A5059972628- Stellar, planetary, and galactic studies
- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Astrophysical Phenomena and Observations
- Astronomical Observations and Instrumentation
- Gamma-ray bursts and supernovae
- Astrophysics and Cosmic Phenomena
- Impact of Light on Environment and Health
- Adaptive optics and wavefront sensing
- Astro and Planetary Science
- Cosmology and Gravitation Theories
- Spectroscopy and Laser Applications
- History and Developments in Astronomy
- Radio Astronomy Observations and Technology
- Dark Matter and Cosmic Phenomena
- Spectroscopy Techniques in Biomedical and Chemical Research
- Spectroscopy and Chemometric Analyses
- Plant Water Relations and Carbon Dynamics
- Atmospheric Ozone and Climate
- Remote Sensing in Agriculture
- Water Quality Monitoring and Analysis
- Particle Accelerators and Free-Electron Lasers
- Advanced Fluorescence Microscopy Techniques
- Atomic and Molecular Physics
Swinburne University of Technology
2003-2024
University of California, Santa Cruz
2015-2024
ARC Centre of Excellence for All-sky Astrophysics
2023-2024
ASTRO-3D
2023-2024
Queensland University of Technology
2024
San Jose State University
2021
Diego Portales University
2021
Max Planck Institute for Astronomy
2017
University of Colorado Colorado Springs
2001-2012
University of California System
2010
Globular cluster (GC) systems have now been studied in galaxies ranging from dwarfs to giants and spanning the full Hubble sequence of morphological types. Imaging spectroscopy with Space Telescope large ground-based telescopes together established that most bimodal color distributions reflect two subpopulations old GCs: metal-poor metal-rich. The characteristics both are correlated those their parent galaxies. We argue GCs formed low-mass dark matter halos early universe properties biased...
Variable X-ray and gamma-ray emission is characteristic of the most extreme physical processes in Universe, studying sources these energetic photons has been a major driver astronomy for past 50 years. Here we present multiwavelength observations unique selected transient, discovered by Swift, which was accompanied bright across electromagnetic spectrum, whose properties are unlike any previously observed source. We pinpoint event to center small, star-forming galaxy at redshift z=0.3534....
Recently a population of large, very low surface brightness, spheroidal galaxies was identified in the Coma cluster. The apparent survival these Ultra Diffuse Galaxies (UDGs) rich cluster suggests that they have high masses. Here we present stellar kinematics Dragonfly 44, one largest UDGs, using 33.5 hr integration with DEIMOS on Keck II telescope. We find velocity dispersion 47 km/s, which implies dynamical mass M_dyn=0.7x10^10 M_sun within its deprojected half-light radius r_1/2=4.6 kpc....
Perhaps the most noteworthy of recent findings in extragalactic globular cluster (GC) research are multimodal GC metallicity distributions seen massive early-type galaxies. We explore origin these distinct populations, implications for galaxy formation and evolution, identify several new properties systems. First, when we separate metal-rich metal-poor subpopulations, galaxies with bimodal distributions, find that mean GCs correlates well parent luminosity but ones does not. This indicates...
We present a new catalog of photometric and spectroscopic data on M31 globular clusters (GCs). The includes optical near-infrared photometry for substantial fraction the 435 cluster candidates. use these to determine reddening intrinsic colors individual clusters, we find that extinction laws in Galaxy are not significantly different. There significant (up 0.2 mag V-K) offsets between clusters' simple stellar population predicted by synthesis models; suggest due systematic errors models....
We present a study of globular clusters (GCs) in 17 relatively nearby early-type galaxies, based on deep F555W and F814W images from the Wide Field Planetary Camera 2, board Hubble Space Telescope. A detailed analysis color distributions, cluster sizes, luminosity functions is performed compared with GCs Milky Way. In nearly all cases, KMM test returns high confidence level for hypothesis that sum two Gaussians provides better fit to observed distribution than single Gaussian, although...
view Abstract Citations (262) References (55) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Extragalactic Globular Clusters. III. Metallicity Comparisons and Anomalies Brodie, Jean P. ; Huchra, John Using a method based on the strengths of six absorption line indices measured in integrated spectra, we have derived metallicities for 22 globular clusters associated with Sc galaxy, M33, 10 giant elliptical M87, eight Sb(r)I-II M81, three Fornax dwarf galaxy....
We use a combined imaging and spectroscopic survey of the nearby central cluster galaxy, M87, to assemble sample 34 confirmed ultra compact dwarfs (UCDs) with half-light radii >~ 10 pc measured from Hubble Space Telescope images. This doubles existing in making it largest such for any while extending detection UCDs unprecedentedly low luminosities (MV = -9). With this expanded sample, we find no correlation between size luminosity, contrast previous suggestions, general galactocentric...
We introduce and provide the scientific motivation for a wide-field photometric spectroscopic chemodynamical survey of nearby early-type galaxies (ETGs) their globular cluster (GC) systems. The SAGES Legacy Unifying Globulars GalaxieS (SLUGGS) is being carried out primarily with Subaru/Suprime-Cam Keck/DEIMOS. former provides deep gri imaging over 900 arcmin2 field-of-view to characterize GC host galaxy colors spatial distributions, identify targets. NIR Ca ii triplet line-of-sight...
We present the most extensive combined photometric and spectroscopic study to date of enormous globular cluster (GC) system around M87, central giant elliptical galaxy in nearby Virgo cluster. Using observations from DEIMOS LRIS at Keck, Hectospec on MMT, we derive new, precise radial velocities for 451 GCs with projected radii ~ 5 185 kpc. combine these measurements literature data a total sample 737 objects, which use re-examination kinematics GC M87. The are analyzed context archival...
We present a spectro-photometric survey of 2522 extragalactic globular clusters (GCs) around twelve early-type galaxies, nine which have not been published previously. Combining space-based and multi-colour wide field ground-based imaging, with spectra from the Keck DEIMOS instrument, we obtain an average 160 GC radial velocities per galaxy, high velocity precision 15 km/s GC. After studying photometric properties systems, such as their spatial colour distributions, focus on kinematics...
We describe the structural and kinematic properties of first compact stellar systems discovered by AIMSS project. These spectroscopically confirmed objects have sizes ($\sim$6 $<$ R$_{\rm e}$ [pc] 500) masses ($\sim$2$\times$10$^{6}$ M$_*$/M$_\odot$ 6$\times$10$^{9}$) spanning range massive globular clusters (GCs), ultra dwarfs (UCDs) elliptical galaxies (cEs), completely filling gap between star galaxies. Several are close analogues to prototypical cE, M32. objects, which more than...
A candidate diffuse stellar substructure was previously reported in the halo of nearby dwarf starburst galaxy NGC 4449 by Karachentsev et al. We map and analyze this feature using a unique combination deep integrated-light images from Black Bird 0.5-meter telescope, high-resolution wide-field 8-meter Subaru which resolve nebulosity into stream red giant branch stars, confirm its physical association with 4449. The properties imply massive spheroidal progenitor, after complete disruption will...
Although the colour distribution of globular clusters in massive galaxies is well known to be bimodal, spectroscopic metallicity has been measured only a few galaxies. After redefining calcium triplet index–metallicity relation, we use our relation derive 903 11 early-type This largest sample cluster metallicities yet assembled. We compare these with those derived from Lick indices finding good agreement. In six eight sufficient numbers high-quality spectra find bimodality distribution. Our...
We present Hubble Space Telescope imaging of two ultra diffuse galaxies (UDGs) with measured stellar velocity dispersions in the Coma cluster. The galaxies, Dragonfly 44 and DFX1, have effective radii 4.7 kpc 3.5 $47^{+8}_{-6}$ km/s $30^{+7}_{-7}$ km/s, respectively. Both are associated a striking number compact objects, tentatively identified as globular clusters: $N_{\rm gc}=74\pm 18$ for gc}=62\pm 17$ DFX1. clusters is far higher than expected from luminosities but consistent expectations...
We study the total mass–density profile for a sample of 14 fast-rotator early-type galaxies (stellar masses ). combine observations from SLUGGS and ATLAS surveys to map out stellar kinematics in two dimensions, median radius four half-light radii Re (or 10 kpc) maximum 2.0–6.2 4–21 kpc). use axisymmetric dynamical models based on Jeans equations, which allow spatially varying anisotropy; employ quite general profiles dark halos; and, particular, do not place any restrictions slope. This is...
We present stellar kinematics of 22 nearby early-type galaxies (ETGs), based on two-dimensional (2D) absorption line spectroscopy out to ∼2–4 Re (effective radii), as part the ongoing SLUGGS Survey. The span a factor 20 in intrinsic luminosity, well full range environment and ETG morphology. Our data consist good velocity resolution (σinst ∼ 25 km s−1) integrated stellar-light spectra extracted from individual slitlets custom made Keck/DEIMOS slitmasks. extract measurements (V, σ, h3, h4)...
Abstract We present spatially resolved stellar kinematics of the well-studied ultra-diffuse galaxy (UDG) Dragonfly 44, as determined from 25.3 hr observations with Keck Cosmic Web Imager. The luminosity-weighted dispersion within half-light radius is <?CDATA ${\sigma }_{1/2}={33}_{-3}^{+3}$?> km s −1 , lower than what we had inferred before a DEIMOS spectrum in H α region. There no evidence for rotation, ${V}_{\max }/\langle \sigma \rangle \lt 0.12$?> (90% confidence) along major axis,...
There is good evidence that the centers of massive early-type galaxies have a bottom-heavy stellar initial mass function (IMF) compared to IMF Milky Way. Here we study radial variation within such galaxies, using combination high quality Keck spectroscopy and new suite population synthesis models cover wide range in metallicity. As previous studies this series, are fitted directly spectra treat all elemental abundance ratios as free parameters. Using newly obtained for six including deep...
Abstract The large and diffuse galaxies NGC 1052–DF2 1052–DF4 have been found to very low dark matter content a population of luminous globular clusters (GCs). Accurate distance measurements are key interpreting these observations. Recently, the was be 20.0 ± 1.6 Mpc by identifying tip red giant branch (TRGB) in 12 orbits Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) imaging. Here we present 40 HST ACS data use measure its TRGB. TRGB is readily apparent color–magnitude...
Abstract It has been shown that ultra-diffuse galaxies (UDGs) have higher specific frequencies of globular clusters, on average, than other dwarf with similar luminosities. The UDG NGC 5846-UDG1 is among the most extreme examples cluster–rich found so far. Here we present new Hubble Space Telescope observations and analysis this galaxy its cluster system. We find hosts 54 ± 9 three to four times more any previously known a luminosity reported in previous studies. With L V ,gal ≈ 6 × 10 7 ⊙ (...
ABSTRACT We use spectral energy distribution fitting to place constraints on the stellar populations of 59 ultra-diffuse galaxies (UDGs) in low-to-moderate density fields MATLAS survey. routine prospector, coupled with archival data optical from Dark Energy Camera Legacy Survey, and near- mid-infrared imaging Wide-field Infrared Survey Explorer, recover masses, ages, metallicities, star formation time-scales UDGs. find that a subsample UDGs lies within scatter mass–metallicity relation (MZR)...