Discovery of a high-z protocluster with tunable filters: the case of 6C0140+326 at z=4.4

作者：Kuiper E^*; Hatch N A; Venemans B P; Miley G K; Rottgering H J A; Kurk J D; Overzier R A; Pentericci L; Bland Hawthorn J; Cepa J

来源：Monthly Notices of the Royal Astronomical Society, 2011, 417(2): 1088-1097.

DOI：10.1111/j.1365-2966.2011.19324.x

• galaxies: clusters: general
• galaxies: evolution
• galaxies: high-redshift
• cosmology: observations
• early Universe

We present the first results obtained using a tunable narrow-band filter in the search for high-z protoclusters. Using the recently commissioned red tunable filter on the Gran Telescopio Canarias, we have searched for Lya emitters in a 75 arcmin2 field centred on the z= 4.413 radio galaxy 6C0140+326. With three different wavelength tunings, we find a total of 27 unique candidate Lya emitters. The availability of three different wavelength tunings allows us to make estimates of the redshifts for each of the objects. It also allows us to separate a possible protocluster from a structure in the immediate foreground. This division shows that the foreground region contains significantly fewer Lya emitters. Also, the spatial distribution of the objects in the protocluster field deviates from a random distribution at the 2.5s level. The observed redshift distribution of the emitters is different from the expected distribution of a blank field at the similar to 3s level, with the Lya emitters concentrated near the radio galaxy at z > 4.38. The 6C0140+326 field is denser by a factor of 9 +/- 5 than a blank field, and the number density of Lya emitters close to the radio galaxy is similar to that of the z similar to 4.1 protocluster around TN J1338-1942. We thus conclude that there is an overdensity of Lya emitters around the radio galaxy 6C0140+326. This is one of few known overdensities at such a high redshift.

• 出版日期2011-10