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Publication - Professor Mark Birkinshaw

    Candidate high-z proto-clusters among the Planck compact sources, as revealed by Herschel-SPIRE


    Greenslade, J, Clements, DL, Cheng, T, De Zotti, G, Scott, D, Valiante, E, Eales, S, Bremer, MN, Dannerbauer, H, Birkinshaw, M, Farrah, D, Harrison, DL, Michałowski, MJ, Valtchanov, I, Oteo, I, Baes, M, Cooray, A, Negrello, M, Wang, L, Werf, Pvd, Dunne, L & Dye, S, 2018, ‘Candidate high-z proto-clusters among the Planck compact sources, as revealed by Herschel-SPIRE’. Monthly Notices of the Royal Astronomical Society, vol 476., pp. 3336-3359


    By determining the nature of all the Planck compact sources within 808.4 deg2 of large Herschel
    surveys, we have identified 27 candidate protoclusters of dusty
    star-forming galaxies (DSFGs) that are at least 3σ overdense in either
    250, 350, or 500 μm sources. We find roughly half of all the Planck compact sources are resolved by Herschel into multiple discrete objects, with the other half remaining unresolved by Herschel. We find a significant difference between versions of the Planck
    catalogues, with earlier releases hosting a larger fraction of
    candidate protoclusters and Galactic cirrus than later releases, which
    we ascribe to a difference in the filters used in the creation of the
    three catalogues. We find a surface density of DSFG candidate
    protoclusters of (3.3 ± 0.7) × 10−2 sources deg−2, in good agreement with previous similar studies. We find that a Planck colour selection of S857/S545 < 2 works well to select candidate protoclusters, but can miss protoclusters at z < 2. The Herschel colours of individual candidate protocluster members indicate our candidate protoclusters all likely all lie at z > 1.
    Our candidate protoclusters are a factor of 5 times brighter at 353 GHz
    than expected from simulations, even in the most conservative
    estimates. Further observations are needed to confirm whether these
    candidate protoclusters are physical clusters, multiple protoclusters
    along the line of sight, or chance alignments of unassociated sources.

    Full details in the University publications repository