A5079110937- Stellar, planetary, and galactic studies
- Astro and Planetary Science
- Gamma-ray bursts and supernovae
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Nuclear Physics and Applications
- Nuclear physics research studies
- Astronomical and nuclear sciences
- Radiation Detection and Scintillator Technologies
- Nuclear reactor physics and engineering
- Astronomical Observations and Instrumentation
- Pulsars and Gravitational Waves Research
- Astrophysical Phenomena and Observations
- Galaxies: Formation, Evolution, Phenomena
- History and Developments in Astronomy
- Particle Detector Development and Performance
- Atomic and Subatomic Physics Research
- High-pressure geophysics and materials
- Superconducting Materials and Applications
- Scientific Research and Discoveries
- Geomagnetism and Paleomagnetism Studies
- Planetary Science and Exploration
- Radiation Therapy and Dosimetry
- Calibration and Measurement Techniques
- Phase Equilibria and Thermodynamics
Istituto Nazionale di Fisica Nucleare, Sezione di Trieste
2021-2025
University of Trieste
2007-2025
Trieste Astronomical Observatory
2009-2024
Istituto Nazionale di Fisica Nucleare
2024
Instituto de Física Corpuscular
2024
Universitat de València
2024
Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas
2024
Institute for Fundamental Physics of the Universe
2019-2022
OncoArendi Therapeutics (Poland)
2021
University of Hertfordshire
2015-2019
Aims. We investigate statistical equilibrium of Cr in the atmospheres late-type stars to show whether systematic abundance discrepancy between I and II lines, as often encountered literature, is due deviations from LTE. Furthermore, we attempt interpret NLTE trend [Cr/Fe] with [Fe/H] using chemical evolution models for solar neighborhood. Methods. calculations are performed model atom, comprising 340 levels 6806 transitions total. make use quantum-mechanical photoionization cross-sections...
We present a semi-empirical, largely model-independent approach for estimating Galactic birth radii, r_birth, Milky Way disk stars. The technique relies on the justifiable assumption that negative radial metallicity gradient in interstellar medium (ISM) existed most of lifetime. Stars are projected back to their positions according observationally derived age and [Fe/H] with no kinematical information required. Applying our AMBRE:HARPS HARPS-GTO local samples, we show can constrain ISM...
Context: Manganese is predominantly synthesised in Type Ia supernova (SN Ia) explosions. Owing to the entropy dependence of Mn yield explosive thermonuclear burning, SNe involving near Chandrasekhar-mass white dwarfs (WDs) are predicted produce Fe ratios significantly exceeding those SN explosions sub-Chandrasekhar mass primary WDs. Of all current explosion models, only models near-Chandrasekhar WDs [Mn/Fe] > 0.0. Aims: Using specific yields for competing scenarios, we aim constrain relative...
Aims. We explore the problem of site production Eu. use also information present in observed spread Eu abundances early Galaxy, not only its average trend. Moreover, we extend to other heavy elements (Ba, Sr, Rb, Zr) our investigations provide additional constraints results. Methods. adopt a stochastic chemical evolution model taking into account inhomogeneous mixing. The adopted yields from neutron star mergers (NSM) and core-collapse supernovae (SNII) are those that able explain...
Very old halo stars were previously found to show at least four different abundance 'anomalies', which models of fast rotating massive (spinstars) can successfully account for: rise N/O and C/O, low 12C/13C a primary-like evolution Be B. Here we the impact these same in enrichment Sr Ba early Universe. We study if s-process production offer an explanation for observed spread [Sr/Ba] ratio with metallicity [Fe/H]< -2.5. By means chemical inhomogeneous model compute by Galactic halo. Our takes...
We present the first chemical evolution model for Enceladus, alias Gaia Sausage, to investigate star formation history of one most massive satellites accreted by Milky Way during a major merger event. Our best Enceladus nicely fits observed stellar [$\alpha$/Fe]-[Fe/H] abundance trends, and reproduces metallicity distribution function, assuming low efficiency, fast infall time scale, mild outflow intensity. predict median age stars $12.33^{+0.92}_{-1.36}$ Gyr, - at with our Galaxy...
We introduce the 4-metre Multi-Object Spectroscopic Telescope (4MOST), a new high-multiplex, wide-field spectroscopic survey facility under development for four-metre-class Visible and Infrared Survey Astronomy (VISTA) at Paranal. Its key specifications are: large field of view (FoV) 4.2 square degrees high multiplex capability, with 1624 fibres feeding two low-resolution spectrographs ($R = λ/Δλ\sim 6500$), 812 transferring light to high-resolution spectrograph \sim 20\,000$). After...
4MOST is a wide-field, high-multiplex spectroscopic survey facility under development for the VISTA telescope of European Southern Observatory (ESO). Its main science drivers are in fields galactic archeology, high-energy physics, galaxy evolution and cosmology. will particular provide complements to large area surveys coming from space missions like Gaia, eROSITA, Euclid, PLATO ground-based facilities VISTA, VST, DES, LSST SKA. The baseline concept features 2.5 degree diameter field-of-view...
We model the abundance gradients in disk of Milky Way for several chemical elements (O, Mg, Si, S, Ca, Sc, Ti, Co, V, Fe, Ni, Zn, Cu, Mn, Cr, Ba, La and Eu), compare our results with most recent homogeneous observational data. adopt a evolution able to well reproduce main properties solar vicinity. The assumes that formed inside-out timescale formation thin 7 Gyr vicinity, whereas halo on 0.8 Gyr. new empirical stellar yields derived best fit abundances ratios compute, first time, all...
Context. Thanks to the heroic observational campaigns carried out in recent years we now have large samples of metal-poor stars for which measurements detailed abundances exist. [...] These data hold important clues on nature contribution first stellar generations enrichment our Galaxy. Aims. We aim explain scatter Sr, Ba, Y, and Eu abundance ratio diagrams unveiled by halo stars. Methods. computed inhomogeneous chemical evolution models Galactic assuming different scenarios r-process site:...
Context. Strontium has proven itself to be one of the most important neutron-capture elements in study metal-poor stars. Thanks strong absorption lines Sr, they can detected even stars and also low-resolution spectra. However, we still cannot explain large star-to-star abundance scatter derive for
Nuclear uncertainties in the production of $p$ nuclei massive stars have been quantified a Monte Carlo procedure. Bespoke temperature-dependent were assigned to different types reactions involving from Fe Bi. Their simultaneous impact was studied postprocessing explosive trajectories for three stellar models. It found that grid mass zones model 25 $M_\odot$ star, which is widely used investigations nucleosynthesis, too crude properly resolve detailed temperature changes required describing...
The merging of two neutron stars (MNS) is thought to be the source short gamma-ray bursts (SGRB) and gravitational wave transients, as well main production site r-process elements like Eu. We have derived a new delay time distribution (DTD) for MNS from theoretical considerations we tested it against (i) SGRB redshift (ii) Galactic evolution Eu Fe, in particular [Eu/Fe] versus [Fe/H] relation. For comparison, also other DTDs, proposed literature. To address first item, convolved DTD with...
Abstract The ultrafaint dwarf galaxy Reticulum II was enriched by a single rare and prolific r -process event. content of thus provides unique opportunity to study metal mixing in relic first galaxy. Using multi-object high-resolution spectroscopy with VLT/GIRAFFE Magellan/M2FS, we identify 32 clear spectroscopic member stars measure abundances Mg, Ca, Fe, Ba where possible. We find <?CDATA ${72}_{-12}^{+10} \% $?> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll">...
ABSTRACT Stars move away from their birthplaces over time via a process known as radial migration, which blurs chemo–kinematic relations used for reconstructing the Milky Way (MW) formation history. To understand true evolution of MW, one needs to take into account effects this process. We show that stellar birth radii can be derived directly data with minimum prior assumptions on Galactic enrichment This is done by first recovering metallicity gradient, $\mathrm{ d}\mathrm{[Fe/H]}(R,...
We compute the evolution of abundances barium and europium in Milky Way we compare our results with observed from recent UVES Large Program "First Stars". use a chemical model which already reproduces majority observational constraints. confirm that is neutron capture element mainly produced low mass AGB stars during thermal-pulsing phase by 13C source, slow process. However, order to reproduce [Ba/Fe] vs. [Fe/H] as well Ba solar abundance, suggest should be also an r-process massive range...
We compute the chemical evolution of Galactic bulge to explain existence two main stellar populations recently observed. After comparing model results and observational data we suggest that old more metal poor population formed very fast (on a timescale 0.1-0.3 Gyr) by means an intense burst star formation initial mass function flatter than in solar vicinity whereas rich on longer (3 Gyr). predict differences mean abundances (-0.52 dex for <[Fe/H]>) which can be interpreted as metallicity...
An increasing fraction of carbon-enhanced metal-poor (CEMP) stars is found as their iron abundance, [Fe/H], decreases below [Fe/H] = -2.0. The CEMP-s have the highest absolute carbon abundances, [C/H], and are thought to owe enrichment in slow neutron-capture (s-process) elements mass transfer from a former asymptotic giant-branch (AGB) binary companion. most Fe-poor CEMP normally single, exhibit somewhat lower [C/H] than stars, but show no s-process element enhancement (CEMP-no stars). CNO...
The [Sr/Ba] and [Y/Ba] scatter observed in some galactic halo stars that are very metal-poor a few individual of the oldest known Milky Way globular cluster NGC 6522,have been interpreted as evidence early enrichment by massive fast-rotating (spinstars). Because 6522 is bulge cluster, suggestion was not only very-metal poor stars, but also at [Fe/H]~-1 could be used probes stellar nucleosynthesis signatures from earlier generations much higher metallicity. For suggestions were based on...
Galactic disc chemical evolution models generally ignore azimuthal surface density variation that can introduce abundance gradients. Recent observations, however, have revealed changes with azimuth in the gas and stellar components of both Milky Way external galaxies. To quantify effects spiral arm fluctuations on variations oxygen iron abundances We develop a new 2D galactic model, capable following not just radial but also inhomogeneities. The resulting from Way-like N-body formation...
The abundance ratios of manganese to iron in late-type stars across a wide metallicity range place tight constraints on the astrophysical production sites Fe-group elements. In this work, we investigate chemical evolution Mn Milky Way galaxy using high-resolution spectroscopic observations Galactic disc and halo stars, as well sample globular clusters. Our analysis shows that local thermodynamic equilibrium (LTE) leads strong imbalance ionisation I II lines. produces systematically (up 0.6...
Analysis of several spectroscopic surveys indicates the presence a bimodality between disc stars in abundance ratio space alpha /Fe versus Fe/H . The two stellar groups are commonly referred to as high-alpha and low-alpha sequences. Some models capable reproducing such invoke hiatus star formation history our Galaxy, whereas other explain sequences by means migration. Our aim is show that existence gap rate evident APOGEE DR17, if one plots Fe/alpha /H confirming previous suggestions. We...
Aims. We propose an explanation for the considerable scatter of abundances neutron capture elements observed in low-metallicity stars solar vicinity, compared to small star-to-star α-elements.
Aims. We model the chemical evolution of manganese relative to iron in three different stellar systems: Solar neighbourhood, Galactic bulge, and Sagittarius dwarf spheroidal galaxy, we compare our results with recent homogeneous observational data sets.
<i>Context. <i/>The evolution of C and O abundances in the Milky Way can impose strong constraints on stellar nucleosynthesis help understanding formation our Galaxy.<i>Aims. aim this paper is to review measured disk bulge Galaxy compare results predictions Galactic chemical models.<i>Methods. <i/>We adopt two successful models for disk, respectively. They assume same prescriptions but different histories star formation.<i>Results. data show a clear distinction between trend [C/O] thick thin...