Institute of Astronomy and Astrophysics, Academia Sinica

Why Azimuthal Averaging Works in Halo Lensing: Symmetry and Power Counting for Nonlinear Shear and Magnification

Keiichi Umetsu

Cluster weak-lensing analyses often compress two-dimensional lensing fields into azimuthally averaged radial profiles and evaluate nonlinear observables from the averaged convergen…

A Universal Relation Between Primordial Density-Potential Cross-correlation Coefficient and Spin Factor Distribution

Jun-Sung Moon, Jounghun Lee, Juhan Kim

Recent studies have revealed that the key properties of visible galaxies like their optical sizes, stellar ages, star formation rates and morphologies are closely linked with the a…

Merging Galaxy Clusters and the Search for New Physics of Dark Matter: A Review

Rogério Monteiro-Oliveira

Merging galaxy clusters represent one of the most powerful macroscopic laboratories in the Universe for searching for new physics within the dark sector. High-velocity cosmic colli…

CLASH-VLT: The Fifth Force in Chameleon Gravity from Joint Lensing and Kinematics Cluster Mass Profiles

Lorenzo Pizzuti, Federico Rivano, Keiichi Umetsu +1

We present a high-precision joint gravitational-lensing and kinematic analysis of nine massive galaxy clusters from the CLASH and CLASH-VLT surveys to test chameleon screening grav…

Clustering of emission line galaxies with IllustrisTNG -- II. cosmology challenge with anisotropic correlation functions and ELG-halo connections

Ken Osato, Teppei Okumura

Emission line galaxies (ELGs) are the primary tracers of the large-scale structures of the Universe in ongoing Stage-IV cosmological spectroscopic surveys, which aim to measure the…

Catalogs of optically-selected clusters and photometric luminous red galaxies from the Hyper Suprime-Cam Subaru Strategic Program final year dataset

Masamune Oguri, Yen-Ting Lin, Nobuhiro Okabe +9

We construct samples of optically-selected clusters and photometric luminous red galaxies (LRGs) from the Hyper Suprime-Cam Subaru Strategic Program final year dataset covering $\s…

A high-significance detection of primordial tidal torque imprints

Ming-Jie Sheng, Hao-Ran Yu, Min Bao +8

Tidal-torque theory predicts that galaxy angular momenta are imprinted by the primordial tidal field acting on proto-structures and that they can retain information about the early…

The eROSITA Final Equatorial-Depth Survey (eFEDS): X-ray stacking analysis of Subaru's optically selected clusters spanning low richness regime

N. T. Nguyen-Dang, N. Ota, N. Okabe +17

This is the second paper in a series exploring the X-ray properties of galaxy clusters optically selected by the Subaru Hyper Suprime-Cam (HSC) survey, using data from the SRG/eROS…

The Binary Ballet: Mapping Local Expansion Around M81 & M82

Jenny Wagner, David Benisty, Igor D. Karachentsev

This study of the M81 complex and its Hubble flow delivers new and improved Tip of the Red Giant Branch (TRGB)-based distances for nine member galaxies, yielding a total of 58 gala…

Luminosity-Dependent Assembly Bias of Central Galaxies from Weak Lensing and Clustering

Zhenjie Liu, Hironao Miyatake, Joop Schaye +3

Assembly bias, which is the variation in halo clustering at fixed mass driven by formation history, has long been predicted by numerical simulations but remains difficult to confir…

astro-ph.CO2025★ 4 cited

Fuzzy dark matter simulations

Hsi-Yu Schive

Fuzzy dark matter (FDM), composed of ultralight bosons, exhibits intricate wave phenomena on galactic scales. Compared to cold dark matter, FDM simulations are significantly more c…

Evidence for Intrinsic Galaxy Alignments in Ellipticity Autocorrelations out to $100 h^{- 1} Mpc$ from SDSS Galaxies with DESI Imaging

Teppei Okumura

Measuring the autocorrelation of galaxy shapes, known as the intrinsic-intrinsic (II) correlation, is important for both cosmology and understanding the formation of massive ellipt…

CHEX-MATE: Cluster Multi-Probes in Three Dimensions (CLUMP-3D) II. Combined Gas and Dark Matter Analysis from X-ray, SZE, and WL

Adriana Gavidia, Junhan Kim, Jack Sayers +15

Under the standard model of hierarchical structure formation, the overall geometry of galaxy clusters is better described by a triaxial ellipse than a sphere. As a result, applying…

astro-ph.CO2025★ 3 cited

Simulating a Gaussian stochastic gravitational wave background signal in pulsar timing arrays

Reginald Christian Bernardo, Kin-Wang Ng

We revisit the theoretical modeling and simulation of a Gaussian stochastic gravitational wave background (SGWB) signal in a pulsar timing array (PTA). We show that the correlation…

astro-ph.CO2025★ 2 cited

Galaxy cluster count cosmology with simulation-based inference

M. Regamey, D. Eckert, R. Seppi +4

The abundance and mass distribution of galaxy clusters is a sensitive probe of cosmological parameters, through the sensitivity of the high-mass end of the halo mass function to $Ω…

Infalling ultra-faint dwarfs as emissaries of the Axiverse

A. Pozo, T. Broadhurst, H. N. Luu +8

Recent discoveries of ultra-faint dwarf galaxies (UFDs) infalling onto the Milky Way, namely Leo K \& M at $r ≃ 450$ kpc, considerably strengthens the case that UFDs constitute…

Probing dipolar power asymmetry with galaxy clustering and intrinsic alignments

Keita Minato, Atsushi Taruya, Teppei Okumura +1

We investigate the prospects for probing large-scale statistical anisotropy through galaxy clustering and intrinsic alignments (IA) in Stage IV galaxy surveys. Specifically, we con…

Robustness of pairwise kinematic Sunyaev-Zel'dovich effect to optical-cluster-selection bias

Y. -H. Hsu, D. Gruen, P. A. Gallardo +5

The pairwise kinematic Sunyaev-Zel'dovich(kSZ) effect measures both the pairwise motion between galaxy groups and clusters and the amount of gas within them, providing a tracer for…

astro-ph.CO2025★ 8 cited

TDCOSMO XVII. New time delays in 22 lensed quasars from optical monitoring with the ESO-VST 2.6m and MPG 2.2m telescopes

Frédéric Dux, Martin Millon, Aymeric Galan +29

We present new time delays, the main ingredient of time delay cosmography, for 22 lensed quasars resulting from high-cadence r-band monitoring on the 2.6 m ESO VLT Survey Telescope…