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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>

2024.12.06

Investigating the Squeezed Limit of Primordial Non-Gaussianity: New Constraints from CMB Anisotropies [EN]

<p>The Primordial non-Gaussianity provides fundamental insights into the early Universe and constitutes a crucial area of research in contemporary cosmology. Recently, we extended the cosmological analysis presented in Ibitoye2024 beyond the intergalactic medium (IGM) to investigate the primordial non-Gaussianity parameter (f^0_NL) in the squeezed limit, using the auto- and cross-power spectra of ...</p>

2024.12.04

Imaging Giant Planet Formation [EN]

<p>The new generation of infrared high-contrast imagers and sub-mm interferometer has been revolutionising our view of planet formation for the last decade. Protoplanetary discs have now been imaged at a high level of detail, revealing a wealth of structures including cavities, annular gaps, spiral arms, shadows and asymmetries. In order to connect these structures to forming planets and provide t...</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>

2024.11.29

The research of dark matter halos with galaxy-galaxy lensing method

<p>In the standard LambdaCDM cosmological framework, cosmic structures grow through a hierarchical process. As fundamental building blocks of the dark matter universe, halos are believed to follow a self-similar structure distribution. Thus, we could stacking the weak lensing signal of multiple halos with the galaxy-galaxy lensing (gglens) method, and obtain the average profile of halos. (A.) With...</p>

2024.11.22

On the Role of Structural Bimodality on Galaxy Quenching in Local Universe [EN]

<p>Observations have shown that the termination of the star-forming activity in galaxies (quenching of star formation) is closely related to the structure of the galaxies, in the sense that passive galaxies tend to possess more compact structure. The surface mass density in the core region effectively describes the compactness of galaxies, and therefore have served to be one of the most sensitive ...</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>