Dana Kullgren

My Experience With The CIERA REU

About Me Project Introduction Methods Results and Next Steps

Methods

I looked at a total of 33 star clusters which were simulated using the Cluster Monte Carlo (CMC) code, a Hénon-type Monte Carlo code that computes the long-term evolution of stellar clusters (Kremer et al. 2020b). These simulations all had the following initial conditions:

By contrast, these initial conditions were varied among the models:

The canonical value of α3 is 2.3 so the values of α3 used for these models were chosen around that value (Kroupa 2001).

From these simulations, I determined the rate of BBH mergers and the masses of BHs that collide in BBH mergers for each α3 value. These variables from the simulation data were compared to data from the Laser Interferometer Gravitational-Wave Observatory (LIGO), which detects BBH mergers by observing gravitational waves. The LIGO data used in this analysis includes the 01, 02, and 03 observations (LIGO/Virgo/KAGRA 2020).

As in Fragione and Banerjee 2021, I applied a detectability weight to each simulated BBH merger based on that merger’s signal-to-noise ratio.

By comparing the rates and component masses obtained from different α3 values to rates and component masses in LIGO data, I aim to better constrain the IMF in stellar clusters.


Acknowledgements
This material is based upon work supported by the National Science Foundation under Grant No. AST-2149425, a Research Experiences for Undergraduates (REU) grant awarded to CIERA at Northwestern University. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation. This research was supported in part through the computational resources and staff contributions provided for the Quest high performance computing facility at Northwestern University which is jointly supported by the Office of the Provost, the Office for Research, and Northwestern University Information Technology. This research was also supported by Aaron Geller and Tjitske Starkenburg who oversaw the CIERA REU.