The 2nd Shanghai Assembly on Cosmology and Structure Formation

Session

Cosmology: probes

Nov 2, 2023, 2:00 PM

Conference Hall (TD Lee Library)

Conveners

Cosmology: probes

• Yi Zheng (SYSU)

Cosmology: probes

• Yu Yu (SJTU)

53. Constructing observables on the sky

Zvonimir Vlah

11/2/23, 2:00 PM

Structure Formation

Talk

I shall first present a novel approach to the flat-sky angular power spectrum approximation, highlighting its comparison to the full-sky formalism and presenting fast and efficient computational methods paramount for the data analysis of upcoming galaxy surveys. I will then construct the 3D galaxy observables like the power spectrum, systematically exploring the projection effects and...

51. On model selection, validation and reconstruction in the context of physical cosmology

Arman Shafieloo (Korea Astronomy and Space Science Institute)

11/2/23, 2:25 PM

Tensions & Challenges

Talk

I revisit the old subject of comparing Bayesian and frequentist approaches in model selection and validation in the context of physical cosmology. I discuss caveats of both approaches dealing with unknowns and how using reliable non-parametric methods of reconstruction can help validating models without comparing them with each other. I discus the importance of this subject in the era of Big...

38. A new marked correlation function scheme for testing gravity

Joaquin Armijo (Kavli IPMU)

11/2/23, 2:50 PM

Inference & Statistics

Talk

We apply the marked correlation function test proposed by Armijo et al. 2023 to samples of luminous red galaxies (LRGs) from the final data release of the Sloan Digital Sky Survey (SDSS) III. The test assigns a density dependent mark to galaxies in the estimation of the projected marked correlation function. Two gravity models are compared: general relativity (GR) and $f(R)$ gravity. We build...

52. Suppressing the sample variance of DESI-like galaxy clustering via fast simulations

Zhejie Ding (Shanghai Jiao Tong University)

11/2/23, 3:05 PM

Inference & Statistics

Talk

The current and forthcoming Stage-IV galaxy surveys are going to map the Unvierse in a large sky area and redshift range. The statistical error will be dramatically reduced, hence, controlling the modelling systematics below the statistical error becomes crucial in the era of precision cosmology. Usually, N-body simulations are adopted to study theoretical systematics of models. In order to...

35. Accurate Kappa Reconstruction Algorithm for masked shear catalog (AKRA) Algorithm

Yuan Shi (SJTU)

11/2/23, 3:20 PM

Inference & Statistics

Talk

Weak gravitational lensing is an invaluable tool for understanding fundamental cosmological physics.
In this study, we introduce the Accurate Kappa Reconstruction Algorithm for masked shear catalog (AKRA), a novel approach that overcomes the limitations in traditional methods and significantly improves the accuracy of the reconstructions. Using simulated experiments, we demonstrate that...

22. Statistics of thermal gas pressure as a probe of cosmology and galaxy formation

Ziyang Chen (SJTU)

11/2/23, 4:05 PM

Inference & Statistics

Talk

The statistics of thermal gas pressure are a new and promising probe of cosmology and astrophysics. The large-scale cross-correlation between galaxies and the thermal Sunyaev-Zeldovich effect gives the bias-weighted mean electron pressure, $\langle b_\mathrm{h}P_e\rangle$. In this paper, we show that $\langle b_\mathrm{h}P_e\rangle$ is sensitive to the amplitude of fluctuations in matter...

11. synergy of RSD and kSZ effects

Yi Zheng (SYSU)

11/2/23, 4:20 PM

Inference & Statistics

Talk

I will talk about the synergy between the RSD and kSZ effects on detecting the cosmic growth history and gas contents within dark matter halos, for the next generation of LSS and CMB surveys.

42. Estimation of line-of-sight velocities of individual galaxies using neural networks I. Modelling redshift space distortion at large scales

Hongxiang Chen (NAOC)

11/2/23, 4:35 PM

Inference & Statistics

Talk

Line-of-sight velocity disturbs the observed spatial positions of galaxies, thereby introducing anisotropies in their observed distribution, which is known as redshift space distortions (RSD). This complication inevitably affects the accurate extraction of important feature of the density field, such as baryonic acoustic oscillations (BAO). In this work, we propose a new scheme based on...

26. Photometric BAO reconstruction

Kwan Chuen Chan (Sun-Yat Sen University)

11/2/23, 4:50 PM

Inference & Statistics

Talk

The reconstruction technique has been widely used to improve the BAO measurement in spectroscopic survey data. In this work, we explore reconstruction of the BAO signals in photometric data. We generalize the standard Zel’dovich reconstruction technique to study the transverse BAO reconstruction in the presence of photo-z uncertainties. The performance of the BAO reconstruction is checked with...