科学研究
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2023.12.29
Solutions towards the Hubble tension and S8 tension
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...
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2023.12.29
The lively radio transient sky
Making use of exponential increases in computing power, radio astronomers have been able to search larger areas of the sky at high time and frequency resolution. These surveys facilitate the studies of radio transients, particularly contributing to the thriving investigation of fast radio bursts (FRBs), enigmatic radio bursts observable at cosmological distances. I will provide an overview of t...
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2023.12.26
The “Missing baryons” in the cosmic web—what is it? Where is it? How much?
Previous studies of galaxy formation have shown that only 10 per cent of the cosmic baryons are in stars and galaxies, while 90 per cent of them are missing. In this talk, I will present several observational studies that coherently find significant evidences of the missing baryons. The first measurement is the cross-correlation between the thermal Sunyaev-Zeldovich effect with gravitational le...
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2023.12.25
A cooling anomaly of white dwarfs
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...
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2023.12.25
Constraining the Cosmic Partition of IGM and CGM Baryons with FRB Foreground Mapping
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 spectroscopic observations of foreground galaxies, the information content is enhanced. The wide-field data (∼10s of Mpc scales) allows us to reconstruct the u...
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