STREAMFINDER II: A possible fanning structure parallel to the GD-1 stream in Pan-STARRS1

Abstract

STREAMFINDER is a new algorithm that we have built to detect stellar streams in an automated and systematic way in astrophysical datasets that possess any combination of positional and kinematic information. In Paper I, we introduced the methodology and the workings of our algorithm and showed that it is capable of detecting ultra-faint and distant halo stream structures containing as few as $\sim 15$ members (${\Sigma }_{\mathrm{G}}\sim 33.6\mathrm{mag}\mathrm{arcse}{\mathrm{c}}^{-2}$) in the Gaia dataset. Here, we test the method with real proper motion data from the Pan-STARRS1 survey, and by selecting targets down to $r_0=18.5$ mag we show that it is able to detect the GD-1 stellar stream, whereas the structure remains below a useful detection limit when using a Matched Filter technique. The radial velocity solutions provided by STREAMFINDER for GD-1 candidate members are found to be in good agreement with observations. Furthermore, our algorithm detects a $\sim 40^{°}$ long structure approximately parallel to GD-1, and which fans out from it, possibly a sign of stream-fanning due to the triaxiality of the Galactic potential. This analysis shows the promise of this method for detecting and analysing stellar streams in the upcoming Gaia DR2 catalogue.

10 pages, 7 figures, Accepted for publication in MNRAS

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Cited by in corpus (18)

• Constraining the Milky Way Halo Potential with the GD-1 stellar stream
• An all-sky proper motion map of the Sagittarius stream using Gaia DR2
• Evidence of a dwarf galaxy stream populating the inner Milky Way Halo
• Butterfly in a Cocoon, Understanding the origin and morphology of Globular Cluster Streams: The case of GD-1
• Probing the nature of dark matter with accreted globular cluster streams
• Detection of Strong Epicyclic Density Spikes in the GD-1 Stellar Stream. An Absence of Evidence for the Influence of Dark Matter Subhalos?
• Identifying Stellar Streams in Gaia DR2 with Data Mining Techniques
• Via Machinae: Searching for Stellar Streams using Unsupervised Machine Learning
• A chemo-dynamical link between the Gjöll stream and NGC 3201
• The e-TidalGCs Project: Modeling the extra-tidal features generated by Galactic globular clusters
• The tidal stream generated by the globular cluster NGC 3201
• GD-1 Stellar Stream and Cocoon in the DESI Early Data Release
• Probability of forming gaps in the GD-1 stream by close encounters of globular clusters
• The retrograde orbit of the globular cluster FSR1758 revealed with Gaia DR2
• Member stars of the GD1 tidal stream from the SDSS, LAMOST and Gaia surveys
• Modelling the Track of the GD-1 Stellar Stream Inside a Host with a Fermionic Dark Matter Core-Halo Distribution
• The influence of dark matter halo on the stellar stream asymmetry via dynamical friction
• The Nephele ecosystem: stars, globular clusters, and stellar streams associated with the progenitor galaxy of $\omega$ Centauri