2008/06/12 by E. Zackrisson, Erik Zackrisson, T. Riehm +4
Engineering · Physics and Astronomy · #CCD and CMOS Imaging Sensors #Galaxies: Formation, Evolution, Phenomena #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/590541
7 pages, 3 figures, accepted for publication in ApJ
arxiv created 2008/06/12 · openalex publication_date 2008/09/04 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The cold dark matter scenario predicts that a large number of dark subhalos should be located within the halo of each Milky WayYsized galaxy.One telltale signature of such dark subhalos could be additional milliarcsecond-scale image splitting of quasars previously known to be multiply imaged on arcsecond scales.Here we estimate the image separations for the subhalo density profiles favored by recent N-body simulations and compare these to the angular resolution of both existing and upcoming observational facilities.We find that the image separations produced are very sensitive to the exact subhalo density profile assumed, but in all cases they are considerably smaller than previous estimates based on the premise that subhalos can be approximated by singular isothermal spheres.Only the most optimistic subhalo models produce image separations that would be detectable with current technology, and many models produce image separations that will remain unresolved with all telescopes expected to become available in the foreseeable future.Detections of dark subhalos through image-splitting effects will therefore be far more challenging than currently believed, albeit not necessarily impossible.