The tidal tails of NGC 2298

TL;DR

This paper develops and tests a matched-filter technique to detect tidal tails of globular clusters, successfully applied to NGC 2298, revealing its extended tidal structures and assessing the method's sensitivity to cluster properties.

Contribution

The paper introduces a novel application of the matched-filter technique to identify tidal tails in globular clusters, including NGC 2298, and evaluates its effectiveness and limitations.

Findings

Matched-filter increases tail contrast by 2.5 times for NGC 2298.

Detected leading and trailing tidal tails of NGC 2298.

Disregarding mass segregation reduces detection sensitivity.

Abstract

We present an implementation of the matched-filter technique to detect tidal tails of globular clusters. The method was tested using SDSS data for the globular cluster Palomar 5 revealing its well known tidal tails. We also ran a simulation of a globular cluster with a tidal tail where we successfully recover the tails for a cluster at the same position and with the same characteristics of NGC 2298. Based on the simulation we estimate that the matched-filter increases the contrast of the tail relative to the background of stars by a factor of 2.5 for the case of NGC 2298. We also present the photometry of the globular cluster NGC 2298 using the MOSAIC2 camera installed on the CTIO 4m telescope. The photometry covers ~ 3deg2 reaching V ~ 23. A fit of a King profile to the radial density profile of NGC 2298 shows that this cluster has a tidal radius of 15.91' \pm 1.07' which is twice as in the literature. The application of the matched-filter to NGC 2298 reveals several extra-tidal structures, including a leading and trailing tail. We also find that NGC 2298 has extra-tidal structures stretching towards and against the Galactic disk, suggesting strong tidal interaction. Finally, we assess how the matched-filter performs when applied to a globular cluster with and without mass segregation taken into account. We find that disregarding the effects of mass segregation may significantly reduce the detection limit of the matched-filter.