Research
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2024.10.10
Probing the spacetime variation of the fine-structure constant using emission-line galaxies
The Standard Model of particle physics assumes that fundamental physical constants, including the fine-structure constant alpha, are universal and constant. On the other hand, modern theories beyond the Standard Model predict or even require the variation of the fundamental constants. Recently, we developed a new method to probe the variation in alpha using narrow and strong [O III] emitting ga...
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2024.09.27
AGN SED Modeling: AGN luminosity in the simulated universe and implications on the era of reionization
The study of the spectral energy distribution (SED) of active galactic nuclei (AGN) plays an important role in several aspects of the evolution of the galaxy. In this work, we model the black hole (BH) accretion flow for a wide range of BH mass and accretion rate. The accretion flow is divided into two regimes based on the Eddington-normalized accretion rate value - the ADAFs for low accretion ...
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2024.09.26
Quest for the origin of neutrinos
The discovery of neutrino oscillation established a non-zero mass of neutrino. The origin of neutrino and its non-zero mass is an one of the most important experimental clues to the new physics beyond the standard model. Neutrinos are ubiquitous in the universe, accompanying most of the weak-interacting physics processes. I shall review natural and artificial sources of neutrinos with an emph...
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2024.09.25
Lyman-alpha Intensity Mapping with optical imaging surveys: Future prospects
Being the first spectral line of HI, Lyman-alpha permeates the cosmic web in emission. It has been largely used to study the close environment of galaxies and QSOs (Lyman-alpha blobs/nebulae); but being a resonant line it should scatter through the intergalactic medium. This should make Lyman-alpha an interesting candidate for Intensity Mapping (IM): the study of large-scale by integrating the ...
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2024.09.20
Unveiling the 70-year mystery of the nature of carbon-deficient red giants
Weak G-band stars, or carbon-deficient red giants (CDGs), characterised by weak or absent G-band absorption of the CH molecule driven by low carbon abundances, have remained mysterious for decades. Here, we present a significant increase in the known CDG population identified through systematic spectroscopic surveys. This expanded sample confirms their rarity (
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