A5069354285- Galaxies: Formation, Evolution, Phenomena
- Dark Matter and Cosmic Phenomena
- Astronomy and Astrophysical Research
- Stellar, planetary, and galactic studies
- Cosmology and Gravitation Theories
- Scientific Research and Discoveries
- Astrophysics and Star Formation Studies
- Gamma-ray bursts and supernovae
- Astrophysics and Cosmic Phenomena
- CCD and CMOS Imaging Sensors
- Categorization, perception, and language
- Astronomical Observations and Instrumentation
- Solar and Space Plasma Dynamics
- Language, Metaphor, and Cognition
- Particle physics theoretical and experimental studies
- Adaptive optics and wavefront sensing
- Advanced Thermodynamics and Statistical Mechanics
- Language and cultural evolution
- Color perception and design
- Astro and Planetary Science
- Geophysics and Gravity Measurements
- History and Developments in Astronomy
- Topic Modeling
- Computational Physics and Python Applications
- Remote Sensing in Agriculture
Carnegie Observatories
2021-2025
University of Southern California
2021-2025
Southern California University for Professional Studies
2025
University of California System
2025
University of California, San Diego
2025
Carnegie Institution for Science
2022-2023
Stanford University
2018-2022
Kavli Institute for Particle Astrophysics and Cosmology
2018-2022
Columbia University
2020-2022
École Polytechnique Fédérale de Lausanne
2022
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%...
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...
Abstract We report the results of a systematic search for ultra-faint Milky Way satellite galaxies using data from Dark Energy Survey (DES) and Pan-STARRS1 (PS1). Together, DES PS1 provide multi-band photometry in optical/near-infrared wavelengths over ∼80% sky. Our targets ∼25,000 deg 2 high-Galactic-latitude sky reaching 10 σ point-source depth ≳22.5 mag g r bands. While galaxy searches have been performed independently on before, this is first time that self-consistent across both sets....
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...
Joint analyses of small-scale cosmological structure probes are relatively unexplored and promise to advance measurements microphysical dark matter properties using heterogeneous data. Here, we present a multidimensional analysis substructure strong gravitational lenses the Milky Way (MW) satellite galaxy population, accounting for degeneracies in model predictions covariances constraining power these individual first time. We simultaneously infer projected subhalo number density half-mode...
While astrophysical and cosmological probes provide a remarkably precise consistent picture of the quantity general properties dark matter, its fundamental nature remains one most significant open questions in physics. Obtaining more comprehensive understanding matter within next decade will require overcoming number theoretical challenges: groundwork for these strides is being laid now, yet much to be done. Chief among upcoming challenges establishing foundation needed harness full...
We report the discovery of six ultra-faint Milky Way satellites discovered through matched-filter searches conducted using Dark Energy Camera (DECam) data processed as part second release DECam Local Volume Exploration (DELVE) survey. Leveraging deep Gemini/GMOS-N imaging (for four candidates) well follow-up two candidates), we characterize morphologies and stellar populations these systems. find that candidates all share faint absolute magnitudes ($M_{V} \geq -3.2$ mag) old, metal-poor...
The scale-free gravothermal fluid formalism has long proved effective in describing the evolution of self-interacting dark matter halos with a constant particle cross section. However, whether solutions match numerical simulations for velocity-dependent cross-section scenarios remains untested. In this work, we provide fast mapping method that relates constant-cross-section solution to models arbitrary velocity dependence We show after are good agreement Arepo N-Body simulation results....
We perform a high-resolution cosmological zoom-in simulation of Milky Way (MW)--like system, which includes realistic Large Magellanic Cloud analog, using large differential elastic dark matter self-interaction cross section that reaches $\approx 100~\mathrm{cm}^2\ \mathrm{g}^{-1}$ at relative velocities 10~\mathrm{km\ s}^{-1}$, motivated by the diverse and orbitally dependent central densities dwarf galaxies within surrounding MW. explore effects self-interactions on satellite, splashback,...
Abstract We present Symphony, a compilation of 262 cosmological, cold-dark-matter-only zoom-in simulations spanning four decades host halo mass, from 10 11 –10 15 M ⊙ . This includes three existing simulation suites at the cluster and Milky Way–mass scales, two new suites: 39 Large Magellanic Cloud-mass (10 ) 49 strong-lens-analog 13 group-mass hosts. Across entire mass range, highest-resolution regions in these are resolved with dark matter particle ≈3 × −7 times virial Plummer-equivalent...
Constraining the distribution of small-scale structure in our universe allows us to probe alternatives cold dark matter paradigm. Strong gravitational lensing offers a unique window into small halos ($<10^{10} M_\odot$) because these impart signal even if they do not host luminous galaxies. We create large datasets strong images with realistic low-mass halos, Hubble Space Telescope (HST) observational effects, and galaxy light from HST's COSMOS field. Using simulation-based inference...
Abstract The properties of low-mass dark matter (DM) halos appear to be remarkably diverse relative cold, collisionless DM predictions, even in the presence baryons. We show that self-interacting (SIDM) can simultaneously explain observations halo diversity at two opposite extremes—the inner density profile dense substructure perturbing strong lens galaxy SDSSJ0946+1006 and rotation curves isolated, gas-rich ultradiffuse galaxies (UDGs). To achieve this, we present first cosmological zoom-in...
Abstract Each year, people spend less time reading and more viewing images 1 , which are proliferating online 2–4 . Images from platforms such as Google Wikipedia downloaded by millions every day 2,5,6 interacting through social media, Instagram TikTok, that primarily consist of exchanging visual content. In parallel, news agencies digital advertisers increasingly capturing attention the use 7,8 process quickly, implicitly memorably than text 9–12 Here we show rise significantly exacerbates...
Abstract We report results from a systematic wide-area search for faint dwarf galaxies at heliocentric distances 0.3 to 2 Mpc using the full 6 yr of data Dark Energy Survey (DES). Unlike previous searches over DES data, this specifically targeted field population located beyond Milky Way virial radius. derive our detection efficiency faint, resolved in Local Volume with set synthetic and expect be complete M V ∼ (−7, −10) mag D = (0.3, 2.0) Mpc. find no new dwarfs footprint, but we discovery...
Abstract We propose a parametric model for studying self-interacting dark matter (SIDM) halos. The uses an analytical density profile, calibrated using controlled N-body SIDM simulation that covers the entire gravothermal evolution, including core-forming and -collapsing phases. By normalizing we obtain universal description halos at any evolution phase. allows us to infer properties of based on their cold (CDM) counterparts. As basic application, only require two characteristic parameters...
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 In this study, we modify the semi-analytic model galacticus in order to accurately reproduce observed properties of dwarf galaxies Milky Way. We find that reproducing observational determinations halo occupation fraction and mass–metallicity relation for requires us include H2 cooling, an updated ultraviolet background radiation model, introduce a metal content intergalactic medium. By fine-tuning various parameters incorporating empirical constraints, have tailored match...
Abstract A major question in ΛCDM is what this theory actually predicts for the properties of subhalo populations. Subhalos are difficult to accurately simulate and find within simulations, propagates into uncertainty theoretical predictions satellite galaxies. We present Symfind , a new particle-tracking-based finder, demonstrate that it can track subhalos orders-of-magnitude lower masses than commonly used halo-finding tools, with focus on Rockstar consistent-trees . These longer survival...
Abstract The GD-1 stellar stream exhibits spur and gap structures that may result from a close encounter with dense substructure. When interpreted as dark matter subhalo, the perturber is denser than predicted in standard cold (CDM) model. In self-interacting (SIDM), however, halo could evolve into phase of gravothermal collapse, resulting higher central density its CDM counterpart. We conduct high-resolution controlled N -body simulations to show collapsed SIDM account for perturber's high...
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...
Alternatives to the cold, collisionless dark matter (DM) paradigm in which DM behaves as a collisional fluid generically suppress small-scale structure. Herein we use observed population of Milky Way (MW) satellite galaxies constrain nature DM, focusing on DM-baryon scattering. We first derive analytic upper limits velocity-independent scattering cross section by translating bound lowest mass halos inferred host satellites into characteristic cutoff scale linear power spectrum. then confirm...
We explore the impact of elastic, anisotropic, velocity-dependent dark matter (DM) self-interactions on host halo and subhalos Milky Way (MW)--mass systems. consider a generic self-interacting (SIDM) model parameterized by masses light mediator DM particle. The ratio these masses, $w$, sets velocity scale above which momentum transfer due to becomes inefficient. perform high-resolution zoom-in simulations an MW-mass for values $w$ that span scenarios in either between its or only within...