2016/06/30 by Denis Erkal, Vasily Belokurov, Jo Bovy +1 · 2 citations
Physics and Astronomy · #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Density contrast #Flux (metallurgy) #Galactic Center #Galaxies: Formation, Evolution, Phenomena #Galaxy #Milky Way #Physics #STREAMS #Stellar, planetary, and galactic studies #astro-ph.GA
paper · pdf · doi:10.1093/mnras/stw1957
18 pages, 19 figures. Accepted for publication in MNRAS. Minor revisions in response to the referee
openalex publication_date 2016/08/04 · arxiv created 2016/08/09 · arxiv updated 2016/08/17 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Ample observational capabilities exist today to detect the small density perturbations that low-mass dark matter subhaloes impart on stellar streams from disrupting Galactic satellites. In anticipation of these observations, we investigate the expected number and size of gaps by combining an analytic prescription for gap evolution on circular orbits with the flux of subhaloes near the stream. We explore the distribution of gap sizes and depths for a typical cold stream around the Milky Way and find that for a given stream age and gap depth, each subhalo mass produces a characteristic gap size. For a stream with an age of a few Gyr, orbiting at a distance of 10–20 kpc from the Galactic centre, even modest subhaloes with a mass of 106–107 M⊙ produce gaps with sizes that are of the order of several degrees. We consider the number and distribution of gap sizes created by subhaloes with masses 105–109 M⊙, accounting for the expected depletion of subhaloes by the Milky Way disc, and present predictions for six cold streams around the Milky Way. For Pal 5, we forecast 0.7 gaps with a density depletion of at least 25 per cent and a typical gap size of 8°. Thus, there appears to be no tension between the recent non-detection of density depletions in the Pal 5 tidal tails and ΛCDM expectations. These predictions can be used to guide the scale of future gap searches.