Uniform Modelling of the Stellar Density of Thirteen Tidal Streams within the Galactic Halo

TL;DR

This paper models the density and structure of thirteen stellar streams in the Milky Way's halo, revealing substructures and differences based on progenitor types, aiding future dynamical and spectroscopic studies.

Contribution

It introduces a uniform method for modeling stellar stream densities and characterizes their properties across multiple streams, including substructures and progenitor distinctions.

Findings

Streams with globular cluster progenitors are narrower than those from dwarf galaxies.

Globular cluster streams have lower luminosities than intact clusters.

Several streams exhibit substructures like gaps and density variations.

Abstract

We present the results of fitting a flexible stellar stream density model to a collection of thirteen streams around the Milky Way, using photometric data from DES, DECaLS, and Pan-STARRS. We construct density maps for each stream and characterise their tracks on the sky, width, and distance modulus curves along the length of each stream. We use these measurements to compute lengths and total luminosities of streams and identify substructures. Several streams show prominent substructures, such as stream broadening, gaps, large deviations of stream tracks and sharp changes in stream densities. Examining the group of streams as a population, as expected we find that streams with globular cluster progenitors are typically narrower than those with dwarf galaxy progenitors, with streams around 100 pc wide showing overlap between the two populations. We also note the average luminosity of globular cluster streams is significantly lower than the typical luminosity of intact globular clusters. The likely explanation is that observed globular cluster streams preferentially come from lower luminosity and lower density clusters. The stream measurements done in a uniform manner presented here will be helpful for more detailed stream studies such as identifying candidate stream members for spectroscopic follow up and stellar stream dynamical modeling.