Astronomy and Astrophysics – Astrophysics – Cosmology and Extragalactic Astrophysics
Scientific paper
2010-01-12
Astronomy and Astrophysics
Astrophysics
Cosmology and Extragalactic Astrophysics
6 pages, 4 figures, accepted for publication in MNRAS
Scientific paper
We present the discovery of a large-scale structure of emission-line galaxies at redshift z=4.86 behind a massive cluster of galaxies, A1689. Previous spectroscopic observations of a galaxy, A1689-7.1 at z=4.87, near this structure, revealed a possible overdense region of inter-galactic medium (IGM) around the galaxy, which extends at least ~80 comoving Mpc along the line of sight. In order to investigate whether this z~5 IGM overdense region contains a galaxy overdensity, we undertook narrow- and broad-band imaging observations around A1689-7.1 with Subaru/Suprime-Cam. We detected 51 candidate Ly-alpha emitters at redshift z=4.86+-0.03 in the 32 x 24 arcmin^2 field of view. After correction for lensing by the foreground cluster, we found a large-scale (~20 x 60 comoving Mpc) overdense region of galaxies around A1689-7.1 in the source plane at z=4.86. The densest peak in this region has an overdensity of delta~4, suggesting that this structure is probably a good candidate for a protocluster. A1689-7.1 is located at the edge of this region, where the local galaxy density is ~1.6 times the mean density and is close to the density contrast in the IGM along the line of sight to A1689-7.1 estimated from the optical depth. The overdensities of galaxies we have found may suggest that at least some parts of the IGM overdense region have already started to form galaxies and moreover they relate to the formation of a protocluster. Although we lack information on the three dimensional distributions of both IGM and galaxy overdense regions, the similarity of the scales of both regions may suggest that the two are parts of a single large-scale structure, which would be an large edge-on sheet along the line of sight with a size of ~20 x 60 x 80 comoving Mpc.
Frye Brenda L.
Fujii Takenori
Hayashino Tomoki
Kashikawa Nobunari
Matsuda Yuichi
No associations
LandOfFree
A search for galaxies in and around an HI overdense region at z=5 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 A search for galaxies in and around an HI overdense region at z=5, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and A search for galaxies in and around an HI overdense region at z=5 will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-459677