• DOI:10.1111/j.1365-2966.2009.15746.x
• Corpus ID: 12884630

The structure of the outer Galactic disc as revealed by IPHAS early A stars

@article{Sale2010TheSO,
  title={The structure of the outer Galactic disc as revealed by IPHAS early A stars},
  author={S E Sale and J E Drew and Christian Knigge and Albert A. Zijlstra and Michael J. Irwin and R. A. H. Morris and Steven Phillipps and Jeremy J. Drake and Robert Greimel and Yvonne C Unruh and Paul J. Groot and Antonio Mampaso and Nicholas A. Walton},
  journal={Monthly Notices of the Royal Astronomical Society},
  year={2010},
  volume={402},
  pages={713-723}
}

• S. Sale, J. Drew, +10 authors N. Walton
• Published 21 September 2009
• Physics
• Monthly Notices of the Royal Astronomical Society

This study is an investigation of the stellar density profile of the Galactic disc in the Anticentre direction. We select over 40,000 early A stars from IPHAS photometry in the Galactic longitude range 160 ◦ < l < 200 ◦ close to the equatorial plane (−1 ◦ < b < +1 ◦ ). We then compare their observed reddening-corrected apparent magnitude distribution with simulated photometry obtained from parameterised models in order to set constraints on the Anticentre stellar density profile. By selecting A stars, we are appraising the properties of a population only ∼ 100 Myrs old. We find the stellar density profile of young stars is well fit to an exponential with length scale of (3020 ± 120statistical ± 180systematic) pc, which is comparable to that obtained in earlier studies, out to a Galactocentric radius of RT = (13.0 ± 0.5statistical ± 0.6systematic) kpc. At larger radii the rate of decline appears to increase with the scale length dropping to (1200 ± 300statistical ± 70systematic) pc. This result amounts to a refinement of the conclusions reached in previou s studies that the stellar density profile is abruptly truncated. The IPHAS A star data are n ot compatible with models that propose a sudden change in metallicity at RG = 10 kpc.