Physics / Stellar & Compact Objects
Stellar physics, compact objects, and high-energy astrophysical phenomena. Research spans black hole thermodynamics, stellar evolution, radiative processes, and accretion physics.
Massive stars are the progenitors of black holes such as those detected in gravitational wave (GW) observations. As such, understanding their formation has been a multi- disciplinary effort involving theory, computations and observations. With the detection of GW190521 providing the largest stellar
We study the capability of future space-based gravitational-wave (GW) detectors to constrain supermassive black hole (SMBH) properties through observations of inspiraling stellar-mass binary black holes (BBHs) orbiting them. Focusing on stable hierarchical triple systems, we model the BBH motion in
We constrain the cosmological constant $Λ$ using astrometric and spectroscopic observations of the S2, S1, and S14 stars orbiting Sgr A$^*$. The stellar motion is modelled by numerically integrating timelike geodesics in Schwarzschild-de Sitter spacetime, including relativistic redshift and time-del
The spectra of an accretion disk around black holes are the basic diagnostic tool to enlighten the underlying flows and then black holes. Accretion flows around black holes, however, are controlled by parameters like the magnetic field, spin of the black hole, accretion rate and temperature of the f
How stellar-mass black holes are formed is an open question in astrophysics, with very limited observational constraints. It is not known which types of stars are more likely to produce black holes, and whether the formation process is accompanied by strong or weak electromagnetic transients - or no
We have recently shown evidence that the most relativistic jets (with Lorentz factor >2) from stellar-mass black holes in X-ray binary systems may be locked to a fixed axis, likely the spin axis of the black hole. Slower, mildly relativistic jets (with velocities typically ~ 0.3c) are often seen to
JWST discoveries of the earliest ($z \gtrsim 9$) supermassive black holes (BHs, $M_\bullet \gtrsim 10^6\,\rm{M}_\odot$) challenge the BH seeding and accretion models of most cosmological simulations. In this work, we compare early BH growth arising from three different accretion prescriptions charac
GW190521 and GW231123 have been reported as short-duration gravitational-wave transients consistent with very massive binary black hole (BBH) coalescences whose inferred parameters, i.e., exceptionally high total masses and spin magnitudes, challenge standard isolated binary stellar evolution. We te
This study investigates the concept of “collective bricolage” within the framework of creating a universe science observatory in France. In the face of significant transformations in higher education and research, this article examines how university stakeholders can employ collective bricolage to a
This thesis investigates the underexplored role of music within early Coptic literature to address a significant gap in early Christian musicology. While substantial research has been conducted on Greek, Latin, and Syriac language sources (McKinnon, 1987; Page 2010), Coptic-language texts have been
Overview This dataset provides the results of a high-fidelity cosmological simulation exploring the non-linear dynamics of a universe dominated by Primordial Black Holes (PBHs). The simulation was executed on NVIDIA Blackwell (B200) hardware at a native resolution of $2560^3$ ($16.7$ billion voxels)
This supplement extends the dimensionless predictions of the main document to absolute mass scales and cosmological observables, addressing the dimensional transmutation problem. It bridges dimensionless topological predictions to physical mass scales in GeV.
This supplement extends the dimensionless predictions of the main document to absolute mass scales and cosmological observables, addressing the dimensional transmutation problem. It bridges dimensionless topological predictions to physical mass scales in GeV.
This work presents a rigorous mathematical formulation of cosmological mechanics within the Cosmological Thermosynthesis Theory v3.2 (TTC v3.2). The theory posits that spacetime and all fundamental interactions emerge from a primordial superfluid of ultralight scalar bosons termed etherions, with ma
The third paper in a four-paper series connecting FCC lattice cohomology, Apollonian circle packing, and post-quantum cryptography. Papers 1 and 2 proved that the FCC cycle space carries a natural V4 symmetry and that the FCC primitive cell is the symmetric Apollonian seed in R³’¹, with the directed
The philosopher Giorgio Agamben has argued that the ‘human/nonhuman distinction is the conceptual ground for any further ontological elaboration’, (Grieve-Carlson, 179) that humans must distinguish themselves from their environment and other beings before the work of culture can begin. However, obje