Optical validation and characterization of Planck PSZ1 sources at the Canary Islands observatories: I. First year of ITP13 observations

Indexación: Scopus.Planck (http://www.esa.int/Planck) is a project of the European Space Agency (ESA) with instruments provided by two scientific consortia funded by ESA member states and led by principal investigators from France and Italy, telescope reflectors provided through a collaboration between ESA and a scientific consortium led and funded by Denmark, and additional contributions from NASA (USA).6 IRAF (http://iraf.noao.edu/) is distributed by the National Optical Astronomy Observatories, which are operated by the Association of Universities for Research in Astronomy, Inc., under cooperative agreement with the National Science Foundation.Gran Telescopio Canarias operated by the Instituto de Astrofísica de Canarias, b) the Isaac Newton Telescope, and the William Herschel Telescope operated by the Isaac Newton Group of Telescopes, and c) the Italian Telescopio Nazionale Galileo operated by the Fundación Galileo Galilei of the INAF (Istituto Nazionale di Astrofisica). All these facilities are located at the Spanish del Roque de los Muchachos Observatory of the Instituto de Astrofísica de Canarias on the island of La Palma. This research has been carried out with telescope time awarded by the CCI International Time Programme at the Canary Islands Observatories (programmes ITP13B-15A). Funding for the Sloan Digital Sky Survey (SDSS) has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Aeronautics and Space Administration, the National Science Foundation, the U.S. Department of Energy, the Japanese Monbukagakusho, and the Max Planck Society. AAB, AF, AS, RB, DT, RGS, and JARM acknowledge financial support from Spain’s Ministry of Economy and Competitiveness (MINECO) under the AYA2014-60438-P and ESP2013-48362-C2-1-P projects. HL is supported by the project PUT1627 of Estonian Research Council and by the project TK133, financed by the European Union through the European Regional Development Fund. JD, MA, and RFJvdB acknowledge support from the European Research Council under FP7 grant number 340519.We have identified new clusters and characterized previously unknown Planck Sunyaev-Zeldovich (SZ) sources from the first Planck catalogue of SZ sources (PSZ1). The results presented here correspond to an optical follow-up observational programme developed during approximately one year (2014) at Roque de los Muchachos Observatory, using the 2.5 m Isaac Newton telescope, the 3.5 m Telescopio Nazionale Galileo, the 4.2 m William Herschel telescope and the 10.4 m Gran Telescopio Canarias. We have characterized 115 new PSZ1 sources using deep optical imaging and spectroscopy. We adopted robust criteria in order to consolidate the SZ counterparts by analysing the optical richness, the 2D galaxy distribution, and velocity dispersions of clusters. Confirmed counterparts are considered to be validated if they are rich structures, well aligned with the Planck PSZ1 coordinate and show relatively high velocity dispersion. Following this classification, we confirm 53 clusters, which means that 46% of this PSZ1 subsample has been validated and characterized with this technique. Sixty-Two SZ sources (54% of this PSZ1 subset) remain unconfirmed. In addition, we find that the fraction of unconfirmed clusters close to the galactic plane (at |b| 25°), which indicates contamination produced by radio emission of galactic dust and gas clouds on these SZ detections. In fact, in the majority of the cases, we detect important galactic cirrus in the optical images, mainly in the SZ target located at low galactic latitudes, which supports this hypothesis. © ESO 2018.https://www.aanda.org/articles/aa/abs/2018/08/aa32315-17/aa32315-17.htm