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2024.02.28

Weak Lensing Without Shape Noise

<p>Weak gravitational lensing imprints a coherent distortion onto the observed shapes of distant galaxies. At the image level, this gravitational shear degenerates with the intrinsic shape of galaxies, and the weak lensing signal-to-noise from an individual galaxy is of order 0.01. I will describe Kinematic Lensing, a new technique combining imaging and galaxy kinematics to measure weak lensing wi...</p>

2023.12.25

Constraining the Cosmic Partition of IGM and CGM Baryons with FRB Foreground Mapping

<p>The frequency shifts measured in extragalactic Fast radio bursts (FRB)s probe the total column of ionized gas in the foreground, including large contributions from the CGM and IGM. By combining this information with both deep and wide &nbsp;spectroscopic observations of foreground galaxies, the information content is enhanced. The wide-field data &nbsp;(∼10s of Mpc scales) allows us to reconstruct the u...</p>

2023.12.25

A cooling anomaly of white dwarfs

<p>Data from the Gaia satellite are revolutionizing many fields of astronomy. I will present two related discoveries about white dwarfs: one is an extreme cooling anomaly upon phase transition of some white dwarfs, which stops their cooling for almost 10 Gyrs, and the other is the existence of merger products among single white dwarfs. I will show interesting solution to explain the anomaly and th...</p>

2023.12.18

Probing Parity with Galaxy Distributions and Beyond

<p>Galaxies&#39; four-point correlation functions provide insights into parity symmetry at cosmological scales. In this talk, I will present our data analysis on the BOSS galaxy sample with a focus on various observational effects. I will also discuss some future aspects of extending the analysis, including models and connection with other observables. In addition, I will also discuss an alternative i...</p>

2023.12.18

Electromagnetic fireworks from erupting magnetars

<p>Highly magnetized neutron stars are a source of extreme transients observed in different bands, like the fast radio burst (FRB) and associated hard X-ray burst from the Galactic magnetar SGR 1935+2154. The origin of such outbursts, hard X-rays on the one hand and millisecond duration FRBs on the other hand, is still unknown. We present a global model for various kinds of such magnetar outbursti...</p>

2023.11.27

Multi-Messenger Probes on Dark Matter Beyond WIMPs

<p>We will discuss two promising dark matter scenarios: axion-like particle dark matter and primordial black hole dark matter. We begin with radio telescope probes on axion-like dark matter. We will discuss the axion-photon conversion around neutron stars which results in the radio emission and the 21 cm probes through the effects on large scale structure formation suppression. We then turn our at...</p>

2023.11.24

Tidal Disruption Events: Probes of Accretion Physics and Black Hole Demographics

<p>Tidal disruption events (TDEs) provide unique laboratories to&nbsp;study the demographics, immediate stellar and gaseous environments, and&nbsp;accretion physics of the massive black hole population. Over the past&nbsp;few years, time domain sky surveys such as the optical Zwicky Transient&nbsp;Facility (ZTF) have led to a surge of TDE discoveries in galaxy centers.&nbsp;This talk highlights our efforts to constrain th...</p>

2023.11.21

High contrast imaging science with coronagraphic instruments

<p>While high-contrast imaging surveys in the past decade have produced only a handful of self-luminous exoplanets, they opened new gates for studying the forming environments of planetary systems. With multi-epoch and multi-wavelength imaging, I will talk about our ongoing efforts on scientific expeditions using current flagship observatories. They include (1) pinpointing the orbits of hidden pla...</p>

2023.11.10

Exploring galaxy dark matter with dynamical models using combined stellar and HI kinematics

<p>The dynamical modelling technique is one of the major methods to measure the dark matter distribution in galaxies. Due to the degeneracy of baryonic and dark matter and the limitation of extended tracers in galaxies, accurate measurements of dark matter distribution in large sample of galaxies are still inadequate. We introduce our method to constrain the dark matter distribution in galaxies wi...</p>

2023.11.13

Understanding the galaxy formation and metal-enrichment in the view of gas-regulator framework

<p>Star-forming galaxies are actively accreting gas from surrounding materials during the cosmic time, while the feedback from star formation on the other hand blows the gas away as well as enriches the inter-stellar/-galactic medium. The interplay between inflow, outflow and star formation is then the key to understand the formation and evolution of star-forming galaxies, as well as the relevant...</p>