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2024.03.19

Can we test cosmic homogeneity and isotropy?

<p>The Cosmological Principle (CP) was a major achievement of modern cosmology to turn qualitative statements into quantitative ones. It makes the strong assumption that space is globally homogeneous and isotropic. By doing so, it reduces Einstein’s Field Equations to provide highly symmetric cosmological models. The latter then enable us to interpret a very sparse amount of data and put them int...</p>

2024.03.22

4MOST Galactic pipeline: radial velocity and pysme stellar parameters

<p>The 4-m Multi-Object Spectroscopic Telescope (4MOST) is one of the ESO community survey with a large field-of-view to survey the southern sky in a few years, delivering spectra for ≥25 million objects over ≥15 000 square degrees in R~6000 and R~20000. 4MOST is currently in its manufacturing, assembly, integration and test phase with an expected start of full science operations within a year. ...</p>

2024.03.12

A decelerating bar in the Galaxy

<p>The bar of the Galaxy is believed to slow down. We use an axisymmetric background potential plus a central bar model to perform the test particle simulations in order to investigate the possible origin of the phase space spirals and the thin-disc-like low-metallicity stars (VMPs). The Gaia data reveal a two-armed phase spiral pattern in the local &nbsp;plane inside the solar radius. On the contrary,...</p>

2024.03.15

The Merian Survey: Characterizing dark matter and feedback in star-forming dwarf galaxies with medium-band filters on DECam

<p>The Merian survey is an ongoing medium-band imaging survey on the CTIO 4-meter Blanco telescope. With two new medium-band filters on DECam, we expect to detect ~100,000 star-forming dwarf galaxies at z~0.1 in the HSC-SSP wide field (~800 deg^2), aiming to characterize dark matter halo and stellar feedback in dwarf galaxies. The Merian survey will allow us to measure the full dark matter profile...</p>

2024.03.05

Towards a Unified Model of Dwarf Galaxy Star Formation and Halo Connection with UniverseMachine

<p>Dwarf galaxies provide rich constraints on galaxy formation, reionization, and the nature of dark matter. However, flexible models of their star formation histories in a cosmological context are lacking. We introduce a novel framework for connecting dwarf galaxy dark matter assemblies and star formation histories based on the empirical model UniverseMachine (UM). Our framework is flexible, such...</p>

2024.03.08

Pathway to high-z SMBHs: seed formation and growth in the statistical perspective

<p>The early evolution of the black hole mass function (BHMF) and quasar luminosity function (QLF) encodes key information on the physics determining the radiative and accretion processes of black holes (BHs) growing in high-redshift galaxies. Starting from the formation of seed BHs as their parent halos evolve, we study primordial gas collapse in the biased quasar host halos, computing gas chemic...</p>

2024.02.28

Weak Lensing Without Shape Noise

<p>Weak gravitational lensing imprints a coherent distortion onto the observed shapes of distant galaxies. At the image level, this gravitational shear degenerates with the intrinsic shape of galaxies, and the weak lensing signal-to-noise from an individual galaxy is of order 0.01. I will describe Kinematic Lensing, a new technique combining imaging and galaxy kinematics to measure weak lensing wi...</p>

2024.06.20

Towards a Unified Story for Planet Formation

<p>While the exoplanetary field is replete with remarkable discoveries, perhaps the two most intriguing findings have been the detection of hot Jupiters – giant planets orbiting perilously close to their parent stars, and the startling abundance of super-Earths. The mere existence of these worlds was wholly unpredicted based on the expectations that were gleaned from centuries of observation of o...</p>

2024.06.13

Weak lensing cosmology beyond two-point shear correlations

<p>With the fast development of high-precision large photometric surveys, weak lensing (WL) effects have become one of the major probes in cosmology. While the two-point shear correlations are the most extensively employed analyses, other statistics beyond that are desired because of the non-Gaussian nature of cosmic structures. In this presentation, I will discuss the cosmological application of ...</p>

2024.06.06

From Subaru to WFST: The Past, Present, and Future of Fast Transient Studies

<p>Transients with fast brightness variance in UV/optical wavelengths (&quot;fast transients,&quot; such as early-phase supernovae, fast blue optical transients, kilonovae) are of great interest in astronomy. Although great progresses in time-domain astronomy have been made via wide, shallow, and day(s)-cadence surveys, the limited observing depth and low time resolution make traditional time-domain surveys...</p>