The hidden past of M92: Detection and characterization of a newly formed 17 • long stellar stream using the Canada-France Imaging Survey

Guillaume F Thomas , Jaclyn Jensen , Alan Mcconnachie , Patrick Côté , Kim Venn , Nicolas Longeard , Raymond Carlberg , Scott Chapman , Jean-Charles Cuillandre (1) , Benoit Famaey (2) , Laura Ferrarese , Stephen Gwyn , François Hammer , Rodrigo A Ibata , Khyati Malhan , Nicolas Martin , Simona Mei , Julio F Navarro , Céline Reylé , Else Starkenburg

1 AIM (UMR_7158 / UMR_E_9005 / UM_112) - Astrophysique Interprétation Modélisation
2 ObAS - Observatoire astronomique de Strasbourg

We present an analysis of the structure, kinematics and orbit of a newly found stellar stream emanating from the globular cluster M92 (NGC 6341). This stream was discovered in an improved matched-filter map of the outer Galaxy, based on a "color-color-magnitude" diagram, created using photometry from the Canada-France Imaging Survey (CFIS) and the Pan-STARRS 1 3π survey (PS1). We find the stream to have a length of 17 • (2.5 kpc at the distance of M92), a width dispersion of 0.29 • (42 pc) and a stellar mass of [3.17 ± 0.89] × 10 4 M (10% of the stellar mass of the current main body of M92). We examine the kinematics of main sequence, red giant and blue horizontal branch stars belonging to the stream and that have proper motion measurements from the second data release of Gaia. N-body simulations suggest that the stream was likely formed very recently (during the last ∼ 500 Myr) forcing us to question the orbital origin of this ancient, metal-poor globular cluster.

Domaines: Physique [physics]; Astrophysique [astro-ph]

Guillaume F Thomas, Jaclyn Jensen, Alan Mcconnachie, Patrick Côté, Kim Venn, et al.. The hidden past of M92: Detection and characterization of a newly formed 17 • long stellar stream using the Canada-France Imaging Survey. The Astrophysical Journal, 2020, 902 (2), pp.89. ⟨10.3847/1538-4357/abb6f7⟩. ⟨hal-02985015⟩