A deeper look at the GD1 stream: density variations and wiggles

作者：de Boer T J L^*; Belokurov V; Koposov S E; Ferrarese L; Erkal D; Cote P; Navarro J F

来源：Monthly Notices of the Royal Astronomical Society, 2018, 477(2): 1880-1889.

DOI：10.1093/mnras/sty677

• Galaxy: fundamental parameters
• Galaxy: halo
• Galaxy: structure

Using deep photometric data from Canada-France-Hawaii Telescope/Megacam, we study the morphology and density of the GD-1 stream, one of the longest and coldest stellar streams in the MilkyWay. Our deep data recovers the lower main sequence of the stream with unprecedented quality, clearly separating it from Milky Way foreground and background stars. An analysis of the distance to different parts of the stream shows that GD-1 lies at a heliocentric distance between 8 and 10 kpc, with only a shallow gradient across 45 degrees on the sky. Matched filter maps of the stream density show clear density variations, such as deviations from a single orbital track and tentative evidence for stream fanning. We also detect a clear underdensity in the middle of the stream track at phi(1) = -45 degrees surrounded by overdense stream segments on either side. This location is a promising candidate for the elusive missing progenitor of the GD-1 stream. We conclude that the GD-1 stream has clearly been disturbed by interactions with the Milky Way disc or other subhaloes.

• 出版日期2018-6