Assistant Professor
Department of Astronomy and Astrophysics
University of Toronto
jeremy.webb@utoronto.ca
Globular clusters are spherical collections of between 106 and 107 stars that are found in all types of galaxies. The Milky Way contains over 150 globular clusters, while some giant elliptical galaxies have been found to contain over 10,000. My research focuses on studying the dynamical evolution of globular clusters from birth to present day. More specifically, I am interested in the relationship between a globular cluster and the gravitational field of its host galaxy. What role does the host galaxy play in a cluster's evolution? Is the cluster's location and orbit within a galaxy a contributing factor? (Image Credit: apod.nasa.gov)
As stars escape from a globular cluster, due to internal and external mechanisms, tidal tails begin to form. Once a cluster has fully dissolved, a long thin stellar stream of escaped of stars will continue along on the cluster's intitial orbit. Due to their length and the minimal amount of interaction between stars along a stream, streams are ideal for studying the gravitational field of their host galaxy. I am interested in how the properties of stellar streams depend on the initial host cluster and its orbit within the Milky Way. Understanding the details of how stellar streams form and evolve will allow for them to be used to trace out the distribution of dark matter in our own galaxy's halo and even search for evidence of dark matter substructure. (Image Credit: Carlberg 2018)
The Cold Dark Matter framework predicts that galaxies consist of a large number of dark matter sub-halos. While the most massive sub-halos can be observed as satellite galaxies, lower mass sub-halos will likely have no luminous component to observe. Therefore astronomers are constantly searching for ways of indirectly determining that sub-halos exists in order to validate different cosmological theories and the nature of dark matter itself. I am interested in how sub-halos themselves evolve and interact with things like stellar streams and globular clusters. More specifically, do these interactions leave fingerprints of the properties of dark matter sub-halos? (Image Credit: Diemand et al. 2008)
Exoplanets have been observed to have a wide range of orbital properties compared to planets in our solary sytems. While the planets in our solary system all have nearly circular orbits with similar orbital planes, sevaral exoplanets have been found to have highly eccentric orbits and/or highly inclined orbits. Furthermore, some exoplanetary systems have exoplanets orbiting much closer too or much farther away from their host star than any of the planet's in our solar system. I am interested in how gravitational interactions between planets and gravitational interactions between planets and nearby stars can alter the orbital dynamics of planetary sytems (Image Credit: Marois et al. 2010).
Listed below is a complete list of my publications, as of November 2022. Students I have supervised are underlined. Click here to view my publications on NASA/ADS.:
Searching for the extra-tidal stars of globular clusters using high-dimensional analysis and a core particle spray code
The thermodynamics of stellar multiplicity: an analytic model for the dynamical evolution of binary star populations in dense stellar environments due to single-binary interactions
Bayesian Inference of Globular Cluster Properties Using Distribution Functions
The Effect of Dwarf Galaxies on the Tidal Tails of Globular Clusters
Variation in the Stellar Mass Function Along Stellar Streams
The Effects of ΛCDM Substructure on the Orbital Evolution of Star Clusters
Mass loss from massive globular clusters in tidal fields
The Likelihood of Undiscovered Globular Clusters in the Outskirts of the Milky Way
The Initial Properties of Young Star Clusters in M83
High-Resolution Simulations of Dark Matter Subhalo Disruption in a Milky Way-like Tidal Field
The effects of dwarf galaxies on the orbital evolution of galactic globular clusters
Radial variation of the stellar mass functions in the globular clusters M15 and M30: clues of a non-standard IMF?
Strong chemical tagging with APOGEE: 21 candidate star clusters that have dissolved across the Milky Way disc
Searching for solar siblings in APOGEE and Gaia DR2 with N-body simulations
An extended Pal 5 stream in Gaia DR2
Star Clusters Near and Far
There and Back Again: Globular cluster ejection, infall and the host dark matter halo of the Pegasus dwarf galaxy
Characteristic radii of the Milky Way Globular Clusters
Modelling the Effects of Dark Matter Substructure on Globular Cluster Evolution with the Tidal Approximation
The evolution of kicked stellar-mass black holes in star cluster environments - II. Rotating star clusters
The orbital anisotropy profiles of nearby globular clusters from Gaia Data Release 2
A systematic analysis of star cluster disruption by tidal shocks -- I. Controlled N-body simulations and a new theoretical model
Searching for the GD-1 Stream Progenitor in Gaia DR2 with Direct N-body Simulations
Rediscovering the Tidal Tails of NGC 288 with Gaia DR2
Spatial mixing of binary stars in multiple-population globular clusters
The effect of stellar helium abundance on dynamics of multiple populations in globular clusters
The Structural and Kinematic Evolution of Central Star Clusters in Dwarf Galaxies and Their Dependence on Dark Matter Halo Profiles
Evolution of the stellar mass function in multiple-population globular clusters
The Peculiar Radial Distribution of Multiple Populations in the Massive Globular Cluster M80s
Kinematic fingerprint of core-collapsed globular clusters
The evolution of kicked stellar-mass black holes in star cluster environments
Modelling the observed stellar mass function and its radial variation in galactic globular clusters
The early evolution of star clusters in compressive and extensive tidal fields
On the link between energy equipartition and radial variation in the stellar mass function of star clusters
Radial variation in the stellar mass functions of star clusters
Globular cluster scale sizes in giant galaxies: orbital anisotropy and tidally underfilling clusters in M87, NGC 1399 and NGC 5128
The dynamical evolution of accreted star clusters in the Milky Way
The dynamics of multiple populations in the globular cluster NGC 6362
Back to the future: estimating initial globular cluster masses from their present-day stellar mass functions
The state of globular clusters at birth - II. Primordial binaries
The size of star clusters accreted by the Milky Way
The effects of orbital inclination on the scale size and evolution of tidally filling star clusters
The effect of orbital eccentricity on the dynamical evolution of star clusters
The state of globular clusters at birth: emergence from the gas-embedded phase
Globular Cluster Scale Sizes in Giant Galaxies: The Case of M87 and the Role of Orbital Anisotropy and Tidal Filling
The influence of orbital eccentricity on tidal radii of star clusters
The Size Difference between Red and Blue Globular Clusters is not due to Projection Effects
The Observational and Theoretical Tidal Radii of Globular Clusters in M87
In the core of a globular cluster, the night sky would contain 130,000 stars visible to the naked eye and the brightest stars would be 100 times brighter than Venus. At night, the sky would be twenty times brighter than during a full moon.
Near the half-light radius of the cluster, the brightest object in the sky would be the main body of the cluster. However, far from the cluster center one would be able to faintly see distant globular clusters as well as the bulge and disk of the host galaxy.
In the outer regions of a globular cluster, you would still get a spectacular view when its center was in the night sky while still being able to perform astronomy at locations that faced away from the cluster at night.