A5034455604- Cosmology and Gravitation Theories
- Galaxies: Formation, Evolution, Phenomena
- Radio Astronomy Observations and Technology
- Dark Matter and Cosmic Phenomena
- Geophysics and Gravity Measurements
- Black Holes and Theoretical Physics
- Particle physics theoretical and experimental studies
- Gamma-ray bursts and supernovae
- Computational Physics and Python Applications
- Superconducting and THz Device Technology
- Astrophysical Phenomena and Observations
- Pulsars and Gravitational Waves Research
- Solar and Space Plasma Dynamics
- Radio, Podcasts, and Digital Media
- Astrophysics and Cosmic Phenomena
- Climate variability and models
- Astronomy and Astrophysical Research
Korea Astronomy and Space Science Institute
2023-2025
Korean Association for the Study of Intestinal Diseases
2025
Université Paris Cité
2025
Laboratoire AstroParticule et Cosmologie
2025
University of Cambridge
2019-2023
Abstract We implement Crossing Statistics to reconstruct in a model-agnostic manner the expansion history of universe and properties dark energy, using DESI Data Release 1 (DR1) BAO data combination with one three different supernova compilations (PantheonPlus, Union3, DES-SN5YR) Planck CMB observations. Our results hint towards an evolving emergent energy behaviour, negligible presence at z ≳ 1, varying significance depending on sets combined. In all these reconstructions, cosmological...
Baryon acoustic oscillation data from the first year of Dark Energy Spectroscopic Instrument (DESI) provide near percent-level precision cosmic distances in seven bins over redshift range $z=0.1$-$4.2$. We use this data, together with other distance probes, to constrain expansion history using some well-motivated physical classes dark energy. In particular, we explore three physics-focused behaviors energy equation state and density perspectives: thawing class (matching many simple...
Abstract In this paper, we present the first comprehensive CMB data analysis of cosmological collider physics. New heavy particles during inflation can leave imprints in primordial correlators which are observable today's surveys. This remarkable detection channel provides an unsurpassed opportunity to probe new physics at extremely high energies. Here initiate search for these relic signals cosmic microwave background (CMB) from Planck legacy release. On theory side, guided by recent...
We implement Crossing Statistics to reconstruct in a model-agnostic manner the expansion history of universe and properties dark energy, using DESI Data Release 1 (DR1) BAO data combination with one three different supernova compilations (PantheonPlus, Union3, DES-SN5YR) Planck CMB observations. Our results hint towards an evolving emergent energy behaviour, negligible presence at $z\gtrsim 1$, varying significance depending on sets combined. In all these reconstructions, cosmological...
Abstract Using Gaussian Processes we perform a thorough, non-parametric consistency test of the ΛCDM model when confronted with state-of-the-art TT, TE, and EE measurements anisotropies in Cosmic Microwave Background by Planck , ACT, SPT collaborations. ΛCDM's best-fit predictions to TTTEEE data from find no statistically significant deviations looking for signatures residuals across different datasets. The results are good agreement data, while ACT only marginally consistent. However, using...
We present a transfer function-based method to estimate angular power spectra from filtered maps for cosmic microwave background (CMB) surveys. This is especially relevant experiments targeting the faint primordial gravitational wave signatures in CMB polarisation at large scales, such as Simons Observatory (SO) small aperture telescopes. While timestreams can be mitigate contamination low-frequency noise, usual methods that calculate mode coupling individual multipoles challenging covering...
We present a new independent pipeline for the Cosmic Microwave Background bispectrum estimation of primordial non-Gaussianity and release public code constraining shapes interest based on Planck 2018 temperature polarization data. The estimator combines strengths conventional Komatsu-Spergel-Wandelt modal estimators at cost increased computational complexity, which has been made manageable through intensive algorithmic implementation optimization. also detail some methodological advances in...
ABSTRACT We present a novel methodology for exploring local features directly in the primordial power spectrum using genetic algorithm pipeline coupled with Boltzmann solver and Cosmic Microwave Background data (CMB). After testing robustness of our mock data, we apply it to latest CMB including Planck 2018 CamSpec PR4. Our model-independent approach provides an analytical reconstruction spectra that best fits unsupervised machine learning functional space built off simple ‘grammar’...
Abstract While the simplest inflationary models predict primordial perturbations to be near scale-invariant, power spectrum (PPS) can exhibit oscillatory features in many physically well-motivated models. We search for hints of such via free-form reconstructions PPS based on Planck 2018 CMB temperature and polarization anisotropies. In order robustly invert integrals handle noisy unbinned data, we draw inspiration from image analysis techniques. previous works, Richardson-Lucy deconvolution...
Abstract We present the first direct constraints on a Degenerate Higher Order Scalar Tensor (DHOST) inflation model using Planck 2018 Cosmic Microwave Background (CMB) results non-Gaussianities. identify that bispectrum consists of fixed contribution following from power spectrum and linear combination terms depending five free parameters defining cubic perturbations to DHOST model. The former peaks in squeezed limit, while latter is maximised equilateral limit. directly confront predictions...
We present forecasts on the primordial non-Gaussianity parameter ${f}_{\mathrm{NL}}$ of feature models for future Cosmic Microwave Background Stage-4 (CMB-S4) experiments. The Fisher matrix bispectrum estimator was computed using noise covariances expected preliminary CMB-S4 specifications including ones Simons Observatory. introduce a novel method that improves computation by orthonormalizing covariance matrix. most sensitive experiment with 1' beam and $1\text{ }\text{...
Abstract Strong gravitational lensed quasars (QSOs) have emerged as powerful and novel cosmic probes they can deliver crucial cosmological information, such a measurement of the Hubble constant, independent other probes. Although upcoming LSST survey is expected to discover 10 3 –10 4 QSOs, large fraction will remain unresolved due seeing. The stochastic nature quasar intrinsic flux makes it challenging identify measure time delays using light-curve data only. In this regard, Bag et al....
In this paper, we present the first comprehensive CMB data analysis of cosmological collider physics. New heavy particles during inflation can leave imprints in primordial correlators which are observable today's surveys. This remarkable detection channel provides an unsurpassed opportunity to probe new physics at extremely high energies. Here initiate search for these relic signals cosmic microwave background (CMB) from Planck legacy release. On theory side, guided by recent progress...
Using Gaussian Processes we perform a thorough, non-parametric consistency test of the $\Lambda$CDM model when confronted with state-of-the-art TT, TE, and EE measurements anisotropies in Cosmic Microwave Background by Planck, ACT, SPT collaborations. $\Lambda$CDM's best-fit predictions to TTTEEE data from find no statistically significant deviations looking for signatures residuals across different datasets. The results are good agreement Planck data, while ACT only marginally consistent....
While the simplest inflationary models predict primordial perturbations to be near scale-invariant, power spectrum (PPS) can exhibit oscillatory features in many physically well-motivated models. We search for hints of such via free-form reconstructions PPS based on \textit{Planck} 2018 CMB temperature and polarization anisotropies. In order robustly invert integrals handle noisy unbinned data, we draw inspiration from image analysis techniques. previous works, Richardson-Lucy deconvolution...
We present a new independent pipeline for the CMB bispectrum estimation of primordial non-Gaussianity and release public code constraining shapes interest based on Planck 2018 temperature polarization data. The estimator combines strengths conventional KSW Modal estimators at cost increased computational complexity, which has been made manageable through intensive algorithmic implementation optimization. also detail some methodological advances in numerical integration over tetrapyd - domain...
We present a novel methodology for exploring local features directly in the primordial power spectrum using genetic algorithm (GA) pipeline coupled with Boltzmann solver and Cosmic Microwave Background data (CMB). After testing robustness of our mock data, we apply it to latest CMB including Planck 2018 CamSpec PR4. Our model-independent approach provides an analytical reconstruction spectra that best fits unsupervised machine learning functional space built off simple ``grammar'' functions....
We present the first direct constraints on a Degenerate Higher Order Scalar Tensor (DHOST) inflation model using Planck 2018 Cosmic Microwave Background (CMB) results non-Gaussianities. identify that bispectrum consists of fixed contribution following from power spectrum and linear combination terms depending five free parameters defining cubic perturbations to DHOST model. The former peaks in squeezed limit, while latter is maximised equilateral limit. directly confront predictions CMB...
Strong gravitational lensed quasars (QSOs) have emerged as powerful and novel cosmic probes they can deliver crucial cosmological information, such a measurement of the Hubble constant, independent other probes. Although upcoming LSST survey is expected to discover $10^3-10^4$ QSOs, large fraction will remain unresolved due seeing. The stochastic nature quasar intrinsic flux makes it challenging identify ones measure time delays using light curve data only. In this regard, Bag et al (2022)...