We report the serendipitous discovery of a stellar stream in the constellation Pegasus in the south Galactic hemisphere. The stellar stream was detected using the SDSS Data Release 14 by means of a matched filter in the color--magnitude diagram that is optimised for a stellar population that is 8 Gyr old with [Fe/H] = −0.46 dex, and located at heliocentric distance of 18 kpc. The candidate stream is faint (turnoff point at r0∼ 19.6), sparse and barely visible in SDSS photometry. It is also detected in the (shallower) Pan-STARRs data. The residual stellar density in the (u−g)0, (g−r)0 color--color diagram gives the same estimate for the age and [Fe/H] of this stellar population. The stream is located at a Galactic coordinates (l,b)=(79.4,−24.6) and extends over 9∘ (2.5 kpc), with a width of 112 pc. The narrow width suggests a globular cluster progenitor.
@article{arxiv.1903.08840,
title = {A Cold Stellar Stream in Pegasus},
author = {H. D. Perottoni and C. Martin and H. J. Newberg and H. J. Rocha-Pinto and F. de Almeida-Fernandes and A. R. Gomes-Junior},
journal= {arXiv preprint arXiv:1903.08840},
year = {2019}
}