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2025.01.09

How to quantify textures and random fields in astrophysics?

<p>Extracting information from stochastic fields is a ubiquitous task in science. &nbsp;However, from cosmology to biology, it tends to be done either through correlation analyses, which is often too limited to capture the full complexity, or through the use of neural nets, which require large training sets and lack interpretability. &nbsp;I will present a new approach that borrows ideas from both extremes ...</p>

2025.01.06

The Coming Asteroseismic Revolution

<p>The field of asteroseismology has grown explosively in the past two decades. It has evolved from bespoke examination of individual variable stars, to now having become both our main means of constraining stellar properties at large scale, and our sole observational probe into the astrophysics of their interiors. I will lay out recent developments of its observational methods and discoveries, pa...</p>

2025.01.03

Deciphering the intriguing nature of early AGN with JWST

<p>The first two-year results of JWST have unveiled an unexpectedly large number of accreting black holes in the early Universe. Unlike the general populations of super massive black holes at the low redshifts, these early black holes exhibit distinctly different properties. They appear over-massive compared to the stellar content of their host galaxies, generally show non-detection in the hard X-...</p>

2024.12.24

Uncovering Early Galaxy Formation with JWST: A Modeling Perspective

<p>The James Webb Space Telescope (JWST) is transforming our understanding on galaxy formation and evolution, revealing distant galaxies deep into the epoch of reionization and uncovering red sources that were simply unknown pre-JWST. In this talk, I will discuss two key areas, with a focus on the challenges in modeling the spectral energy distributions in the JWST era. First, a central science go...</p>

2024.12.27

On Precise Correction of the Milky Way Dust Extinction

<p>Extinction correction is crucial for understanding the intrinsic properties of celestial objects within and beyond the Milky Way, especially with Gaia’s photometric precision reaching millimagnitude levels. Leveraging millions of high-quality spectra and precise atmospheric parameters from LAMOST, we have achieved unprecedented accuracy in extinction measurements. Using the “star-pair” techn...</p>

2024.12.25

Studying cosmology and astrophysics by the synergy of RSD and kSZ effects

<p>As one main target of cosmological surveys, the galaxy peculiar velocity field encodes information about the cosmic structure growth history and significantly contributes to the study of dark energy and dark matter. Its detection is typically made by the redshift space distortion (RSD) and kinetic Sunyaev-Zel’dovich (kSZ) effects in cosmology. In this talk, I will present high signal-to-noise ...</p>

2024.12.20

TOI-880 Has An Aligned, Coplanar Multi-planet System [EN]

<p>We present the stellar obliquity measurement of TOI-880 c (TOI-880.01) using Rossiter-McLaughlin (RM) observations obtained with the Keck Planet Finder (KPF). TOI-880 is a compact multi-transiting system with 3 transiting planets. Our independent analysis revealed that the host star is a K-type star. Planet b (TOI-880.02) has a radius of 2.23 ± 0.10R⊕ and an orbital period of 2.6 days; planet ...</p>

2024.12.11

Discussion on DESI Y1 results [EN]

<p>Since DESI has released their cosmological constraints from BAO and Full-shape Analysis with DESI Y1 data in April and November respectively, in the seminar next week, Siyi Zhao and Wenshuo Xu (both are 4th year graduate students) are going to briefly present and discuss DESI Y1 results, including a general introduction to DESI project, methodology and their key cosmological constraints. Welcom...</p>

2024.12.13

A potential mass-gap black hole in a wide binary with a circular orbit

<p>The mass distribution of black holes identified through X-ray emission suggests a paucity of black holes in the mass range of 3 to 5 solar masses. Modified theories have been devised to explain this mass gap, and it is suggested that natal kicks during a supernova explosion can more easily disrupt binaries with lower-mass black holes. Although recent Laser Interferometer Gravitational-Wave Obse...</p>

2024.12.12

Dark Matter under the Gravitational Lens [EN]

<p>Dark Matter (DM) is the clearest sign that the Standard Model of particle physics is incomplete. &nbsp;A determination of the DM particle mass will rule out entire classes of hypothetical extensions to the Standard Model, thus pointing the correct path towards New Physics. &nbsp;In this talk, I describe how gravitational lensing can differentiate between the two top contenders for DM: ultra-massive (WIMP...</p>