Publications (15)
A trail of dark matter-free galaxies from a bullet dwarf collision
Pieter van Dokkum, Zili Shen, Michael A. Keim +8
The ultra-diffuse galaxies DF2 and DF4 in the NGC1052 group share several unusual properties: they both have large sizes, rich populations of overluminous and large globular cluste…
Wide-Field Precision Kinematics of the M87 Globular Cluster System
Jay Strader, Aaron Romanowsky, Jean Brodie +6
We present the most extensive combined photometric and spectroscopic study to date of the enormous globular cluster (GC) system around M87, the central giant elliptical galaxy in t…
Kinematics and Angular Momentum in Early Type Galaxy Halos
Jean P. Brodie, Aaron Romanowsky, the SLUGGS team
We use the kinematics of discrete tracers, primarily globular clusters (GCs) and planetary nebulae (PNe), along with measurements of the integrated starlight to explore the assembl…
The Densest Galaxy
Jay Strader, Anil Seth, Duncan Forbes +8
We report the discovery of a remarkable ultra-compact dwarf galaxy around the massive Virgo elliptical galaxy NGC 4649 (M60), which we term M60-UCD1. With a dynamical mass of 2.0 x…
Filling the gap: a new class of old star cluster?
Duncan Forbes, Vincenzo Pota, Christopher Usher +5
It is not understood whether long-lived star clusters possess a continuous range of sizes and masses (and hence densities), or if rather, they should be considered as distinct type…
Discovery of Two Ultra-Diffuse Galaxies with Unusually Bright Globular Cluster Luminosity Functions via a Mark-Dependently Thinned Point Process (MATHPOP)
Dayi Li, Gwendolyn Eadie, Patrick Brown +8
We present \textsc{Mathpop}, a novel method to infer the globular cluster (GC) counts in ultra-diffuse galaxies (UDGs) and low-surface brightness galaxies (LSBGs). Many known UDGs…
The Distance of the Dark Matter Deficient Galaxy NGC1052-DF2
Pieter van Dokkum, Shany Danieli, Yotam Cohen +2
We recently inferred that the galaxy NGC1052-DF2 has little or no dark matter and a rich system of unusual globular clusters. We assumed that the galaxy is a satellite of the lumin…
A Revised Velocity for the Globular Cluster GC-98 in the Ultra Diffuse Galaxy NGC1052-DF2
Pieter van Dokkum, Yotam Cohen, Shany Danieli +9
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…
The Stellar Initial Mass Function in Early-Type Galaxies from Absorption Line Spectroscopy. III. Radial Gradients
Pieter van Dokkum, Charlie Conroy, Alexa Villaume +2
There is good evidence that the centers of massive early-type galaxies have a bottom-heavy stellar initial mass function (IMF) compared to the IMF of the Milky Way. Here we study t…
Evidence for Two Phases of Galaxy Formation from Radial Trends in the Globular Cluster System of NGC 1407
Duncan Forbes, Lee Spitler, Jay Strader +3
Here we present the colours of individual globular clusters (GCs) around the massive elliptical galaxy NGC 1407 out to a projected galactocentric radius of 140 kpc or 17 galaxy eff…
Spectroscopic Confirmation of the Existence of Large, Diffuse Galaxies in the Coma Cluster
Pieter van Dokkum, Aaron Romanowsky, Roberto Abraham +6
We recently identified a population of low surface brightness objects in the field of the z=0.023 Coma cluster, using the Dragonfly Telephoto Array. Here we present Keck spectrosco…
New Surface Brightness Fluctuations Spectroscopic Technique: NGC4449 and its Stellar Tidal Stream
Elisa Toloba, Puragra Guhathakurta, Aaron Romanowsky +5
We present a new spectroscopic technique based in part on targeting the upward fluctuations of the surface brightness for studying the internal stellar kinematics and metallicities…
The distance to NGC1042 in the context of its proposed association with the dark matter-deficient galaxies NGC1052-DF2 and NGC1052-DF4
Pieter van Dokkum, Shany Danieli, Aaron Romanowsky +2
It has been suggested that the dark matter-deficient galaxies NGC1052-DF2 and NGC1052-DF4 might not be members of the NGC1052 group but in the foreground at Mpc, and sate…
A High Stellar Velocity Dispersion and ~100 Globular Clusters for the Ultra Diffuse Galaxy Dragonfly 44
Pieter van Dokkum, Roberto Abraham, Jean Brodie +6
Recently a population of large, very low surface brightness, spheroidal galaxies was identified in the Coma cluster. The apparent survival of these Ultra Diffuse Galaxies (UDGs) in…
Candidate Dark Galaxy-2: Validation and Analysis of an Almost Dark Galaxy in the Perseus Cluster
Dayi Li, Qing Liu, Gwendolyn Eadie +8
Candidate Dark Galaxy-2 (CDG-2) is a potential dark galaxy consisting of four globular clusters (GCs) in the Perseus cluster, first identified in Li et al. (2025) through a sophist…