Research
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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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2023.12.18
Electromagnetic fireworks from erupting magnetars
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...
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2023.12.18
Probing Parity with Galaxy Distributions and Beyond
Galaxies' 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...
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2023.11.27
Multi-Messenger Probes on Dark Matter Beyond WIMPs
We will discuss two promising dark matter scenarios: axion-like particle dark matter and primordial black hole dark matter. We begin with radio telescope probes on axion-like dark matter. We will discuss the axion-photon conversion around neutron stars which results in the radio emission and the 21 cm probes through the effects on large scale structure formation suppression. We then turn our at...
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