* Astronomy

Title: Serendipitous Discovery of a Thin Stellar Stream near the Galactic Bulge in the Pan-STARRS1 3Pi Survey
Author: Edouard J. Bernard, Annette M. N. Ferguson, Edward F. Schlafly, Mohamad Abbas, Eric F. Bell, Niall R. Deacon, Nicolas F. Martin, Hans-Walter Rix, Branimir Sesar, Colin T. Slater, Jorge Peñarrubia, Rosemary F. G. Wyse, William S. Burgett, Kenneth C. Chambers, Peter W. Draper, Klaus W. Hodapp, Nicholas Kaiser, Rolf-Peter Kudritzki, Eugene A. Magnier, Nigel Metcalfe, Jeffrey S. Morgan, Paul A. Price, John L. Tonry, Richard J. Wainscoat, Christopher Waters

We report the discovery of a thin stellar stream found in Pan-STARRS1 photometry near the Galactic bulge in the constellation of Ophiuchus. It appears as a coherent structure in the colour-selected stellar density maps produced to search for tidal debris around nearby globular clusters. The stream is exceptionally short and narrow; it is about 2.5{\deg} long and 6' wide in projection. The colour-magnitude diagram of this object, which harbours a blue horizontal-branch, is consistent with an old and relatively metal-poor population ([Fe/H]~-1.3) located 9.5 +/- 0.9 kpc away at (l,b) ~ (5{\deg},+32{\deg}), and 5.0 +/- 1.0 kpc from the Galactic centre. These properties argue for a globular cluster as progenitor. The finding of such a prominent, nearby stream suggests that many streams could await discovery in the more densely populated regions of our Galaxy.

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