Submillimeter observations of the J2142-4423 Lyα protocluster at z = 2.38
Abstract
Aims: We present observations aimed at exploring both the nature of Lyα emitting nebulae (“Lyα blobs”) at z=2.38 and the way they trace large scale structure (LSS), 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.
Methods: 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 × 10 arcmin map at 870 μ m}, and we performed multiple checks of the quality of data processing and source extraction.
Results: 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 {μ m} 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× 1012 L_⊙. Only one of the four 50 kpc-extended Lyα blobs has a secure 870 {μ m} counterpart. The 870 {μ m} 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 {μ m}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.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- July 2008
- DOI:
- 10.1051/0004-6361:200809500
- arXiv:
- arXiv:0803.1615
- Bibcode:
- 2008A&A...485..645B
- Keywords:
-
- galaxies: starburst;
- galaxies: high-redshift;
- submillimeter;
- infrared: galaxies;
- ultraviolet: galaxies;
- large-scale structure of Universe;
- Astrophysics
- E-Print:
- 14 pages, 9 figures, accepted for publication in A&