A Revised Velocity for the Globular Cluster GC-98 in the Ultra Diffuse Galaxy NGC1052-DF2

Pieter van Dokkum; Yotam Cohen; Shany Danieli; Aaron Romanowsky; Roberto Abraham; Jean Brodie; Charlie Conroy; J. M. Diederik Kruijssen; Deborah Lokhorst; Allison Merritt; Lamiya Mowla; Jielai Zhang

arXiv · 1806.04685

A Revised Velocity for the Globular Cluster GC-98 in the Ultra Diffuse Galaxy NGC1052-DF2

Pieter van Dokkum·Yotam Cohen·Shany Danieli·Aaron Romanowsky·Roberto Abraham·Jean Brodie·Charlie Conroy·J. M. Diederik Kruijssen·Deborah Lokhorst·Allison Merritt·Lamiya Mowla·Jielai Zhang

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Abstract

We recently published velocity measurements of luminous globular clusters in the galaxy NGC1052-DF2, concluding that it lies far off the canonical stellar mass - halo mass relation. Here we present a revised velocity for one of the globular clusters, GC-98, and a revised velocity dispersion measurement for the galaxy. We find that the intrinsic dispersion $\sigma=5.6^{+5.2}_{-3.8}$ km/s using Approximate Bayesian Computation, or $\sigma=7.8^{+5.2}_{-2.2}$ km/s using the likelihood. The expected dispersion from the stars alone is ~7 km/s. Responding to a request from the Editors of ApJ Letters and RNAAS, we also briefly comment on the recent analysis of our measurements by Martin et al. (2018).

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Pieter van Dokkum, Yotam Cohen, Shany Danieli, Aaron Romanowsky, Roberto Abraham, Jean Brodie, Charlie Conroy, J. M. Diederik Kruijssen, Deborah Lokhorst, Allison Merritt, Lamiya Mowla, Jielai Zhang. 2018-06-12. A Revised Velocity for the Globular Cluster GC-98 in the Ultra Diffuse Galaxy NGC1052-DF2. https://arxiv.org/abs/1806.04685

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