A5033013341- Galaxies: Formation, Evolution, Phenomena
- Cosmology and Gravitation Theories
- Astrophysics and Cosmic Phenomena
- Radio Astronomy Observations and Technology
- Dark Matter and Cosmic Phenomena
- Astrophysics and Star Formation Studies
- Astronomy and Astrophysical Research
- Stellar, planetary, and galactic studies
- Scientific Research and Discoveries
- Astrophysical Phenomena and Observations
- Geophysics and Gravity Measurements
- Gamma-ray bursts and supernovae
- Superconducting and THz Device Technology
- Particle physics theoretical and experimental studies
- Relativity and Gravitational Theory
- Astronomical Observations and Instrumentation
- Solar and Space Plasma Dynamics
- Radioactive Decay and Measurement Techniques
- Atmospheric Ozone and Climate
- Black Holes and Theoretical Physics
- Computational Physics and Python Applications
- Calibration and Measurement Techniques
- Neutrino Physics Research
- Statistical and numerical algorithms
- History and Developments in Astronomy
University of Southern California
2015-2024
Southern California University for Professional Studies
2020
California Institute of Technology
2005-2019
Sahlgrenska University Hospital
2018
Boston University
2013
Princeton University
2003-2009
Harvard University
2009
University of California, Santa Barbara
2009
Institute of Space Sciences
2009
University of California, Berkeley
2009
We summarize the utility of precise cosmic microwave background (CMB) polarization measurements as probes physics inflation. focus on prospects for using CMB to differentiate various inflationary mechanisms. In particular, a detection primordial B‐mode would demonstrate that inflation occurred at very high energy scale, and inflaton traversed super‐Planckian distance in field space. explain how such or constraint illuminate aspects Planck scale. Moreover, can constrain scale‐dependence...
Primordial gravitational waves (GWs) with frequencies > or approximately equal to 10(-15) Hz contribute the radiation density of Universe at time decoupling cosmic microwave background (CMB). This affects CMB and matter power spectra in a manner identical massless neutrinos, unless initial perturbation for GWs is nonadiabatic, as may occur if such are produced during inflation some post-inflation phase transition. In either case, current observations provide constraint GW amplitude that...
One of the possible methods to distinguish among various dark matter candidates is study effects decays. We consider four different (light matter, gravitinos, neutralinos and sterile neutrinos), for each them deriving decaying/annihilation rate, influence on reionization, temperature CMB spectra. find that light particles (1-10 MeV) neutrinos (2-8 keV) can be sources partial early reionization (z
We present a new cluster catalog extracted from the Sloan Digital Sky Survey Data Release 6 (SDSS DR6) using an adaptive matched filter (AMF) finder. identify 69,173 galaxy clusters in redshift range 0.045 $\le z <$ 0.78 8420 sq. deg. of sky. provide angular position, redshift, richness, core and virial radii estimates for these clusters, as well error analysis each quantities. also more than 205,000 galaxies representing three brightest $r$ band which are possible BCG candidates. show basic...
The number density of rich galaxy clusters still provides the most robust way normalizing power spectrum dark matter perturbations on scales relevant to large-scale structure. We revisit this constraint in light several recent developments: (1) availability well-defined samples local with relatively accurate X-ray temperatures; (2) new theoretical mass functions for haloes, which provide a good fit large numerical simulations; (3) more mass-temperature relations from larger catalogues...
Different determinations currently suggest scattered values for the power spectrum normalization on scale of galaxy clusters, σ8. Here we concentrate constraints coming from X-ray temperature and luminosity functions (XTF XLF), investigate several possible sources discrepancies in results. We conclude that main source error both methods is mass scaling relation involved, particular way its intrinsic scatter systematic are treated.
We propose a solution to the CMB component separation problem based on standard parameter estimation techniques. assume parametric spectral model for each signal component, and fit corresponding parameters pixel by in two-stage process. First we full set (e.g., amplitudes indices) low-resolution high signal-to-noise ratio maps using MCMC, obtaining both best-fit values parameter, associated uncertainty. The goodness-of-fit is evaluated chi^2 statistic. Then fix all non-linear at their...
The radiation background produced by the 21 cm spin-flip transition of neutral hydrogen at high redshifts can be a pristine probe fundamental physics and cosmology. At $z\ensuremath{\sim}30--300$, intergalactic medium (IGM) is visible in absorption against cosmic microwave (CMB), with strength that depends on thermal (and ionization) history IGM. Here we examine constraints this place dark matter decay annihilation, which could heat ionize IGM through production high-energy particles. Using...
We describe Sunyaev–Zel'dovich (SZ) effect measurements and analysis of the intracluster medium (ICM) pressure profiles a set 45 massive galaxy clusters imaged using Bolocam at Caltech Submillimeter Observatory. deproject average profile our sample into 13 logarithmically spaced radial bins between 0.07R500 3.5R500, we find that generalized Navarro, Frenk, White (gNFW) describes data with sufficient goodness-of-fit best-fit parameters (C500, α, β, γ, P0 = 1.18, 0.86, 3.67, 0.67, 4.29). use...
We analyze the radial pressure profiles, ICM clumping factor and Sunyaev-Zel'dovich (SZ) scaling relations of a sample simulated galaxy clusters groups identified in set hydrodynamical simulations based on an updated version TreePM-SPH GADGET-3 code. Three different sets are performed: first assumes non-radiative physics, others include, among other processes, AGN and/or stellar feedback. Our results analyzed as function redshift, cluster mass cool-coreness or dynamical state. In general,...
A millimeter-wave survey over half the sky, that spans frequencies in range of 30 to 350 GHz, and is both an order magnitude deeper higher-resolution than currently funded surveys would yield enormous gain understanding fundamental physics astrophysics. By providing such a deep, high-resolution (about 0.5 uK-arcmin noise 15 arcsecond resolution at 150 GHz), CMB-HD will enable major advances. It allow 1) use gravitational lensing primordial microwave background map distribution matter on...
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...
We forecast the number of galaxy clusters that can be detected via thermal Sunyaev-Zeldovich (tSZ) signals by future cosmic microwave background (CMB) experiments, primarily wide area survey CMB-S4 experiment but also CMB-S4's smaller delensing and proposed CMB-HD experiment. predict will detect 75,000 with its $f_{\rm sky}$ = 50% 14,000 deep 3%. Of these, approximately 1350 at $z \ge 2$, a regime is difficult to probe optical or X-ray surveys. assume same sky as S4-Wide{}, find $\times3$...
We investigate signatures of neutrino scattering in the cosmic microwave background (CMB) and matter power spectra, extent to which present cosmological data can distinguish between a free-streaming or tightly coupled fluid neutrinos. If neutrinos have strong nonstandard interactions, for example, through coupling light boson, they may be kept equilibrium until late times. show how spectra these models differ from more conventional scenarios, use CMB large scale structure constrain models....
We present constraints on the presence of isocurvature modes from temperature and polarization cosmic microwave background (CMB) spectrum data WMAP satellite alone, in combination with other sets including SDSS galaxy survey SNLS supernovae. find that inclusion allows as well complementary observations, to place improved limits contribution CDM neutrino density components individually. With general correlations, upper these subdominant are reduced $\ensuremath{\sim}60%$ first year results,...
Measuring the intrinsic shape and orientation of dark matter (DM) intracluster (IC) gas in galaxy clusters is crucial to constraining their formation evolution, for enhancing use as more precise cosmological probes. Extending our previous works, we present first time results from a triaxial joint analysis cluster Abell 1835, by means X-ray, strong lensing (SL) Sunyaev Zel'dovich (SZ) data. We parametrically reconstruct full three-dimensional structure (triaxial principal axis orientation)...
We present 90, 140, and 268GHz sub-arcminute resolution imaging of the Sunyaev-Zel'dovich effect (SZE) in MACSJ0717.5+3745. Our 90GHz SZE data result a sensitive, 34uJy/bm map at 13" using MUSTANG. 140 imaging, with resolutions 58" 31" sensitivities 1.8 3.3mJy/beam respectively, was obtained Bolocam. compare these maps to 2-dimensional pressure derived from Chandra X-ray observations. MUSTANG confirm previous indications enhancement due shock-heated, >20keV gas immediately adjacent extended...
We report our analysis of MACS J0717.5+3745 using 140 and 268 GHz Bolocam data collected at the Caltech Submillimeter Observatory. detect extended Sunyaev-Zel'dovich (SZ) effect signal high significance in both bands, we employ Herschel-SPIRE observations to subtract from dusty background galaxies data. constrain two-band SZ surface brightness toward two sub-clusters J0717.5+3745: main sub-cluster (named C), a identified spectroscopic optical have line-of-sight velocity +3200 km/s B)....
We have looked for bulk motions of galaxy clusters in the Wilkinson Microwave Anisotropy Probe (WMAP) seven-year data. isolate kinetic Sunyaev–Zeldovich (SZ) signal by filtering WMAP Q-, V-, and W-band maps with multi-frequency matched filters that utilize spatial properties SZ to optimize detection. try two filters: a filter has no spectral dependence, utilizes thermal signals remove bias. measure monopole dipole spherical harmonic coefficients signal, as well ℓ = 2–5 modes, at locations...
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...
SPHEREx is a proposed SMEX mission selected for Phase A. will carry out the first all-sky spectral survey and provide every 6.2" pixel spectra between 0.75 4.18 $\mu$m [with R$\sim$41.4] 5.00 R$\sim$135]. The team has three specific science investigations to be carried with this unique data set: cosmic inflation, interstellar circumstellar ices, extra-galactic background light. It readily apparent, however, that many other questions in astrophysics planetary sciences could addressed data....
CMB-HD is a proposed millimeter-wave survey over half the sky that would be ultra-deep (0.5 uK-arcmin) and have unprecedented resolution (15 arcseconds at 150 GHz). Such answer many outstanding questions about fundamental physics of Universe. Major advances 1.) use gravitational lensing primordial microwave background to map distribution matter on small scales (k~10 h Mpc^(-1)), which probes dark particle properties. It will also allow 2.) measurements thermal kinetic Sunyaev-Zel'dovich...
We investigate the possibility that Universe is significantly reionized by decay products of heavy particles. The ionization produced decaying particles implies a high optical depth even if maximum level ever low (10(-2)). As consequence, fraction (x approximately equal to 0.5) at redshifts (z 20) fails fit cosmic microwave background (CMB) spectra l> or =30. Recent CMB data limit primordial abundance particles, favoring long times. Other significant sources reionization are still needed z...