A5038762170- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Galaxies: Formation, Evolution, Phenomena
- Gamma-ray bursts and supernovae
- Astrophysics and Star Formation Studies
- Astronomical Observations and Instrumentation
- Astro and Planetary Science
- History and Developments in Astronomy
- Adaptive optics and wavefront sensing
- Solar and Space Plasma Dynamics
- Time Series Analysis and Forecasting
- Neural Networks and Applications
- Advanced Control Systems Optimization
- Advanced Database Systems and Queries
- Simulation Techniques and Applications
- Advanced Image and Video Retrieval Techniques
- Ionosphere and magnetosphere dynamics
- Theological Perspectives and Practices
- Medical Image Segmentation Techniques
- Scientific Research and Discoveries
- Alkaline Phosphatase Research Studies
- Distributed and Parallel Computing Systems
- Radio Astronomy Observations and Technology
- Scientific Computing and Data Management
- Distributed systems and fault tolerance
University of Washington
2015-2023
City University of Seattle
2019-2022
Seattle University
2019-2022
University of Michigan–Ann Arbor
2011-2016
Large Synoptic Survey Telescope Corporation
2015
Michigan United
2012
Case Western Reserve University
2009
In a companion paper by Koposov et al., RR Lyrae from \textit{Gaia} Data Release 2 are used to demonstrate that stars in the Orphan stream have velocity vectors significantly misaligned with track, suggesting it has received large gravitational perturbation satellite of Milky Way. We argue such mismatch cannot arise due any realistic static Way potential and then explore perturbative effects Large Magellanic Cloud (LMC). find LMC can produce precisely observed motion-track we therefore use...
We present the discovery of three new Milky Way satellites from our search for compact stellar overdensities in photometric catalog Panoramic Survey Telescope and Rapid Response System 1 (Pan-STARRS 1, or PS1) 3pi survey. The first satellite, Laevens 3, is located at a heliocentric distance d=67+/-3 kpc. With total magnitude Mv=-4.4+/-0.3 half-light radius rh=7+/-2 pc, its properties resemble those outer halo globular clusters. second system, Draco II/Laevens 4 (Dra II), closer fainter...
We present the discovery of a faint Milky Way satellite, Laevens 2/Triangulum II, found in Panoramic Survey Telescope And Rapid Response System 3π imaging data and confirmed with follow-up wide-field photometry from Large Binocular Cameras. The stellar system, an absolute magnitude MV = −1.8 ± 0.5, heliocentric distance , half-mass–radius shows remarkable similarity to faint, nearby, small satellites such as Willman 1, Segue 2, Boötes II. II further populates region parameter space for which...
The Large Synoptic Survey Telescope (LSST) is a large-aperture, wide-field, ground-based survey system that will image the sky in six optical bands from 320 to 1050 nm, uniformly covering approximately $18,000$deg$^2$ of over 800 times. LSST currently under construction on Cerro Pachón Chile, and expected enter operations 2022. Once operational, explore wide range astrophysical questions, discovering "killer" asteroids examining nature Dark Energy. generate average 15 TB data per night,...
The Large Synoptic Survey Telescope is designed to provide an unprecedented optical imaging dataset that will support investigations of our Solar System, Galaxy and Universe, across half the sky over ten years repeated observation. However, exactly how LSST observations be taken (the observing strategy or "cadence") not yet finalized. In this dynamically-evolving community white paper, we explore detailed performance anticipated science expected depend on small changes strategy. Using...
We report on $g$, $r$ and $i$ band observations of the Interstellar Object 'Oumuamua (1I) taken 2017 October 29 from 04:28 to 08:40 UTC by Apache Point Observatory (APO) 3.5m telescope's ARCTIC camera. find that 1I's colors are $g-r=0.41\pm0.24$ $r-i=0.23\pm0.25$, consistent with visible spectra Masiero (2017), Ye et al. (2017) Fitzsimmons most comparable population Solar System C/D asteroids, Trojans, or comets. no evidence any cometary activity at a heliocentric distance 1.46 au,...
We use astrometry, broad-band photometry and variability information from the Data Release 2 of ESA's Gaia mission (GDR2) to identify members Orphan Stream (OS) across whole sky. The stream is traced above below celestial equator in both Galactic hemispheres, thus increasing its visible length ~ 210 degrees equivalent ~150 kpc physical extent. Taking advantage large number RR Lyrae stars OS, we extract accurate distances proper motions entire stretch tidal debris studied. As delineated by...
We present a deep imaging survey of the Virgo Cluster, designed to study connection between cluster galaxies and Virgo's diffuse intracluster light (ICL). Our observations span roughly 16 square degrees reach 3-sigma depth mu(B)=29.5 mu(V)=28.5 mag/arcsec^2. At these depths, limiting systematic uncertainties are astrophysical: scattered starlight from foreground Galactic dust, variations in faint background sources. The dust-scattered is well-traced by far-infrared imaging, making it...
The dwarf satellites of `giant' Milky Way (MW)-mass galaxies are our primary probes low-mass dark matter halos. number and velocities the satellite MW M31 initially puzzled galaxy formation theorists, but now reproduced well by many models. Yet, MW's M31's representative? Were models `overfit'? These questions motivate deep searches for outside Local Group. We present a survey `classical' ($M_{\star}$$\geqslant$4$\times$10$^5 M_{\odot}$) MW-mass M94 out to 150 kpc projected distance. find...
Vera C. Rubin Observatory is a ground-based astronomical facility under construction, joint project of the National Science Foundation and U.S. Department Energy, designed to conduct multi-purpose 10-year optical survey southern hemisphere sky: Legacy Survey Space Time. Significant flexibility in strategy remains within constraints imposed by core science goals probing dark energy matter, cataloging Solar System, exploring transient sky, mapping Milky Way. The survey's massive data...
We present a new satellite in the outer halo of Galaxy, first Milky Way found stacked photometric catalog Panoramic Survey Telescope and Rapid Response System 1 (Pan-STARRS1) Survey. From follow-up photometry obtained with WFI on MPG/ESO 2.2m telescope, we argue that object, located at heliocentric distance 145+/-17 kpc, is most distant globular cluster yet known. With total magnitude M_V=-4.3+/-0.2 half-light radius 20+/-2 pc, it shares properties extended clusters our Galaxy Andromeda...
We report the discovery of two new dwarf galaxies, Lacerta I/Andromeda XXXI (Lac I/And XXXI) and Cassiopeia III/Andromeda XXXII (Cas III/And XXXII), in stacked Pan-STARRS1 r_P1- i_P1-band imaging data. Both are luminous systems (M_V ~ -12) located at projected distances 20.3° 10.5° from M31. Lac I Cas III likely satellites Andromeda galaxy with heliocentric 756^{+44}_{-28} kpc 772^{+61}_{-56} kpc, respectively, corresponding M31-centric 275+/-7 144^{+6}_{-4} . The brightest recent Local...
We study the vertical structure of a stellar disc obtained from fully cosmological high-resolution hydrodynamical simulation formation Milky Way-like galaxy. At present day, disc's mean height shows well defined and strong pattern, with amplitudes as large 3 kpc in its outer regions. This pattern is result satellite– host halo–disc interaction reproduces, qualitatively, many observable properties Monoceros Ring. In particular we find material at distance (R ∼ 12–16 kpc, galactocentric)...
We present a means of characterizing and removing internal reflections between the CCD other optical surfaces in an astronomical camera. The stellar appear as out-of-focus images are not necessarily axisymmetric about star. Using long exposures very bright stars calibration we able to measure position, size, intensity function their position on field. also extended point-spread out one degree. Together this information can be used create empirical model excess light from reduce systematic...
We report the discovery of a thin stellar stream found in Pan-STARRS1 photometry near Galactic bulge constellation Ophiuchus. It appears as coherent structure colour-selected density maps produced to search for tidal debris around nearby globular clusters. The is exceptionally short and narrow; it about 2.5{\deg} long 6' wide projection. colour-magnitude diagram this object, which harbours blue horizontal-branch, consistent with an old relatively metal-poor population ([Fe/H]~-1.3) located...
We present a panoptic view of the stellar structure in Galactic disk's outer reaches commonly known as Monoceros Ring, based on data from Pan-STARRS1. These observations clearly show large extent overdensities both sides disk, extending between b = −25° and +35° covering over 130° longitude. The exhibits complex morphology with stream-like features sharp edge to north south. compare this map mock two published simulations aimed at explaining such structures one postulating an origin tidal...
We present the discovery of a new dwarf galaxy, Perseus I/Andromeda XXXIII, found in vicinity Andromeda (M31) stacked imaging data from Pan-STARRS1 3{\pi} survey. Located 27.9{\deg} away M31, I has heliocentric distance 785 +/- 65 kpc, compatible with it being satellite M31 at 374 +14/-10 kpc its host. The properties are typical for reasonably bright galaxy (M_V = -10.3 0.7), an exponential half-light radius r_h 1.7 0.4 arcminutes or 400 +105/-85 pc this distance, and moderate ellipticity...
ABSTRACT Using the Pan-STARRS1 survey, we derive limiting magnitude, spatial completeness, and density maps that use to probe three-dimensional structure estimate stellar mass of so-called Monoceros Ring. The Ring is an enormous complex sub-structure in outer Milky Way disk. It most visible across large Galactic Anticenter region, <?CDATA $120^\circ \lt l\lt 240^\circ $?> , $-30^\circ b\lt +40^\circ . We its profile along every line sight 2° × pixels over entire 30,000 deg 2 survey using...
Abstract Recent work has shown that Milky Way–mass galaxies display an incredible range of stellar halo properties, yet the origin this diversity is unclear. The nearby galaxy M81—currently interacting with M82 and NGC 3077—sheds unique light on problem. We present a Subaru Hyper Suprime-Cam survey resolved populations around M81, revealing M81's in never-before-seen detail. resolve to unprecedented V -band equivalent surface brightnesses 33 mag arcsec −2 produce first-ever global mass...
We report the discovery of a new dwarf galaxy, Andromeda XXIX, using data from recently-released Sloan Digital Sky Survey DR8, and confirmed by Gemini North telescope Multi-Object Spectrograph imaging data. And XXIX appears to be spheroidal separated on sky little more than 15 degrees M31, with distance inferred tip red giant branch 730kpc+/-75kpc, corresponding three dimensional separation M31 between 205kpc 227kpc (close M31's virial radius). Its absolute magnitude, as determined...
We use data from the Pan-STARRS1 survey to present a panoramic view of Sagittarius tidal stream in southern Galactic hemisphere. As result extensive sky coverage Pan-STARRS1, is visible along more than 60 degrees its orbit, nearly double length seen by SDSS. The recently discovered bifurcation also apparent, with fainter branch over at least 30 degrees. Using combination fitting both main sequence turn-off and red clump, we measure distance arms south. find that distances bright arm agree...
Using deep 21 cm H i data from the Green Bank Telescope we have detected an ≳18.3 kpc long gaseous extension associated with starbursting dwarf galaxy IC 10. The newly found feature stretches 13 to northwest and has a large radial velocity gradient reaching ∼65 km s−1 lower than 10 systemic velocity. A region of higher column density at end that possesses coherent (∼10 across ∼26') transverse suggests rotation may be satellite mass is 9.5 × 107 (d/805 kpc)2 M☉ new 7.1 105 M☉. An 10–M31 orbit...
We report the discovery of a new dwarf galaxy, Andromeda XXVIII, using data from recently released Sloan Digital Sky Survey Data Release 8. The galaxy is likely satellite Andromeda, and, at separation 365+17− 1 kpc, would be one most distant Andromeda's satellites. Its heliocentric distance 650+150− 80 and analysis its structure luminosity shows that it has an absolute magnitude MV = −8.5+0.4− 1.0 half-light radius rh 210+60− 50 pc, similar to many other faint Local Group dwarfs. With...
We present the fiducial sequences of a sample Galactic star clusters in five bands Pan-STARRS1 (PS1) photometric system (gP1, rP1, iP1, zP1, and yP1). These empirical – which include red giant sub-giant branches, main sequence, horizontal branch were defined from deep colour–magnitude diagrams reaching below oldest main-sequence turn-offs 13 globular 3 old open covering wide range metallicities ( − 2.4 ≲ [Fe/H] +0.4). find excellent agreement for nine common with previous studies similar...