Abstract
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 INT/WFC Photometric Hα Survey of the Northern Galactic Plane (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 parametrized 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 Myr old. We find that 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 scalelength dropping to (1200 ± 300statistical ± 70systematic) pc. This result amounts to a refinement of the conclusions reached in previous studies that the stellar density profile is abruptly truncated. The IPHAS A star data are not compatible with models that propose a sudden change in metallicity at RG = 10 kpc. © 2009 The Authors. Journal compilation © 2009 RAS.
Original language | English |
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Pages (from-to) | 713-723 |
Number of pages | 10 |
Journal | Monthly Notices of the Royal Astronomical Society |
Volume | 402 |
Issue number | 2 |
DOIs | |
Publication status | Published - Feb 2010 |
Keywords
- Galaxy: abundances
- Galaxy: disc
- Galaxy: stellar content
- Galaxy: structure
- Surveys