GalNUC

GalNUC: Astrophysical Dynamics and Statiscal Mechanics of Galactic Nuclei

The GALNUC Astrodynamics and Statistical Mechanics Group (PI: Bence Kocsis) at Oxford and Eötvös does research on topics related to galactic dynamics, dense stellar systems, physics of compact objects, statistical mechanics, ordered/disordered systems, and phase transitions. The group is funded by the ERC Starting Grant GalNUC and strives to develop a comprehensive model to describe the long term behavior of astrophysical multibody systems using revolutionary multidisciplanary methods. The project has officially moved from Eötvös University to Oxford in July 2020 but we are continuing collaborations with Eötvös.

We solve some of the major unsolved questions of galactic nuclei. Galactic nuclei host a central supermassive black hole, a dense population of stars and compact objects, and in many cases a bright gaseous disk feeding the supermassive black hole. The observed stellar distribution exhibits both spherical and counterrotating disk-like structures. Existing theoretical models cannot convincingly explain the origin of the stellar disks. Is there also a “dark cusp” or “dark disk” of stellar mass black holes? Are there intermediate mass black holes in the Galactic center? We examine the statistical physics of galactic nuclei and their long term dynamical evolution. A star orbiting a supermassive black hole on an eccentric precessing orbit covers an axisymmetric annulus. The long-term gravitational interaction between such annuli is similar to the Coulomb interaction between axisymmetric molecules constituting a liquid crystal. We apply standard methods of condensed matter physics to examine these astrophysical systems. The observed disk and spherical structures represent isotropic-nematic phase transitions. We derive the phase space distribution and time-evolution of different stellar components including a population of black holes. Further, we investigate the interaction of a stellar cluster with a gaseous disk, if present. This leads to the formation of gaps, warps, and spiral waves in the disk, the redistribution of stellar objects, and possibly the formation of intermediate mass black holes. We explore the implications for electromagnetic and gravitational wave observatories. Dark disks of black holes could provide the most frequent source of gravitational waves for LIGO and VIRGO. These detectors will open a new window on the Universe; the proposed project will open a new field in gravitational wave astrophysics to interpret the sources. We also explore implications for electromagnetic observations.

GalNUC Members

PI:

Bence Kocsis — theoretical astrophysics including black hole physics, sources of gravitational waves, relativity, accretion physics, disk-satellite interactions, dynamics, statistical mechanics. publications and personal webpage

Postdoctoral fellows:

Taras Panamarev — dynamics of nuclear star clusters and globular clusters, GPU supercomputing. publications
Alexander Rasskazov — dynamics of nuclear star clusters, supermassive black holes. publications
Hiromichi Tagawa — hydrodynamics in astrophysics, black hole accretion. publications (galnuc member: 2017-2020)
Yohai Meiron — astrophysical dynamics of stellar systems, GPU supercomputing. publications and personal webpage (galnuc member: 2016-2018)

PhD students:

Laszlo Gondan — gravitational wave astrophysics, expected measurement accuracy for eccentric mergers, astrophysical parameter distribution. publications
Gergely Mathe — statistical mechanics of nuclear star clusters using time-evolution simulations.
Akos Szolgyen — assembly of the nuclear star clusters and the formation of black hole disks using Monte Carlo Markov Chain simulations. publications

MSc students:

Barnabas Deme — stochastic model of three body evolution.
Kristof Jakovac — gravitational wave diffraction in general relativity, exploring the gravitational wave echo phenomenon.
Adam Takacs — statistical mechanics of nuclear star clusters using mean field theory, non-additive systems, non-extensive thermodynamics publications

Eötvös University in Budapest

Eötvös University is located on the Danube River in Budapest within walking distance to the historic inner city. Budapest is the capital of Hungary, its political, cultural, commercial, industrial, and transportation center; Europe's most welcoming city. The city is known for its lively nightlife (see e.g. ruin pubs), its thermal baths (e.g. Szechenyi thermal bath), and its great food (see also My Amused Bouche).

Refereed Publications

Disrupted Globular Clusters Can Explain the Galactic Center Gamma Ray Excess
T. Brandt, B. Kocsis
Astrophysical Journal, 812, 15 (2015) [ADS] [arXiv] [Scientific American] [Blog] [Zenodo]
Dynamical Formation Signatures of Black Hole Binaries in the First Detected Mergers by LIGO
R. M. OLeary, Y. Meiron, B. Kocsis
Astrophysical Journal Letters, 824, L12 (2016) [ADS] [arXiv] [Blogs]
Merging binaries in the Galactic Center: the eccentric Kozai-Lidov mechanism with stellar evolution
A. P. Stephan, S. Naoz, A. M. Ghez, G. Witzel, B. N. Sitarski, T. Do, B. Kocsis
Monthly Notices of the Royal Academic Society, 460, 3494 (2016) [ADS] [arXiv]
The influence of mergers and ram-pressure stripping on black hole-bulge correlations
Y. B. Ginat, Y. Meiron, N. Soker
Monthly Notices of the Royal Astronomical Society, 461, 3533 (2016) [ADS] [arXiv]
Star-disc interaction in galactic nuclei: orbits and rates of accreted stars
G. F. Kennedy, Y. Meiron, B. Shukirgaliyev, T. Panamarev, P. Berczik, A. Just, R. Spurzem
Monthly Notices of the Royal Astronomical Society, 460, 240 (2016) [ADS] [arXiv]
Rapid and Bright Stellar-mass Binary Black Hole Mergers in Active Galactic Nuclei
I. Bartos, B. Kocsis, Z. Haiman, S. Marka
Astrophysical Journal, 835, 165 (2017) [ADS] [arXiv]
Detecting Triple Systems with Gravitational Wave Observations
Y. Meiron, B. Kocsis, A. Loeb
Astrophysical Journal, 834, 200 (2017) [ADS] [arXiv]
Isotropic-Nematic Phase Transitions in Gravitational Systems
Z. Roupas, B. Kocsis, S. Tremaine
Astrophysical Journal, 842, 90 (2017) [ADS] [arXiv]
Testing the binary hypothesis: pulsar timing constraints on supermassive black hole binary candidates
A. Sesana, Z. Haiman, B. Kocsis, L. Z. Kelley
Astrophysical Journal, 856, 42 (2018) [ADS] [arXiv]
Accuracy of Estimating Highly Eccentric Binary Black Hole Parameters with Gravitational-Wave Detections
L. Gondan, B. Kocsis, P. Raffai, Z. Frei
Astrophysical Journal, 855, 34 (2018) [ADS] [arXiv]
Eccentric Black Hole Gravitational-Wave Capture Sources in Galactic Nuclei: Distribution of Binary Parameters
L. Gondan, B. Kocsis, P. Raffai, Z. Frei
Astrophysical Journal 860, 5 (2018) [ADS] [arXiv]
Black Hole Mergers in Galactic Nuclei Induced by the Eccentric Kozai-Lidov Effect
B. Hoang, S. Naoz, B. Kocsis, F. A. Rasio, F. Dosopoulou
Astrophysical Journal, 856, 140 (2018) [ADS] [arXiv][astrobites]
Gamma-ray and X-ray emission from the Galactic centre: hints on the nuclear star cluster formation history
M. Arca-Sedda, B. Kocsis, T. Brandt
Monthly Notices of the Royal Academic Society, 479, 900 (2018) [ADS] [arXiv]
Hidden universality in the merger rate distribution in the primordial black hole scenario
B. Kocsis, T. Suyama, T. Tanaka, S. Yokoyama
Astrophysical Journal, 854, 41, (2018) [ADS] [arXiv]
Gravitational Waves and Intermediate-Mass Black Hole Retention in Globular Clusters
G. Fragione, I. Ginsburg, B. Kocsis
Astrophysical Journal, 856, 92 (2018) [ADS] [arXiv]
Isotropic-Nematic Phase Transitions in Gravitational Systems II: Higher Order Multipoles
A. Takacs, B. Kocsis
Astrophysical Journal, 856, 113 (2018) [arXiv]
Diffusion and mixing in globular clusters
Y. Meiron, B. Kocsis
Astrophysical Journal, 855, 87 (2018) [ADS] [arXiv]
Spiral arms, warping, and clumps formation in the Galactic center young stellar disk
H. B. Perets, A. Mastrobuono-Battisti, Y. Meiron, A. Gualandris
submitted to Science [ADS] [arXiv]
Star-disc interaction in galactic nuclei: formation of a central stellar disc
T. Panamarev, B. Shukirgaliyev, Y. Meiron, P. Berczik, A. Just, R. Spurzem, C. Omarov, E. Vilkoviskij
Monthly Notices of the Royal Academic Society, 476, 4224 (2018) [ADS] [arXiv]
Merger of multiple accreting black holes concordant with gravitational wave events
H Tagawa, M. Umemura
Astrophysical Journal, 856, 47 (2018) [ADS] [arXiv] [astrobites]
Metallicity dependence of the Hercules stream in Gaia/RAVE data -- explanation by non-closed orbits
K. Hattori, N. Gouda, T. Yano, N. Sakai, H. Tagawa, J. Baba, J. Kumamoto
Monthly Notices of the Royal Academic Society, 484, 4540 (2019) [ADS] [arXiv]
Compact object mergers driven by gas fallback
H. Tagawa, T. R. Saitoh, B. Kocsis
Physical Review Letters, 120, 261101 (2018) [ADS] [arXiv]
Black hole disks in galactic nuclei
A. Szolgyen, B. Kocsis
Physical Review Letters, 121, 101101 (2018) [ADS] [arXiv] [News]
Black hole mergers from an evolving population of globular clusters
G. Fragione, B. Kocsis
Physical Review Letters, 121, 161103 (2018) [ADS] [arXiv]
Black holes, gravitational waves and fundamental physics: a roadmap
L. Barack, et al.; chapter I.5 by A. Askar and B. Kocsis
submitted to Classical Quantum Gravity [ADS] [arXiv]
Resonant relaxation in globular clusters
Y. Meiron, B. Kocsis
submitted to the Astrophysical Journal [ADS] [arXiv]
Tidal Disruption Events and Gravitational Waves from Intermediate Mass Black Holes in Evolving Globular Clusters Across Space and Time
G. Fragione, N. Leigh, I. Ginsburg, B. Kocsis
Astrophysical Journal, 856, 92 (2018) [ADS] [arXiv]
Hypervelocity Stars from a Supermassive Black Hole-Intermediate Mass Black Hole binary
A. Rasskazov, G. Fragione, N. W. C. Leigh, H. Tagawa, A. Sesana, A. Price-Whelan, E. M. Rossi
submitted to the Astrophysical Journal [ADS] [arXiv]
The impact of stripped Nuclei on the Super-Massive Black Hole number density in the local Universe
K. T. Voggel, A. C. Seth, H. Baumgardt, S. Mieske, J. Pfeffer, A. Rasskazov
submitted to the Astrophysical Journal [ADS] [arXiv]
Ordering the chaos: stellar black hole mergers from non-hierarchical triples
M. Arca-Sedda, G. Li, B. Kocsis
submitted to Monthly Notices of the Royal Academic Society [ADS] [arXiv]
Measurement Accuracy of Inspiraling Eccentric Neutron Star and Black Hole Binaries Using Gravitational Waves
L. Gondan, B. Kocsis
Astrophysical Journal, 871, 178 (2019) [ADS] [arXiv]
Localization of Binary Black-Hole Mergers with Known Inclination
K. R. Corley, I. Bartos, L. P. Singer, A. R. Williamson, Z. Haiman, B. Kocsis, S. Nissanke, Z. Marka, S. Marka
submitted (2019) [ADS] [arXiv]
The rate of stellar mass black hole scattering in galactic nuclei
A. Rasskazov, B. Kocsis
submitted to the Astrophysical Journal (2019) [ADS] [arXiv]
Detecting Supermassive Black Hole-Induced Binary Eccentricity Oscillations with LISA
B-M. Hoang, S. Naoz, B. Kocsis, W. Farr, J. McIver
submitted to the Astrophysical Journal Letters (2019) [ADS] [arXiv]
AGN Disks Harden the Mass Distribution of Stellar-mass Binary Black Hole Mergers
Y. Yang, I. Bartos, Z. Haiman, B. Kocsis, Z. Marka, N. C. Stone, S. Marka
submitted to the Astrophysical Journal Letters [ADS] [arXiv]
Black Hole Mergers from Quadruples
G. Fragione, B. Kocsis
submitted to the Astrophysical Journal (2019) [ADS] [arXiv]
Anisotropic Mass Segregation in Rotating Globular Clusters
A. Szolgyen, Y. Meiron, B. Kocsis
submitted to the Astrophysical Journal (2019) [ADS] [arXiv]

Related URLs

GALNUC official webpage

Bence Kocsis's home page

HPC resources

Bence Kocsis Homepage

GalNUC

Other Links

GalNUC: Astrophysical Dynamics and Statiscal Mechanics of Galactic Nuclei