首页

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>

2023.12.26

The “Missing baryons” in the cosmic web—what is it? Where is it? How much?

<p>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...</p>

2023.12.01

The UV luminosity function at 0.6 < z < 1 from UVCANDELS

<p>UVCANDELS is a HST Cycle-26 Treasury Program awarded 164 orbits of primary ultraviolet (UV) F275W imaging and coordinated parallel optical F435W imaging in four CANDELS fields: GOODS-N, GOODS-S, EGS, and COSMOS, covering a total area of ～426 arcmin^2. This is ～2.7 times larger than the area covered by previous deep-field space UV data combined, reaching a depth of about 27 and 28 ABmag (5 \si...</p>

2023.11.24

Directly detecting dark matter and neutron stars with gravitational waves

<p>The third observing run of advanced LIGO, Virgo and KAGRA brought unprecedented sensitivity towards a variety of quasi-monochromatic, persistent gravitational-wave signals. Continuous waves allow us to probe not just the canonical asymmetrically rotating neutron stars, but also different forms of dark matter, thus showing the wide-ranging astrophysical implications of using a relatively simple ...</p>

2023.11.27

Multi-Messenger Probes on Dark Matter Beyond WIMPs

<p>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...</p>

2023.11.24

Tidal Disruption Events: Probes of Accretion Physics and Black Hole Demographics

<p>Tidal disruption events (TDEs) provide unique laboratories to&nbsp;study the demographics, immediate stellar and gaseous environments, and&nbsp;accretion physics of the massive black hole population. Over the past&nbsp;few years, time domain sky surveys such as the optical Zwicky Transient&nbsp;Facility (ZTF) have led to a surge of TDE discoveries in galaxy centers.&nbsp;This talk highlights our efforts to constrain th...</p>

2023.11.14

The star formation, dust, and abundance of galaxies with CIB cross-correlations

<p>The cosmic infrared background (CIB) is the accumulated infrared radiation mainly generated from dust emissions in star-forming galaxies. It bears rich information about star formation history, dust thermodynamics, and galaxy abundance in the distant Universe. The CIB auto- and cross-correlations with other large-scale structure (LSS) tracers have been used to probe the star formation, dust, an...</p>

2023.11.21

A two-phase model of galaxy formation: the growth of galaxies and supermassive black holes

<p>I will describe a model for galaxy formation and&nbsp;the growth of supermassive black holes (SMBHs), based on the fact that cold dark&nbsp;matter halos form their gravitational potential wells through a fast phase with rapid change&nbsp;in the potential, and that the high universal baryon fraction makes cooled gas in halos self-gravitating&nbsp;and turbulent before it can form rotation-supported disks. Gas fragme...</p>