VPHAS+: The VST/OmegaCam Photometric Hα Survey of the Southern Galactic Plane
VPHAS+ is a public survey to be carried out on the VLT Survey Telescope (VST) operated by ESO. This is the southern counterpart to IPHAS and UVEX. Below: a first VST Hα image mosaic of the Lagoon Nebula, obtained during the initial testing phase in September 2011. The area shown is about one quarter of a square degree.
In autumn 2010, approval was given to extend the survey footprint to include the Galactic Bulge, within the Galactic latitude range -10 < b < +10 degrees, thereby providing the optical counterpart to VISTA's VVV survey.
Survey data-taking began in January 2012.
VPHAS+ is expected to reach to r(AB) = 21, and will reveal emission line objects falling into the following classes:
- Wolf-Rayet and other massive evolved emission line stars in the inner Milky Way
- compact planetary nebulae and rapidly evolving post-AGB stars
- Be stars of all types - including young Herbig stars
- clustered and field T Tau stars
- a range of interacting binary stars: symbiotics, 'supersoft' compact binaries, WD/NS/BH accreting binaries
- white dwarfs, horizontal branch stars and large numbers of early A-type stars via their strong Hα absorption
Because of the Hα selection for ionized stellar winds and nebulae, VPHAS+ will add to the stock of known OB associations and young open clusters. The sensitivity of the r-Hα colour to intrinsic colour (spectral type) can also be exploited to achieve high spatial resolution 3D extinction maps. So, as well as stimulating a better understanding of stellar evolution, VPHAS+ has a role to play in the quest to clarify the Galaxy's structure as a star-forming spiral galaxy.
VPHAS+ will also provide high spatial resolution imaging of ionized nebulae. It will be the digital successor to the AAO UK Schmidt Southern Galactic Plane Survey (which may be accessed here)