Thu, 21 Aug 2008 01:20:50 BST CiteULike: isudal's bjs http://www.citeulike.org/user/isudal/tag/bjs CiteULike.org en-gb Copyright © 2004-2008 citeulike.org http://www.citeulike.org/user/isudal/article/2361527 <i>Mon. Not. Roy. Astron. Soc., Vol. 288 (June 1997), pp. 365-374.</i><br /><br />The light distribution in the inner few kiloparsecs of the Milky Way is recovered non-parametrically from a dust-corrected near-infrared COBE/DIRBE surface brightness map of the inner Galaxy. The best fits to the photometry are obtained when the Sun is assumed to lie ~14+/-4pc above the plane. The recovered density distributions clearly show an elongated three-dimensional bulge set in a highly non-axisymmetric disc. In the favoured models, the bulge has axis ratios 1:0.6:0.4 and semi-major axis length ~2kpc. Its nearer long axis lies in the first quadrant. The bulge is surrounded by an elliptical disc that extends to ~2kpc on the minor axis and ~3.5kpc on the major axis. In all models there is a local density minimum ~2.2kpc down the minor axis. The subsequent maximum ~3kpc down the minor axis (corresponding to l~=-22 deg and l~=17 deg) may be associated with the Lagrange point L_4. From this identification and the length of the bulge-bar, we infer a pattern speed Omega_b~=60-70^-1kms kpc^-1 for the bar. Experiments in which pseudo-data derived from models with spiral structure were deprojected under the assumption that the Galaxy is either eight-fold or four-fold symmetric indicate that the highly non-axisymmetric discs recovered from the COBE data could reflect spiral structure within the Milky Way if that structure involves density contrasts greater than >~3 at near-infrared wavelengths. These experiments indicate that the angle phi_0 between the Sun-centre line and a major axis of the bulge lies near 20 deg. The photometric structure of the inner Galaxy J Binney O Gerhard D Spergel Mon. Not. Roy. Astron. Soc., Vol. 288 (June 1997), pp. 365-374. 2008-02-11T06:52:42-00:00 1997 Mon. Not. Roy. Astron. Soc. 288 365 374 bjs galaxy