In the first part of the presentation, I shall recapitulate my recent endeavours in investigating the role of dynamical interactions in moderate mass star clusters in producing stellar-mass binary black hole (BBH) mergers over cosmic time. Dynamical BBH mergers are obtained from long-term direct N-body evolutionary models of ~10^4 M_sun, pc-scale young massive clusters evolving into...
One of the great challenges for gravitational-wave astrophysics is disentangling different formation channels of binary black-hole (BBH) mergers. Achieving this requires in-depth understanding of BBH formation pathways and robust predictions for observable channel characteristics. We tackle this challenge for binary evolution scenarios by systematically modeling mass transfer evolution in...
Repeated stellar collisions and hierarchical mergers in dense and massive star clusters are among the most straightforward mechanisms to produce intermediate-mass black holes (IMBHs).
In my talk, I will investigate the formation channels of IMBHs in globular clusters up to $10^6\,\rm{M_{\odot}}$. To do this, I will rely on an extensive set of accurate N-body models run with the...
Intermediate mass black holes (IMBHs) serve as a crucial link between stellar-mass black holes, resulting from the death of massive stars, and supermassive black holes residing at the center of galaxies. Yet, we do not fully understand the necessary conditions for IMBH production, raising questions about whether they could constitute a completely distinct category of black holes.
Star...
The intermediate mass black hole (IMBH) regime is still poorly constrained with few detections between 150 and 10$^5$ M$_\odot$.
An IMBH in ω Centauri, the Milky Way’s most massive globular cluster, has been suspected for almost two decades, but all previous detections have been questioned due to their assumptions and the possible mass contribution of a central cluster of stellar mass black...
Globular clusters (GCs) are thought to harbor the long-sought population of intermediate-mass black holes (IMBHs). We present a systematic search for a putative IMBH in 81 Milky Way GCs, based on archival {\it Chandra} X-ray observations. We find in only six GCs a significant X-ray source positionally coincident with the cluster center, which have 0.5--8 keV luminosities between $\sim1\times...
We present the results of direct N-body simulations focusing on stellar discs interacting with a central supermassive black hole (SMBH) and an off-plane intermediate mass black hole (IMBH) embedded within a spherical star cluster. For models with a high-mass IMBH ($m_{\bullet} \simeq M_{\rm d}$) on a retrograde orbit with respect to the stellar disc, we find that the IMBH tends to anti-align...
Next-generation (XG) ground-based gravitational wave observatories are expected to be sensitive to mergers of intermediate-mass black holes (IMBHs) with a total source-frame mass in the hundreds out to a high redshift. Runaway tidal encounters lead to the formation of IMBHs in the cores of dense stellar clusters. I will discuss how single IMBH–IMBH merger events, occurring after the...
Supermassive black holes (SMBHs) are found to co-exist with a nuclear star cluster (NSC) in the nuclei of most galaxies. The work presented in this talk builds on the idea that the NSC forms before the SMBH through the merger of several stellar clusters that may contain intermediate-mass black holes (IMBHs). These IMBHs can subsequently grow in the NSC, and form an SMBH. To check the...
There are indications that stellar-origin black holes (BHs) are efficiently paired up in binary black holes (BBHs) in Active Galactic Nuclei (AGN) disc environments, which can undergo interactions with single BHs in the disc. Such binary-single interactions can potentially lead to an exceptionally high fraction of gravitational-wave mergers with measurable eccentricity in LIGO/Virgo/KAGRA. We...
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...
It is well established that massive black holes reside in the central regions of virtually all types of known galaxies. Recent observational and numerical studies however challenge this picture, suggesting that intermediate-mass black holes in dwarf galaxies may be found on orbits far from the center. In this talk, I will present my recent work on the dynamics of off-center black holes in...
LIGO/VIRGO/KAGRA collaboration announced over 90 gravitational waves detections from double compact objects (DCOs) mergers, however, the origin and evolution scenario of their progenitors remains elusive.
One of the promising candidates for DCOs progenitors are the X-ray binaries (XRBs) where X-ray emission arises from the accretion of matter transferred from the companion star onto a black...
With nearly 200 hundred gravitational-wave detection candidates reported by the LIGO-Virgo-KAGRA Collaboration over the past decade, we are now entering an era where the statistical analysis of the properties of double compact objects provides us with a better understanding of the physical processes behind these extreme objects. However, the question of the astrophysical origin of merging...
Dense stellar clusters are prime environments for the formation and evolution of bound binary black hole (BBH) systems, leading to eventual mergers. These BBHs can form through direct interactions among stellar objects or evolve from primordial binaries — binaries that originated within the cluster. Importantly, the dynamical interactions within these clusters have the potential to...
Isolated evolution of massive stars is expected to leave a “gap" in the mass spectrum of black holes (BHs) at birth between ~40-120 Msun due to (pulsational) pair-instability supernovae ((P)PISN). Recent detections of gravitational waves (GWs) from mergers of BHs with pre-merger source-frame individual masses in this so-called upper mass-gap, have created immense interest in a detailed...
The first direct detection of gravitational waves (GWs), back in 2015, marked the beginning of a new era for the study of compact objects, and the upcoming next-generation detectors, such as Einstein Telescope (ET), are expected to add hundreds of thousands of compact binary coalescences to the list. We discovered up to 90 GW signals, from which we were able to put some constrains on the...
