TriAnd and its siblings: satellites of satellites in the Milky Way halo

Deason, A.J.; Belokurov, V.; Hamren, K.M.; Koposov, S.E.; Gilbert, K.M.; Beaton, R.L.; Dorman, C.E.; Guhathakurta, P.; Majewski, S.R.; Cunningham, E.C.

Abstract

We explore the Triangulum–Andromeda (TriAnd) overdensity in the SPLASH (Spectroscopic and Photometric Landscape of Andromeda's Stellar Halo) and SEGUE (the Sloan Extension for Galactic Understanding and Exploration) spectroscopic surveys. Milky Way main-sequence turn-off stars in the SPLASH survey reveal that the TriAnd overdensity and the recently discovered Pan-Andromeda Archaeological Survey (PAndAS) stream share a common heliocentric distance (D ∼ 20 kpc), position on the sky, and line-of-sight velocity (VGSR ∼ 50 km s−1). Similarly, A-type, giant, and main-sequence turn-off stars selected from the SEGUE survey in the vicinity of the Segue 2 satellite show that TriAnd is prevalent in these fields, with a velocity and distance similar to Segue 2. The coincidence of the PAndAS stream and Segue 2 satellite in positional and velocity space to TriAnd suggests that these substructures are all associated, and may be a fossil record of group-infall on to the Milky Way halo. In this scenario, the Segue 2 satellite and PAndAS stream are ‘satellites of satellites’, and the large, metal-rich TriAnd overdensity is the remains of the group central.

Citation

Deason, A., Belokurov, V., Hamren, K., Koposov, S., Gilbert, K., Beaton, R., …Cunningham, E. (2014). TriAnd and its siblings: satellites of satellites in the Milky Way halo. Monthly Notices of the Royal Astronomical Society, 444(4), 3975-3985. https://doi.org/10.1093/mnras/stu1764

• Journal Article Type: Article
• Acceptance Date: Aug 25, 2014
• Online Publication Date: Sep 18, 2014
• Publication Date: Sep 18, 2014
• Deposit Date: Feb 20, 2017
• Publicly Available Date: Jan 18, 2019
• Journal: Monthly Notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Electronic ISSN: 1365-2966
• Publisher: Royal Astronomical Society
• Peer Reviewed: Peer Reviewed
• Volume: 444
• Issue: 4
• Pages: 3975-3985
• DOI: https://doi.org/10.1093/mnras/stu1764
• Public URL: https://durham-repository.worktribe.com/output/1385906
• Related Public URLs: http://adsabs.harvard.edu/abs/2014MNRAS.444.3975D