A two-color CCD survey of the North Celestial Cap: I. The method

Astrophysics and Space Science (Impact Factor: 2.4). 12/2009; 326(2). DOI: 10.1007/s10509-009-0242-0
Source: OAI

ABSTRACT We describe technical aspects of an astrometric and photometric survey of the North Celestial Cap (NCC), from the Pole ( δ=90°) to δ=80°, in support of the TAUVEX mission. This region, at galactic latitudes from ˜17° to ˜37°, has poor coverage in modern CCD-based surveys. The observations are performed with the Wise Observatory one-meter reflector and with a new mosaic CCD camera (LAIWO) that images in the Johnson-Cousins R and I bands a one-square-degree field with sub-arcsec pixels. The images are treated using IRAF and SExtractor to produce a final catalogue of sources. The astrometry, based on the USNO-A2.0 catalogue, is good to ˜1 arcsec and the photometry is good to ˜0.1 mag for point sources brighter than R=20.0 or I=19.1 mag. The limiting magnitudes of the survey, defined at photometric errors smaller than 0.15 mag, are 20.6 mag ( R) and 19.6 ( I). We separate stars from non-stellar objects based on the object shapes in the R and I bands, attempting to reproduce the SDSS star/galaxy dichotomy. The completeness test indicates that the catalogue is complete to the limiting magnitudes.


Available from: Noah Brosch, Jun 14, 2015
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The Korean Microlensing Telescope Network (KMTNet) will consist of three 1.6m telescopes each with a 4 deg^{2} field of view (FoV) and will be dedicated to monitoring the Galactic Bulge to detect exoplanets via gravitational microlensing. KMTNet's combination of aperture size, FoV, cadence, and longitudinal coverage will provide a unique opportunity to probe exoplanet demographics in an unbiased way. Here we present simulations that optimize the observing strategy for, and predict the planetary yields of, KMTNet. We find preferences for four target fields located in the central Bulge and an exposure time of t_{exp} = 120s, leading to the detection of ~2,200 microlensing events per year. We estimate the planet detection rates for planets with mass and separation across the ranges 0.1 <= M_{p}/M_{Earth} <= 1000 and 0.4 <= a/AU <= 16, respectively. Normalizing these rates to the cool-planet mass function of Cassan (2012), we predict KMTNet will be approximately uniformly sensitive to planets with mass 5 <= M_{p}/M_{Earth} <= 1000 and will detect ~20 planets per year per dex in mass across that range. For lower-mass planets with mass 0.1 <= M_{p}/M_{Earth} < 5, we predict KMTNet will detect ~10 planets per year. We also compute the yields KMTNet will obtain for free-floating planets (FFPs) and predict KMTNet will detect ~1 Earth-mass FFP per year, assuming an underlying population of one such planet per star in the Galaxy. Lastly, we investigate the dependence of these detection rates on the number of observatories, the photometric precision limit, and optimistic assumptions regarding seeing, throughput, and flux measurement uncertainties.
    The Astrophysical Journal 06/2014; 794(1). DOI:10.1088/0004-637X/794/1/52 · 6.28 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We describe the final product of the North Celestial Cap Survey (NCC Survey, NCCS) - the optical-UV-IR merged catalogue for the region within 10 deg of the North Celestial Pole. The NCC region at DEC > 80 deg is poorly covered by modern CCD-based surveys. The optical part of the survey was observed in V, R and I with the Wise Observatory telescopes and was merged with GALEX UV and WISE IR data, producing the catalogue. More than four million objects were observed in at least one optical band. The final catalogue contains ~1.6 million sources observed in all three optical bands, of which some 1.4 million have WISE counterparts and ~300,000 have GALEX counterparts. The astrometric accuracy of the optical NCCS data, derived from a comparison with the UCAC3 catalogue, is better than 0.2 arcsec and the photometry, when compared with SDSS, is good to ~0.15 mag for sources brighter than V = 20.3, R = 21.0 and I = 19.2 mag. The SDSS point-extended source separation is reproduced with >92% efficiency.
    Monthly Notices of the Royal Astronomical Society 06/2014; 443(1). DOI:10.1093/mnras/stu1183 · 5.23 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We present preliminary results of an optical-UV survey of the North Celestial Cap (NCCS) based on ~5% areal coverage. The NCCS will provide good photometric and astrometric data for the North Celestial Cap region (80 < DEC < 90). This region, at galactic latitudes 17 < b < 37, is poorly covered by modern CCD-based surveys. The expected number of detected objects in NCCS is ~1,500,000. We discuss issues of galactic structure, extinction, and the galaxy clustering in the colour-colour diagrams.
    Astrophysics and Space Science 01/2011; 335(1). DOI:10.1007/s10509-011-0603-3 · 2.40 Impact Factor