A5088453908- 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
- Astro and Planetary Science
- Adaptive optics and wavefront sensing
- History and Developments in Astronomy
- Scientific Research and Discoveries
- Astrophysical Phenomena and Observations
- Dark Matter and Cosmic Phenomena
- Cosmology and Gravitation Theories
- Geophysics and Gravity Measurements
- Astrophysics and Cosmic Phenomena
- Solar and Space Plasma Dynamics
- Pulsars and Gravitational Waves Research
- Spectroscopy and Laser Applications
- Material Science and Thermodynamics
- Astronomical and nuclear sciences
- Atmospheric Ozone and Climate
- Radio Astronomy Observations and Technology
- Impact of Light on Environment and Health
- Historical Astronomy and Related Studies
- Phase Equilibria and Thermodynamics
Australian National University
2016-2025
ARC Centre of Excellence for All-sky Astrophysics
2019-2025
ASTRO-3D
2021-2024
North Carolina Central University
2024
Mount Stromlo Observatory
2014-2023
ACT Government
2023
NASA Research Park
2022
Boston University
2019
Quest University Canada
2019
University of Virginia
2017
view Abstract Citations (2369) References (40) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS On the Disks of Spiral and S0 Galaxies Freeman, K. C. Surface photometry shows that most spiral galaxies have two main components: a spheroidal component, an exponential disk component with radial surface-brightness distribution 1(R) = Ioe 5. The is subject this paper. First, for in centrifugal equilibrium surface density (R) , we derive circular-velocity field...
▪ Abstract The formation and evolution of galaxies is one the great outstanding problems astrophysics. Within broad context hierachical structure formation, we have only a crude picture how like our own came into existence. A detailed physical where individual stellar populations can be associated with (tagged to) elements protocloud far beyond current understanding. Important clues begun to emerge from both Galaxy (near-field cosmology) high redshift universe (far-field cosmology). Here...
One of the world's most distinguished astrophysicists presents a comprehensive theoretical treatment dynamical evolution globular clusters. Lyman Spitzer's research in this field established framework for decades investigation. Now he summarizes unified, systematic way branch astrophysics with its still challenging problems.Originally published 1988.The Princeton Legacy Library uses latest print-on-demand technology to again make available previously out-of-print books from backlist...
We report on our search for microlensing towards the Large Magellanic Cloud (LMC). Analysis of 5.7 years photometry 11.9 million stars in LMC reveals 13 - 17 events. This is significantly more than $\sim$ 2 to 4 events expected from lensing by known stellar populations. The timescales ($\that$) range 34 230 days. estimate optical depth with $2 < \that 400$ days be 1.2 ^{+0.4}_ {-0.3} \ten{-7}$, an additional 20% 30% systematic error. spatial distribution mildly inconsistent LMC/LMC disk...
We present the first data release of Radial Velocity Experiment (RAVE), an ambitious spectroscopic survey to measure radial velocities and stellar atmosphere parameters (temperature, metallicity, surface gravity) up one million stars using Six Degree Field multiobject spectrograph on 1.2 m UK Schmidt Telescope Anglo-Australian Observatory. The RAVE program started in 2003, obtaining medium-resolution spectra (median R = 7500) Ca-triplet region (8410-8795 Å) for southern hemisphere drawn from...
The GALAH survey is a large high-resolution spectroscopic using the newly commissioned HERMES spectrograph on Anglo-Australian Telescope. provides (R ~28,000) spectra in four passbands for 392 stars simultaneously over 2 degree field of view. goal to unravel formation and evolutionary history Milky Way, fossil remnants ancient star events which have been disrupted are now dispersed throughout Galaxy. Chemical tagging seeks identify such solely from their common unique chemical signatures;...
We report new constraints on the local escape speed of our Galaxy. Our analysis is based a sample high velocity stars from RAVE survey and two previously published datasets. use cosmological simulations disk galaxy formation to motivate assumptions shape distribution, allowing for significantly more precise measurement compared previous studies. find that lies within range $498\kms < \ve 608 \kms$ (90 per cent confidence), with median likelihood $544\kms$. The fact $\ve^2$ greater than...
The HI Parkes All-Sky Survey (HIPASS) Catalogue forms the largest uniform catalogue of sources compiled to date, with 4,315 identified purely by their content. data comprise southern region declination <+2 deg HIPASS, first blind survey cover entire sky. RMS noise for this is 13 mJy/beam and velocity range -1,280 12,700 km/s. Data search, verification parametrization methods are discussed along a description measured quantities. Full made available astronomical community including positions,...
The acquisition of H i Parkes All Sky Survey (HIPASS) southern sky data commenced at the Australia Telescope National Facility's 64-m telescope in 1997 February, and was completed 2000 March. HIPASS is deepest survey yet south declination +2°, sensitive to emission out 170 h75−1 Mpc. characteristic root mean square noise images 13.3 mJy. This paper describes observations, which comprise 23 020 eight-degree scans 9-min duration, details techniques used calibrate image data. processing...
The ACS Nearby Galaxy Survey Treasury (ANGST) is a systematic survey to establish legacy of uniform multi-color photometry resolved stars for volume-limited sample nearby galaxies (D < 4 Mpc).The volume encompasses 69 in diverse environments, including close pairs, small & large groups, filaments, and truly isolated regions.The include nearly complete range morphological types spanning factor ∼ 10 luminosity star formation rate.The data consists images taken with the Advanced Camera Surveys...
The MACHO Project is a search for dark matter in the form of massive compact halo objects (MACHOs). Photometric monitoring millions stars Large Magellanic Cloud (LMC), Small (SMC), and Galactic bulge used to gravitational microlensing events caused by these otherwise invisible objects. Analysis first 2.1 yr photometry 8.5 million LMC reveals eight candidate events. This substantially more than number expected (~1.1) from lensing known stellar populations. timescales (t) range 34 145 days. We...
We present the HIPASS Bright Galaxy Catalog (BGC), which contains 1000 H I brightest galaxies in southern sky as obtained from Parkes All-Sky Survey (HIPASS). The selection of sources is based on their peak flux density (Speak ≳ 116 mJy) measured spatially integrated spectrum. derived masses range ∼107 to 4 × 1010 M⊙. While BGC (z < 0.03) complete Speak, only a subset ∼500 can be considered (F 25 Jy km s-1). total 158 new redshifts. These belong 91 for no optical or infrared counterparts...
Data Release 5 (DR5) of the Radial Velocity Experiment (RAVE) is fifth data release from a magnitude-limited (9< I < 12) survey stars randomly selected in southern hemisphere. The RAVE medium-resolution spectra ($R\sim7500$) covering Ca-triplet region (8410-8795\AA) span complete time frame start observations 2003 to their completion 2013. velocities 520,781 457,588 unique are presented, which 255,922 stellar have parallaxes and proper motions Tycho-Gaia astrometric solution (TGAS) Gaia DR1....
The structure and kinematics of the recognized stellar components Milky Way are explored, based on well-determined atmospheric parameters kinematic quantities for 32360 "calibration stars" from Sloan Digital Sky Survey (SDSS) its first extension, SDSS-II, which included sub-survey Extension Galactic Understanding Exploration (SEGUE). Full space motions a sub-sample 16,920 stars, exploring local volume within 4 kpc Sun, used to derive velocity ellipsoids inner- outer-halo Galaxy, as well...
The ensemble of chemical element abundance measurements for stars, along with precision distances and orbit properties, provides high-dimensional data to study the evolution Milky Way. With this third release Galactic Archaeology HERMES (GALAH) survey, we publish 678 423 spectra 588 571 mostly nearby stars (81.2% are within <2 kpc), observed spectrograph at Anglo-Australian Telescope. This (hereafter GALAH+ DR3) includes all observations from GALAH Phase 1 (bright, main, faint 70%),...
Several extragalactic H I surveys using a λ 21 cm 13-beam focal plane array will begin in early 1997 the Parkes 64 m telescope. These are designed to detect efficiently nearby galaxies that have failed be identified optically because of low optical surface brightness or high extinction. We discuss scientific and technical aspects multibeam receiver, including astronomical objectives, feed, receiver correlator design data acquisition. A comparison with other telescopes shows has significant...
view Abstract Citations (431) References (83) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Structure of Young Star Clusters in the Large Magellanic Cloud Elson, Rebecca A. W. ; Fall, S. Michael Freeman, Kenneth C. authors present surface brightness profiles, based on star counts and aperture photometry, for 10 rich young clusters Cloud. To investigate dynamical evolution clusters, they derive mass-to-light ratios from stellar population models. They...
We present the stellar atmospheric parameters (effective temperature, surface gravity, overall metallicity), radial velocities, individual abundances, and distances determined for 425,561 stars, which constitute fourth public data release of RAdial Velocity Experiment (RAVE). The are computed using a new pipeline, based on algorithms MATISSE DEGAS. spectral degeneracies Two Micron All Sky Survey photometric information now better taken into consideration, improving parameter determination...
The disk galaxy simulated using our chemodynamic formation code, GCD+, is shown to have a thick-disk component. This evidenced by the velocity dispersion versus age relation for solar neighborhood stars, which clearly shows an abrupt increase in at look-back time of approximately 8 Gyr, and excellent agreement with observation. These stars are formed from gas that accreted during chaotic period hierarchical clustering high redshift. scenario be consistent observations both Milky Way...
The Galactic Archaeology with HERMES (GALAH) survey is a large-scale stellar spectroscopic of the Milky Way and designed to deliver chemical information complementary large number stars covered by $Gaia$ mission. We present GALAH second public data release (GALAH DR2) containing 342,682 stars. For these stars, collaboration provides parameters abundances for up 23 elements community. Here we target selection, observation, reduction detailed explanation how spectra were analysed estimate...
We made new estimates of the Galactic escape speed at various Galactocentric radii using latest data release RAdial Velocity Experiment (RAVE DR4). Compared to previous studies we have a database that is larger by factor 10, as well reliable distance for almost all stars. Our analysis based on statistical rigorously selected sample 90 high-velocity halo stars from RAVE and previously published set. calibrated extensively tested our method suite cosmological simulations formation Milky...
We present the metallicity results from ARGOS spectroscopic survey of Galactic bulge. Our aim is to understand formation bulge: did it form via mergers, as expected Lambda CDM theory, or disk instabilities, suggested by its boxy/peanut shape, both? have obtained spectra for 28,000 stars at a spectral resolution R = 11,000. From these spectra, we determined stellar parameters and distances an accuracy < 1.5 kpc. The in inner Galaxy span large range [Fe/H], -2.8 [Fe/H] +0.6. spatial...
The RAdial Velocity Experiment survey, combined with proper motions and distance estimates, can be used to study in detail stellar kinematics the extended solar neighbourhood (solar suburb). Using 72 365 red-clump stars, we examine mean velocity components 3D between 6 < R 10 kpc −2 Z 2 kpc, concentrating on north–south differences. Simple parametric fits (R, Z) trends for Vϕ dispersions are presented. We confirm recently discovered gradient Galactocentric radial velocity, VR, finding that...