# Tidal tails around the outer halo globular clusters Eridanus and Palomar 15

## TL;DR

This paper reports the discovery of extensive tidal tails around the remote outer halo globular clusters Eridanus and Palomar 15, revealing their interactions with the Milky Way and nearby dwarf galaxies.

## Contribution

It presents the first detection of tidal tails around these distant clusters using DECam imaging, expanding knowledge of globular cluster disruption in the outer halo.

## Key findings

- Tidal tails extend over 760 pc for Eridanus and 1160 pc for Palomar 15.
- Both clusters show deviations from King profiles in their outer regions.
- The tidal tails' great circles relate to the Galactic Center and dwarf satellites.

## Abstract

We report the discovery of tidal tails around the two outer halo globular clusters, Eridanus and Palomar 15, based on $gi$-band images obtained with DECam at the CTIO 4-m Blanco Telescope. The tidal tails are among the most remote stellar streams presently known in the Milky Way halo. Cluster members have been determined from the color-magnitude diagrams and used to establish the radial density profiles, which show, in both cases, a strong departure in the outer regions from the best-fit King profile. Spatial density maps reveal tidal tails stretching out on opposite sides of both clusters, extending over a length of $\sim$760 pc for Eridanus and $\sim$1160 pc for Palomar 15. The great circle projected from the Palomar 15 tidal tails encompasses the Galactic Center, while that for Eridanus passes close to four dwarf satellite galaxies, one of which (Sculptor) is at a comparable distance to that of Eridanus.