Detalles de publicación
PP 020062
Optical validation and characterisation of Planck PSZ1 sources at the Canary Islands observatories. II. Second year of ITP13 observations
(1) IAC, (2) ULL, (3) University of KwaZulu-Natal, Westville Campus, Private Bag X54001, Durban 4000, South Africa, (4) Universidad Andrés Bello, Departemento de Ciencias Físicas, 7591538 Santiago de Chile, Chile, (5) Max-Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg, Germany, (6) Tartu Observatory, University of Tartu, 61602 Tõravere, Tartumaa, Estonia, (7) Institut d’Astrophysique Spatiale, Universitè Paris-Sud, CNRS, UMR8617, 91405 Orsay Cedex, France, (8) IRFU, CEA, Université Paris-Saclay, F-91191 Gif-sur-Yvette, France, (9) Université Paris Diderot, AIM, Sorbonne Paris Cité, CEA, CNRS, F-91191 Gif-sur-Yvette, France, (10) Max-Planck-Institut für extraterrestrische Physik, D-85748 Garching, Germany, (11) Institute of Theoretical Astrophysics, University of Oslo, PO Box 1029, Blindern, 0315 Oslo, Norway, (12) Astrophysics Group, Cavendish Laboratory, JJ Thomson Av., Cambridge, CB3 0HE, UK, (13) Kavli Institute for Cosmology, Madingley Road, Cambridge, CB3 0HA, UK, (14) Dipartimento di Fisica, Università degli Studi di Roma “Tor Vergata”, via della Ricerca Scientifica, 1, I-00133 Roma, Italy, (15) Université de Toulouse, UPS-OMP, Institut de Recherche en Astrophysique et Planétologie (IRAP), 31400 Toulouse, France, (16) CNRS, IRAP, 9 avenue Colonel Roche, BP 44346, 31028 Toulouse Cedex 4, France, (17) IASF-Milano, Istituto Nazionale di Astrofisica, via A. Corti 12, 20133 Milano, Italy
We report new galaxy clusters previously unknown included in the PSZ1 catalogue. The results here presented have been achieved during the second year of a 2-year observational programme, the ITP13, developed at the Roque de los Muchachos Observatory (La Palma, Spain). We characterise 75 SZ sources with low SZ significance, SZ S/N<5.32 by performing deep optical imaging and spectroscopy in order to associate actual galaxy clusters to the SZ Planck source. We adopt robust criteria, based on the 2D-spatial distribution, richness and velocity dispersions to confirm actual optical counterparts up to z<0.85. At the end of the ITP13 observational programme, we study 256 SZ sources with Dec>−15∘ (212 of them completely unknown), finding optical counterparts for 152 SZ sources. The ITP13 validation programme has allowed us to update the PSZ1 purity, which is now more refined, increasing from 72% to 83% in the low SZ S/N regime. Our results are consistent with the predicted purity curve for the full PSZ1 catalogue and with the expected fraction of false detections caused by the non-Gaussian noise of foreground signals. Indeed, we find a strong correlation between the number of unconfirmed sources and the thermal emission of diffuse galactic dust at 857 GHz, thus increasing the fraction of false Planck SZ detections at low galactic latitudes.

