Stars of the LMS-1 stream with sp. obs.

Here, we present the first comprehensive study of the LMS-1 stellar stream, that we detect by searching for wide streams in the Gaia EDR3 data set using the STREAMFINDER algorithm. This stream was recently discovered by Yuan et al. We detect LMS-1 as a 60{deg} long stream to the north of the galactic bulge, at a distance of ~20kpc from the Sun, together with additional components that suggest that the overall stream is completely wrapped around the inner Galaxy.

Using spectroscopic measurements from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope, the Sloan Digital Sky Survey, and the Apache Point Observatory Galactic Evolution Experiment, we infer that the stream is very metal-poor (<[Fe/H]>=-2.1) with a significant metallicity dispersion ({sigma}_[Fe/H]_=0.4), and it possesses a large radial velocity dispersion ({sigma}_v_=20+/-4km/s). These estimates together imply that LMS-1 is a dwarf galaxy stream.