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

TL;DR

This paper reports the discovery and analysis of a 17-degree long stellar stream originating from globular cluster M92, using data from CFIS, Pan-STARRS, and Gaia, revealing its recent formation and properties.

Contribution

It introduces a newly identified stellar stream from M92, characterizes its structure and kinematics, and suggests a recent formation epoch based on N-body simulations.

Findings

Stream length of 17 degrees (2.5 kpc)

Stream width dispersion of 0.29 degrees (42 pc)

Stellar mass of approximately 3.17 x 10^4 solar masses

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 (CFIS) and the Pan-STARRS 1 3$\pi$ survey (PS1). We find the stream to have a length of 17{\deg} (2.5 kpc at the distance of M92), a width dispersion of $0.29${\deg}(42 pc) and a stellar mass of $[3.17 \pm{0.89}] \times 10^{4} $ M$_\odot$ ($10 \%$ 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 $\sim 500$ Myr) forcing us to question the orbital origin of this ancient, metal-poor globular cluster.