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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>

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>

2023.12.22

The three regimes of atmospheric evaporation for super-Earths and sub-Neptunes

<p>A significant fraction of super-Earths and sub-Neptunes are thought to experience an extreme loss of volatiles because of atmospheric evaporation in the early stages of their life. Though the mechanisms behind the extreme mass loss are not fully understood, two contenders have been widely discussed: photoevaporation from X-ray and ultraviolet irradiation and core powered mass loss. In this talk...</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>

2023.12.19

A New AGN Photoionization Model and Multi-wavelength Metallicity Diagnostics

<p>The photoionization model of narrow-line regions (NLRs) in active galactic nuclei (AGNs) has been investigated for decades. Many published models are restricted to simple linear scaling abundance relations, dust-free assumption, uniform AGN radiation field, and using one specific photoionization code, which restricts them from providing a satisfactory prediction on a broad range of AGN observa...</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>

2023.12.15

Bridging the gap between luminous red novae and common envelope evolution with radiation hydrodynamic models

<p>Luminous red novae (LRNe) are relatively new transients that have the luminosity between classic novae and supernovae, initially classified as &quot;gap transients&quot;. Even though many more &quot;gap transients&quot; have been observed by telescopes such as ZTF and Keck, their origin and physical processes remain mysterious. To initiate the study of the nature of LRNe, I built a 1D and 2D radiation hydrodynamic...</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>

2023.12.12

Cross-correlation between the Thermal Sunyaev–Zeldovich Effect and the Integrated Sachs–Wolfe Effect

<p>Understanding the composition and distribution of baryonic matter in the Universe is a crucial step toward unraveling the mysteries of its formation and evolution. Early estimates and numerical simulations show that most baryons are “missing,” whereas the baryons that are already made into stars and galaxies constitute a small portion of the total baryon budget. Therefore accurate constraints...</p>

2023.12.05

Reconstruction of Cosmological Initial Density Field with Observations from the Epoch of Reionization

<p>Initial density distribution provides a basis for understanding the complete evolution of cosmological density fluctuations. While reconstruction in our local Universe exploits the observations of galaxy surveys with large volumes, observations of high-redshift galaxies are performed with a small field of view and therefore can hardly be used for reconstruction. Here we propose to reconstruct t...</p>