A5070286426- Cosmology and Gravitation Theories
- Galaxies: Formation, Evolution, Phenomena
- Dark Matter and Cosmic Phenomena
- Astronomy and Astrophysical Research
- Stellar, planetary, and galactic studies
- Astrophysics and Cosmic Phenomena
- Scientific Research and Discoveries
- Adaptive optics and wavefront sensing
- Gamma-ray bursts and supernovae
- Radio Astronomy Observations and Technology
- Particle physics theoretical and experimental studies
- Computational Physics and Python Applications
- Solar and Space Plasma Dynamics
- Black Holes and Theoretical Physics
- Climate variability and models
- Geophysics and Gravity Measurements
- Plant Water Relations and Carbon Dynamics
- Neutrino Physics Research
- Relativity and Gravitational Theory
- Atomic and Subatomic Physics Research
- Advanced Thermodynamics and Statistical Mechanics
- History and Developments in Astronomy
- CCD and CMOS Imaging Sensors
- Astronomical Observations and Instrumentation
- Meteorological Phenomena and Simulations
Harvard University
2015-2024
Harvard University Press
2019
Center for Astrophysics Harvard & Smithsonian
2015
Institute for Advanced Study
2012-2014
Princeton University
2014
University of Chicago
2009-2012
Fermi National Accelerator Laboratory
2009-2012
We derive constraints on elastic scattering between baryons and dark matter using the cosmic microwave background (CMB) data from Planck satellite Lyman-alpha forest Sloan Digital Sky Survey. Elastic allows to exchange momentum, affecting dynamics of linear density perturbations in early Universe. cross sections form sigma \propto v^n, allowing for a wide range velocity dependencies with n -4 2. improve correct previous estimates where they exist, including velocity-independent section as...
We derive new limits on the elastic scattering cross section between baryons and dark matter using cosmic microwave background data from Planck satellite measurements of Lyman-alpha forest flux power spectrum Sloan Digital Sky Survey. Our analysis addresses generic sections form $\ensuremath{\sigma}\ensuremath{\propto}{v}^{n}$, where $v$ is matter--baryon relative velocity, allowing for constraints independent specific particle physics models. include high-$\ensuremath{\ell}$ polarization in...
Optimal extraction of the non-Gaussian information encoded in Large-Scale Structure (LSS) universe lies at forefront modern precision cosmology. We propose achieving this task through use Wavelet Scattering Transform (WST), which subjects an input field to a layer non-linear transformations that are sensitive non-Gaussianity spatial density distributions generated set WST coefficients. In order assess its applicability context LSS surveys, we apply on 3D overdensity obtained by Quijote...
We explore the cosmology of dark-dimension scenario taking into account perturbations in linear regime. In context scenario, a natural candidate for dark matter our Universe is excitations tower massive spin-2 Kaluza-Klein (KK) gravitons. These gravitons are produced early and decay to lighter KK during course cosmological evolution. The causes average mass decrease as evolves. addition, kinetic energy liberated each leads kick velocity particles, leading suppression structure formation....
Dark matter (DM) could couple to Standard Model (SM) particles through a light mediator and this be responsible for the observed DM abundances $f\phantom{\rule{0}{0ex}}r\phantom{\rule{0}{0ex}}e\phantom{\rule{0}{0ex}}e\phantom{\rule{0}{0ex}}z\phantom{\rule{0}{0ex}}e\ensuremath{-}i\phantom{\rule{0}{0ex}}n$. Here, authors identify an additional production channel decay of photons that have acquired in-medium plasma mass. They contribute relic abundance, lowering by order magnitude target...
We provide analytic solutions for the power spectrum and bispectrum of curvature fluctuations produced by a step feature in inflaton potential, valid limit that is short sharp. In this limit, strongly scale dependent its effective non-linearity attains large oscillatory amplitude. The perturbations to spectrum, on other hand, remain small component top usual generated slow roll. utilize our assess observability predicted non-Gaussian signatures show that, if present, only very sharp steps...
The distribution of matter fluctuations in our universe is key for understanding the nature dark and physics early cosmos. Different observables have been able to map this at large scales, corresponding wavenumbers $k\lesssim 10$ Mpc$^{-1}$, but smaller scales remain much less constrained. 21-cm line a promising tracer stellar formation, which took place small haloes (with masses $M\sim 10^6-10^8M_\odot$), formed out overdensities with as $k\approx100$ Mpc$^{-1}$. Here we forecast how well...
Dark matter (DM) could be a relic of freeze-in through light mediator, where the DM is produced by extremely feeble, IR-dominated processes in thermal standard model plasma. In simplest viable models with lighter than 1 MeV, has small effective electric charge and born nonthermal phase-space distribution. This candidate would cause observable departures from cosmological evolution. this work, we combine data cosmic microwave background (CMB), Lyman-$\ensuremath{\alpha}$ forest, quasar...
We set the strongest limits to date on velocity-independent dark matter (DM)-proton cross section σ for DM masses m=10 keV 100 GeV, using large-scale structure traced by Lyman-alpha forest: e.g., a 95% lower limit σ<6×10^{-30} cm^{2}, m=100 keV. Our results complement direct detection, which has limited sensitivity sub-GeV DM. use an emulator of cosmological simulations, combined with data from smallest scales used date, model and search imprint primordial DM-proton collisions. Cosmological...
We perform the first application of wavelet scattering transform (WST) to actual galaxy observations, through a WST analysis BOSS DR12 CMASS dataset. included effects redshift-space anisotropy, non-trivial survey geometry, systematic weights, and Alcock-Paczynski distortion effect, following commonly adopted steps for power spectrum analysis. In order capture cosmological dependence WST, we use mocks obtained from state-of-the-art ABACUSSUMMIT simulations, tuned match anisotropic correlation...
Self-interacting dark matter (SIDM) arises generically in scenarios for physics beyond the Standard Model that have sectors with light mediators or strong dynamics. The self-interactions allow energy and momentum transport through halos, altering their structure dynamics relative to those produced by collisionless matter. SIDM models provide a promising way explain diversity of galactic rotation curves, they form predictive versatile framework interpreting astrophysical phenomena related...
We perform a reanalysis of the BOSS CMASS DR12 galaxy dataset using simulation-based emulator for wavelet scattering transform (WST) coefficients. Moving beyond our previous works, which laid foundation first clustering application this estimator, we construct neural net-based cosmological dependence WST coefficients and 2-point correlation function multipoles, trained from state-of-the-art suite abacussummit simulations combined with flexible halo occupation distribution (HOD) model. In...
The angular power spectrum of the cosmic microwave background temperature anisotropy observed by WMAP has an anomalous dip at $\ensuremath{\ell}\ensuremath{\sim}20$ and a bump $\ensuremath{\ell}\ensuremath{\sim}40$. One explanation for this structure is presence features in primordial curvature spectrum, possibly caused step inflationary potential. detection these only marginally significant from data alone. However, feature hypothesis predicts specific shape $E$-mode polarization with...
Primordial features are one of the most important extensions Standard Model cosmology, providing a wealth information on primordial Universe, ranging from discrimination between inflation and alternative scenarios, new particle detection, to fine structures in inflationary potential. We study prospects future large-scale structure (LSS) surveys detection constraints these features. classify feature models into several classes, for each class we present simple template power spectrum that...
In this follow-up work to the High Energy Physics Community Summer Study 2013 (HEP CSS 2013, a.k.a. Snowmass), we explore scientific capabilities of a future Stage-IV Cosmic Microwave Background polarization experiment (CMB-S4) under various assumptions on detector count, resolution, and sky coverage. We use Fisher matrix technique calculate expected uncertainties in cosmological parameters $\nu \Lambda$CDM that are especially relevant physics fundamental interactions, including neutrino...
Many scenarios of physics beyond the standard model predict new light, weakly coupled degrees freedom, populated in early universe and remaining as cosmic relics today. Due to their high abundances, these can significantly affect evolution universe. For instance, massless produce a shift $\Delta N_{\rm eff}$ expectation effective number active neutrinos. Massive relics, on other hand, additionally become part cosmological dark matter later universe, though light nature allows them freely...
We develop a fast technique based on the generalized slow-roll (GSR) approach for computing curvature bispectrum of inflationary models with features. show that all triangle configurations can be expressed in terms three simple integrals over background typical accuracy better than $\ensuremath{\sim}20%$. With first-order GSR improved to $\ensuremath{\sim}5%$ level. illustrate this step potential model has been invoked explain WMAP temperature power spectrum glitches at...
We show that intrinsic (not lensing-induced) correlations between galaxy shapes offer a new probe of primordial non-Gaussianity and inflationary physics which is complementary to number counts. Specifically, alignment are sensitive an anisotropic squeezed limit bispectrum the perturbations. Such feature arises in solid inflation, as well more broadly presence light higher spin fields during inflation (as pointed out recently by Arkani-Hamed Maldacena). present derivation all-sky two-point...
Correlations between intrinsic galaxy shapes on large scales arise due to the effect of tidal field large-scale structure. Anisotropic primordial non-Gaussianity induces a distinct scale-dependent imprint in these alignments scales. Motivated by observational finding that alignment strength luminous red galaxies depends how are measured, we study use two different shape estimators as multitracer probe alignments. We show, means Fisher analysis, this technique promises significant improvement...
SPHEREx is a proposed NASA MIDEX mission selected for Phase A study. would carry out the first all-sky spectral survey in near infrared. At end of its two-year mission, obtain 0.75-to-5$\mu$m spectra every 6.2 arcsec pixel on sky, with resolution R>35 and 5-$\sigma$ sensitivity AB$>$19 per spectral/spatial element. More details concerning are available at http://spherex.caltech.edu. The team has three specific science investigations to be carried this unique data set: cosmic inflation,...
Recent advances in cosmic observations have brought us to the verge of discovery absolute scale neutrino masses. Nonzero masses are known evidence new physics beyond Standard Model. Our understanding clustering matter presence massive neutrinos has significantly improved over past decade, yielding cosmological constraints that tighter than any laboratory experiment, and which will improve next resulting a guaranteed detection mass scale.
In recent years, machine learning (ML) methods have remarkably improved how cosmologists can interpret data. The next decade will bring new opportunities for data-driven cosmological discovery, but also present challenges adopting ML methodologies and understanding the results. could transform our field, this transformation require astronomy community to both foster promote interdisciplinary research endeavors.
Abstract Detecting substructure within strongly lensed images is a promising route to shed light on the nature of dark matter. However, it challenging task, which traditionally requires detailed lens modeling and source reconstruction, taking weeks analyze each system. We use machine learning circumvent need for develop neural network both locate subhalos in an image as well determine their mass using technique segmentation. The trained with single subhalo located near Einstein ring across...
Observations of structure at sub-galactic scales are crucial for probing the properties dark matter, which is dominant source gravity in universe. It will become increasingly important future surveys to distinguish between line-of-sight halos and subhalos avoid wrong inferences on nature matter. We reanalyze a (in lens JVAS B1938+666) that has been previously found using gravitational imaging technique galaxy-galaxy lensing systems. This assumed be satellite halo main galaxy. fit redshift...