Beelen, A.; Omont, A.; Bavouzet, N.; Kovács, A.; Lagache, G.; De Breuck, C.; Weiss, A.; Menten, K. M.; Colbert, J. W.; Dole, H.; Siringo, G.; Kreysa, E.

We present observations aimed at exploring both the nature of Ly-α emitting nebulae ("Ly-α blos") at $$z=2.38$$ and the way they trace large scale structure, by exploring their proximity to "maximum starbursts" through submillimeter emission. Our most important objectives are to make a census of associated submillimeter galaxies (SMGs), check their properties, and look for a possible overdensity in the protocluster J2142-4426 at $$z=2.38$$. We used the newly commissioned Large APEX Bolometer Camera (LABoCa) on the Atacama Pathfinder EXperiment (APEX) telescope, in its Science Verification phase, to carry out a deep 10 arcmin  x  arcmin map at 870  µm, and we performed multiple checks of the quality of data processing and source extraction. Our map, the first published deep image, confirms the capabilities of APEX/LABoCa as the most efficient current equipment for wide and deep submm mapping. Twenty-two sources were securely extracted with 870  µm flux densities in the range 3-21 mJy, rms noise 0.8-2.4 mJy, and far-IR luminosities probably in the range $$5-20 \times 10^{12}\ \mathrm{L_\odot}$$. Only one of the four 50 kpc-extended Ly-α blobs has a secure 870  µm counterpart. The 870  µm source counts in the whole area are marginally higher than in the SHADES SCUBA survey, with a possible over-density around this blob. The majority of the 3.6-24 µm SEDs of the submillimeter sources indicate they are starburst dominated, with redshifts mostly  ≥  2. However, there is evidence of a high-z AGN in 30\% of the sources.

Accepted for publication in AandA, Volume 423, Pages 485-645 (2008).

Find this paper on ADS under the reference 2008A&A...485..645B, or on the arXiv service under the reference arXiv:0803.1615.

• LABoCa map of the Francis Cluster reduced by BoA :
• Table 1 of the paper : LABoCa source list :