A5070581589- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Music Technology and Sound Studies
- Cosmology and Gravitation Theories
- Radio Astronomy Observations and Technology
- Astrophysics and Cosmic Phenomena
- Scientific Research and Discoveries
- Stellar, planetary, and galactic studies
- Geophysics and Gravity Measurements
- Astronomical Observations and Instrumentation
- Dark Matter and Cosmic Phenomena
- Computational Physics and Python Applications
- Astrophysical Phenomena and Observations
- Gamma-ray bursts and supernovae
- Solar and Space Plasma Dynamics
- Geomagnetism and Paleomagnetism Studies
University of Zurich
2022-2025
University of Waterloo
2019-2022
Scuola Internazionale Superiore di Studi Avanzati
2017-2019
Istituto Nazionale di Fisica Nucleare, Sezione di Trieste
2017-2019
Istituto Nazionale di Fisica Nucleare
2017-2019
[Abridged] We study the abundance and clustering properties of HI at redshifts $z\leqslant5$ using TNG100, a large state-of-the-art magneto-hydrodynamic simulation 75 Mpc/h box size. show that most lies within dark matter halos quantify average mass hosted by M redshift z. find only with circular velocities larger than $\simeq$ 30 km/s contain HI. While density profiles exhibit halo-to-halo scatter, mean are universal across redshift. The in low-mass is mostly located central galaxy, while...
This white paper envisions a revolutionary post-DESI, post-LSST dark energy program based on intensity mapping of the redshifted 21cm emission line from neutral hydrogen at radio frequencies. The proposed survey has unique capability to quadruple volume Universe surveyed by optical programs, provide percent-level measurement expansion history $z \sim 6$, open window explore physics beyond concordance $Λ$CDM model, and significantly improve precision standard cosmological parameters. In...
The Quijote simulations are a set of 44,100 full N-body spanning more than 7,000 cosmological models in the $\{\Omega_{\rm m}, \Omega_{\rm b}, h, n_s, \sigma_8, M_\nu, w \}$ hyperplane. At single redshift contain 8.5 trillions particles over combined volume $(h^{-1}{\rm Gpc})^3$; each simulation follow evolution $256^3$, $512^3$ or $1024^3$ box $1~h^{-1}{\rm Gpc}$ length. Billions dark matter halos and cosmic voids have been identified simulations, whose runs required 35 million core hours....
We present evidence of anisotropic galaxy assembly bias in the Baryon Oscillation Spectroscopic Survey Data Release 12 sample at a level exceeding 5σ. use measurements line-of-sight velocity dispersion σ⋆ and stellar mass M⋆ to perform simple split into subsamples galaxies. show that amplitude monopole quadrupole moments power spectrum depend differently on M⋆, allowing us subsets with matching monopoles but significantly different quadrupoles all scales. Combining data from LOWZ CMASS NGC...
We use an analytical forward model based on perturbation theory to predict the neutral hydrogen (HI) overdensity maps at low redshifts. investigate its performance by comparing it directly field level simulated HI from IllustrisTNG magneto-hydrodynamical simulation TNG300-1 ($L=205\text{ }\text{ }{h}^{\ensuremath{-}1}\text{ }\mathrm{Mpc}$), in both real and redshift space. demonstrate that is a biased tracer of underlying matter find cubic bias describes power spectrum within 1% up...
We investigate the possibility of performing cosmological studies in redshift range $2.5<z<5$ through suitable extensions existing and upcoming radio-telescopes like CHIME, HIRAX FAST. use Fisher matrix technique to forecast bounds that those instruments can place on growth rate, BAO distance scale parameters, sum neutrino masses number relativistic degrees freedom at decoupling, $N_{\rm eff}$. point out quantities depend amplitude 21cm power spectrum, $f\sigma_8$, are completely degenerate...
We combine information from the clustering of HI galaxies in 100% data release Arecibo Legacy Fast ALFA survey (ALFALFA), and content optically-selected galaxy groups found Sloan Digital Sky Survey (SDSS) to constrain relation between halo mass $M_h$ its average total $M_{\rm HI}$. model abundance neutral hydrogen through a halo-model-based approach, parametrizing HI}(M_h)$ as power law with an exponential cutoff. To break degeneracy amplitude low-mass cutoff relation, we also include recent...
We explore full-shape analysis with simulation-based priors, which is the simplest approach to galaxy clustering data that combines effective field theory (EFT) on large scales and numerical simulations small scales. The core ingredient of our prior density EFT parameters we extract from a suite 10500 based halo occupation distribution (HOD) model. measure field-level forward model, enables us cancel cosmic variance. On side, develop new efficient calculate transfer functions using...
Gravitational non-linear evolution induces a shift in the position of baryon acoustic oscillations (BAO) peak together with damping and broadening its shape that bias degrades accuracy which can be determined. BAO reconstruction is technique developed to undo part effect non-linearities. We present analyse method consists displacing pixels instead galaxies whose implementation easier than standard method. show this equivalent limit where number becomes very large. This particularly useful...
We study the effect of large-scale tidal fields on internal halo properties using a set N-body simulations. measure significant cross-correlations between and several non-scalar properties: shapes, velocity dispersion, angular momentum. Selection effects that couple to these can produce anisotropic clustering even in real-space. investigate size this show it non-zero quadrupole similar one generated by linear redshift-space distortions (RSD). Finally, we halos identified find enormous...
We present an efficient approach to set informative physically motivated priors for EFT-based full-shape analyses of galaxy survey data. extract these from simulated catalogs based on halo occupation distribution (HOD) models. As a first step, we build joint between EFT bias and HOD parameters 10,500 mock catalogs. make use the field level technique that allows cosmic variance cancellation, enabling precision calibration computationally inexpensive small-volume simulations. second neural...
PUMA is a proposal for an ultra-wideband, low-resolution and transit interferometric radio telescope operating at $200-1100\,\mathrm{MHz}$. Its design driven by six science goals which span three themes: the physics of dark energy (measuring expansion history growth universe up to $z=6$), inflation (constraining primordial non-Gaussianity features) transient sky (detecting one million fast bursts following SKA-discovered pulsars). We propose two array configurations composed hexagonally...
A typical galaxy survey geometry results in pairs of different separation and angle to the line-of-sight having distributions redshift consequently a effective redshift. However, clustering measurements are analysed assuming that is representative at single We investigate impact variations galaxy-pair on large-scale measured surveys. find surveys spanning large range have redshifts as function both pair angle. Furthermore, when considering tracers whose amplitude evolves strongly with...
High-number-density tracers of large-scale structure, such as the HI-rich galaxies measured by 21 cm intensity mapping, have low sampling noise, making them particularly promising cosmological probes. At large scales, this noise can be subdominant to other scale-independent contributions power spectrum, arising from nonlinear bias. This has important consequences for constraints obtained tracers, since it indicates that using spectrum does not lead optimal even in linear regime. In paper, we...
Cosmological analyses of redshift space clustering data are primarily based on using luminous ``red'' galaxies (LRGs) and ``blue'' emission line (ELGs) to trace underlying dark matter. Using the large high-fidelity high-resolution MillenniumTNG (MTNG) Astrid simulations, we study these with effective field theory (EFT)-based level forward model. We confirm that both red blue can be accurately modeled EFT at their parameters match those phenomenological halo-based models. Specifically,...
Development of the hardware, data analysis, and simulation techniques for large compact radio arrays dedicated to mapping 21 cm line neutral hydrogen gas has proven be more difficult than imagined twenty years ago when such telescopes were first proposed. Despite tremendous technical methodological advances, there are several outstanding questions on how optimally calibrate analyze data. On positive side, it become clear that issues purely in nature can solved with sufficient development...