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2024.04.26

Research on the Structure, Chemistry and Kinematics of the Milky Way Based on the Large-scale Sky Surveys

<p>With the advent of massive large-scale sky surveys, such as, the SDSS for photometry, the LAMOST for spectroscopy, and Gaia for astrometry, we are entering a golden era of Galactic studies and precise multi-dimensional information (e.g., 3D position, 3D velocity, chemical element abundance ratios, and stellar age) is now available for some huge samples of stars in the Milky Way. Leveraging thes...</p>

2024.04.19

SgrA∗ spin and mass estimates through the detection of an extremely large mass-ratio inspiral

<p>Estimating the spin of SgrA∗ is one of the current challenges we face in understanding the center of our Galaxy. In the present work, we show that detecting the gravitational waves (GWs) emitted by a brown dwarf inspiraling around SgrA∗ will allow us to measure the mass and the spin of SgrA∗ with unprecedented accuracy. Such systems are known as extremely large mass-ratio inspirals (XMRIs) a...</p>

2024.04.12

Dynamical Modelling of Galactic Kinematics using Neural Networks

<p>The advent of integral field data has revolutionised the study of galaxy evolution. A key component of this is dynamical modelling methods which have allowed for crucial insights to be made from kinematic data. Despite this importance, most dynamical models make a number of key assumptions which do not hold for real galaxies. At the same time, machine learning methods are becoming increasingly ...</p>

2024.03.29

Kinematic Signatures of Circumbinary Discs: Spiral arms, Fast Flows, and Doppler Flips

<p>Kinematic studies of protoplanetary discs are becoming a valuable method for uncovering hidden companions. While there exists a substantial amount of literature on the understanding of planet-disc interactions and their observational implications, little attention has been made towards circumbinary discs. Using 3D hydrodynamical simulations post-processed with Monte Carlo radiative transfer, I ...</p>

2024.03.22

4MOST Galactic pipeline: radial velocity and pysme stellar parameters

<p>The 4-m Multi-Object Spectroscopic Telescope (4MOST) is one of the ESO community survey with a large field-of-view to survey the southern sky in a few years, delivering spectra for ≥25 million objects over ≥15 000 square degrees in R~6000 and R~20000. 4MOST is currently in its manufacturing, assembly, integration and test phase with an expected start of full science operations within a year. ...</p>

2024.03.15

The Merian Survey: Characterizing dark matter and feedback in star-forming dwarf galaxies with medium-band filters on DECam

<p>The Merian survey is an ongoing medium-band imaging survey on the CTIO 4-meter Blanco telescope. With two new medium-band filters on DECam, we expect to detect ~100,000 star-forming dwarf galaxies at z~0.1 in the HSC-SSP wide field (~800 deg^2), aiming to characterize dark matter halo and stellar feedback in dwarf galaxies. The Merian survey will allow us to measure the full dark matter profile...</p>

2024.03.08

Pathway to high-z SMBHs: seed formation and growth in the statistical perspective

<p>The early evolution of the black hole mass function (BHMF) and quasar luminosity function (QLF) encodes key information on the physics determining the radiative and accretion processes of black holes (BHs) growing in high-redshift galaxies. Starting from the formation of seed BHs as their parent halos evolve, we study primordial gas collapse in the biased quasar host halos, computing gas chemic...</p>

2024.01.12

Ultra-compact dwarf galaxies caught in the act of transformation

<p>In the past two decades, systematic studies have revealed hundreds of ultra-compact dwarf galaxies (UCDs) in the nearby Universe. While similar in appearance to massive globular clusters, the detection of extended stellar envelopes, complex star formation histories, elevated mass-to-light ratio, and supermassive black holes suggest that some UCDs are remnant nuclear star clusters of tidally-str...</p>

2024.01.05

The circumnuclear gas in M81: a unique testbed for AGN and stellar photoionization

<p>The origin of the low-ionization nuclear emission-line region (LINER) prevalent in local galaxies and its relationship with supermassive black holes are debated for decades. We preform a comprehensive evaluation of traditional photoionization models against the circumnuclear ionized gas in M81, for which recent CAHA/PPAK integral-field spectroscopic observations reveal a LINER characteristic ou...</p>

2023.12.29

Solutions towards the Hubble tension and S8 tension

<p>The standard LCDM model seems to fail to reconcile the discrepancy of the H0 measurements between the early and late Universe. This H0 tension has become an increasingly mystery in the cosmology community. Moreover, the galaxy survey measurement of S8 value, namely the amplitude of matter density fluctuation, is smaller than the value inferred from CMB assuming LCDM, although with a less signif...</p>