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A renewed interest about the origin of \emph{r}-process elements has been stimulated by the multi-messenger observation of the gravitational event GW170817, with the detection of both gravitational waves and electromagnetic waves corresponding to the merger of two neutron stars. Such phenomenon has been proposed as one of the main sources of the \emph{r}-process. However, the origin of the \emph{r}-process elements at different metallicities is still under debate. We aim at investigating the origin of the \emph{r}-process elements in the Galactic thin disc population. From the sixth internal data release of the \emph{Gaia}-ESO we have collected a large sample of Milky Way thin- and thick-disc stars for which abundances of Eu, O, and Mg are available. The sample consists of members of 62 open clusters, located at a Galactocentric radius from $\sim 5$ kpc to $\sim 20$ kpc in the disc, in the metallicity range $[-0.5, 0.4]$ and covering an age interval from 0.1 to 7 Gy, and about 1300 Milky Way disc field stars in the metallicity range $[-1.5, 0.5]$. We compare the observations with the results of a chemical evolution model, in which we varied the nucleosynthesis sources for the three considered elements. Our main result is that Eu in the thin disc is predominantly produced by sources with short lifetimes, such as magneto-rotationally driven SNe. There is no strong evidence for additional sources at delayed times. Our findings do not imply that there cannot be a contribution from mergers of neutron stars in other environments, as in the halo or in dwarf spheroidal galaxies, but such a contribution is not needed to explain Eu abundances at thin disc metallicities., 20 pages, accepted for publication in A&A

Aims. In this work, we aim to make a differential comparison of the neutron-capture and p-process element molybdenum (Mo) in the stellar populations in the local disk(s) and the bulge, focusing on minimising possible systematic effects in the analysis. Methods. The stellar sample consists of 45 bulge and 291 local disk K-giants, observed with high-resolution optical spectra. The abundances are determined by fitting synthetic spectra using the SME-code. The disk sample is separated into thin- and thick-disk components using a combination of abundances and kinematics. The cosmic origin of Mo is investigated and discussed by comparing with previous published abundances of Mo and the neutron-capture elements cerium (Ce) and europium (Eu). Results. We determine reliable Mo abundances for 35 bulge and 282 disk giants with a typical uncertainty of [Mo/Fe]~0.2 and ~0.1 dex for the bulge and disk, respectively. Conclusions. We find that the bulge possibly is enhanced in [Mo/Fe] compared to the thick disk, which we do not observe in either [Ce/Fe] nor [Eu/Fe]. This might suggest a higher past star-formation rate in the bulge, however, since we do not observe the bulge to be enhanced in [Eu/Fe], the origin of the molybdenum enhancement is yet to be constrained. Although, the scatter is large, we may be observing evidence of the p-process contributing to the heavy element production in the chemical evolution of the bulge., Comment: Accepted for publication in A&A. 12 pages, 8 figures

In this study, L?/L?1 and L?/L?2 X-ray intensity ratios for gadolinium, dysprosium and erbium elements were experimentally determined. L X-ray intensity ratio measurements were gauged at several temperatures (50, 100, 50, 150, 200, 250, 300, 350 and 400 ?C) using an excitation energy of 59.54 keV ?-rays emitted from a 100 mCi 241Am radioactive source. L X-ray emission spectra were detected using a Si (Li) detector system with a resolution of 160 eV at 5.96 keV coupled with a computer-controlled multi-channel analyzer. L X-ray production crosssections (?L?, ?L?1 and ?L?2) of the lanthanide elements were calculated by assessing the emission spectra. The variation with temperature of each parameter was given in graphical forms and tabulated. It was observed that the parameters were affected by temperature. According to these results, it is determined that the L X-ray intensity ratios and L X-ray production cross-sections of pure Gd, Dy and Er elements changed and were affected by temperature., Scientific and Technological Research Council of Turkey (TUBITAK), Mrs. Cinan is thankful to the Scientific and Technological Research Council of Turkey (TUBITAK) for doctoral scholarship support.

High-resolution spectroscopy of stars on the red giant branch (RGB) of the globular cluster M15 has revealed a large (~1 dex) dispersion in the abundances of r-process elements, like Ba and Eu. Neutron star mergers (NSMs) have been proposed as a major source of the r-process. However, most NSM models predict a delay time longer than the timescale for cluster formation. One possibility is that a NSM polluted the surfaces of stars in M15 long after the cluster finished forming. In this case, the abundances of the polluting elements would decrease in the first dredge-up as stars turn on to the RGB. We present Keck/DEIMOS abundances of Ba in 66 stars along the entire RGB and the top of the main sequence. The Ba abundances have no trend with stellar luminosity (evolutionary phase). Therefore, the stars were born with the Ba they have today, and Ba did not originate in a source with a delay time longer than the timescale for cluster formation. In particular, if the source of Ba was a neutron star merger, it would have had a very short delay time. Alternatively, if Ba enrichment took place before the formation of the cluster, an inhomogeneity of a factor of 30 in Ba abundance needs to be able to persist over the length scale of the gas cloud that formed M15, which is unlikely., 10 pages, 2 figures, accepted to ApJL

The ground-state rotational band of the neutron-deficient californium (Z = 98) isotope 244Cf was identified for the first time and measured up to a tentative spin and parity of I I-pi = 20(+). The observation of the rotational band indicates that the nucleus is deformed. The kinematic and dynamic moments of inertia were deduced from the measured gamma-ray transition energies. The behavior of the dynamic moment of inertia revealed an up-bend due to a possible alignment of coupled nucleons in high-j orbitals starting at a rotational frequency of about (h) over bar (omega) = 0.20 MeV. The results were compared with the systematic behavior of the even-even N = 146 isotones as well as with available theoretical calculations that have been performed for nuclei in the region.

WOS: 000377324200034, In this paper, a summary of experimental data published in the period of time between 1955 to february-2016 was presented in a tabular form for L, subshell fluorescence yields (omega(L1), omega(L2) and omega(L3)) taken from different sources. First, a critical examination of these data using the weighted average values omega(Li-W) was presented. Then, an interpolation using the famous analytical function (omega(Li-W)/(1-omega(Li-W)))(1/4) the atomic number Z was proformed to deduce a new empirical L-i subshell fluorescence yields for elements in the range 40

Primordial nucleosynthesis, or Big-Bang Nucleosynthesis (BBN), is one of the three evidences for the Big-Bang model, together with the expansion of the Universe and the Cosmic Microwave Background. There is a good global agreement over a range of nine orders of magnitude between abundances of 4He, D, 3He and 7Li deduced from observations, and calculated in primordial nucleosynthesis. This comparison was used to determine the baryonic density of the Universe. For this purpose, it is now superseded by the analysis of the Cosmic Microwave Background (CMB) radiation anisotropies. However, there remain, a yet unexplained, discrepancy of a factor 3-5, between the calculated and observed lithium primordial abundances, that has not been reduced, neither by recent nuclear physics experiments, nor by new observations. We review here the nuclear physics aspects of BBN for the production of 4He, D, 3He and 7Li, but also 6Li, 9Be, 11B and up to CNO isotopes. These are, for instance, important for the initial composition of the matter at the origin of the first stars. Big-Bang nucleosynthesis, that has been used, to first constrain the baryonic density, and the number of neutrino families, remains, a valuable tool to probe the physics of the early Universe, like variation of "constants" or alternative theories of gravity., Invited Plenary Talk given at the 11th International Conference on Nucleus-Nucleus Collisions (NN2012), San Antonio, Texas, USA, May 27-June 1, 2012. To appear in the NN2012 Proceedings in Journal of Physics: Conference Series (JPCS)

In this paper we investigate the rotational band built upon a two-quasiparticle ${8}^{\ensuremath{-}}$ isomeric state of ${}^{252}$No up to spin ${I}^{\ensuremath{\pi}}$ $=$ ${22}^{\ensuremath{-}}$. The excited states of the band were populated with the ${}^{206}$Pb(${}^{48}\text{Ca},2n$) fusion-evaporation reaction. An unambiguous assignment of the structure of the ${8}^{\ensuremath{-}}$ isomer as a $7/{2}^{+}{[624]}_{\ensuremath{\nu}}\ensuremath{\bigotimes}9/{2}^{\ensuremath{-}}{[734]}_{\ensuremath{\nu}}$ configuration has been made on the basis of purely experimental data. Comparisons with triaxial self-consistent Hartree-Fock-Bogoliubov calculations using the D1S force and breaking time-reversal as well as $z$-signature symmetries are performed. These predictions are in agreement with present measurements. Mean-field calculations extended to similar states in ${}^{250}$Fm support the interpretation of the same two-neutron quasiparticle structure as the bandhead in both $N=150$ isotones.

The energies of 2-quasiparticle (2-qp) states in heavy shell-stabilized nuclei provide information on the single-particle states that are responsible for the stability of superheavy nuclei. We have calculated the energies of 2-qp states in (256)Rf, which suggest that a long-lived, low-energy 8(-) isomer should exist. A search was conducted for this isomer through a calorimetric conversion electron signal, sandwiched in time between implantation of a (256)Rf nucleus and its fission decay, all within the same pixel of a double-sided Si strip detector. A 17(5)-mu s isomer was identified. However, its low population, similar to 5(2)% that of the ground state instead of the expected similar to 30%, suggests that it is more likely a 4-qp isomer. Possible reasons for the absence of an electromagnetic signature of a 2-qp isomer decay are discussed. These include the favored possibility that the isomer decays by fission, with a half-life indistinguishably close to that of the ground state. Another possibility, that there is no 2-qp isomer at all, would imply an abrupt termination of axially symmetric deformed shapes at Z = 104, which describes nuclei with Z = 92-103 very well.

The neutron capture cross section of (14)C is of relevance for several nucleosynthesis scenarios such as inhomogeneous Big Bang models, neutron induced CNO cycles, and neutrino driven wind models for the r process. The (14)C(n,gamma) reaction is also important for the validation of the Coulomb dissociation method, where the (n,gamma) cross section can be indirectly obtained via the time-reversed process. So far, the example of (14)C is the only case with neutrons where both, direct measurement and indirect Coulomb dissociation, have been applied. Unfortunately, the interpretation is obscured by discrepancies between several experiments and theory. Therefore, we report on new direct measurements of the (14)C(n,gamma) reaction with neutron energies ranging from 20 to 800 keV. Physical Review C

High-resolution spectroscopic VLT/UVES observations are presented for the B-type main-sequence star, AV 304, in the Small Magellanic Cloud (SMC). These spectra have been analysed using LTE model-atmosphere techniques, to derive stellar atmospheric parameters and chemical compositions. As AV 304 is located within the hydrogen burning main-sequence band, its chemical composition should reflect that of the SMC interstellar medium (ISM). A detailed line-by-line differential analysis has been undertaken relative to a Galactic comparison star. A general metal deficiency for the a-process elements O, Si & S of -0.43 +/- 0.05 dex is found for AV 304, with iron having a similar underabundance. Oxygen may be relatively over-abundant by similar to0.1 dex and carbon and aluminium underabundant by similar to0.2 dex. A large nitrogen underabundance (of -1.2 dex relative to hydrogen and -0.7 dex relative to iron) is found. This is interpreted in terms of the CNO bi-cycle having been suppressed in the SMC. Furthermore, the large nitrogen deficiency is in excellent agreement with that found for SMC H II regions. Indeed, this represents a first for stellar astrophysics - confirming the low base-line nitrogen composition of the SMC ISM (viz. 12+log(N/H) similar to 6.66 +/- 0.10 dex).

The production of the p-process nuclides that we observe today in the Solar Systemis still uncertain. Recent Galactic Chemical Evolution (GCE) calculations, showedthat explaining the inventory of the p-nuclides by the contribution from Core col-lapse supernovae (ccSNe) alone is challenging, thus requiring a complementary con-tribution from thermonuclear supernovae (SNe Ia), assuming in this last case ans-process rich pre-explosive seeds distribution, built byneutron captures during theaccretion phase. Presently there are no complete stellar models calculating theseabundances. We calculate accreting white dwarfs (WDs) models with five differentinitial masses using the stellar code MESA. We then focus on the nucleosynthesiscalculating the full abundance distribution. In these models the dominant neutronsource are22Ne(α,n)25Mg, activated at the bottom of the convective thermal pulsedriven by the Helium flashes along the accretion phase, for WDmasses lower than1.26 M⊙, and13C(α,n)16O for WD masses equal or higher than 1.26 M⊙. We foundneutron densities up to few 1015cm−3in the most massive WDs. In particular, weobtain a strong production by neutron captures up to the Pb region, showing howthe classic assumption of a neutron-capture rich pre-explosive seeds distribution isjustified. Using these results, we compute the resulting explosive nucleosynthesis ofproton rich heavy stable isotopes using a multi-D SNe Ia model, and discuss the un-certainties affecting our results, focusing in particular on the nuclear reaction-rateswhich provide the dominant contribution to the production uncertainty, highlightingwhich of the identified key reactions are realistic candidates for future experiments.

The production of the p-process nuclides that we observe today in the Solar Systemis still uncertain. Recent Galactic Chemical Evolution (GCE) calculations, showedthat explaining the inventory of the p-nuclides by the contribution from Core col-lapse supernovae (ccSNe) alone is challenging, thus requiring a complementary con-tribution from thermonuclear supernovae (SNe Ia), assuming in this last case ans-process rich pre-explosive seeds distribution, built byneutron captures during theaccretion phase. Presently there are no complete stellar models calculating theseabundances. We calculate accreting white dwarfs (WDs) models with five differentinitial masses using the stellar code MESA. We then focus on the nucleosynthesiscalculating the full abundance distribution. In these models the dominant neutronsource are22Ne(α,n)25Mg, activated at the bottom of the convective thermal pulsedriven by the Helium flashes along the accretion phase, for WDmasses lower than1.26 M⊙, and13C(α,n)16O for WD masses equal or higher than 1.26 M⊙. We foundneutron densities up to few 1015cm−3in the most massive WDs. In particular, weobtain a strong production by neutron captures up to the Pb region, showing howthe classic assumption of a neutron-capture rich pre-explosive seeds distribution isjustified. Using these results, we compute the resulting explosive nucleosynthesis ofproton rich heavy stable isotopes using a multi-D SNe Ia model, and discuss the un-certainties affecting our results, focusing in particular on the nuclear reaction-rateswhich provide the dominant contribution to the production uncertainty, highlightingwhich of the identified key reactions are realistic candidates for future experiments.