23 citations · 32 across the 8 of their papers we have counts for
11 papers
Angular structure of finite-field vacuum birefringence in magnetars
Shahram Abbassi, S. R. Valluri
Vacuum birefringence in a strong magnetic field is often modelled by combining the finite-field splitting for perpendicular propagation with the familiar angular factor.…
Validating Inverse Fundamental-Plane IMBH Mass Estimates in the SKA/ngVLA Era
Shahram Abbassi, Samik Mitra, Ramananda Santra
The radio/X-ray/black-hole-mass Fundamental Plane (FP) is widely used to estimate masses of accreting intermediate-mass black hole (IMBH) candidates. Its inverse use is justified o…
Thermal Stability of Radiation-Pressure-Dominated Accretion Disks Threaded by Net Vertical Magnetic Flux
Shahram Abbassi, Armin Memarian, Samik Mitra
The classical radiation-pressure instability predicts strong thermal variability in luminous black-hole accretion disks, whereas most disk-dominated X-ray binary soft states remain…
Classifying Quasar Types Without a Spectrum
Adrien Hélias, Pauline Barmby, Sarah C. Gallagher +2
Distinguishing between Type 1 and Type 2 quasars is important because it helps us understand accretion regimes, black hole mass scaling, disk instabilities and feedback processes i…
Braking indices as probes of r-mode spin-down in young pulsars
Shahram Abbassi, Armin Memarian, Evelyn Sophia Guest +1
We present a timing-based framework for interpreting braking-index measurements in young pulsars using a four-channel spin-down model that includes particle-wind, magnetic-dipole,…
Early Stages of Protostellar Disk Evolution: A Link to the Initial Cloud Core
Majd Noel, Rahul Khanna, Shahram Abbassi +2
We study the structure and evolution of the very early protostellar disk (``protodisk'') just after protostar formation, where disk self-gravity dominates and the stellar contribut…
Long Term (250 years) Hydrodynamical Simulation of the Supermassive Black Hole Binary OJ287
Ariel Chitan, Sarah C. Gallagher, Shahram Abbassi
With upcoming facilities capable of detecting photometric and gravitational wave signals from supermassive black hole (SMBH) binaries, studying their long-term accretion-driven var…
Prospects for Revealing Intermediate-Mass Black Holes in NGC 1399 using SKA
B. Karimi, P. Barmby, S. Abbassi
This study investigates the detectability of intermediate-mass black holes (IMBHs) within the mass range solar masses in the globular star clusters of NGC 1399 at a fre…
The redshift evolution of galactic bar pattern speed in TNG50
Asiyeh Habibi, Mahmood Roshan, Mohammad Hosseinirad +4
In this paper, the redshift evolution of the galactic bar properties, like the bar length, pattern speed, and bar fraction, has been investigated for simulated galaxies at stellar…
The Role of r-Modes in Pulsar Spin-down, Pulsar Timing, and Gravitational Waves
Xiyuan Li, Shahram Abbassi, Varenya Upadhyaya +2
We investigate the role of r-mode oscillations in pulsar spin-down and their implications for gravitational wave emission and pulsar timing analysis. Using a non-linear differentia…
Neural Network Prediction of solar cycle 24
A. Ajabshirizadeh, N. Masoumzadeh Jouzdani, S. Abbassi
The ability to predict the future behavior of solar activity has become of extreme importance due to its effect on the near Earth environment. Predictions of both the amplitude and…