A5025002435- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Galaxies: Formation, Evolution, Phenomena
- Astrophysics and Star Formation Studies
- Astronomical Observations and Instrumentation
- Gamma-ray bursts and supernovae
- Mass Spectrometry Techniques and Applications
- Forensic Fingerprint Detection Methods
- Astrophysical Phenomena and Observations
- Forensic and Genetic Research
- Pregnancy and preeclampsia studies
- Advanced Proteomics Techniques and Applications
- Geophysics and Gravity Measurements
- Identification and Quantification in Food
- Speech and Audio Processing
- Neonatal skin health care
- Astrophysics and Cosmic Phenomena
- Seed Germination and Physiology
- Neonatal Respiratory Health Research
- Birth, Development, and Health
- History and Developments in Astronomy
- Ophthalmology and Eye Disorders
- Plant tissue culture and regeneration
- Adaptive optics and wavefront sensing
- Maternal and fetal healthcare
University of California, Berkeley
2020-2024
University of Utah
2023-2024
University of Arizona
2016-2024
University of California, San Diego
2022-2024
Punjab Agricultural University
2017-2024
University of Phoenix
2024
University of Chicago
2023
Miller College
2020-2023
Medicines Discovery Catapult
2020-2022
Institute for Environmental Policy
2022
Abstract With the release of Gaia DR2, it is now possible to measure proper motions (PMs) lowest-mass, ultrafaint satellite galaxies in Milky Way’s (MW) halo for first time. Many these faint satellites are posited have been accreted as Magellanic Clouds (MCs). Using their six-dimensional phase-space information, we calculate orbital histories 13 and five classical dwarf spheroidals a combined MW+LMC+SMC potential determine which dynamically associated with MCs. These 18 separated into four...
Abstract Diffuse Galactic cirrus, or diffuse light (DGL), can be a prominent component in the background of deep wide-field imaging surveys. The DGL provides unique insights into physical and radiative properties dust grains our Milky Way, it also serves as contaminant on images, obscuring detection sources such low surface brightness galaxies. However, is challenging to disentangle from other components night sky. In this paper, we present technique for photometric characterization cirrus...
The Milky Way (MW) and M31 both harbor massive satellite galaxies, the Large Magellanic Cloud (LMC) M33, which may comprise up to 10 per cent of their host's total mass. Massive satellites can change orbital barycentre host-satellite system by tens kiloparsecs are cosmologically expected dwarf galaxies own. Assessing impact these effects depends crucially on histories LMC M33. Here, we revisit dynamics MW-LMC present first detailed analysis M31-M33 utilizing high precision proper motions...
Abstract The 3D velocities of M31 and M33 are important for understanding the evolution cosmological context Local Group. Their most massive stars detected by Gaia , we use Data Release 2 (DR2) to determine galaxy proper motions (PMs). We select members based on, e.g., parallax, PM, color–magnitude diagram location, local stellar density. PM rotation both galaxies is confidently detected, consistent with known line-of-sight curves: <?CDATA ${V}_{\mathrm{rot}}=-206\pm...
Abstract We measure homogeneous distances to M31 and 38 associated stellar systems (−16.8 ≤ M V −6.0), using time-series observations of RR Lyrae stars taken as part the Hubble Space Telescope Treasury Survey Satellites. From >700 orbits new/archival Advanced Camera for Surveys imaging, we identify >4700 determine their periods mean magnitudes a typical precision 0.01 day 0.04 mag. Based on period–Wesenheit–metallicity relationships consistent with Gaia eDR3 distance scale, uniformly...
Abstract We present Dark Energy Spectroscopic Instrument (DESI) observations of the inner halo M31, which reveal kinematics a recent merger—a galactic immigration event—in exquisite detail. Of 11,416 sources studied in 3.75 hr on-sky exposure time, 7438 are M31 with well-measured radial velocities. The intricate coherent kinematic structure positions and velocities individual stars: streams, wedges, chevrons. While hints structures have been previously detected this is first time they seen...
Abstract We present deep Hubble Space Telescope photometry of 10 targets from Treasury Program GO-14734, including six confirmed ultrafaint dwarf (UFD) galaxies, three UFD candidates, and one likely globular cluster. Six these are satellites of, or have interacted with, the Large Magellanic Cloud (LMC). determine their structural parameters using a maximum-likelihood technique. Using our newly derived half-light radius ( r h ) V -band magnitude M values in addition to literature for other...
Abstract We have determined the proper motions (PMs) of 12 dwarf galaxies in Local Group (LG), ranging from outer Milky Way (MW) halo to edge LG. used Hubble Space Telescope (HST) as first and Gaia second epoch using GaiaHub software. For Leo A Sag DIG, we also multi-epoch HST measurements relative background galaxies. Orbital histories derived these PMs show that two-thirds our sample are on infall with >90% certainty. The observed star formation first-infall dwarfs generally consistent...
Abstract High precision proper motion (PM) measurements are available for approximately 20% of all known dwarf satellite galaxies the Milky Way (MW). Here we extend Bayesian framework Patel et al. to include MW satellites with measured 6D phase-space information and apply it Illustris-Dark simulation constrain MW’s mass. Using properties each individually, find that scatter among mass estimates is reduced when magnitude specific orbital angular momentum ( j ) adopted, rather than their...
Abstract We present the first proper-motion (PM) measurements for dwarf elliptical galaxies NGC 147 and 185, two satellite of M31, using multiepoch Hubble Space Telescope (HST) imaging data with time baselines ∼8 yr. For each galaxy, we take an error-weighted average from HST Advanced Camera Surveys/WFC Wide Field 3/UVIS to determine PMs. Our final results PMs are ( μ W , N ) N147 = (−0.0232, 0.0378) ± (0.0143, 0.0146) mas yr −1 N185 (−0.0242, 0.0058) (0.0141, 0.0147) 185. The 2D direction...
Abstract We present the color–magnitude diagrams and star formation histories (SFHs) of seven ultra-faint dwarf galaxies: Horologium 1, Hydra 2, Phoenix Reticulum Sagittarius Triangulum Tucana derived from high-precision Hubble Space Telescope photometry. find that SFH each galaxy is consistent with them having created at least 80% stellar mass by z ∼ 6. For all galaxies, we quenching times older than 11.5 Gyr ago, compatible scenario in which reionization suppresses small dark matter halos....
Abstract A significant fraction of Milky Way (MW) satellites exhibit phase-space properties consistent with a coherent orbital plane. Using tailored N -body simulations spherical MW halo that recently captured massive (1.8 × 10 11 M ⊙ ) LMC-like satellite, we identify the physical mechanisms may enhance clustering poles objects orbiting MW. The LMC deviates dark matter particles from present-day random distribution. Instead, beyond R ≈ 50 kpc cluster near pole along sinusoidal pattern across...
Abstract We present new mass estimates for Andromeda (M31) using the orbital angular momenta of four satellite galaxies (M33, NGC 185, 147, and IC 10) derived from existing proper motions, distances, line-of-sight velocities. infer two masses M31: <?CDATA ${M}_{\mathrm{vir}}={2.85}_{-0.77}^{+1.47}\times {10}^{12}\,{M}_{\odot }$?> <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>vir</mml:mi> </mml:msub>...
Abstract We present the lifetime star formation histories (SFHs) for six ultrafaint dwarf (UFD; M V > − 7.0, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mn>4.9</mml:mn> <mml:mo><</mml:mo> <mml:msub> <mml:mrow> <mml:mi>log</mml:mi> </mml:mrow> <mml:mn>10</mml:mn> </mml:msub> <mml:mo stretchy="false">(</mml:mo> <mml:mi>M</mml:mi> <mml:mo>*</mml:mo> <mml:mi>z</mml:mi> <mml:mo>=</mml:mo> <mml:mn>0</mml:mn> stretchy="false">)</mml:mo>...
Abstract We present uniformly measured stellar metallicities of 463 stars in 13 Milky Way (MW) ultra-faint dwarf galaxies (UFDs; M V = −7.1 to −0.8) using narrowband CaHK (F395N) imaging taken with the Hubble Space Telescope. This represents largest homogeneous set UFDs, increasing number these by a factor 5 and doubling all known MW UFDs. provide first well-populated MDFs for this sample, 〈[Fe/H]〉 ranging from −3.0 −2.0 dex, σ [Fe/H] 0.3–0.7 dex. find nearly constant [Fe/H]∼ −2.6 over 3...
[Abbreviated] Context: Studies of the LMC's internal kinematics have provided a detailed view its structure, largely by exquisite proper motion data supplied Gaia. However, LoS velocities are only available for small subset Gaia data, limiting studies perpendicular to LMC disc plane. Aims: We synergise new SDSS-IV/V velocity measurements with increasing 5D phase-space sample almost factor three. interpret and model vertical structure disc. Methods: Split our into different stellar types....
Abstract The Panchromatic Hubble Andromeda Southern Treasury (PHAST) is a large 195-orbit Space Telescope program imaging ∼0.45 deg 2 of the southern half M31's star-forming disk at optical and near-ultraviolet (NUV) wavelengths. PHAST survey area extends northern coverage (PHAT) down to M31, covering out radius ∼13 kpc along major axis in total ∼two-thirds disk. This new legacy yields stellar photometry over 90 million resolved stars using Advanced Camera for Surveys (F475W F814W), Wide...
From $>1000$ orbits of HST imaging, we present deep homogeneous resolved star color-magnitude diagrams that reach the oldest main sequence turnoff and uniformly measured formation histories (SFHs) 36 dwarf galaxies ($-6 \ge M_V -17$) associated with M31 halo, for 10 additional fields in M31, M33, Giant Stellar Stream. our SFHs find: i) median stellar age quenching epoch satellites correlate galaxy luminosity galactocentric distance. Satellite present-day distance from predict satellite to...
Abstract Stellar streams in the Milky Way are promising detectors of low-mass dark matter (DM) subhalos predicted by ΛCDM. Passing induce perturbations that indicate presence subhalos. Understanding how known DM-dominated satellites impact is a crucial step toward using stream to constrain properties perturbers. Here, we cross-match Gaia Early Data Release 3 and SEGUE member catalog Cetus-Palca (CPS) with H3 for additional radial velocity measurements fit orbit CPS this six-dimensional (6D)...
Abstract From >1000 orbits of HST imaging, we present deep homogeneous resolved star color–magnitude diagrams that reach the oldest main-sequence turnoff and uniformly measured formation histories (SFHs) 36 dwarf galaxies (−6 ≥ M V −17) associated with M31 halo, for 10 additional fields in M31, M33, Giant Stellar Stream. our SFHs, find: (i) The median stellar age quenching epoch satellites correlate galaxy luminosity galactocentric distance. Satellite present-day distance from predict...
Abstract We present new proper motion (PM) measurements of the dwarf spheroidal galaxies (dSphs) Draco and Sculptor using multiepoch images obtained with Hubble Space Telescope ACS/WFC. Our PM results have uncertainties far lower than previous measurements, even those made same instrument. The for are , . implied Galactocentric velocity vectors radial tangential components: study detailed orbital histories both via numerical orbit integrations. Orbital periods found to be 1–2 Gyr 2–5 Gyr,...
A bottom up in situ proteomic method has been developed enabling the mapping of multiple blood signatures on intact ridges fingermarks by Matrix Assisted Laser Desorption Mass Spectrometry Imaging (MALDI‐MSI). This method, at a proof concept stage, builds upon recently published work demonstrating opportunity to profile and identify bloodstains via approach. The present protocol addresses limitation previously profiling with respect destructivity; destructivity should be avoided for evidence...
Space observatories like the Hubble Telescope and Gaia are providing unprecedented 6D phase space information of satellite galaxies. Such measurements can shed light on structure assembly history Local Group, but improved statistical methods needed to use them efficiently. Here we illustrate such a method using analogs Group's two most massive galaxies, Large Magellanic Cloud (LMC) Triangulum (M33), from Illustris dark-matter-only cosmological simulation. We Bayesian inference scheme...
We quantify the frequency of companions low redshift ($0.013 < z 0.0252$), dwarf galaxies ($2 \times 10^8$ M$_\odot <$ M$_{*} 5 10^9$ M$_\odot$) that are isolated from more massive in SDSS and compare against cosmological expectations using mock observations Illustris simulation. Dwarf multiples defined as 2 or dwarfs have angular separations > 55'', projected r$_p 150$ kpc relative line-of-sight velocities $\Delta V_{\rm LOS} km/s. While catalogs predict a factor than observed SDSS, mean...