The Hidden Past of M92: Detection and Characterization of a Newly Formed 17° Long Stellar Stream Using the Canada-France Imaging Survey
Jensen, Jaclyn; Navarro, Julio F.; Cuillandre, Jean-Charles; Gwyn, Stephen; Malhan, Khyati; Ibata, Rodrigo A.; Martin, Nicolas F.; Famaey, Benoit; Chapman, Scott; Carlberg, Raymond; Starkenburg, Else; Côté, Patrick; Ferrarese, Laura; Mei, Simona; Hammer, François; Thomas, Guillaume F.; Reylé, Céline; Longeard, Nicolas; Venn, Kim; McConnachie, Alan
Canada, Switzerland, France, Sweden, United States, Germany
Abstract
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 and the Pan-STARRS 1 3π survey. 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] × 104 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.