A5085593747- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Astronomical Observations and Instrumentation
- Gamma-ray bursts and supernovae
- Astro and Planetary Science
- Galaxies: Formation, Evolution, Phenomena
- Astronomical and nuclear sciences
- Astrophysical Phenomena and Observations
- Adaptive optics and wavefront sensing
- History and Developments in Astronomy
- Astrophysics and Cosmic Phenomena
- Pulsars and Gravitational Waves Research
- Spectroscopy and Laser Applications
- Atmospheric Ozone and Climate
- Space Exploration and Technology
- Phase Equilibria and Thermodynamics
- SAS software applications and methods
- Spectroscopy and Chemometric Analyses
- Natural Products and Biological Research
- Calibration and Measurement Techniques
- Scientific Measurement and Uncertainty Evaluation
- Archaeology and ancient environmental studies
- Laser Design and Applications
- X-ray Spectroscopy and Fluorescence Analysis
Lund University
2015-2024
Lund Science (Sweden)
2016-2024
Campbell Collaboration
2019
Max Planck Institute for Astronomy
2019
Max Planck Society
2019
University of Cambridge
2014
Leibniz Institute for Astrophysics Potsdam
2014
University of Arizona
2013
National Observatory
2013
European Southern Observatory
2007-2011
ABRIDGED: METHODS: We have conducted a high-resolution spectroscopic study of 714 F and G dwarf subgiant stars in the Solar neighbourhood. The star sample has been kinematically selected to trace Galactic thin thick disks their extremes...... determination stellar parameters elemental abundances is based on standard 1-D LTE analysis using equivalent width measurements (R=40000-110000) high signal-to-noise (S/N=150-300) spectra obtained with..... RESULTS: .... Our data show that there an old...
Based on spectra from F and G dwarf stars, we present elemental abundance trends in the Galactic thin thick disks metallicity regime . Our findings can be summarized as follows. 1) Both show smooth distinct that, at sub-solar metallicities, are clearly separated. 2) For α-elements disk shows signatures of chemical enrichment SNe type Ia. 3) The age sample is mean older than sample. 4) Kinematically, there exist stars with super-solar metallicities. these findings, together other constraints...
Based on high-resolution spectra obtained during gravitational microlensing events we present a detailed elemental abundance analysis of 32 dwarf and subgiant stars in the Galactic bulge. [ABRIDGED], now have 58 microlensed bulge dwarfs subgiants that been homogeneously analysed. The main characteristics sample findings can be drawn are: (i) metallicity distribution (MDF) is wide spans all metallicities between [Fe/H]=-1.9 to +0.6; (ii) dip MDF around solar was apparent our previous smaller...
(Abridged) We have used the atmospheric parameters, [alpha/Fe] abundances and radial velocities, determined from Gaia-ESO Survey GIRAFFE spectra of FGK-type stars (iDR1), to provide a chemo-kinematical characterisation disc stellar populations. focuss on subsample 1016 with high quality covering volume |Z|<4.5kpc R in range 2-13kpc. identified thin thick separation vs [M/H] plane, thanks presence low-density region number density distribution. The seem lie progressively thinner layers...
The Gaia-ESO Survey is obtaining high-quality spectroscopic data for about 10^5 stars using FLAMES at the VLT. UVES high-resolution spectra are being collected 5000 FGK-type stars. These analyzed in parallel by several state-of-the-art methodologies. Our aim to present how these analyses were implemented, discuss their results, and describe a final recommended parameter scale defined. We also precision (method-to-method dispersion) accuracy (biases with respect reference values) of...
Spectroscopic surveys of the Milky Way's stars have revealed spatial, chemical and kinematical structures that encode its history. In this work, we study their origins using a cosmological zoom simulation, VINTERGATAN, Way-mass disc galaxy. We find in connection to last major merger at $z\sim 1.5$, accretion leads rapid formation an outer, metal-poor, low-[$\alpha$/Fe] gas around inner, metal-rich galaxy containing old high-[$\alpha$/Fe] stars. This event bimodality [$\alpha$/Fe] over range...
In the last 15 years different ground-based spectroscopic surveys have been started (and completed) with general aim of delivering stellar parameters and elemental abundances for large samples Galactic stars, complementing Gaia astrometry. Among those surveys, Gaia-ESO Public Spectroscopic Survey (GES), only one performed on a 8m class telescope, was designed to target 100,000 stars using FLAMES ESO VLT (both Giraffe UVES spectrographs), covering all Milky Way populations, special focus open...
WEAVE, the new wide-field, massively multiplexed spectroscopic survey facility for William Herschel Telescope, will see first light in late 2022. WEAVE comprises a 2-degree field-of-view prime-focus corrector system, nearly 1000-multiplex fibre positioner, 20 individually deployable 'mini' integral field units (IFUs), and single large IFU. These systems feed dual-beam spectrograph covering wavelength range 366$-$959\,nm at $R\sim5000$, or two shorter ranges $R\sim20\,000$. After summarising...
Context. The Gaia-ESO Public Spectroscopic Survey is an ambitious project designed to obtain astrophysical parameters and elemental abundances for 100 000 stars, including large representative samples of the stellar populations in Galaxy, a well-defined sample 60 (plus 20 archive) open clusters. We provide internally consistent results calibrated on benchmark stars star clusters, extending across very wide range ages. This provides legacy data set intrinsic value, equally wide-ranging...
Based on high-resolution spectra obtained with the MIKE spectrograph Magellan telescopes, we present detailed elemental abundances for 20 red giant stars in outer Galactic disk, located at Galactocentric distances between 9 and 13 kpc. The disk sample is complemented samples of giants from inner solar neighborhood, analyzed using identical methods. For beyond 10 kpc, only find chemical patterns associated local thin even far above plane. Our results show that relative densities thick disks...
We study the relationship between age, metallicity, and alpha-enhancement of FGK stars in Galactic disk. The results are based upon analysis high-resolution UVES spectra from Gaia-ESO large stellar survey. explore limitations observed dataset, i.e. accuracy parameters selection effects that caused by photometric target preselection. find colour magnitude cuts survey suppress old metal-rich young metal-poor stars. This suppression may be as high 97% some regions age-metallicity relationship....
We present a detailed elemental abundance study of 90 F and G dwarf, turn-off, subgiant stars in the Galactic bulge. Based on high-resolution spectra acquired during gravitational microlensing events, stellar ages abundances for 11 elements (Na, Mg, Al, Si, Ca, Ti, Cr, Fe, Zn, Y Ba) have been determined. Four main findings are presented: (1) wide metallicity distribution with distinct peaks at [Fe/H] = −1.09, −0.63, −0.20, + 0.12, 0.41; (2) ahigh fraction intermediate-age to young where > 0...
[ABRIDGED] Based on high-resolution (R~42000 to 48000) and high signal-to-noise (S/N~50 150) spectra obtained with UVES/VLT, we present detailed elemental abundances (O, Na, Mg, Al, Si, Ca, Ti, Cr, Fe, Ni, Zn, Y, Ba) stellar ages for 26 microlensed dwarf subgiant stars in the Galactic bulge. The analysis is based equivalent width measurements standard 1-D LTE MARCS model atmospheres. We also NLTE Li line synthesis of 7Li at 670.8 nm. show that bulge metallicity distribution (MDF)...
We show that the Galactic thick disk reaches at least solar metallicities, and it experienced strong chemical enrichment during a period of ~3 Gyr, ending around 8-9 Gyr ago. This finding puts further constraints on relation interface between thin disks, their formation processes. Our results are based detailed elemental abundance analysis 261 kinematically selected F G dwarf stars in neighborhood: 194 likely members 67 disk, range -1.3<[Fe/H]<+0.4.
Knowledge of abundance ratios as functions metallicity can lead to insights on the origin and evolution our Galaxy its stellar populations. We aim trace chemical neutron-capture elements Sr, Zr, La, Ce, Nd, Sm, Eu in Milky Way disk constrain formation sites these well probe Galactic thin thick disks. Using spectra high resolution signal-to-noise we determine abundances for a sample 593 F G dwarf stars Solar neighbourhood. present results Sm Eu. find that show trends similar what is observed...
AIMS: The aim of this study is to investigate the origin and evolution Sc, V, Mn, Co for a homogeneous statistically significant sample stars probing different populations Milky Way, in particular thin thick disks. METHODS: Using high-resolution spectra obtained with MIKE, FEROS, SOFIN, FIES, UVES HARPS spectrographs, we determine abundances large F G dwarfs Solar neighbourhood. method based on spectral synthesis using one-dimensional (1-D), plane-parallel, LTE model stellar atmospheres...
(Abridged) We analyzed the stellar parameters and radial velocities of ~1200 stars in five bulge fields as determined from Gaia-ESO survey data (iDR1). use VISTA Variables The Via Lactea (VVV) photometry to obtain reddening values by using a semi-empirical T_eff-color calibration. From Gaussian decomposition metallicity distribution functions, we unveil clear bimodality all fields, with relative size components depending specific position on sky. In agreement some previous studies, find mild...
Aims. Until recently, most high-resolution spectroscopic studies of the Galactic thin and thick discs were mostly confined to objects in solar vicinity. Here we aim at enlarging volume which individual chemical abundances are used characterise discs, using first internal data release Gaia-ESO survey (GES iDR1).
The spatial distribution of elemental abundances in the disc our Galaxy gives insights both on its assembly process and subsequent evolution, stellar nucleogenesis different elements. Gradients can be traced using several types objects as, for instance, (young old) stars, open clusters, HII regions, planetary nebulae. We aim at tracing radial distributions elements produced through nucleosynthetic channels -the alpha-elements O, Mg, Si, Ca Ti, iron-peak Fe, Cr, Ni Sc - by Gaia-ESO idr4...
Photometry alone is not sufficient to unambiguously distinguish between ultra-faint star clusters and dwarf galaxies because of their overlap in morphological properties. Here we report on VLT/GIRAFFE spectra candidate member stars two recently discovered satellites Reticulum 2 Horologium 1, obtained as part the ongoing Gaia-ESO Survey. We identify 18 members 5 1. find have a velocity dispersion ~3.22 km/s, implying M/L ratio ~ 500. inferred stellar parameters for all candidates mean...