A5005428357- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Stellar, planetary, and galactic studies
- Dark Matter and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Quantum Chromodynamics and Particle Interactions
- Astrophysics and Star Formation Studies
- Particle physics theoretical and experimental studies
- High-Energy Particle Collisions Research
- Scientific Research and Discoveries
- Cosmology and Gravitation Theories
- Remote Sensing in Agriculture
- Astronomical Observations and Instrumentation
- CCD and CMOS Imaging Sensors
- Radio Astronomy Observations and Technology
- Black Holes and Theoretical Physics
- Physics of Superconductivity and Magnetism
- Astrophysics and Cosmic Phenomena
- Gaussian Processes and Bayesian Inference
- Advanced Thermodynamics and Statistical Mechanics
- Impact of Light on Environment and Health
- Advanced Fluorescence Microscopy Techniques
- Atomic and Subatomic Physics Research
- Advanced Data Storage Technologies
- Theoretical and Computational Physics
University of Utah
2023-2024
Rutgers, The State University of New Jersey
2019-2023
Rutgers Sexual and Reproductive Health and Rights
2022
University of Pittsburgh
2016-2021
University of California, Santa Barbara
2017-2018
Stanford University
2013-2017
Kavli Institute for Particle Astrophysics and Cosmology
2013-2017
SLAC National Accelerator Laboratory
2013-2016
Space Telescope Science Institute
2014
National Taiwan University
2009-2012
We report the discovery of eight new ultra-faint dwarf galaxy candidates in second year optical imaging data from Dark Energy Survey (DES). Six these are detected at high confidence, while two lower-confidence identified regions non-uniform survey coverage. The stellar systems found by three independent automated search techniques and as overdensities stars, consistent with isochrone luminosity function an old metal-poor simple population. faint (Mv > -4.7 mag) span a range physical sizes...
We perform a comprehensive study of Milky Way (MW) satellite galaxies to constrain the fundamental properties dark matter (DM). This analysis fully incorporates inhomogeneities in spatial distribution and detectability MW satellites marginalizes over uncertainties mapping between DM halos, system, disruption subhalos by disk. Our results are consistent with cold, collisionless paradigm yield strongest cosmological constraints date on particle models warm, interacting, fuzzy matter. At 95%...
We present the survey strategy and early results of "Satellites Around Galactic Analogs" (SAGA) Survey. The SAGA Survey's goal is to measure distribution satellite galaxies around 100 systems analogous Milky Way down luminosity Leo I dwarf galaxy ($ M_r < -12.3 $). define a analog based on $K$-band local environment. Here, we functions for 8 between 20 40 Mpc. These have nearly complete spectroscopic coverage candidate satellites within projected host virial radius $ r_o 20.75 using low...
ABSTRACT We study the abundance of substructure in matter density near galaxies using ALMA Science Verification observations strong lensing system SDP.81. present a method to measure subhalos around interferometric gravitational lenses. Using simulated we explore effects various systematics, including antenna phase errors and source priors, show how such may be measured or marginalized. apply our formalism find evidence for presence M = 10 8.96±0.12 ⊙ subhalo one images, with significance...
Abstract We present the Stage II results from ongoing Satellites Around Galactic Analogs (SAGA) Survey. Upon completion, SAGA Survey will spectroscopically identify satellite galaxies brighter than M r , o = −12.3 around 100 Milky Way (MW) analogs at z ∼ 0.01. In II, we have more quadrupled sample size of I, delivering 127 satellites 36 MW with an improved target selection strategy and deep photometric imaging catalogs Dark Energy Legacy Surveys. obtained 25,372 galaxy redshifts, peaking...
The population of Milky Way (MW) satellites contains the faintest known galaxies and thus provides essential insight into galaxy formation dark matter microphysics. Here we combine a model galaxy--halo connection with newly derived observational selection functions based on searches for in photometric surveys over nearly entire high Galactic latitude sky. In particular, use cosmological zoom-in simulations MW-like halos that include realistic Large Magellanic Cloud (LMC) analogs to fit...
ABSTRACT Empirical methods for connecting galaxies to their dark matter halos have become essential interpreting measurements of the spatial statistics galaxies. In this work, we present a novel approach parameterizing degree concentration dependence in abundance matching method. This new parameterization provides smooth interpolation between two commonly used proxies: peak halo mass and maximal circular velocity. controls amount galaxy luminosity on at fixed mass. Effectively scheme enables...
We present measurements of the redshift-dependent clustering a DESI-like luminous red galaxy (LRG) sample selected from Legacy Survey imaging dataset, and use halo occupation distribution (HOD) framework to fit signal. The photometric LRG in this study contains 2.7 million objects over redshift range $0.4 < z 0.9$ 5655 deg$^2$. have developed new (photo-$z$) estimates using DECam WISE photometry, with $\sigma_{\mathrm{NMAD}} = 0.02$ precision for LRGs. compute projected correlation function...
Abstract Existing models for the dependence of halo mass function on cosmological parameters will become a limiting source systematic uncertainty cluster cosmology in near future. We present emulator and demonstrate improved accuracy relative to state-of-the-art analytic models. In this work, is defined using an overdensity criteria 200 mean background density. Our constructed from Aemulus simulations, suite 40 N -body simulations with snapshots z = 3 0. These cover flat w CDM parameter...
We present the first stable release of Halotools (v0.2), a community-driven Python package designed to build and test models galaxy-halo connection. provides modular platform for creating mock universes galaxies starting from catalog dark matter halos obtained cosmological simulation. The supports many common forms used describe models: halo occupation distribution (HOD), conditional luminosity function (CLF), abundance matching, alternatives these that include effects such as environmental...
Abstract Using the N -body simulations of Aemulus Project, we construct an emulator for nonlinear clustering galaxies in real and redshift space. We our model galaxy bias using halo occupation framework, accounting possible velocity bias. The includes 15 parameters, including both cosmological parameters. demonstrate that achieves ∼1% precision at scales interest, 0.1 h −1 Mpc < r 10 Mpc, recovers true cosmology when tested against independent simulations. Our primary parameters interest...
Secondary halo bias, commonly known as 'assembly bias', is the dependence of clustering on a property other than mass. This prediction Λ Cold Dark Matter cosmology essential to modelling galaxy distribution high precision and interpreting measurements. As name suggests, different manifestations secondary bias have been thought originate from assembly histories. We show conclusively that this incorrect for cluster-size haloes. present an up-to-date summary biases high-mass haloes due various...
We examine the velocity distribution function (VDF) in dark matter halos from Milky Way to cluster mass scales. identify an empirical model for VDF with a wider peak and steeper tail than Maxwell–Boltzmann distribution, discuss physical explanations. quantify sources of scatter cosmological their implication direct detection matter. Given modern simulations observations, we find that most significant uncertainty arises unknown radial position solar system relative halo scale radius.
Hierarchical structure formation implies that the number of subhalos within a dark matter halo depends not only on mass, but also history halo. This dependence history, which is highly correlated with concentration, can account for super-Poissonian scatter in subhalo occupation at fixed mass has been previously measured simulations. Here we propose model to predict abundance function individual host halos, incorporates both and concentration. We combine results cosmological simulations new...
Abstract This paper introduces cosmoDC2, a large synthetic galaxy catalog designed to support precision dark energy science with the Large Synoptic Survey Telescope (LSST). CosmoDC2 is starting point for second data challenge (DC2) carried out by LSST Dark Energy Science Collaboration (LSST DESC). The based on trillion-particle, (4.225 Gpc) 3 box cosmological N -body simulation, Outer Rim run. It covers 440 deg 2 of sky area redshift z = and matches expected number densities from...
ABSTRACT We study the mass spectrum of destroyed dwarfs that contribute to accreted stellar Milky Way (MW)-mass ( M vir ∼ 10 12.1 ⊙ ) halos using a suite 45 zoom-in dissipationless simulations. Empirical models are employed relate (peak) subhalo dwarf mass, and we use constraints from z = 0 observations hydrodynamical simulations estimate metallicity distribution material. The dominant contributors relatively massive with star 8 –10 . Halos more quiescent accretion histories tend have lower...
We introduce the Southern Stellar Stream Spectroscopy Survey (${S}^5$), an on-going program to map kinematics and chemistry of stellar streams in Hemisphere. The initial focus ${S}^5$ has been spectroscopic observations recently identified within footprint Dark Energy (DES), with eventual goal surveying across entire southern sky. are composed material that tidally striped from dwarf galaxies globular clusters hence excellent dynamical probes gravitational potential Milky Way, as well...
Abstract We describe the simulated sky survey underlying second data challenge (DC2) carried out in preparation for analysis of Vera C. Rubin Observatory Legacy Survey Space and Time (LSST) by LSST Dark Energy Science Collaboration (LSST DESC). Significant connections across multiple science domains will be a hallmark LSST; DC2 program represents unique modeling effort that stresses this interconnectivity way has not been attempted before. This encompasses full end-to-end approach: starting...
We analyze clustering measurements of BOSS galaxies using a simulation-based emulator two-point statistics. focus on the monopole and quadrupole redshift-space correlation function, projected at scales $0.1\sim60~h^{-1}$Mpc. Although our simulations are based $w$CDM with general relativity (GR), we include scaling parameter halo velocity field, $\gamma_f$, defined as amplitude field relative to GR prediction. divide data into three redshift bins. After marginalizing over other cosmological...
Abstract We present Symphony, a compilation of 262 cosmological, cold-dark-matter-only zoom-in simulations spanning four decades host halo mass, from 10 11 –10 15 M ⊙ . This includes three existing simulation suites at the cluster and Milky Way–mass scales, two new suites: 39 Large Magellanic Cloud-mass (10 ) 49 strong-lens-analog 13 group-mass hosts. Across entire mass range, highest-resolution regions in these are resolved with dark matter particle ≈3 × −7 times virial Plummer-equivalent...
Abstract The abundance of faint dwarf galaxies is determined by the underlying population low-mass dark matter (DM) halos and efficiency galaxy formation in these systems. Here, we quantify potential DM constraints from future satellite surveys. We generate populations using a suite Milky Way (MW)–mass cosmological zoom-in simulations an empirical galaxy–halo connection model, assess sensitivity to signals when marginalizing over uncertainties. find that survey all satellites around one...
Abstract We report the discovery of two ultrafaint dwarf galaxies, Leo M and K, that lie outside halo Milky Way (MW). Using Hubble Space Telescope imaging resolved stars, we create color–magnitude diagrams reaching oldest main-sequence turnoff each system (i) fit for structural parameters galaxies; (ii) measure their distances using luminosity horizontal branch stars; (iii) estimate integrated magnitudes stellar masses; (iv) reconstruct star formation histories. Based on location in Local...
Merger trees follow the growth and merger of dark-matter haloes over cosmic history. As well as giving important insights into structure in their own right, they provide an essential backbone to semi-analytic models galaxy formation. This paper is first a series arise from SUSSING MERGER TREES Workshop which ten different tree-building algorithms were applied same set halo catalogues results compared. Although many these codes similar nature, all produced distinct results. Our main...
We develop a comprehensive and flexible model for the connection between satellite galaxies dark matter subhalos in matter-only zoom-in simulations of Milky Way (MW)--mass host halos. systematically identify physical numerical uncertainties galaxy--halo underlying our method, including (i) influence halo properties; (ii) relationship luminosities subhalo properties, effects reionization; (iii) locations; (iv) sizes tidal stripping; (v) disruption due to baryonic effects; (vi) artificial...
ABSTRACT We report a new ultra-faint stellar system found in Dark Energy Camera data from the first observing run of Magellanic Satellites Survey (MagLiteS). MagLiteS J0644−5953 (Pictor II or Pic II) is low surface brightness ( within its half-light radius) resolved overdensity old and metal-poor stars located at heliocentric distance . The physical size ) luminosity this satellite are consistent with locus spectroscopically confirmed galaxies. (Pic Large Cloud (LMC), comparisons simulation...