arising from the unobserved form of the luminosity function. We identify 54 galaxies (and only one star) at z'AB < 28.5 with (i'-z')AB > 1.3 over the deepest 11-arcmin2 portion of the UDF. The characteristic luminosity (L*) is consistent with values observed at z~ 3. The faint end slope (alpha) is less well constrained, but is consistent with only modest evolution. The main change appears to be in the number density (Phi*). Specifically, and regardless of possible contamination from cool stars and lower-redshift sources, the UDF data support our previous result that the star formation rate at z~ 6 was approximately six times less than at z~ 3. This declining comoving star formation rate [0.005h70Msolaryr-1Mpc-3 at z~ 6 at LUV > 0.1L* for a Salpeter initial mass function (IMF)] poses an interesting challenge for models which suggest that LUV > 0.1L* star-forming galaxies at z~= 6 reionized the Universe. The short-fall in ionizing photons might be alleviated by galaxies fainter than our limit, or a radically different IMF. Alternatively, the bulk of reionization might have occurred at z>> 6.

Printing Options

Print whole paper
Print Page(s) through

Return 600 dpi PDF to Acrobat/Browser. Different resolutions (200 or 600 dpi), formats (Postscript, PDF, etc), page sizes (US Letter, European A4, etc), and compression (gzip,compress,none) can be set through the Printing Preferences


More Article Retrieval Options

HELP for Article Retrieval
Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)
  New!

Find Similar Abstracts:

Use: Authors
Title
Keywords (in text query field)
Abstract Text
Return: Query Results Return    items starting with number
Query Form
Database: Astronomy
Physics
arXiv e-prints