A5079277840- 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
- Cosmology and Gravitation Theories
- Astro and Planetary Science
- Adaptive optics and wavefront sensing
- Astrophysical Phenomena and Observations
- History and Developments in Astronomy
- Astronomical and nuclear sciences
- Astrophysics and Cosmic Phenomena
- Remote Sensing in Agriculture
- Radio Astronomy Observations and Technology
- CCD and CMOS Imaging Sensors
- Impact of Light on Environment and Health
- Geomagnetism and Paleomagnetism Studies
- Advanced Optical Sensing Technologies
- Scientific Research and Discoveries
- Historical Astronomy and Related Studies
- Dark Matter and Cosmic Phenomena
- Alexander von Humboldt Studies
- Historical Geography and Cartography
- Structural Health Monitoring Techniques
Australian National University
2016-2025
Mount Stromlo Observatory
2008-2019
Université de Montréal
2004
Netherlands Institute for Radio Astronomy
2003
Max Planck Institute for Astrophysics
2003
University of Basel
1992-1998
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...
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...
Predictions of the concordance cosmological model (CCM) structures in environment large spiral galaxies are compared with observed properties Local Group galaxies. Five new, most probably irreconcilable problems uncovered: 1) A wide variety published CCM models consistently predict some form relation between dark-matter-mass and luminosity for Milky Way (MW) satellite galaxies, but none is observed. 2) The mass function luminous sub-haloes predicted by contains too few satellites dark matter...
As part of preparations for a southern sky search faint Milky Way dwarf galaxy satellites, we report the discovery stellar overdensity in Sloan Digital Sky Survey Data Release 5, lying at an angular distance only 1.5 degrees from recently discovered Bo{\"o}tes dwarf. The was detected well above statistical noise by employing sophisticated data mining algorithm and does not correspond to any catalogued object. Overlaid isochrones using population synthesis models show that color-magnitude...
We present a new accurate measurement of the HI mass function galaxies from HIPASS Bright Galaxy Catalog, sample 1000 with highest peak flux densities in southern hemisphere (Koribalski et al. 2003). This spans nearly four orders magnitude (from log M_HI/M_sun=6.8 to 10.6, H0=75) and is largest selected date. develop bivariate maximum likelihood technique measure space density galaxies, show that this robust method, insensitive effects large scale structure. The resulting can be fitted...
In this study we present first results from multi-wavelength Hubble Space Telescope (HST) observations of the Galactic globular cluster GC NGC2808 as an extension UV Legacy Survey GCs (GO-13297 and previous proprietary HST archive data). Our analysis allowed us to disclose a multiple-stellar-population phenomenon in even more complex than previously thought. We have separated at least five different populations along main sequence red giant branch (RGB), that name A, B, C, D E (though finer...
Both major galaxies in the Local Group host planar distributions of co-orbiting satellite galaxies, Vast Polar Structure (VPOS) Milky Way and Great Plane Andromeda (GPoA). The Λ cold dark matter (ΛCDM) cosmological model did not predict these features. However, according to three recent studies properties GPoA flattening VPOS are common features among subhalo based ΛCDM systems, can be naturally explained by satellites being acquired along gas streams. We point out some methodological issues...
Both major galaxies in the Local Group (LG) are surrounded by thin planes of mostly co-orbiting satellite galaxies, vast polar structure (VPOS) around Milky Way (MW) and Great Plane Andromeda (GPoA) M31. We summarize current knowledge concerning these structures compare their relative orientations re-determining properties a common coordinate system. The existence similar, coherent both LG motivates an investigation distribution more distant non-satellite LG. This results discovery two...
We present a high resolution spectroscopic analysis of 62 red giants in the Milky Way globular cluster NGC5286. have determined abundances representative light proton-capture, alpha, Fe-peak and neutron-capture element groups, combined them with photometry multiple sequences observed along colour-magnitude diagram. Our principal results are: (i) broad, bimodal distribution s-process abundance ratios, two main s-poor s-rich groups; (ii) substantial star-to-star Fe variations, stars having...
We have analysed deep R-band images, down to a limiting surface brightness of 26.5 R-mag arcsec$^{-2}$ (equivalent ~28 B-mag arcsec$^{-2}$), 5 cD galaxies determine the shape profiles their extended stellar envelopes. Both de Vaucouleurs R^{1/4} model and Sersic's R^{1/n} model, on own, provide poor description galaxies. This is due presence outer envelopes, thought accumulated over merger history central cluster galaxy also from tidal stripping at larger radii. therefore simultaneously fit...
We present an abundance analysis of 96 horizontal branch (HB) stars in NGC2808, a globular cluster exhibiting complex multiple stellar population pattern. These are distributed different portions the HB and cover wide range temperature. By studying chemical abundances this sample, we explore connection between morphology enrichment history populations. For lying on red HB, use GIRAFFE UVES spectra to determine Na, Mg, Si, Ca, Sc, Ti, Cr, Mn, Fe, Ni, Zn, Y, Ba, Nd abundances. colder, blue...
We present high-precision multi-band photometry for the globular cluster (GC) M2. combine analysis of photometric data obtained from Hubble Space Telescope UV Legacy Survey Galactic GCs GO-13297, with chemical abundances by Yong et al.(2014), and compare models in order to analyze multiple stellar sequences we identified color-magnitude diagram (CMD). find three main components, composed metal-poor, metal-intermediate, metal-rich stars (hereafter referred as population A, B, C,...
We report the discovery of an ultra-faint Milky Way satellite galaxy in constellation Pegasus. The concentration stars was detected by applying our overdensity detection algorithm to SDSS-DR 10 and confirmed with deeper photometry from Dark Energy Camera at 4-m Blanco telescope. Fitting model isochrones indicates that this object, Pegasus III, features old metal-poor stellar population ([Fe/H]$\sim-2.1$) a heliocentric distance $205\pm20$ kpc. new system has estimated half-light radius...
The horizontal branch (HB) morphology of globular clusters (GCs) is mainly determined by metallicity. However, the fact that GCs with almost same metallicity exhibit different HB morphologies demonstrates at least one more parameter needed to explain morphology. It has been suggested these should be a global varies from GC GC, and other non-global within GC. In this study we provide empirical evidence corroborating idea. We used photometric catalogs obtained Advanced Camera for Surveys (ACS)...
The split main sequences (MSs) and extended MS turnoffs (eMSTOs) detected in a few young clusters have demonstrated that these stellar systems host multiple populations differing number of properties such as rotation and, possibly, age.We analyze Hubble Space Telescope photometry for thirteen with ages between ~40 ~1000 Myrs different masses. Our goal is to investigate the first time occurrence large sample clusters. We find all exhibit eMSTO phenomenon stars more massive than ~1.6 solar...
We report the discovery of a new ultra-faint Milky Way satellite candidate, Horologium II (Hor II), detected in Dark Energy Survey Y1A1 public data. Hor features half-light radius pc and total luminosity that place it realm dwarf galaxies on size–luminosity plane. The stellar population is consistent with an old (∼13.5 Gyr) metal-poor ([Fe/H] ) isochrone at distance modulus , or heliocentric 78 ± 8 kpc, color–magnitude diagram. has similar to Sculptor spheroidal galaxy (∼82 kpc) recently...
The Milky Way and Andromeda galaxy are each surrounded by a thin plane of satellite galaxies that may be corotating. Cosmological simulations predict most systems close to isotropic with random motions, so those two well-studied often interpreted as rare statistical outliers. We test this assumption using the kinematics around Centaurus A galaxy. Our analysis reveals evidence for corotation in narrow plane: 16 A's satellites kinematic data, 14 follow coherent velocity pattern aligned long...
The 'chromosome map' diagram (ChM) proved a successful tool to identify and characterize multiple populations (MPs) in 59 Galactic Globular Clusters (GCs). Here, we construct ChMs for 11 GCs of both Magellanic Clouds (MCs) with different ages compare MPs extra-Galactic environments, explore whether this phenomenon is universal through 'place' 'time'. are detected five clusters. fractions 1G stars, ranging from about 50% more than 80%, significantly higher those observed similar present-day...
Dwarf galaxy satellite systems are essential probes to test models of structure formation, making it necessary establish a census dwarf galaxies outside our own Local Group. We present deep FORS2 VI band images from the ESO Very Large Telescope for 15 candidates in Centaurus group galaxies. confirm nine dwarfs be members CenA by measuring their distances using Bayesian approach determine tip red giant branch luminosity. have also fitted theoretical isochrones measure mean metallicities. The...
Abstract We present chemical abundances and velocities of five stars between 0.3 1.1 kpc from the center Tucana II ultrafaint dwarf galaxy (UFD) high-resolution Magellan/MIKE spectroscopy. find that every star is deficient in metals (−3.6 < [Fe/H] −1.9) neutron-capture elements as characteristic UFD stars, unambiguously confirming their association with II. Other (e.g., C, iron peak) largely follow trends suggest faint core-collapse supernovae (SNe) dominated early evolution see a...
A catalog of Southern anomalous-velocity HI clouds at Decl. < +2 deg is presented, based on data from the Parkes All-Sky Survey (HIPASS). The improved sensitivity (5sigma: T_B = 0.04 K) and resolution (15.5') HIPASS results in a substantial increase number individual (1956, as well 41 galaxies) compared to previous surveys. Most high-velocity emission features, HVCs, have filamentary morphology are loosely organized into large complexes extending over tens degrees. In addition, 179...
The Northern HIPASS catalogue (NHICAT) is the northern extension of catalogue, HICAT (Meyer et al. 2004). This adds sky area between declination range +2 deg < dec. +25.5 to HICAT's -90 deg. a blind HI survey using Parkes Radio Telescope covering 71% (including this extension) and heliocentric velocity -1,280 km/s 12,700 . entire Virgo Cluster region has been observed in HIPASS. galaxy NHICAT, contains 1002 sources with v_hel > 300 Sources -300 were excluded avoid contamination by...