2023 Fall Meeting of the APS Prairie Section
Thursday–Saturday, November 30–December 2 2023;
University of Missouri, Columbia, Missouri
Session P01: Poster Session
5:25 PM,
Friday, December 1, 2023
University of Missouri
Room: N214BCDE
Abstract: P01.00004 : Gravitational Wave Predictions from Supermassive Black Hole Mergers in Cosmological Simulations*
Abstract
Presenter:
Thirtha Karmakar
(Truman State University)
Authors:
Thirtha Karmakar
(Truman State University)
Colin DeGraf
(Truman State University)
Supermassive black holes are found at the center of galaxies and play an important role in the evolution of galaxies. Since the first LIGO detection, gravitational waves (GW) have become an area of increasing interest, and with the upcoming LISA mission, it is important to characterize the relationship between merging black hole properties and the gravitational wave signals we expect LISA to detect. In particular, by generating catalogs of simulated merger events and their associated gravitational wave signals, we can maximize our understanding of the LISA data and our ability to connect GW detections with the physical events that produced the signal. To do this, we consider a population of black hole mergers using the TNG simulations, investigating the connection between merger events and the resulting GW signal. Most mergers involve at least one very low-mass black hole: the secondary black hole has a mass (M2) within 0.5dex of the black hole seed mass (87% of mergers have M2 < 106.5 M☉), though the primary mass is typically larger (1> ~ 4*107 M☉, compared to 2> ~ 2.0*106 M☉). We also find significant redshift evolution: the majority of mergers in the simulation occur at low redshift (77% at z<2), though the peak of the GW signal rate comes from a slightly earlier time (z~2.2). We also estimate the Signal-to-Noise ratio (SNR) of LISA detections from each merger, using predicted frequency & strain calculations for their gravitational waves. We show that the average SNR has very little redshift dependence at z≳1, but shows a substantial increase at the lowest redshifts (with the maximum signals producing SNR > 106). From this, we show that the strongest SNR occurs when black holes with mass ~ 106.5-107 M☉ merge with slightly smaller black holes (M2 ~ 106.5 M☉). Finally, we show that although mergers involving black hole masses of ~ 107 M☉ produce very strong signals, these events tend to be rarer than either larger or smaller mergers.
*Emerging Innovators Undergraduate Summer Research Program