Discussions are made on an alternative interpretation for the Hubble constant of red-shift. The expansion of the space is relaxed to a relative scaling between the space and the matter with gravity. The possible mechanism and results including the energy difference between space and matterd are discussed.
The enigma of the missing baryons poses a prominent and unresolved problem in astronomy. Dispersion measures (DM), serving as a distinctive observable of fast radio bursts (FRBs), quantify the electron column density along each line-of-sight, revealing the missing baryons described in the Macquart (DM-z) relation. The scatter of this relation is anticipated to be caused by the variation of...
This study aims to investigate the properties of host galaxies of Fast Radio Burst (FRB). We begin by extracting FRB event data from the Transient Name Server (TNS), using their sky positions (Right Ascension and Declination) and observed Dispersion Measures (DMs) to identify potential host galaxy candidates. By cross-matching with astronomical catalogs such as SDSS and Gaia, we filter out...
Aims. Cold gas ( $T \sim 10^4$ K) filamentary structures with H$\alpha$ emissions were found around central regions of some
cool-core galaxy clusters. We wish to compare the results
between the observation of the Perseus cluster and our simulation
in order to interpret velocity structures of observed filaments.
Methods. We perform hydrodynamic simulations to trace gas
motions in...
Galaxy clusters are the most massive gravitationally bound systems and represent the most recently formed structures in the Universe under the hierarchical formation model. In this work, we reconstruct the dynamical mass profiles of galaxy clusters from the TNG300 and TNG-Cluster simulations by numerically solving the Jeans equation based on the kinematics of member galaxies. By comparing our...
We present weak lensing shear measurements of two ICM-selected galaxy cluster samples. The cluster samples, RASS-MCMF and ACT-DR5 MCMF, are selected by applying the Multi-Component Matched Filter (MCMF) algorithm to the second ROSAT All-Sky-Survey (RASS) source catalog (2RXS) and the ACT-DR5 dataset, respectively. For the RASS-MCMF catalog, 171 out of 8449 clusters within the redshift range...
Previous studies have investigated the quenching mechanisms of quiescent galaxies at high redshift. However, due to limitations in angular resolution and sample size, the underlying processes remain poorly understood. In this study, as an initial step, we aim to explore the quenching process by analyzing the spatially resolved color profiles of quiescent galaxies at $z > 3$ using data from...
The interstellar medium (ISM) is inherently non-uniform. The inhomogeneous structures on both large and small scales influence the propagation of EM waves. Theoretical studies and simulations of the ISM are typically performed on parsec-scale resolution, yet, structures on AU or sub-AU scales are not well explored. Pulsar scintillation is a powerful probe of the small scale structures...
The interstellar medium (ISM) is fundamental to star formation and galaxy evolution, with dust serving as a pivotal regulator of various astrophysical processes. Yet, the mechanisms driving dust evolution in stellar feedback–dominated environments remain elusive. While photoionization feedback from massive stars—responsible for generating HII regions and reshaping the ISM’s structure and...
In this project, our goal is to measure the stellar mass function of galaxy clusters selected in X-rays in the eROSITA Final Equatorial Depth Survey (eFEDS), which is the deepest X-ray survey over a contiguous footprint.
The sample consists of galaxy clusters spanning a mass range of $10^{13}\,h^{-1}M_\odot \leq M \leq 10^{15}\,h^{-1}M_\odot$, and a redshift range of $0.1 < z_{\mathrm{cl}} <...
Galaxy interactions play a crucial role in the evolution of galaxies in the local universe, often triggering enhanced star formation. Simulations consistently suggest that such interactions significantly reshape the distribution of molecular gas within galactic disks, thereby altering the spatial distribution of star formation. In this study, we aim to observationally investigate the...
The cosmic infrared background (CIB) originated from reprocessed dust emission after dust in galaxies absorbs the UV light from young massive stars and accreting supermassive blackholes. Resolving the diffuse CIB into individual galaxies provides insights into the cosmic star-forming activities that are obscured at the optical wavelength. Previous studies have constructed number counts of...
Fast Radio Bursts (FRBs) are millisecond-duration radio wave transients that emit enormous energy with unknown origins. In this project, we aim to constrain the environment of galaxies hosting FRBs by measuring their cross correlations with other populations of galaxies. To explore the methodology, we construct realistic mock catalogs of FRBs and galaxies using a semi-analytical method.
To...
