2006/11/10 by F. J. Castander, Ezequiel Treister, E. Treister +3 · 1 citation
Physics and Astronomy · #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Galaxies: Formation, Evolution, Phenomena #Galaxy #Gravitational lens #Halo #Mass distribution #Physics #Quasar #RADIUS #Spiral galaxy #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/508148
8 pages, 5 figures, ApJ accepted (scheduled Dec 1 2006, 652, 955)
arxiv created 2006/11/10 · openalex publication_date 2006/11/27 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We present the CXOCY J220132.8-320144 system, which is composed of an edge-on spiral galaxy at z = 0.32 lensing a z = 3.9 background quasar. Two images of the quasar are seen. The geometry of the system is favorable to separate the relative mass contribution of the disk and halo in the inner parts of the galaxy. We model the system with one elliptical mass component with the same ellipticity as the light distribution and manage to reproduce the quasar image positions and fluxes. We also model the system with two mass components, disk and halo. Again, we manage to reproduce the quasar image positions and fluxes. However, all models predict at least a third visible image close to the disk that is not seen in our images. We speculate that this is most likely due to extinction by the disk. We also measure the rotational velocity of the galaxy at 2.7 disk scale radius to be v c = 130 ± 20 km s -1 from the [O II] emission lines. When adding the rotational velocity constraint to the models, we find that the contribution to the rotational velocity of the disk is likely to be equal to or larger than the contribution of the halo at this radius. The detection of the third image and a more accurate measurement of the rotational velocity would help to set tighter constraints on the mass distribution of this edge-on spiral galaxy.