Optical surveys

Janet Drew is the Principal Investigator of IPHAS and VPHAS+

The nearly-complete INT/WFC Photometric H-alpha Survey of the Northern Galactic Plane (IPHAS) is a massive imaging programme being carried out, in narrow-band H-alpha, and broadband r and i filters, using the Wide Field Camera (WFC) on the 2.5-metre Isaac Newton Telescope (INT). The area surveyed is the entire northern Plane within +/- 5 degrees of the Galactic Equator (1800 square degrees). IPHAS is described more fully by Drew et al (2005, MNRAS, 362, 753). This is being followed by VPHAS+, an analogous 5-filter survey of the southern Galactic Plane and Bulge on the VLT survey telescope (VST) using OmegaCam. Together, these surveys provide a springboard to a quantitative revolution in our understanding of the extreme phases of stellar evolution, and the means to pursue wide-ranging studies of Galactic Plane stellar populations. The previous generation of H-alpha surveys of the Galaxy, conducted over 30 years ago, begin to be incomplete at visual magnitudes of 12-13: the new generation extends this limit down to red magnitudes fainter than 20 - an increase in sensitivity by a factor of around 1000.