TY - JOUR

T1 - Revisiting the Rates and Demographics of Tidal Disruption Events

T2 - Effects of the Disk Formation Efficiency

AU - Wong, Thomas Hong Tsun

AU - Pfister, Hugo

AU - Dai, Lixin

PY - 2022/3/1

Y1 - 2022/3/1

N2 - Tidal disruption events (TDEs) are valuable probes of the demographics of supermassive black holes as well as the dynamics and population of stars in the centers of galaxies. In this Letter, we focus on studying how debris disk formation and circularization processes can impact the possibility of observing prompt flares in TDEs. First, we investigate how the efficiency of disk formation is determined by the key parameters, namely, the black hole mass MBH, the stellar mass ma, and the orbital penetration parameter ss that quantifies how close the disrupted star would orbit around the black hole. Then we calculate the intrinsic differential TDE rate as a function of these three parameters. Combining these two results, we find that the rates of TDEs with prompt disk formation are significantly suppressed around lighter black holes, which provides a plausible explanation for why the observed TDE host black hole mass distribution peaks between 106 and 107Me. Therefore, the consideration of disk formation efficiency is crucial for recovering the intrinsic black hole demographics from TDEs. Furthermore, we find that the efficiency of the disk formation process also impacts the distributions of both stellar orbital penetration parameter and stellar mass observed in TDEs.

AB - Tidal disruption events (TDEs) are valuable probes of the demographics of supermassive black holes as well as the dynamics and population of stars in the centers of galaxies. In this Letter, we focus on studying how debris disk formation and circularization processes can impact the possibility of observing prompt flares in TDEs. First, we investigate how the efficiency of disk formation is determined by the key parameters, namely, the black hole mass MBH, the stellar mass ma, and the orbital penetration parameter ss that quantifies how close the disrupted star would orbit around the black hole. Then we calculate the intrinsic differential TDE rate as a function of these three parameters. Combining these two results, we find that the rates of TDEs with prompt disk formation are significantly suppressed around lighter black holes, which provides a plausible explanation for why the observed TDE host black hole mass distribution peaks between 106 and 107Me. Therefore, the consideration of disk formation efficiency is crucial for recovering the intrinsic black hole demographics from TDEs. Furthermore, we find that the efficiency of the disk formation process also impacts the distributions of both stellar orbital penetration parameter and stellar mass observed in TDEs.

KW - BLACK-HOLE MASSES

KW - STARS

KW - EMISSION

KW - STELLAR

U2 - 10.3847/2041-8213/ac5823

DO - 10.3847/2041-8213/ac5823

M3 - Letter

VL - 927

JO - The Astrophysical Journal Letters

JF - The Astrophysical Journal Letters

SN - 2041-8205

IS - 1

M1 - 19

ER -