The VST photometric hα survey of the Southern Galactic Plane and Bulge (VPHAS+)

J. E. Drew*, E. Gonzalez-Solares, R. Greimel, M. J. Irwin, A. Küpcü Yoldas, J. Lewis, G. Barentsen, J. Eislöffel, H. J. Farnhill, W. E. Martin, J. R. Walsh, N. A. Walton, M. Mohr-Smith, R. Raddi, S. E. Sale, N. J. Wright, P. Groot, M. J. Barlow, R. L. M. Corradi, J. J. DrakeJ. Fabregat, D. J. Frew, B. T. Gänsicke, C. Knigge, A. Mampaso, R. A. H. Morris, T. Naylor, Q. A. Parker, S. Phillipps, C. Ruhland, D. Steeghs, Y. C. Unruh, J. S. Vink, R. Wesson, A. A. Zijlstra

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    197 Citations (Scopus)


    The VST Photometric Hα Survey of the Southern Galactic Plane and Bulge (VPHAS+) is surveying the southern Milky Way in u, g, r, i and Hα at ~1 arcsec angular resolution. Its footprint spans the Galactic latitude range -5o < b < +5° at all longitudes south of the celestial equator. Extensions around the Galactic Centre to Galactic latitudes ±10° bring in much of the Galactic bulge. This European Southern Observatory public survey, begun on 2011 December 28, reaches down to ~20th magnitude (10σ) and will provide single-epoch digital optical photometry for ~300 million stars. The observing strategy and data pipelining are described, and an appraisal of the segmented narrow-band Hα filter in use is presented. Using model atmospheres and library spectra, we compute main-sequence (u - g), (g - r), (r - i) and (r - Hα) stellar colours in the Vega system. We report on a preliminary validation of the photometry using test data obtained from two pointings overlapping the Sloan Digital Sky Survey. An example of the (u - g, g - r) and (r - Hα, r - i) diagrams for a full VPHAS+ survey field is given. Attention is drawn to the opportunities for studies of compact nebulae and nebular morphologies that arise from the image quality being achieved. The value of the u band as the means to identify planetary-nebula central stars is demonstrated by the discovery of the central star of NGC 2899 in survey data. Thanks to its excellent imaging performance, the VLT Survey Telescope (VST)/OmegaCam combination used by this survey is a perfect vehicle for automated searches for reddened early-type stars, and will allow the discovery and analysis of compact binaries, white dwarfs and transient sources.

    Original languageEnglish
    Pages (from-to)2036-2058
    Number of pages23
    JournalMonthly Notices of the Royal Astronomical Society
    Issue number3
    Publication statusPublished - May 2014


    • Galaxy: bulge
    • Galaxy: disc
    • H II regions
    • Planetary nebulae: general
    • Stars: general
    • Surveys


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