View Full Version : Surface Brightness of the Galaxy

2011-Nov-18, 01:03 PM
This is a spin-off from the Fun Papers in Arxiv thread. The following paper belatedly caught my eye:

http://arxiv.org/abs/1111.2044 is a paper about how the Milky Way compares to other spirals. It is a very quick readable paper that concludes that the Milky Way is similar to about 2% of the nearby spirals, and seems to have not had any major mergers to disturb it since the very early days of its initial formation.

The reason being, it seems to be completely at odds with the findings of this earlier (pub 2008 ?) paper:

The surface brightness of the Galaxy at the Solar Neighbourhood
A.-L. Melchior, F. Combes, A. Gould


...the presence of a local minimum of the stellar density compatible with Gould's belt. According to this result, the global luminosity of the Milky Way should follow the Tully-Fisher relation established for external galaxies.

The recent paper does not cite, nor make any reference to the earlier paper. The plot thickens, because authors of both papers are based at Observatoire de Paris.

Anyway, unlike the recent paper, the earlier Melchior et al paper is very technical and I do not pretend to fully understand it. What it seems to conclude is that estimating the external luminosity of the Milky Way using local stellar populations is going to lead to an underestimate. This is because our local patch of galaxy is in between spiral arms and underluminous compared to the average for our galactic radius.

Anyway, if anyone has a greater understanding of these issues it'd be interesting to hear your take on it.