2006/08/01 by Arthur M. Wolfe, Hsiao-Wen Chen, Hsiao‐Wen Chen · 2 citations
Physics and Astronomy · #Astrophysics #Astrophysics and Star Formation Studies #Galaxies: Formation, Evolution, Phenomena #Galaxy #Gamma-ray bursts and supernovae #Hubble Deep Field #Hubble Ultra-Deep Field #Physics #Redshift #Star (game theory) #Star formation #Surface brightness #astro-ph
paper · pdf · doi:10.1086/507574
published as Astrophys.J.652:981-993,2006 · 35 preprint pages, including 8 figures; ApJ in press; High-resolution version with complete figures is available at http://lambda.uchicago.edu/public/tmp/udflsb.pdf
arxiv created 2006/08/01 · openalex publication_date 2006/11/27 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Applying the Kennicutt-Schmidt law to damped Lyα absorption systems (DLAs), we predict that 3% of the sky should be covered with extended objects brighter than μ V ≈ 28.4 mag arcsec -2 , if DLAs at redshift z = [2.5, 3.5] undergo in situ star formation. We test this hypothesis by searching the Hubble Ultra Deep Field (UDF) F606W image for low surface brightness features of angular sizes, ranging between θ DLA = 0 25 ( d DLA = 2 kpc) and 4 0 ( d DLA = 31 kpc). After convolving the F606W image with smoothing kernels of angular diameters θ kern = θ DLA , we find the number of detected objects to decrease rapidly to zero at θ kern > 1''. Our search yields upper limits on the comoving SFR densities that are between factors of 30 and 100 lower than predictions, suggesting a reduction by more than a factor of 10 in star formation efficiency at z ~ 3. The lower star formation efficiencies may be due to the reduced molecular content of the DLA gas. We also find that the cosmological increase with redshift of the critical surface density for the Toomre instability may be sufficient to suppress star formation to the levels implied by the UDF observations. The upper limits on in situ star formation reduce the predicted metallicities at z ~ 3 to be significantly lower than observed, and reduce the heat input in the gas to be substantially lower than the inferred cooling rates. In contrast, the radiative output from compact Lyman break galaxies (LBGs) with R < 27 is sufficient to balance the comoving cooling rate. Thus, many DLAs may host more compact regions of active star formation, which may chemically enrich these DLAs. Such regions are likely to be LBGs.