R. Smiljanić
A5091598036- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Astro and Planetary Science
- Astronomical Observations and Instrumentation
- Gamma-ray bursts and supernovae
- Astronomical and nuclear sciences
- Nuclear and radioactivity studies
- Graphite, nuclear technology, radiation studies
- Adaptive optics and wavefront sensing
- Scientific Research and Discoveries
- History and Developments in Astronomy
- Spectroscopy and Laser Applications
- Galaxies: Formation, Evolution, Phenomena
- Photocathodes and Microchannel Plates
- Pulsars and Gravitational Waves Research
- Atmospheric Ozone and Climate
- Radioactive contamination and transfer
- Calibration and Measurement Techniques
- Radioactivity and Radon Measurements
- Spectroscopy and Chemometric Analyses
- Nuclear Physics and Applications
- Geomagnetism and Paleomagnetism Studies
- Real-time simulation and control systems
- Particle Accelerators and Free-Electron Lasers
Nicolaus Copernicus Astronomical Center
2015-2024
University of Turku
2024
Brera Astronomical Observatory
2024
Polish Academy of Sciences
2016-2023
Centro de Astrobiología
2022
Arcetri Astrophysical Observatory
2022
Durham University
2022
Trieste Astronomical Observatory
2022
Universidad Nacional Autónoma de México
2006-2014
European Southern Observatory
2006-2014
(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...
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...
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...
Gravitational waves from black-hole merging events have revealed a population of extra-galactic BHs residing in short-period binaries with masses that are higher than expected based on most stellar evolution models - and also known stellar-origin black holes our Galaxy. It has been proposed those high-mass the remnants massive metal-poor stars. Gaia astrometry is to uncover many Galactic wide-binary systems containing dormant BHs, which may not detected before. The study this will provide...
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....
(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...
We use Gaia-ESO Survey iDR4 data to explore the Mg-Al anti-correlation in globular clusters, that were observed as calibrators, a demonstration of quality and analysis. The results compare well with available literature, within 0.1 dex or less, after small (compared internal spreads) offset between UVES GIRAFFE 0.10-0.15 was taken into account. In particular, we present for first time NGC 5927, one most metal-rich clusters studied literature so far [Fe/H]=-0.49 dex, included connect open...
The radial metallicity distribution in the Galactic thin disc represents a crucial constraint for modelling formation and evolution. Open clusters allow us to derive both its evolution over time. In this paper we perform first investigation of present-day based on [Fe/H] determinations late type members pre-main-sequence clusters. Because their youth, these are therefore essential tracing current inter-stellar medium metallicity. We used products Gaia-ESO Survey analysis 12 young regions...
We present an empirical model of age-dependent photospheric lithium depletion, calibrated using a large, homogeneously-analysed sample 6200 stars in 52 open clusters, with ages from 2--6000 Myr and $-0.3<{\rm [Fe/H}]<0.2$, observed the Gaia-ESO spectroscopic survey. The is used to obtain age estimates posterior probability distributions measurements Li I 6708A equivalent width for individual (pre) main sequence $3000 < T_{\rm eff}/{\rm K} <6500$, domain where determination HR diagram either...
The discovery of lithium-rich giants contradicts expectations from canonical stellar evolution. Here we report on the serendipitous 20 Li-rich observed during Gaia-ESO Survey, which includes first nine giant stars known towards CoRoT fields. Most our have near-solar metallicities and parameters consistent with being before luminosity bump. This is difficult to reconcile deep mixing models proposed explain lithium enrichment, because these can only operate at later evolutionary stages: or...
The Gaia-ESO Survey is a large public spectroscopic survey that aims to derive radial velocities and fundamental parameters of about 10^5 Milky Way stars in the field clusters. Observations are carried out with multi-object optical spectrograph FLAMES, using simultaneously medium resolution (R~20,000) GIRAFFE high (R~47,000) UVES spectrograph. In this paper, we describe methods software used for data reduction, derivation velocities, quality control FLAMES-UVES spectra. Data reduction has...
Context. Chemically inhomogeneous populations are observed in most globular clusters, but not open clusters. Cluster mass seems to play a key role the existence of multiple populations.
Context. The nature of the metallicity gradient inside solar circle (RGC < 8 kpc) is poorly understood, but studies Cepheids and a small sample open clusters suggest that it steepens in inner disk.
Stellar evolution models predict that internal mixing should cause some sodium overabundance at the surface of red giants more massive than ~ 1.5--2.0 Msun. The aluminium abundance not be affected. Nevertheless, observational results disagree about presence and/or degree Na and Al overabundances. In addition, Galactic chemical adopting different stellar yields lead to quite predictions for behavior [Na/Fe] [Al/Fe] versus [Fe/H]. Overall, observed trends these abundances with metallicity are...
Context. Open clusters are recognised as excellent tracers of Galactic thin-disc properties. At variance with intermediate-age and old open clusters, for which a significant number studies is now available, younger than ≲150 Myr have been mostly overlooked in terms their chemical composition until recently (with few exceptions). On the other hand, previous investigations seem to indicate an anomalous behaviour young includes (but not limited to) slightly sub-solar iron (Fe) abundances...
The Gaia-ESO survey (GES) is now in its fifth and last year of observations, has already produced tens thousands high-quality spectra stars all Milky Way components. This paper presents the strategy behind selection astrophysical calibration targets, ensuring that GES results on radial velocities, atmospheric parameters, chemical abundance ratios will be both internally consistent easily comparable with other literature results, especially from large spectroscopic surveys Gaia. particularly...
The spatial distribution of elemental abundances and their time evolution are among the major constraints to disentangle scenarios formation Galaxy. We used sample open clusters available in final release Gaia-ESO survey trace Galactic radial abundance iron ratio gradients, evolution. selected member stars 62 clusters, with ages from 0.1 about 7~Gyr, located thin disc at Galactocentric radii 6 21~kpc. analysed shape resulting [Fe/H] gradient, average gradients [El/H] [El/Fe] combining...
The last decade has seen a revolution in our knowledge of the Galaxy thanks to Gaia and asteroseismic space missions ground-based spectroscopic surveys. To complete this picture, it is necessary map ages its stellar populations. During recent years, dependence on time abundance ratios involving slow (s) neutron-capture $\alpha$ elements (called chemical-clocks) been used provide estimates ages, usually limited volume close Sun. We aim analyse relations chemical clocks Galactic disc extending...
<i>Context. <i/>Evolved low-mass stars (0.8 <i>≤<i/> 2.5) of a wide range metallicity bear signatures non-standard mixing event in their surface abundances Li, C, and N, <sup>12<sup/>C/<sup>13<sup/>C ratio. A Na overabundance has also been reported some giants open clusters but remains controversial. The cause the extra-mixing attributed to thermohaline convection that should take place after RGB bump for on early-AGB more massive objects.<i>Aims. <i/>To track occurrence this process over...