A5026732615- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Galaxies: Formation, Evolution, Phenomena
- Astrophysics and Star Formation Studies
- Gamma-ray bursts and supernovae
- Adaptive optics and wavefront sensing
- Astro and Planetary Science
- CCD and CMOS Imaging Sensors
- Dark Matter and Cosmic Phenomena
- Cosmology and Gravitation Theories
- Planetary Science and Exploration
- Big Data Technologies and Applications
- Spectroscopy and Laser Applications
- Advanced Thermodynamics and Statistical Mechanics
- Advanced Vision and Imaging
- Advanced Fluorescence Microscopy Techniques
- Impact of Light on Environment and Health
- Calibration and Measurement Techniques
Kavli Institute for Particle Astrophysics and Cosmology
2021-2025
Menlo School
2024-2025
Stanford University
2021-2024
Campbell Collaboration
2023
University of Chicago
2019-2020
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 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...
Abstract We present the discovery of Aquarius III, an ultra-faint Milky Way satellite galaxy identified in second data release DECam Local Volume Exploration survey. Based on deeper follow-up imaging with DECam, we find that III is a low-luminosity ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>M</mml:mi> </mml:mrow> <mml:mi>V</mml:mi> </mml:msub> <mml:mo>=</mml:mo> <mml:mo>−</mml:mo> <mml:msubsup> <mml:mn>2.5</mml:mn>...
Abstract We present the second public data release (DR2) from DECam Local Volume Exploration survey (DELVE). DELVE DR2 combines new observations with archival Dark Energy Survey, Legacy and other community programs. consists of ∼160,000 exposures that cover >21,000 deg 2 high-Galactic-latitude (∣ b ∣ > 10°) sky in four broadband optical/near-infrared filters ( g , r i z ). provides point-source automatic aperture photometry for ∼2.5 billion astronomical sources a median 5 σ depth =...
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...
We report the discovery of Pegasus IV, an ultra-faint dwarf galaxy found in archival data from Dark Energy Camera processed by DECam Local Volume Exploration Survey. IV is a compact, stellar system ($r_{1/2} = 41^{+8}_{-6}$ pc; $M_V -4.25 \pm 0.2$ mag) located at heliocentric distance $90^{+4}_{-6}$ kpc. Based on spectra seven non-variable member stars observed with Magellan/IMACS, we confidently resolve IV's velocity dispersion, measuring $\sigma_{v} 3.3^{+1.7}_{-1.1} \text{ km s}^{-1}$...
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 use a recent census of the Milky Way (MW) satellite galaxy population to constrain lifetime particle dark matter (DM). consider two-body decaying (DDM) in which heavy DM decays with τ comparable age universe lighter (with mass splitting ϵ ) and radiation species. These impart characteristic “kick velocity,” V kick = c , on daughter particles, significantly depleting content low-mass subhalos making them more susceptible tidal disruption. fit suppression present-day DDM subhalo...
We present the discovery of a candidate ultra-faint Milky Way satellite, Eridanus IV (DELVE J0505$-$0931), detected in photometric data from DECam Local Volume Exploration survey (DELVE). is faint ($M_V = -4.7 \pm 0.2$), extended ($r_{1/2} 75^{+16}_{-13}$ pc), and elliptical ($\epsilon 0.54 0.1$) system at heliocentric distance $76.7^{+4.0}_{-6.1}$ kpc, with stellar population that well-described by an old, metal-poor isochrone (age $\tau \sim 13.0$ Gyr metallicity ${\rm [Fe/H] \lesssim...
Abstract We present the discovery of DELVE 6, an ultra-faint stellar system identified in second data release DECam Local Volume Exploration (DELVE) survey. Based on a maximum-likelihood fit to its structure and population, we find that 6 is old ( τ > 9.8 Gyr at 95% confidence) metal-poor ([Fe/H] < −1.17 dex with absolute magnitude <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>M</mml:mi> </mml:mrow> <mml:mi>V</mml:mi>...
The OpenUniverse2024 simulation suite is a cross-collaboration effort to produce matched simulated imaging for multiple surveys as they would observe common sky. Both the data and associated tools used it are intended uniquely enable wide range of studies maximize science potential next generation cosmological surveys. We have produced approximately 70 deg$^2$ Vera C. Rubin Observatory Legacy Survey Space Time (LSST) Wide-Fast-Deep survey Nancy Grace Roman Telescope High-Latitude Wide-Area...
We perform a search for galaxy-galaxy strong lens systems using convolutional neural network (CNN) applied to imaging data from the first public release of DECam Local Volume Exploration Survey (DELVE), which contains $\sim 520$ million astronomical sources covering 4,000$ $\mathrm{deg}^2$ southern sky $5\sigma$ point-source depth $g=24.3$, $r=23.9$, $i=23.3$, and $z=22.8$ mag. Following methodology similar searches data, we apply color magnitude cuts select catalog 11$ extended sources....
The non-linear process of cosmic structure formation produces gravitationally bound overdensities dark matter known as halos. abundances, density profiles, ellipticities, and spins these halos can be tied to the underlying fundamental particle physics that governs at microscopic scales. Thus, macroscopic measurements offer a unique opportunity determine properties across vast landscape theories. This white paper summarizes ongoing rapid development theoretical experimental methods, well new...
We report the discovery of two ultra-faint stellar systems found in early data from DECam Local Volume Exploration survey (DELVE). The first system, Centaurus I (DELVE J1238-4054), is identified as a resolved overdensity old and metal-poor stars with heliocentric distance ${\rm D}_{\odot} = 116.3_{-0.6}^{+0.6}$ kpc, half-light radius $r_h 2.3_{-0.3}^{+0.4}$ arcmin, an age $\tau > 12.85$ Gyr, metallicity $Z 0.0002_{-0.0002}^{+0.0001}$, absolute magnitude $M_V -5.55_{-0.11}^{+0.11}$ mag. This...
We present the discovery of a faint, resolved stellar system, BLISS J0321+0438 (BLISS 1), found in Dark Energy Camera data from first observing run Blanco Imaging Southern Sky (BLISS) Survey. 1) is located at (RA, Dec) = (177.511, -41.772) deg with heliocentric distance D 23.7$^{+1.9}_{-1.0}$ kpc. It Mv 0.0$^{+1.7}_{-0.7}$ mag, and compact, rh 4.1 +/- 1 pc, system consistent previously discovered faint halo star clusters. Using second release Gaia satellite, we measure proper motion...
We use six years of data from the Dark Energy Survey to perform a detailed photometric characterization Phoenix stellar stream, 15-degree long, thin, dynamically cold, low-metallicity system in southern hemisphere. natural splines, non-parametric modeling technique, simultaneously fit stream track, width, and linear density. This updated model allows us improve measurements heliocentric distance ($17.4 \pm 0.1\,{\rm (stat.)} 0.8\,{\rm (sys.)}$ kpc) gradient ($-0.009 0.006$ kpc deg$^{-1}$)...
Abstract We are conducting a survey using twilight time on the Dark Energy Camera with Blanco 4 m telescope in Chile to look for objects interior Earth’s and Venus’ orbits. To date we have discovered two rare Atira/Apohele asteroids, 2021 LJ4 PH27, which orbits completely orbit. also one new Apollo-type Near Earth Object (NEO) that crosses orbit, 2022 AP7. Two of discoveries diameters ≳1 km. AP7 is likely largest Potentially Hazardous Asteroid (PHA) about eight years. covered 624 square...
We perform a detailed photometric and astrometric analysis of stars in the Jet stream using data from first release DECam Local Volume Exploration Survey (DELVE) DR1 \emph{Gaia} EDR3. discover that extends over $\sim 29 ^{\circ}$ on sky (increasing known length by $18^{\circ}$), which is comparable to kinematically cold Phoenix, ATLAS, GD-1 streams. Using blue horizontal branch stars, we resolve distance gradient along 0.2 kpc/deg, with distances ranging $D_\odot \sim 27-34$ kpc. use natural...
Abstract The DECam Local Volume Exploration survey (DELVE) is a 126-night program on the 4 m Blanco Telescope at Cerro Tololo Inter-American Observatory in Chile. DELVE seeks to understand characteristics of faint satellite galaxies and other resolved stellar substructures over range environments Volume. will combine new observations with archival data cover ∼15,000 deg 2 high Galactic latitude (∣ b ∣ > 10°) southern sky 5 σ depth g , r i z ∼ 23.5 mag. In addition, region ∼2200 around...
Abstract We report the detection of three RR Lyrae (RRL) stars (two RRc and one RRab) in ultra-faint dwarf (UFD) galaxy Centaurus I (Cen I) two Milky Way (MW) δ Scuti/SX Phoenicis based on multi-epoch giz DECam observations. The are located within times half-light radius ( r h ) Cen I, while RRab star (CenI-V3) is at ∼6 . presence distant RRL clustered this tightly space represents a 4.7 σ excess relative to smooth distribution Galactic halo. Using newly detected stars, we obtain distance...
Abstract The Vera C. Rubin Observatory’s LSST Camera (LSSTCam) pixel response has been characterized using laboratory measurements with a grid of artificial stars. We quantify the contributions to photometry, centroid, point-spread function size, and shape measurement errors due small anomalies in LSSTCam CCDs. main sources those are quantum efficiency variations area induced by amplifier segmentation boundaries “tree-rings”—circular silicon doping concentration. This study stars projected...
We report the discovery of a new ultra-faint stellar system found near Magellanic Clouds in DECam Local Volume Exploration (DELVE) Survey. This system, DELVE J0155$-$6815 (DELVE 2), is located at heliocentric distance $D_{\odot} = 71 \pm 4\text{ kpc}$, which places it 3D physical separation 12 kpc from center Small Cloud (SMC) and 28 Large (LMC). 2 identified as resolved overdensity old ($\tau > 13.3\text{ Gyr}$) metal-poor (${\rm [Fe/H]} -2.0_{-0.5}^{+0.2}$ dex) stars with projected...