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JWST Observations of the Double Nucleus in NGC 4486B: Possible Evidence for a Recent Binary SMBH Merger and Recoil
Behzad Tahmasebzadeh, Monica Valluri, Shashank Dattathri +19
A recent study of the compact elliptical galaxy NGC 4486B using JWST-NIRSpec IFU kinematics confirmed a supermassive black hole (SMBH) of mass (~8% of…
A JWST View of the Overmassive Black Hole in NGC 4486B
Behzad Tahmasebzadeh, Matthew A. Taylor, Monica Valluri +19
We present a new stellar dynamical measurement of the supermassive black hole (SMBH) in the compact elliptical galaxy NGC 4486B, based on integral field spectroscopy with JWST/NIRS…
On the Formation of S-stars from a Recent Massive Black Hole Merger in the Galactic Center
Tatsuya Akiba, Smadar Naoz, Ann-Marie Madigan
The Galactic Center hosts a rotating disk of young stars between 0.05 and 0.5 pc of Sgr A*. The ``S-stars'' at a distance pc, however, are on eccentric orbits with nearly i…
Counter-Rotation and Slow Precession in Aligned Eccentric Nuclear Disks due to Gravitational Wave Recoil Kicks
Jane C. Bright, Tatsuya Akiba, Ann-Marie Madigan
The M31 nucleus contains a supermassive black hole embedded in a massive stellar disk of apsidally-aligned eccentric orbits. It has recently been shown that this disk is slowly pre…
How to Flip a Bar
Angela Collier, Ann-Marie Madigan
Galactic bars, made up of elongated and aligned stellar orbits, can lose angular momentum via resonant torques with dark matter particles in the halo and slow down. Here we show th…
Anisotropic Star Clusters around Recoiling Supermassive Black Holes
Tatsuya Akiba, Ann-Marie Madigan
Gravitational wave recoil kicks from merging supermassive black hole binaries can have a profound effect on the surrounding stellar population. In this work, we study the dynamic a…
Forming Young and Hypervelocity Stars in the Galactic Centre via Tidal Disruption of a Molecular Cloud
A. Generozov, S. Nayakshin, A. M. Madigan
The Milky Way Galaxy hosts a four million solar mass black hole, Sgr A*, that underwent a major accretion episode approximately 3-6 Myr ago. During the episode, hundreds of young m…
On the Formation of an Eccentric Nuclear Disk following the Gravitational Recoil Kick of a Supermassive Black Hole
Tatsuya Akiba, Ann-Marie Madigan
The anisotropic emission of gravitational waves during the merger of two supermassive black holes can result in a recoil kick of the merged remnant. We show here that eccentric nuc…
Bar-driven Leading Spiral Arms in a Counter-rotating Dark Matter Halo
Emma Lieb, Angela Collier, Ann-Marie Madigan
An overwhelming majority of galactic spiral arms trail with respect to the rotation of the galaxy, though a small sample of leading spiral arms has been observed. The formation of…
Photometry and Kinematics of Self-Gravitating Eccentric Nuclear Disks
Heather N. Wernke, Ann-Marie Madigan
The Andromeda Galaxy hosts an elongated nucleus with (at least) two distinct brightness peaks. The double nucleus can be explained by the projection of a thick, apsidally-aligned e…
The Coupling of Galactic Dark Matter Halos with Stellar Bars
Angela Collier, Ann-Marie Madigan
Resonant torques couple stellar bars to dark matter halos. Here we use high-resolution numerical simulations to demonstrate long-term angular momentum transfer between stellar bars…
Galactic merger implications for eccentric nuclear disks: a mechanism for disk alignment
Alexander Rodriguez, Aleksey Generozov, Ann-Marie Madigan
The nucleus of our nearest, large galactic neighbor, M31, contains an eccentric nuclear disk--a disk of stars on eccentric, apsidally-aligned orbits around a supermassive black hol…
The Hills Mechanism and the Galactic Center S-stars
Aleksey Generozov, Ann-Marie Madigan
Our Galactic center contains young stars, including the few million year old clockwise disk between 0.05 and 0.5 pc from the Galactic center, and the S-star cluster of B-type stars…
Mass Segregation in Eccentric Nuclear Disks: Enhanced Tidal Disruption Event Rates for High Mass Stars
Hayden R. Foote, Aleksey Generozov, Ann-Marie Madigan
Eccentric nuclear disks (ENDs) are a type of star cluster in which the stars lie on eccentric, apsidally-aligned orbits in a disk around a central supermassive black hole (SMBH). T…
Dynamical Properties of Eccentric Nuclear Disks: Stability, Longevity, and Implications for Tidal Disruption Rates in Post-Merger Galaxies
Ann-Marie Madigan, Andrew Halle, Mackenzie Moody +3
In some galaxies, the stars orbiting the supermassive black hole take the form of an eccentric nuclear disk, in which every star is on a coherent, apsidally-aligned orbit. The most…
A Characteristic Scale for Cold Gas
Michael McCourt, S. Peng Oh, Ryan M. O'Leary +1
We find that clouds of optically-thin, pressure-confined gas are prone to fragmentation as they cool below K. This fragmentation follows the lengthscale $\sim{c}_{\text{…
Magnetized Gas Clouds can Survive Acceleration by a Hot Wind
Michael McCourt, Ryan M. O'Leary, Ann-Marie Madigan +1
We present three-dimensional magnetohydrodynamic simulations of magnetized gas clouds accelerated by hot winds. We initialize gas clouds with tangled internal magnetic fields and s…
The Galactic Center cloud G2 and its gas streamer
Oliver Pfuhl, Stefan Gillessen, Frank Eisenhauer +10
We present new, deep near-infrared SINFONI @ VLT integral field spectroscopy of the gas cloud G2 in the Galactic Center, from late summer 2013 and spring 2014. G2 is visible in rec…
On the Origin of Young Stars at the Galactic Center
Ann-Marie Madigan, Oliver Pfuhl, Yuri Levin +3
The center of our galaxy is home to a massive black hole, SgrA*, and a nuclear star cluster containing stellar populations of various ages. While the late type stars may be too old…
On the origin of the B-stars in the Galactic center
Ann-Marie Madigan, Oliver Pfuhl, Yuri Levin +3
We present a new directly-observable statistic which uses sky position and proper motion of stars near the Galactic center massive black hole to identify populations with high orbi…
Secular Dynamical Anti-Friction in Galactic Nuclei
Ann-Marie Madigan, Yuri Levin
We identify a gravitational-dynamical process in near-Keplerian potentials of galactic nuclei that occurs when an intermediate-mass black hole (IMBH) is migrating on an eccentric o…
Secular Stellar Dynamics near a Massive Black Hole
Ann-Marie Madigan, Clovis Hopman, Yuri Levin
The angular momentum evolution of stars close to massive black holes (MBHs) is driven by secular torques. In contrast to two-body relaxation, where interactions between stars are i…
The Eccentric Disc Instability: Dependency on Background Stellar Cluster
Ann-Marie Madigan
In this paper we revisit the "eccentric disc instability", an instability which occurs in coherently eccentric discs of stars orbiting massive black holes (MBHs) embedded in stella…
Mass Segregation in the Galactic Centre
Clovis Hopman, Ann-Marie Madigan
Two-body energy exchange between stars orbiting massive black holes (MBHs) leads to the formation of a power-law density distribution n(r)~r^(-a) that diverges towards the MBH. For…