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2025.12.08
Particle acceleration and emission in jets of microquasars and active galactic nuclei
The origin of cosmic rays (CRs) remains an open question. The CR spectrum is characterized by two significant breaks: the knee at ~3 PeV (PeV=1e15 eV) and the ankle at ~3 EeV (EeV=1e18 eV). It is widely accepted that ultra-high-energy cosmic rays (UHECRs) above the ankle originate from extragalactic sources, with the transition energy between galactic and extragalactic components lying between ...
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2025.12.03
The use of the quasar dataset on Cosmology: consequences and prospects
We try to find an optimized methodology to constrain the cosmological parameters using the quasar dataset. Quasars can be the potential cosmic probe that can fill up the gap between the farthest observed Type Ia Supernovae and the Cosmic Microwave Background CMB. Quasars can be observed to the highest redshift of z ≈ 7.1. It can give valuable insight into the tensions of the cosmological param...
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2025.12.08
Tracing Cosmic Evolution: From the CMB to the Web, the CGM, and Galactic Disks
This is the abstract: Understanding how galaxies form and evolve remains one of the central challenges in modern astrophysics. In this talk, I will present my research over the past decade on the multi-scale processes that govern galaxy formation, from the initial conditions imprinted in the cosmic microwave background to the assembly of galactic disks.I will show that the effect of the cosmic ...
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2025.12.03
Hunting for strong gravitational lenses with Euclid
Euclid is a class-M space mission by ESA launched in July 2023. In the course of its six years lifetime, it will observ ~14,000 sq. degrees of the extragalactic sky with the aim of understanding the nature of dark matter and dark energy combining multiple cosmological probes such as weak lensing and galaxy clusters. Being designed for accurate shape measurements from space and having a space re...
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2025.12.23
A new multiprobe analysis of modified gravity and evolving dark energy
Dark energy has attracted renewed attention since DESI reported a possible dynamical behavior crossing the cosmological constant boundary, favoring the (w0,wa) parametrization over a cosmological constant at more than 3\sigma. This apparent evolution is a manifestation of some discrepancies between DESI BAO, Planck CMB and supernovae measurements. An independent probe from DESI and SN is theref...
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2025.11.27
OJ 287: The Rosetta Stone of Supermassive Black-Hole Binaries
Recent observational campaigns and theoretical investigations strongly indicate the presence ofa spinning supermassive black hole binary that spirals in due to the emission ofnano-Hertz gravitational waves in bright blazar OJ 287.I will briefly describe these efforts while focusingon our August 2019 observations and their implications.Additionally, I will touch upon our ongoing efforts, relev...
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2025.11.26
Free Floating Planets and stellar binary formation
Planet formation is far from understood. Observations of Free Floating Planets (FFPs), on the one hand, and of planets in tight stellar binaries, on the other, are challenging our leading (Core Accretion) scenario for planet formation strongly. This classical framework requires a prolonged epoch of gentle accumulation of small solids into ever larger bodies, yet both FFPs and planets in binarie...
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2025.11.27
Icy ocean worlds -- from the surface to the interior
Icy moon oceans are promising targets in the search for extraterrestrial life, but characterizing their internal dynamics remains challenging, as most oceanic processes are obscured from direct observation by the overlying ice shell. In contrast, the ice shell itself is relatively accessible to observation and may serve as a window into the ocean below. As the only liquid layer in the system, t...
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2025.11.25
SQ-A: A Collision Triggered Starburst in Intra-Group Medium of Stephan's Quintet
SQ-A is a starburst in the intra-group medium (IGrM) of the famous compact group Stephan's Quintet (SQ). There has been a long controversy on whether SQ-A is triggered by a collision of two gas systems, one is associated with the IGrM (v~6900 km/s) and another with the intruder galaxy NGC 7318b (v~6000 km/s). The counter argument against the collisional scenario is based on the fact that in a l...
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2025.11.07
New Insights into the Progenitors of Core-Collapse Supernovae
Core-collapse supernovae (CCSNe) are spectacular explosions of dying massive stars and play significant roles in various astrophysical processes. It is a key topic, and still a major difficulty, to determine the progenitors of different types of CCSNe. In this talk, I will describe the general understanding on this topic from past studies and introduce our recent work in this field on a wide ra...
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