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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>

2024.12.11

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>

2024.12.04

Emulating Extended Lyman Alpha Halos Around Star-Forming Galaxies [EN]

<p>The detection of the extended Lyman-alpha emission (or Lyman-alpha halos) around star-forming galaxies opens a new window for probing the circum-galactic medium (CGM) at high redshifts. With IFU observations (e.g., through MUSE), we are already capable of measuring the spatially resolved Lya spectra around individual galaxies, revealing a diverse population of the Lya emission. However, interpr...</p>

2024.11.27

Five parameters are all you need [EN]

<p>The standard cosmological model (ΛCDM) relies on six free parameters, five of which have direct cosmological origins, while the sixth, the optical depth (τ), is an ad hoc parameter used to model the scattering effects experienced by cosmic microwave background (CMB) photons. CMB photons decoupled from the primordial plasma at z ~ 1100 when neutral hydrogen formed, reducing the abundance of fr...</p>

2024.11.20

Estimating and Studying Dust Attenuation From Galactic Spectra [EN]

<p>In the past few years, we develop a method to estimate the dust attenuation curve of galaxies from full optical spectral fitting. One important advantage of this method is that the estimated dust attenuation curve is independent of the shape of theoretical dust attenuation curves. Based on the method, we investigate the dust attenuation in both stellar populations and ionized gas in kpc-scale r...</p>

2024.11.13

Two Bridges in Galaxy Ecosystem: Star – InterStellar Medium Interaction and Observation – Theory Connection [EN]

<p>The increasing sophistication of research and data quality has revealed a complex interplay between the internal and external environments of galaxies. While galaxies are demonstrably connected to their cosmic ecosystems, their interiors are also comprised of diverse components with intricate interactions, forming a &quot;galaxy ecosystem&quot;. Stars and the interstellar medium (ISM) are two crucial con...</p>

2024.11.06

Breeding seeds to grow supermassive black holes in the cosmological context: theory and semi-analytical forecasts

<p>Supermassive black holes (SMBHs) are indispensable components of galaxy ecosystems. Their origin, growth, and feedback to the host galaxies are among the most fundamental questions in galaxy formation. In this talk, I will introduce a theoretical framework that coherently describes the formation of SMBHs from their seeding epoch to the present within the cosmological context. I will show that t...</p>

2024.10.30

Constraints on the tensor-to-scalar ratio r via a likelihood-based, optimal lensing reconstruction

<p>The cosmic microwave background (CMB) holds valuable information about the early Universe, including an imprint of its mass distribution that overshadows the faint signal from primordial gravitational waves, likely generated during inflation. Removing this imprint is crucial for future CMB observations to tightly constrain the tensor-to-scalar ratio r. This talk focuses on achieving the tightes...</p>

2024.10.23

The influence of GC evolution on the specific frequency in dwarf galaxies

<p>The presence of large fractions of metal-poor stars in dwarf galaxies still belonging to GCs raises questions about cluster mass loss and their formation mechanisms. These high ratios of metal-poor GCs relative to the number of low-metallicity field stars could imply that clusters in dwarfs have not lost enough mass, compared to more massive galaxies, or that the formation of field stars was su...</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>