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2024.10.11

Investigating the link between the growth of SMBHs and their host galaxies with X-ray surveys

<p>X-ray surveys have been an effective way to study growing supermassive black holes (SMBHs). Utilizing X-ray survey fields that have extensive multiwavelength data coverage, we can probe how SMBH growth links with the properties of their host galaxies, which will ultimately help to investigate the physical mechanisms behind the potential coevolution of SMBHs and their hosts. In my talk, I will p...</p>

2024.09.27

AGN SED Modeling: AGN luminosity in the simulated universe and implications on the era of reionization

<p>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 ...</p>

2024.09.25

Lyman-alpha Intensity Mapping with optical imaging surveys: Future prospects

<p>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 ...</p>

2024.09.20

Unveiling the 70-year mystery of the nature of carbon-deficient red giants

<p>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 (&lt;1% of giants). Combining asterose...</p>

2024.09.13

Identifying the Galactic Substructures in 5D Space Using All-sky RR Lyrae Stars in Gaia DR3

<p>Motivated by the vast gap between photometric and spectroscopic data volumes, there is great potential in using 5D kinematic information to identify and study substructures of the Milky Way. We identify substructures in the Galactic halo using 46,575 RR Lyrae stars (RRLs) from Gaia DR3 with the photometric metallicities and distances newly estimated by Li et al. (2023). Assuming a Gaussian prio...</p>

2024.12.19

Magnetospheric Radio Emissions: from Jupiter to exoplanets and stars [EN]

<p>Jupiter&#39;s radio emissions have been intensively studied since their discovery some 70 years ago. Space missions have extended these studies to radio emissions from all planetary magnetospheres in the solar system. Main emission characteristics have been determined (source location, directivity, power, polarization, etc.) and their microscopic generation process elucidated (primarily the electro...</p>

2024.09.04

Comprehensive population synthesis predictions for massive binary stars in the Small Magellanic Cloud

<p>The past and ongoing gravitational wave detections have fostered a wide interest in understanding the formation of binary black holes (BBHs). Several formation scenarios have been proposed, including the evolution of isolated massive binaries. While most of the observed merging black holes are at cosmological distances, and thus likely at low metallicity, the Small Magellanic Cloud (SMC) provid...</p>

2024.09.12

Tensions on small scales: Too many galaxy-galaxy strong lenses in galaxy clusters?

<p>In the standard cosmological model, the matter content of the Universe is dominated by cold dark matter (CDM), collisionless particles that interact with ordinary matter (baryons) only through gravity. Gravitationally bound dark-matter halos form hierarchically, with the most massive systems growing through mergers of smaller ones. As structure assembles in this fashion, large dark-matter halos...</p>

2024.09.03

The role of mixing, mass-loss and rotation in stellar evolution

<p>Despite the efforts made in recent decades to obtain more realistic stellar models, considerable uncertainties still remain due to our incomplete knowledge of some complex physical processes that occur within them, such as accretion, convection, mass loss, rotation, to name a few of them. Modeling these processes still relies on empirical calibrations and this has a significant impact on theore...</p>

2024.09.05

A precise measurement of the supermassive black hole mass in the galaxy NGC 383 using molecular gas kinematics down to the circumnuclear disc

<p>I will present a measurement of the supermassive black hole (SMBH) mass in NGC 383, a nearby lenticular galaxy hosting a low-power radio jet, based on ALMA observations of the CO(2-1) emission line with an angular resolution of 0.′′050 × 0.′′024 (≈ 16 pc × 8 pc). These observations spatially resolve the nuclear molecular gas disc down to ≈ 41300 Schwarzschild radii and the SMBH sphere of...</p>