Estimating the spin of SgrA∗ is one of the current challenges we face in understanding the center of our Galaxy. In the present work, we show that detecting the gravitational waves (GWs) emitted by a brown dwarf inspiraling around SgrA∗ will allow us to measure the mass and the spin of SgrA∗ with unprecedented accuracy. Such systems are known as extremely large mass-ratio inspirals (XMRIs) and are expected to be abundant and loud sources in our galactic center. We consider XMRIs with a fixed orbital inclination and different spins of SgrA∗(s) between 0.1 and 0.9. For both cases, we obtain the number of circular and eccentric XMRIs expected to be detected by space-borne GW detectors like LISA and TianQin. We find that if the orbit is eccentric, then we expect to always have several XMRIs in band while for almost circular XMRIs, we only expect to have one source in band if SgrA∗ is highly spinning. We later perform a Fisher matrix analysis to show that by detecting a single XMRI the mass of SgrA∗ can be determined with an accuracy of the order 10−2M⊙, while the spin can be measured with an accuracy between 10^−7 and 10^−4 depending on the orbital parameters of the XMRI.
https://iopscience.iop.org/article/10.3847/1538-4357/acde51
BIO
In November 2022 I finished my Ph.D. at the Institute of Applied Mathematics and Systems Sciences of the University of the Chinese Academy of Sciences (UCAS) and since July 2023 I am a postdoc at the Kavli Institute of Astronomy and Astrophysics at Peking University. My research focuses on gravitational waves astrophysics and stellar dynamics, particularly in formation mechanisms of gravitational waves sources for space-based detectors, like LISA and TianQin, such as extreme and extremely large mass ratio inspirals.
Host: Richard Grumitt
