Jörg Hennig, Our people, Department of Mathematics and Statistics

(PhD (Dr. rer. nat.) University Jena)

Senior Lecturer
Director of Studies for 200-300-level Mathematics

Office: Science III, room 215
Tel +64 3 479 7765
Email joerg.hennig@otago.ac.nz

About

Jörg completed a PhD in theoretical physics in 2007 under the supervision of Gernot Neugebauer at the Friedrich Schiller University Jena, Germany. After spending four years in Potsdam as a post-doctoral fellow at the Albert Einstein Institute, he was appointed at the University of Otago's Department of Mathematics and Statistics in 2011.

Teaching responsibilities

Teaching responsibilities include:

COMO 303 Numerical Methods
MATH 203 Calculus of Several Variables
MATH 130 Fundamentals of Modern Mathematics 1
MATH 4NT Analytic Number Theory

Research Interests

Jörg's primary research interests lie in the field of General Relativity — Albert Einstein's theory of gravitation. In particular, he is studying:

axisymmetric and stationary spacetimes
cosmological models
numerical relativity
the application of pseudo-spectral methods to the numerical solution of hyperbolic PDEs.

For more details, see this page: https://gravity.otago.ac.nz/people/jorg-hennig/81-2/

Publications

Hennig, J. (2025). Soliton methods and the black hole balance problem. Wave Motion, 134, 103490. doi: 10.1016/j.wavemoti.2025.103490 Journal - Research Article

Hennig, J. (2024). Soliton methods and the black hole balance problem. Proceedings of the 6th Australasian Conference on Wave Science (KOZWaves). (pp. 17). Retrieved from https://www.otago.ac.nz/news/events/kozwaves-2024-the-6th-australasian-conference-on-wave-science2 Conference Contribution - Published proceedings: Abstract

Hennig, J. (2023). The characteristic initial value problem for the conformally invariant wave equation on a Schwarzschild background. Classical & Quantum Gravity. Advance online publication. doi: 10.1088/1361-6382/acc2a9 Journal - Research Article

Arun, K. G., Belgacem, E., Benkel, R., Bernard, L., Berti, E., Bertone, G., … Frauendiener, J., … Hennig, J., … Zumalacárregui, M. (2022). New horizons for fundamental physics with LISA. Living Reviews in Relativity, 25, 4. doi: 10.1007/s41114-022-00036-9 Journal - Research Article

Hennig, J., Frauendiener, J., & Macedo, R. P. (2022). The conformally invariant wave equation near spacelike infinity on Minkowski, Schwarzschild and Kerr. Proceedings of the Australasian Society for General Relativity & Gravitation (ASGRG) 11th Australasian Conference on General Relativity & Gravitation. Retrieved from https://www.asgrg2021.org/ Conference Contribution - Published proceedings: Abstract

2025

Journal - Research Article

Hennig, J. (2025). Soliton methods and the black hole balance problem. Wave Motion, 134, 103490. doi: 10.1016/j.wavemoti.2025.103490

2024

Conference Contribution - Published proceedings: Abstract

2023

Journal - Research Article

2022

Journal - Research Article

Conference Contribution - Published proceedings: Abstract

2021

Journal - Research Article

Hennig, J., & Macedo, R. P. (2021). Fully pseudospectral solution of the conformally invariant wave equation on a Kerr background. Classical & Quantum Gravity, 38(13), 135006. doi: 10.1088/1361-6382/abfd86

2020

Journal - Research Article

Beyer, F., Frauendiener, J., & Hennig, J. (2020). Explorations of the infinite regions of spacetime. International Journal of Modern Physics D, 29(10), 2030007. doi: 10.1142/S0218271820300074

Hennig, J. (2020). Axis potentials for stationary n-black-hole configurations. Classical & Quantum Gravity, 37, 19LT01. doi: 10.1088/1361-6382/abb116

Journal - Research Other

Barausse, E., Berti, E., Hertog, T., Hughes, S. A., Jetzer, P., Pani, P., … Frauendiener, J., … Hennig, J., … Yunes, N. (2020). Prospects for fundamental physics with LISA [Invited report]. General Relativity & Gravitation, 52, 81. doi: 10.1007/s10714-020-02691-1

2019

Journal - Research Article

Hennig, J. (2019). On the balance problem for two rotating and charged black holes. Classical & Quantum Gravity, 36, 235001. doi: 10.1088/1361-6382/ab4f41

Hennig, J. (2019). Smooth Gowdy-symmetric generalised Taub–NUT solutions in Einstein–Maxwell theory. Classical & Quantum Gravity, 36(7), 075013. doi: 10.1088/1361-6382/ab0be0

Conference Contribution - Published proceedings: Abstract

Hennig, J. (2019). Solitons and black holes. Proceedings of the 10th Australasian Conference on General Relativity and Gravitation (ACGRG). Retrieved from https://sms.wgtn.ac.nz/Events/AotearoaACGRG10/

Hennig, J. (2019). Smooth Gowdy-symmetric generalised Taub-NUT solutions in Einstein-Maxwell theory. Proceedings of the 22nd International Conference on General Relativity and Gravitation (GR22) and the 13th Edoardo Amaldi Conference on Gravitational Waves (AMALDI 13). Retrieved from https://gr22amaldi13.com

2018

Journal - Research Article

Frauendiener, J., & Hennig, J. (2018). Fully pseudospectral solution of the conformally invariant wave equation near the cylinder at spacelike infinity. III: Nonspherical Schwarzschild waves and singularities at null infinity. Classical & Quantum Gravity, 35, 065015. doi: 10.1088/1361-6382/aaac8d

Conference Contribution - Published proceedings: Abstract

Hennig, J. (2018). Gowdy-symmetric cosmological models in Einstein-Maxwell theory. Proceedings of the New Zealand Mathematical Society Colloquium. (pp. 22). Retrieved from http://nzmathsoc.org.nz/colloquium2018

Other Research Output

Frauendiener, J., Hennig, J. (2018, March). How to reach infinity? CQG+ companion blog. Retrieved from https://cqgplus.com/2018/03/06/how-to-reach-infinity

2017

Journal - Research Article

Frauendiener, J., & Hennig, J. (2017). Fully pseudospectral solution of the conformally invariant wave equation near the cylinder at spacelike infinity. II: Schwarzschild background. Classical & Quantum Gravity, 34, 045005. doi: 10.1088/1361-6382/aa54c4

Conference Contribution - Published proceedings: Full paper

Hennig, J. (2017). Gowdy-symmetric vacuum and electrovacuum solutions. In M. Bianchi, R. T. Jantzen & R. Ruffini (Eds.), Proceedings of the Fourteenth Marcel Grossmann Meeting on General Relativity. (pp. 2717-2722). Singapore: World Scientific. doi: 10.1142/9789813226609_0334

2016

Journal - Research Article

Hennig, J. (2016). Gowdy-symmetric cosmological models with Cauchy horizons ruled by non-closed null generators. Journal of Mathematical Physics, 57, 082501. doi: 10.1063/1.4961151

Hennig, J. (2016). New Gowdy-symmetric vacuum and electrovacuum solutions. Classical & Quantum Gravity, 33, 135005. doi: 10.1088/0264-9381/33/13/135005

Conference Contribution - Published proceedings: Abstract

Hennig, J. (2016). The conformally invariant wave equation near the cylinder at spacelike infinity. Proceedings of the 21st International Conference on General Relativity and Gravitation (GR21). (pp. 81). Retrieved from http://www.gr21.org/

Conference Contribution - Verbal presentation and other Conference outputs

Hennig, J. (2016, December). Fully pseudospectral time evolution and its application to physical problems. Verbal presentation at the New Zealand Mathematical Society Colloquium, Wellington, New Zealand.

2014

Chapter in Book - Research

Neugebauer, G., & Hennig, J. (2014). Stationary black-hole binaries: A non-existence proof. In J. Bičák & T. Ledvinka (Eds.), General relativity, cosmology and astrophysics. (pp. 209-228). Cham, Switzerland: Springer. doi: 10.1007/978-3-319-06349-2_9

Journal - Research Article

Hennig, J. (2014). Geometric relations for rotating and charged AdS black holes. Classical & Quantum Gravity, 31(13), 135005. doi: 10.1088/0264-9381/31/13/135005

Frauendiener, J., & Hennig, J. (2014). Fully pseudospectral solution of the conformally invariant wave equation near the cylinder at spacelike infinity. Classical & Quantum Gravity, 31(8), 085010. doi: 10.1088/0264-9381/31/8/085010

Beyer, F., & Hennig, J. (2014). An exact smooth Gowdy-symmetric generalized Taub–NUT solution. Classical & Quantum Gravity, 31(9), 095010. doi: 10.1088/0264-9381/31/9/095010

Conference Contribution - Published proceedings: Abstract

Hennig, J. (2014). Soliton methods in general relativity. Proceedings of the 8th Australia and New Zealand Mathematics Convention (AustMS and NZMS). (pp. 115). Retrieved from http://www.austms2014.ms.unimelb.edu.au/

2013

Journal - Research Article

Hennig, J. (2013). Fully pseudospectral time evolution and its application to 1 +1 dimensional physical problems. Journal of Computational Physics, 235, 322-333. doi: 10.1016/j.jcp.2012.10.040

Conference Contribution - Published proceedings: Abstract

Hennig, J. (2013). An exact smooth Gowdy-symmetric generalized Taub-NUT solution. Proceedings of the 20th International Conference on General Relativity (GR20) and Gravitation and 10th Amaldi Conference on Gravitational Waves (Amaldi10). Retrieved from http://gr20-amaldi10.edu.pl/index.php?id=50

Conference Contribution - Verbal presentation and other Conference outputs

Hennig, J. (2013, December). A generalisation of the Taub-NUT cosmological model in general relativity. Verbal presentation at the New Zealand Mathematical Society Colloquium, Tauranga, New Zealand.

2012

Journal - Research Article

Beyer, F., & Hennig, J. (2012). Smooth Gowdy-symmetric generalized Taub–NUT solutions. Classical & Quantum Gravity, 29, 245017. doi: 10.1088/0264-9381/29/24/245017

Neugebauer, G., & Hennig, J. (2012). Stationary two-black-hole configurations: A non-existence proof. Journal of Geometry & Physics, 62, 613-630. doi: 10.1016/j.geomphys.2011.05.008

Conference Contribution - Published proceedings: Full paper

Hennig, J., & Neugebauer, G. (2012). Non-existence of stationary two-black-hole configurations. In T. Damour, R. T. Jantzen & R. Ruffini (Eds.), Proceedings of the Twelfth Marcel Grossman Meeting (MG12) on Recent Developments in Theoretical and Experimental General Relativity, Astrophysics and Relativistic Field Theories. (pp. 1756-1758). Singapore: World Scientific. doi: 10.1142/9789814374552_0317

Conference Contribution - Verbal presentation and other Conference outputs

Hennig, J. (2012, February). Smooth Gowdy symmetric generalized Taub-NUT solutions. Verbal presentation at the Sixth Australasian Conference on General Relativity and Gravitation, Queenstown, New Zealand.

2011

Journal - Research Article

Hennig, J., & Neugebauer, G. (2011). Non-existence of stationary two-black-hole configurations: The degenerate case. General Relativity & Gravitation, 43(11), 3139-3162. doi: 10.1007/s10714-011-1228-0

Ansorg, M., Hennig, J., & Cederbaum, C. (2011). Universal properties of distorted Kerr-Newman black holes. General Relativity & Gravitation, 43(5), 1205-1210. doi: 10.1007/s10714-010-1136-8

Conference Contribution - Published proceedings: Full paper

Ansorg, M., & Hennig, J. (2011). The interior of axisymmetric and stationary black holes: Numerical and analytical studies. Journal of Physics: Conference Series, 314(1), 012017. doi: 10.1088/1742-6596/314/1/012017

2010

Journal - Research Article

Hennig, J., Cederbaum, C., & Ansorg, M. (2010). A universal inequality for axisymmetric and stationary black holes with surrounding matter in the Einstein-Maxwell theory. Communications in Mathematical Physics, 293(2), 449-467. doi: 10.1007/s00220-009-0889-y

Hennig, J., & Ansorg, M. (2010). Regularity of Cauchy horizons in S² x S¹ Gowdy spacetimes. Classical & Quantum Gravity, 27, 065010. doi: 10.1088/0264-9381/27/6/065010

2009

Journal - Research Article

Ansorg, M., & Hennig, J. (2009). Inner Cauchy horizon of axisymmetric and stationary black holes with surrounding matter in Einstein-Maxwell theory. Physical Review Letters, 102, 221102. doi: 10.1103/PhysRevLett.102.221102

Neugebauer, G., & Hennig, J. (2009). Non-existence of stationary two-black-hole configurations. General Relativity & Gravitation, 41, 2113-2130. doi: 10.1007/s10714-009-0840-8

Hennig, J., & Ansorg, M. (2009). The inner Cauchy horizon of axisymmetric and stationary black holes with surrounding matter in Einstein-Maxwell theory: Study in terms of soliton methods. Annales Henri Poincaré, 10(6), 1075-1095. doi: 10.1007/s00023-009-0012-0

Hennig, J., & Ansorg, M. (2009). A fully pseudospectral scheme for solving singular hyperbolic equations on conformally compactified space-times. Journal of Hyperbolic Differential Equations, 6(1), 161-184.

2008

Journal - Research Article

Hennig, J., Ansorg, M., & Cederbaum, C. (2008). A universal inequality between the angular momentum and horizon area for axisymmetric and stationary black holes with surrounding matter. Classical & Quantum Gravity, 25, 162002. doi: 10.1088/0264-9381/25/16/162002

Ansorg, M., & Hennig, J. (2008). The inner Cauchy horizon of axisymmetric and stationary black holes with surrounding matter. Classical & Quantum Gravity, 25, 222001. doi: 10.1088/0264-9381/25/22/222001

Conference Contribution - Published proceedings: Full paper

Neugebauer, G., & Hennig, J. (2008). Thermodynamic description of inelastic collisions in general relativity. In H. Kleinert, R. T. Jantzen & R. Ruffini (Eds.), Proceedings of the Eleventh Marcel Grossmann Meeting (MG11) on Recent Developments in Theoretical and Experimental General Relativity, Gravitation and Relativistic Field Theories. (pp. 2228-2230). World Scientific. doi: 10.1142/9789812834300_0370

2007

Journal - Research Article

Hennig, J., Neugebauer, G., & Ansorg, M. (2007). Thermodynamic description of inelastic collisions in general relativity. Astrophysical Journal, 663, 450-460. doi: 10.1086/518412

2006

Journal - Research Article

Hennig, J., & Neugebauer, G. (2006). Collisions of rigidly rotating disks of dust in general relativity. Physical Review D, 74, 064025. doi: 10.1103/PhysRevD.74.064025