Browsing by Author "Nichol, R. C."

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    First Cosmology Results using Supernovae Ia from the Dark Energy Survey : Survey Overview, Performance, and Supernova Spectroscopy
    (2020) Smith, M.; D'Andrea, C. B.; Sullivan, M.; Moller, A.; Nichol, R. C.; Thomas, R. C.; Kim, A. G.; Sako, M.; Castander, F. J.; Clocchiatti, Alejandro; Filippenko, A. V.; Foley, R. J.; Galbany, L.; González Gaitan, S.; Kasai, E.; Kirshner, R. P.; Lidman, C.; Scolnic, D.; Brout, D.; Davis, T. M.; Gupta, R. R.; Hinton, S. R.; Kessler, R.; Lasker, J.; Macaulay, E.; Wolf, R. C.; Zhang, B.; Asorey, J.; Avelino, A.; Bassett, B. A.; Calcino, J.; Carollo, D.; Casas, R.; Challis, P.; Childress, M.; Crawford, S.; Frohmaier, C.; Glazebrook, K.; Goldstein, D. A.; Graham, M. L.; Hoormann, J. K.; Kuehn, K.; Lewis, G. F.; Mandel, K. S.; Morganson, E.; Muthukrishna, D.; Nugent, P.; Pan, Y. C.; Pursiainen, M.; Sharp, R.
  • Thumbnail Image
    Item
    SPIDERS: selection of spectroscopic targets using AGN candidates detected in all-sky X-ray surveys
    (OXFORD UNIV PRESS, 2017) Dwelly, T.; Salvato, M.; Merloni, A.; Brusa, M.; Buchner, J.; Anderson, S. F.; Boller, Th.; Brandt, W. N.; Budavari, T.; Clerc, N.; Coffey, D.; Del Moro, A.; Georgakakis, A.; Green, P. J.; Jin, C.; Menzel, M. L.; Myers, A. D.; Nandra, K.; Nichol, R. C.; Ridl, J.; Schwope, A. D.; Simm, T.
    SPIDERS (SPectroscopic IDentification of eROSITA Sources) is a Sloan Digital Sky Survey IV (SDSS-IV) survey running in parallel to the Extended Baryon Oscillation Spectroscopic Survey (eBOSS) cosmology project. SPIDERS will obtain optical spectroscopy for large numbers of X-ray-selected active galactic nuclei (AGN) and galaxy cluster members detected in wide-area eROSITA, XMM-Newton and ROSAT surveys. We describe the methods used to choose spectroscopic targets for two sub-programmes of SPIDERS X-ray selected AGN candidates detected in the ROSAT All Sky and the XMM-Newton Slew surveys. We have exploited a Bayesian cross-matching algorithm, guided by priors based on mid-IR colourmagnitude information from the Wide-field Infrared Survey Explorer survey, to select the most probable optical counterpart to each X-ray detection. We empirically demonstrate the high fidelity of our counterpart selection method using a reference sample of bright welllocalized X-ray sources collated from XMM-Newton, Chandra and Swift-XRT serendipitous catalogues, and also by examining blank-sky locations. We describe the down-selection steps which resulted in the final set of SPIDERS-AGN targets put forward for spectroscopy within the eBOSS/TDSS/SPIDERS survey, and present catalogues of these targets. We also present catalogues of similar to 12 000 ROSAT and similar to 1500 XMM-Newton Slew survey sources that have existing optical spectroscopy from SDSS-DR12, including the results of our visual inspections. On completion of the SPIDERS programme, we expect to have collected homogeneous spectroscopic redshift information over a footprint of similar to 7500 deg(2) for > 85 per cent of the ROSAT and XMM-Newton Slew survey sources having optical counterparts in the magnitude range 17 < r < 22.5, producing a large and highly complete sample of bright X-ray-selected AGN suitable for statistical studies of AGN evolution and clustering.