The mass fallback rate of the debris in relativistic stellar tidal disruption events

Abstract

Highly energetic stellar tidal disruption events (TDEs) provide a way to study black hole characteristics and their environment. We simulate TDEs with the PHANTOM code in a general relativistic and Newtonian description of a supermassive black hole's gravity. Stars, which are placed on parabolic orbits with different parameters $\beta$, are constructed with the stellar evolution code MESA and therefore have realistic stellar density profiles. We study the mass fallback rate of the debris $\dot{M}$ and its dependence on the $\beta$, stellar mass and age as well as the black hole's spin and the choice of the gravity's description. We calculate peak value ${\dot{M}}_{\mathrm{peak}}$, time to the peak $t_{\mathrm{peak}}$, duration of the super-Eddington phase $t_{\mathrm{Edd}}$, time $t_{>0.5{\dot{M}}_{\mathrm{peak}}}$ during which $\dot{M}>0.5{\dot{M}}_{\mathrm{peak}}$, early rise-time ${\tau }_{\mathrm{rise}}$ and late-time slope $n_{\infty }$. We recover the trends of ${\dot{M}}_{\mathrm{peak}}$, $t_{\mathrm{peak}}$, ${\tau }_{\mathrm{rise}}$ and $n_{\infty }$ with $\beta$, stellar mass and age, which were obtained in previous studies. We find that $t_{\mathrm{Edd}}$, at a fixed $\beta$, scales primarily with the stellar mass, while $t_{>0.5{\dot{M}}_{\mathrm{peak}}}$ scales with the compactness of stars. The effect of SMBH's rotation depends on the orientation of its rotational axis relative to the direction of the stellar motion on the initial orbit. Encounters on prograde orbits result in narrower $\dot{M}$ curves with higher ${\dot{M}}_{\mathrm{peak}}$, while the opposite occurs for retrograde orbits. We find that disruptions, at the same pericenter distance, are stronger in a relativistic tidal field than in a Newtonian. Therefore, relativistic $\dot{M}$ curves have higher ${\dot{M}}_{\mathrm{peak}}$, and shorter $t_{\mathrm{peak}}$ and $t_{\mathrm{Edd}}$.

arXiv comment18 pages, 11 figures, accepted for publication in ApJ

References in corpus (30)

• Modules for Experiments in Stellar Astrophysics (MESA)
• Hydrodynamical Simulations to Determine the Feeding Rate of Black Holes by the Tidal Disruption of Stars: The Importance of the Impact Parameter and Stellar Structure
• Phantom: A smoothed particle hydrodynamics and magnetohydrodynamics code for astrophysics
• Stellar disruption by a supermassive black hole: is the light curve really proportional to $t^{-5/3}$?
• Seventeen Tidal Disruption Events from the First Half of ZTF Survey Observations: Entering a New Era of Population Studies
• Optical discovery of probable stellar tidal disruption flares
• Disc formation from tidal disruptions of stars on eccentric orbits by Schwarzschild black holes
• Finite, Intense Accretion Bursts from Tidal Disruption of Stars on Bound Orbits
• Stellar Dynamics and Stellar Phenomena Near A Massive Black Hole
• Tidal Disruption of a Solar Type Star by a Super-Massive Black Hole
• Prompt Radiation and Mass Outflows from the Stream-Stream Collisions of Tidal Disruption Events
• The first tidal disruption flare in ZTF: from photometric selection to multi-wavelength characterization
• Partial Stellar Disruption by a Supermassive Black Hole: Is the Lightcurve Really Proportional to $t^{-9/4}$?
• The Prospects of Observing Tidal Disruption Events with the LSST
• Simulating realistic disc formation in tidal disruption events
• Measuring stellar and black hole masses of tidal disruption events
• Stellar Tidal Disruption Events in General Relativity
• Tidal disruptions by rotating black holes: effects of spin and impact parameter
• Tidal disruptions of main sequence stars -- III. Stellar mass dependence of the character of partial disruptions
• Tidal Disruptions of Main Sequence Stars -- I. Observable Quantities and their Dependence on Stellar and Black Hole Mass
• Stellar Tidal Disruption Events with Abundances and Realistic Structures (STARS): Library of Fallback Rates
• An accurate Newtonian description of particle motion around a Schwarzschild black hole
• On the Diversity of Fallback Rates from Tidal Disruption Events with Accurate Stellar Structure
• Black-Hole Spin Dependence in the Light Curves of Tidal Disruption Events
• The Tidal Disruption of Sun-like Stars by Massive Black Holes
• Tidal disruptions by rotating black holes: relativistic hydrodynamics with Newtonian codes
• Tidal disruption of a star in the Schwarzschild spacetime: relativistic effects in the return rate of debris
• Tidal disruptions of main sequence stars -- IV. Relativistic effects and dependence on black hole mass
• A unified treatment of tidal disruption by Schwarzschild black holes
• Density Conversion between 1-D and 3-D Stellar Models with 1D-MESA2HYDRO-3D

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