- ID:
- ivo://CDS.VizieR/J/MNRAS/451/3693
- Title:
- Stellar yields and the initial mass function
- Short Name:
- J/MNRAS/451/3693
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a set of 144 Galactic chemical evolution models applied to a Milky Way analogue, computed using four sets of low+intermediate star nucleosynthetic yields, six massive star yield compilations, and six functional forms for the initial mass function. A comparison is made between a grid of multiphase chemical evolution models computed with these yield combinations and empirical data drawn from the Milky Way's disc, including the solar neighbourhood. By means of a {chi}^2^ methodology, applied to the results of these multiphase models, the best combination of stellar yields and initial mass function capable of reproducing these observations is identified.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/857/111
- Title:
- Stellar yields of rotating first stars. II.
- Short Name:
- J/ApJ/857/111
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Recent theory predicts that first stars are born with a massive initial mass of >~100M_{sun}_. Pair-instability supernova (PISN) is a common fate for such massive stars. Our final goal is to prove the existence of PISNe and thus the high-mass nature of the initial mass function in the early universe by conducting abundance profiling, in which properties of a hypothetical first star is constrained by metal-poor star abundances. In order to determine reliable and useful abundances, we investigate the PISN nucleosynthesis taking both rotating and nonrotating progenitors for the first time. We show that the initial and CO core mass ranges for PISNe depend on the envelope structures: nonmagnetic rotating models developing inflated envelopes have a lower shifted CO mass range of ~70-125_M{sun}_, while nonrotating and magnetic rotating models with deflated envelopes have a range of ~80-135_M{sun}_. However, we find no significant difference in explosive yields from rotating and nonrotating progenitors, except for large nitrogen production in nonmagnetic rotating models. Furthermore, we conduct the first systematic comparison between theoretical yields and a large sample of metal-poor star abundances. We find that the predicted low [Na/Mg]~-1.5 and high [Ca/Mg]~0.5-1.3 abundance ratios are the most important to discriminate PISN signatures from normal metal-poor star abundances, and confirm that no currently observed metal-poor star matches with the PISN abundance. An extensive discussion on the nondetection is presented.
- ID:
- ivo://CDS.VizieR/J/A+A/637/A6
- Title:
- Stripped-envelope stars Binary Evolution Models
- Short Name:
- J/A+A/637/A6
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Massive binaries that merge as compact objects are the progenitors of gravitational-wave sources. Most of these binaries experience one or more phases of mass transfer, during which one of the stars loses part or all of its outer envelope and becomes a stripped-envelope star. The evolution of the size of these stripped stars is crucial in determining whether they experience further interactions and their final fate. We present new calculations of stripped-envelope stars based on binary evolution models computed with the MESA stellar evolution code. We use these to investigate their radius evolution as a function of mass and metallicity. We further discuss their pre- supernova observable characteristics and potential consequences of their evolution on the properties of supernovae from stripped stars. At high metallicity we find that practically all of the hydrogen-rich envelope is removed, in agreement with earlier findings. Only progenitors with initial masses below 10\Msun expand to large radii (up to 100R_{sun}_), while more massive progenitors stay compact. At low metallicity, a substantial amount of hydrogen remains and the progenitors can, in principle, expand to giant sizes (>400R_{sun}_), for all masses we consider. This implies that they can fill their Roche lobe anew. We show that the prescriptions commonly used in population synthesis models underestimate the stellar radii by up to two orders of magnitude. We expect that this has consequences for the predictions for gravitational-wave sources from double neutron star mergers, in particular for their metallicity dependence.
- ID:
- ivo://CDS.VizieR/J/ApJ/819/114
- Title:
- Strong lensing mass modeling of 4 HFF clusters
- Short Name:
- J/ApJ/819/114
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We conduct precise strong lensing mass modeling of four Hubble Frontier Field (HFF) clusters, Abell 2744, MACS J0416.1-2403, MACS J0717.5+3745, and MACS J1149.6+2223, for which HFF imaging observations are completed. We construct a refined sample of more than 100 multiple images for each cluster by taking advantage of the full-depth HFF images, and conduct mass modeling using the glafic software, which assumes simply parametrized mass distributions. Our mass modeling also exploits a magnification constraint from the lensed SN Ia HFF14Tom for Abell 2744 and positional constraints from the multiple images S1-S4 of the lensed supernova SN Refsdal for MACS J1149.6+2223. We find that our best-fitting mass models reproduce the observed image positions with rms errors of ~0.4", which are smaller than rms errors in previous mass modeling that adopted similar numbers of multiple images. Our model predicts a new image of SN Refsdal with a relative time delay and magnification that are fully consistent with a recent detection of reappearance. We then construct catalogs of z~6-9 dropout galaxies behind the four clusters and estimate magnification factors for these dropout galaxies with our best-fitting mass models. The dropout sample from the four cluster fields contains ~120 galaxies at z>~6, about 20 of which are predicted to be magnified by a factor of more than 10. Some of the high-redshift galaxies detected in the HFF have lensing-corrected magnitudes of M_UV_~-15 to -14. Our analysis demonstrates that the HFF data indeed offer an ideal opportunity to study faint high-redshift galaxies. All lensing maps produced from our mass modeling will be made available on the Space Telescope Science Institute website (https://archive.stsci.edu/prepds/frontier/lensmodels/).
- ID:
- ivo://CDS.VizieR/J/MNRAS/448/2766
- Title:
- Strong lines in the optical/NIR for SN 2002bo
- Short Name:
- J/MNRAS/448/2766
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 1D non-local thermodynamic equilibrium time-dependent radiative transfer simulations of a Chandrasekhar-mass delayed-detonation model which synthesizes 0.51 M_{sun}_ of ^56^Ni, and confront our results to the Type Ia supernova (SN Ia) 2002bo over the first 100d of its evolution. Assuming only homologous expansion, this same model reproduces the bolometric and multiband light curves, the secondary near-infrared (NIR) maxima, and the optical and NIR spectra. The chemical stratification of our model qualitatively agrees with previous inferences by Stehle et al. (2005MNRAS.360.1231S), but reveals significant quantitative differences for both iron-group and intermediate-mass elements. We show that +/-0.1 M_{sun}_ (i.e. +/-20 per cent) variations in ^56^Ni mass have a modest impact on the bolometric and colour evolution of our model. One notable exception is the U band, where a larger abundance of iron-group elements results in less opaque ejecta through ionization effects, our model with more ^56^Ni displaying a higher near-ultraviolet flux level. In the NIR range, such variations in ^56^Ni mass affect the timing of the secondary maxima but not their magnitude, in agreement with observational results. Moreover, the variation in the I, J, and K_s_ magnitudes is less than 0.1 mag within ~ 10d from bolometric maximum, confirming the potential of NIR photometry of SNe Ia for cosmology. Overall, the delayed-detonation mechanism in single Chandrasekhar-mass white dwarf progenitors seems well suited for SN 2002bo and similar SNe Ia displaying a broad SiII 6355{AA} line. Whatever multidimensional processes are at play during the explosion leading to these events, they must conspire to produce an ejecta comparable to our spherically symmetric model.
- ID:
- ivo://CDS.VizieR/J/A+A/327/1039
- Title:
- Structure and evolution of low-mass stars
- Short Name:
- J/A+A/327/1039
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Properties of Very Low mass stars for different initial metallicity [M/H] and Helium mass fraction: mass (in solar mass), age (in Gyrs) effective temperature (in K), log of luminosity (in solar L), radius (10^10cm), central temperature Tc (in K) and density RHOc (in gr/cm-3). Abundances of light elements are normalised to their initial abundance (see text).
- ID:
- ivo://CDS.VizieR/J/ApJ/799/95
- Title:
- Structure in 3D galaxy distribution. II. Voids
- Short Name:
- J/ApJ/799/95
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The major uncertainties in studies of the multi-scale structure of the universe arise not from observational errors but from the variety of legitimate definitions and detection methods for individual structures. To facilitate the study of these methodological dependencies, we have carried out 12 different analyses defining structures in various ways. This has been done in a purely geometrical way by utilizing the HOP (Eisenstein+, 1998ApJ...498..137E) algorithm as a unique parameter-free method of assigning groups of galaxies to local density maxima or minima. From three density estimation techniques (smoothing kernels, Bayesian blocks, and self-organizing maps) applied to three data sets (the Sloan Digital Sky Survey Data Release 7, the Millennium simulation, and randomly distributed points) we tabulate information that can be used to construct catalogs of structures connected to local density maxima and minima. We also introduce a void finder that utilizes a method to assemble Delaunay tetrahedra into connected structures and characterizes regions empty of galaxies in the source catalog.
- ID:
- ivo://CDS.VizieR/J/A+A/552/A114
- Title:
- Sun chromospheric CaII-HK emission
- Short Name:
- J/A+A/552/A114
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Monitoring of the photometric and chromospheric HK emission data series of stars similar to the Sun in age and average activity level showed that there is an empirical correlation between the average stellar chromospheric activity level and the photometric variability. In general, more active stars show larger photometric variability. Interestingly, the measurements and reconstructions of the solar irradiance show that the Sun is significantly less variable than indicated by the empirical relationship. We aim to identify possible reasons for the Sun to be currently outside of this relationship. We employed different scenarios of solar HK emission and irradiance variability and compared them with available time series of Sun-like stars.
- ID:
- ivo://CDS.VizieR/J/A+A/627/A46
- Title:
- Sunspot penumbra and umbral flashes models
- Short Name:
- J/A+A/627/A46
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The solar chromosphere and the lower transition region are believed to play a crucial role in the heating of the solar corona. Models that describe the chromosphere (and the lower transition region), accounting for its highly dynamic and structured character are, so far, found to be lacking. This is partly due to the breakdown of complete frequency redistribution (CRD) in the chromospheric layers and also because of the difficulty in obtaining complete sets of observations that adequately constrain the solar atmosphere at all relevant heights. We aim to obtain semi-empirical model atmospheres that reproduce the features of the MgII H & K line profiles that sample the middle chromosphere with focus on a sunspot. We used spectropolarimetric observations of the CaII 8542{AA} spectra obtained with the Swedish 1-m Solar Telescope and used NICOLE inversions to obtain semi-empirical model atmospheres for different features in and around a sunspot. These were used to synthesize MgII H & K spectra using the RH1.5D code, which we compared with observations taken with the Interface Region Imaging Spectrograph (IRIS). Comparison of the synthetic profiles with IRIS observations reveals that there are several areas, especially in the penumbra of the sunspot, where most of the observed MgII H & K profiles are very well reproduced. In addition, we find that supersonic hot downflows, present in our collection of models in the umbra, lead to synthetic profiles that agree well with the IRIS MgII H & K profiles, with the exception of the line core. We put forward and make available four semi-empirical model atmospheres. Two for the penumbra, reflecting the range of temperatures obtained for the chromosphere, one for umbral flashes, and a model representative of the quiet surroundings of a sunspot. These are available in electronic as well as in table formats.
650. Supernova matter EOS
- ID:
- ivo://CDS.VizieR/J/ApJ/789/33
- Title:
- Supernova matter EOS
- Short Name:
- J/ApJ/789/33
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is an introduction to the tabulated database of stellar matter properties calculated within the framework of the Statistical Model for Supernova Matter (SMSM). The tables present thermodynamical characteristics and nuclear abundances for 31 values of baryon density (10^-8^ < {rho}/{rho}_0_< 0.32, {rho}_0_= 0.15 fm^-3^ is the normal nuclear matter density), 35 values of temperature (0.2 MeV < T < 25 MeV), and 28 values of electron-to-baryon ratio (0.02 < Y_e_< 0.56). The properties of stellar matter in {beta} equilibrium are also considered. The main ingredients of the SMSM are briefly outlined, and the data structure and content of the tables are explained.
