科学研究
-
2024.03.26
Primordial non-Gaussianity (PNG) and Its Detection by Cosmolgical Surveys
The simplest single-field inflation models predict a nearly Gaussian distribution of primordial density perturbations. However, the non-Gaussianity of the primordial density field serves as a powerful probe into the physics of the early universe, especially when considering more complex inflation models. The Cosmic Microwave Background (CMB) bispectrum has provided the tightest constraint on th...
详情 -
2024.03.22
4MOST Galactic pipeline: radial velocity and pysme stellar parameters
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. ...
详情 -
2024.03.21
Interstellar X-ray Dust Scattering: Current Research and Future Prospects
Our Universe is pervaded with X-ray sources. When X-ray photons traverse through interstellar space, they can be scattered by dust particles floating in space, producing scattering rings and halos around X-ray sources. This scattering effect can be used to study the distribution of interstellar dust, as well as the size distribution, composition and structure of dust grains. It also affects the...
详情 -
2024.03.20
AGN selection and demographics: a new age with JWST/MIRI
Completing the census of active galactic nuclei (AGN) activity is the key to study the build-up of supermassive black holes (SMBHs) and understand their relations with the host galaxy properties. Nevertheless, many AGNs are obscured by dust and gas, making the identification of such systems a challenging task even today. In this talk, I will present the first results on the AGN identifications ...
详情 -
2024.03.19
Can we test cosmic homogeneity and isotropy?
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...
详情