Supervisors: Angelos Karakonstantakis (karakonang@camk.edu.pl) & Maciek
Wielgus
Title: Distinguishing Black Holes from Naked Singularities via Tidal Disruption Events
Timeline: On-site for 4-8 weeks between July and August.
Description: A star orbiting a supermassive compact object could be ripped apart by tidal forces and produce a luminous transient phenomenon --a "tidal disruption event" (TDE). TDEs could provide us with a new channel for exploring the central compact objects in addition to black hole imaging and gravitational waves studies. While traditionally TDEs are modeled assuming tidal forces originating from a Black Hole (BH), alternative solutions in GR such as Naked Singularities (NkS), lack an event horizon potentially allowing for distinct observational signatures. The student will perform ray-tracing (following a simplified methodology) on data from GR-SPH simulations to produce synthetic light curves and spectra. The project aims to compare the "optical appearance" and late-time decay rates of TDEs in Schwarzschild and Reissner-Nordström spacetime geometries, comparing BHs with NkSs. We will investigate if resulting emission can serve as a "smoking gun" for the absence of an event horizon.
Audience: Undergraduate or master students with an interest in high-energy astrophysics, general relativity, numerical methods, and "connecting theory-simulations with observations". Familiarity with SPH concepts and methods, MHD or radiative transfer will be highly appreciated but not required.
Requirements:
- Proficiency in programming and working in a Linux environment.
- Basic knowledge of General Relativity (metric, geodesics, tensor
calculus).
- Enthusiasm for astrophysics, numerical methods and data visualization.
Literature
- Ray-tracing methodology: Hu, F., et al. (2023). Optical Appearance of Eccentric TDEs. (arXiv:2312.03210).
- Observations: van Velzen, S., et al. (2021). Seventeen Tidal Disruption Events from the First Year of Zwicky Transient Facility. (ApJ, 908, 4).
- Analytical treatment of disruption by a NkS: Joshi, A. B., et al. (2025). Tidal disruption of a neutron star near naked singularity. (arXiv:2509.26108).
- Partial vs full disruption and analytical treatment: Coughlin, E. R., & Nixon, C. J. (2019). Partial Stellar Disruption by a SMBH: Is the Lightcurve Really Proportional to t^{-9/4}? (ApJL, 883, L17).
- Geodesics and dynamical signatures: Karakonstantakis et al. (MNRAS, May 2026). Scattering of massive particles from black holes and naked singularities
- BH Simulations of TDEs: Price, D. J., et al. (2024). Eddington envelopes: The fate of stars on parabolic orbits tidally disrupted by supermassive black holes. (ApJL, 969, L29)
Visualization and Analysis Tools
- splash: interactive visualziation tool written in fortran -- https://splash-viz.readthedocs.io/en/latest/
- Plonk, Sarracen: python libraries for SPH data analysis and visualization.