A5049662152- Cosmology and Gravitation Theories
- Dark Matter and Cosmic Phenomena
- Astrophysics and Cosmic Phenomena
- Galaxies: Formation, Evolution, Phenomena
- Radio Astronomy Observations and Technology
- Astronomy and Astrophysical Research
- Neutrino Physics Research
- Stellar, planetary, and galactic studies
- Gamma-ray bursts and supernovae
- Black Holes and Theoretical Physics
- History and Developments in Astronomy
- Geophysics and Gravity Measurements
- Computational Physics and Python Applications
- Scientific Research and Discoveries
- Solar and Space Plasma Dynamics
- Advanced Thermodynamics and Statistical Mechanics
- Relativity and Gravitational Theory
- Quantum Mechanics and Applications
- Economic theories and models
- Mechanical and Optical Resonators
- Delphi Technique in Research
- Global Cancer Incidence and Screening
- Noncommutative and Quantum Gravity Theories
- Calibration and Measurement Techniques
- Earth Systems and Cosmic Evolution
Canadian Institute for Theoretical Astrophysics
2019-2024
University of Toronto
2020-2024
University of Chicago
2013-2019
Kavli Institute for Particle Astrophysics and Cosmology
2017-2019
Fermi National Accelerator Laboratory
2017
Universidade de Santiago de Compostela
2016
Inflation may provide unique insight into the physics at highest available energy scales that cannot be replicated in any realistic terrestrial experiment. Features primordial power spectrum are generically predicted a wide class of models inflation and its alternatives, observationally one most overlooked channels for finding evidence non-minimal inflationary models. Constraints from observations cosmic microwave background cover widest range feature frequencies, but sensitive constraints...
The hot dense environment of the early universe is known to have produced large numbers baryons, photons, and neutrinos. These extreme conditions may also other long-lived species, including new light particles (such as axions or sterile neutrinos) gravitational waves. effects any such relics can be observed through their unique imprint in cosmic microwave background (CMB), large-scale structure, primordial element abundances, are important determining initial universe. We argue that future...
We apply a recently developed method to directly measure the gravitational lensing power spectrum from CMB spectra Planck satellite data. This allows us analyze tension between temperature and lens reconstruction in model-independent way. Even when allowing for arbitrary variations spectrum, remains at $2.4\ensuremath{\sigma}$ level. By separating unlensed high redshift information spectra, we also show that under $\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$ two are similar level, whereas is...
Chiral symmetry is maximally violated in weak interactions, and such microscopic asymmetries the early Universe might leave observable imprints on astrophysical scales without violating cosmological principle. In this Letter, we propose a helicity measurement to detect primordial chiral violation. We point out that observations of halo-galaxy angular momentum directions (spins), which are frozen during galaxy formation process, provide fossil observable. From clustering mode large scale...
We analyze the final release of Planck satellite data to constrain gravitational lensing potential in a model-independent manner. The amount determined from smoothing acoustic peaks temperature and polarization power spectra is $2\ensuremath{\sigma}$ too high when compared with measurements using reconstruction $2.8\ensuremath{\sigma}$ $\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$ expectation based on ``unlensed'' portion spectra. largest change previous expectation, driven by improved...
We search for evidence of primordial chirality violation in the galaxy data from Sloan Digital Sky Survey by comparing how strongly directions angular momenta correlate with left and right helical components a spin vector field constructed initial density perturbations. Within uncertainties, spins these two identically, which is consistent Universe without violation. Given current data, it not yet possible to rule out maximal chiral violation, although case vanishing correlation component...
We apply a tension metric ${Q}_{\mathrm{UDM}}$, the update difference in mean parameters, to understand source of measured Hubble constant ${H}_{0}$ inferred with cosmic microwave background (CMB) lensing measurements from Planck satellite (${H}_{0}={67.9}_{\ensuremath{-}1.3}^{+1.1}\text{ }\text{ }\mathrm{km}/\mathrm{s}/\mathrm{Mpc}$) and South Pole Telescope (${H}_{0}={72.0}_{\ensuremath{-}2.5}^{+2.1}\text{ when both are combined baryon acoustic oscillation (BAO) priors on density (BBN)....
Self-accelerating solutions in massive gravity provide explicit, calculable examples that exhibit the general interplay between superluminality, well-posedness of Cauchy problem, and strong coupling. For three particular classes vacuum solutions, one which is new to this work, we construct conformal diagram for characteristic surfaces on isotropic stress-energy perturbations propagate. With exception, all necessarily possess spacelike characteristics, indicating perturbative superluminality....
Coherent radiation at radio frequencies from high-energy showers fully contained in a dense radio-transparent medium---like ice, salt, soil, or regolith---has been extensively investigated as promising technique to search for ultrahigh-energy neutrinos. Additional emission the form of transition may occur when neutrino-induced shower produced close Earth's surface emerges ground into atmospheric air. We present first detailed evaluation crossing boundary between two different media. found...
We investigate whether transition radiation from a particle shower crossing the interface between Earth and air induced by an Earth-skimming neutrino can explain upward event announced recently ANITA Collaboration. While properties of observed signal in principle be explained with radiation, conservative upper limit on experiment's aperture for this kind shows that flux necessary successful explanation is tension current best limits Pierre Auger Observatory, IceCube detector, balloon. also...
ABSTRACT Gravitational lensing deflects the paths of photons, altering statistics cosmic backgrounds and distorting their information content. We take infrared background (CIB), which provides plentiful about galaxy formation evolution, as an example to probe effect on non-Gaussian statistics. Using Websky simulations, we first quantify non-Gaussianity CIB, revealing additional detail top its well-measured power spectrum. To achieve this, use needlet-like multipole-band filters calculate...
Gravitational lensing information from the two and higher point statistics of CMB temperature polarization fields are intrinsically correlated because they lensed by same realization structure between last scattering observation. Using an analytic model for lens sample covariance, we show that there is one mode, separately measurable in power spectra reconstruction, carries most this correlation. Once these measurements become variance dominated, mode should provide a useful consistency...
We undertake a complete and covariant treatment for the quadratic Lagrangian of all degrees freedom massive gravity with fixed flat fiducial metric arbitrary parameters around any isotropic self-accelerating background solution. Generically, 3 out 4 Stuckelberg propagate in addition to usual 2 tensor general relativity. The kinetic structure typically is only revealed at an order graviton mass that equivalently retaining curvature terms locally expansion. These results resolve several...
We investigate correlations induced by gravitational lensing on simulated cosmic microwave background data of experiments with an incomplete sky coverage and their effect inferences from the South Pole Telescope (SPT) data. These agree well theoretical expectations, given sum supersample intrasample terms, only a typically negligible $\ensuremath{\sim}5%$ discrepancy in amplitude effect. Including these effects we find that constraints are $3.0\ensuremath{\sigma}$ or $2.1\ensuremath{\sigma}$...
Self-accelerating backgrounds in massive gravity provide an arena to explore the Cauchy problem for derivatively coupled fields that obey complex constraints which reduce phase space degrees of freedom. We present here algorithm based on Kronecker form a matrix pencil finds all hidden constraints, example those associated with derivatives equations motion, and characteristic curves any $1+1$ dimensional system linear partial differential equations. With Regge-Wheeler-Zerilli decomposition...
While Type Ia Supernovae (SNe Ia) are one of the most mature cosmological probes, next era promises to be extremely exciting in number different ways SNe used measure various parameters. Here we review experiments 2020s that will yield orders magnitudes more Ia, and new understandings capabilities constrain systematic uncertainties at a level match these statistics. We then discuss five probes with Ia: conventional Hubble diagram for measuring dark energy properties, distance ladder...
Modern galaxy cluster science is a multi-wavelength endeavor with cornerstones provided by X-ray, optical/IR, mm, and radio measurements. In combination, these observations enable the construction of large, clean, complete catalogs, provide precise redshifts robust mass calibration. The complementary nature data dramatically reduces impact systematic effects that limit utility measurements made in any single waveband. future compelling, catalogs set to expand orders magnitude size, extend,...
Opening up a new window of millimeter-wave observations that span frequency bands in the range 30 to 500 GHz, survey half sky, and are both an order magnitude deeper (about 0.5 uK-arcmin) higher-resolution 10 arcseconds) than currently funded surveys would yield enormous gain understanding fundamental physics astrophysics. In particular, such allow for major advances measuring distribution dark matter gas on small-scales, needed insight 1.) particle properties, 2.) evolution galaxies, 3.)...
Non-Gaussian correlations induced in cosmic microwave background (CMB) power spectra by gravitational lensing must be included likelihood analyses for future CMB experiments. We present a simple but accurate model which includes these and use it Markov Chain Monte Carlo parameter estimation from simulated lensed maps the context of $\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$ extensions include sum neutrino masses or dark energy equation state $w$. If lensing-induced covariance is not taken...
Using data from the Sloan Digital Sky Survey we study correlations between directions of galaxy angular momenta determined images spiral galaxies and various observables derived reconstructed initial conditions. We find an apparent systematic effect consistent with galaxy-orientation-dependent selection function. After restricting our attention to brightest half where this is presumed be absent, hints excess/deficit correlation for two observables. Interestingly, tidal torque theory predicts...
We report on the measurement of coherent radio emission from electron beam sudden appearance at Telescope Array Electron Light Source facility. This was detected by four independent detector setups sensitive to frequencies ranging 50 MHz up 12.5 GHz. show that this phenomenon can be understood as a special case transition radiation comparing observed results with simulations. The in-nature application signal is given cosmic ray or neutrino induced particle cascades traversing different media...