- ID:
- ivo://CDS.VizieR/J/MNRAS/471/1743
- Title:
- Nearby galaxies abundances
- Short Name:
- J/MNRAS/471/1743
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We combine samples of nearby galaxies with Herschel photometry selected on their dust, metal, HI and stellar mass content, and compare these to chemical evolution models in order to discriminate between different dust sources. In a companion paper, we used an HI-selected sample of nearby galaxies to reveal a subsample of very gas-rich (gas fraction >80 per cent) sources with dust masses significantly below predictions from simple chemical evolution models, and well below M_d_/M_*_ and M_d_/M_gas_ scaling relations seen in dust and stellar-selected samples of local galaxies. We use a chemical evolution model to explain these dust-poor, but gas-rich, sources as well as the observed star formation rates (SFRs) and dust-to-gas ratios. We find that (i) a delayed star formation history is required to model the observed SFRs; (ii) inflows and outflows are required to model the observed metallicities at low gas fractions; (iii) a reduced contribution of dust from supernovae (SNe) is needed to explain the dust-poor sources with high gas fractions. These dust-poor, low stellar mass galaxies require a typical core-collapse SN to produce 0.01-0.16M_{sun}_ of dust. To match the observed dust masses at lower gas fractions, significant grain growth is required to counteract the reduced contribution from dust in SNe and dust destruction from SN shocks. These findings are statistically robust, though due to intrinsic scatter it is not always possible to find one single model that successfully describes all the data. We also show that the dust-to-metal ratio decreases towards lower metallicity.
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- ID:
- ivo://CDS.VizieR/J/A+A/649/A18
- Title:
- Nearby galaxy perspective on dust evolution
- Short Name:
- J/A+A/649/A18
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- The efficiency of the different processes responsible for the evolution of interstellar dust on the scale of a galaxy are, to date, very uncertain, spanning several orders of magnitude in the literature. Yet, precise knowledge of the grain properties is key to addressing numerous open questions about the physics of the interstellar medium and galaxy evolution. This article presents an empirical statistical study, aimed at quantifying the timescales of the main cosmic dust evolution processes as a function of the global properties of a galaxy. We have modelled a sample of ~800 nearby galaxies, spanning a wide range of metallicity, gas fraction, specific star formation rate and Hubble stage. We have derived the dust properties of each object from its spectral energy distribution. Throughout this paper, we have adopted a hierarchical Bayesian approach, resulting in a single large probability distribution of all the parameters of all the galaxies, to ensure the most rigorous interpretation of our data. We confirm the drastic evolution with metallicity of the dust-to-metal mass ratio (by two orders of magnitude), found by previous studies. We confirm the well-known evolution of the aromatic-feature-emitting grain mass fraction as a function of metallicity and interstellar radiation field intensity. Our data indicate the relation with metallicity is significantly stronger. Our results provide valuable constraints for simulations of galaxies. They imply that grain growth is the likely dust production mechanism in dusty high-redshift objects. We also emphasize the determinant role of local, low metallicity systems in order to address these questions.
- ID:
- ivo://CDS.VizieR/J/A+AS/144/5
- Title:
- Nearby globular clusters photometric catalog
- Short Name:
- J/A+AS/144/5
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first part of the first large and homogeneous CCD color-magnitude diagram (CMD) data base, comprising 52 nearby Galactic globular clusters (GGC) imaged in the V and I bands using only two telescopes (one for each hemisphere). The observed clusters represent 75% of the known Galactic globulars with (m-M)V<=16.15mag, cover most of the globular cluster metallicity range (-2.2<=[Fe/H]<=-0.4), and span Galactocentric distances from ~1.2 to ~18.5kpc. In this paper, the CMDs for the 39 GGCs observed in the southern hemisphere are presented. The remaining 13 northern hemisphere clusters of the catalog are presented in a companion paper. For four clusters (NGC 4833, NGC 5986, NGC 6543, and NGC 6638) we present for the first time a CMD from CCD data. The typical CMD span from the 22^nd^ V magnitude to the tip of the red giant branch. Based on a large number of standard stars, the absolute photometric calibration is reliable to the ~0.02mag level in both filters. This catalog, because of its homogeneity, is expected to represent a useful data base for the measurement of the main absolute and relative parameters characterizing the CMD of GGCs.
- ID:
- ivo://CDS.VizieR/J/A+AS/145/451
- Title:
- Nearby globular clusters photometric catalog
- Short Name:
- J/A+AS/145/451
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper we present the second and final part of a large and photometrically homogeneous CCD color-magnitude diagram (CMD) data base, comprising 52 nearby Galactic globular clusters (GGC) imaged in the V and I bands. The catalog has been collected using only two telescopes (one for each hemisphere).
- ID:
- ivo://CDS.VizieR/J/ApJ/791/54
- Title:
- Nearby M Dwarfs parameters
- Short Name:
- J/ApJ/791/54
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Comparisons between the planet populations around solar-type stars and those orbiting M dwarfs shed light on the possible dependence of planet formation and evolution on stellar mass. However, such analyses must control for other factors, i.e., metallicity, a stellar parameter that strongly influences the occurrence of gas giant planets. We obtained infrared spectra of 121 M dwarfs stars monitored by the California Planet Search and determined metallicities with an accuracy of 0.08 dex. The mean and standard deviation of the sample are -0.05 and 0.20 dex, respectively. We parameterized the metallicity dependence of the occurrence of giant planets on orbits with a period less than two years around solar-type stars and applied this to our M dwarf sample to estimate the expected number of giant planets. The number of detected planets (3) is lower than the predicted number (6.4), but the difference is not very significant (12% probability of finding as many or fewer planets). The three M dwarf planet hosts are not especially metal rich and the most likely value of the power-law index relating planet occurrence to metallicity is 1.06 dex per dex for M dwarfs compared to 1.80 for solar-type stars; this difference, however, is comparable to uncertainties. Giant planet occurrence around both types of stars allows, but does not necessarily require, a mass dependence of ~1 dex per dex. The actual planet-mass-metallicity relation may be complex, and elucidating it will require larger surveys like those to be conducted by ground-based infrared spectrographs and the Gaia space astrometry mission.
- ID:
- ivo://CDS.VizieR/J/other/KFNT/12.20
- Title:
- Nearby stars metallicities
- Short Name:
- J/other/KFNT/12.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The catalogue for nearby stars' metallicities has been compiled. The catalogue contains 558 values obtained from photometric UBV data
- ID:
- ivo://CDS.VizieR/J/A+A/479/131
- Title:
- Near-IR spectra of inner red giants
- Short Name:
- J/A+A/479/131
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The existence in the Milky Way of either a long thin bar with a half length of 4.5kpc and a position angle of around 45{deg} with respect to the Sun-Galactic centre line or a bulge+bar complex, thicker and shorter, with a smaller tilt respect to the Sun-GC line, has been a matter of discussion in recent decades. In this paper, we present low resolution (R=500) near-infrared spectra for selected and serendipitous sources in six inner in-plane Galactic fields at l=7{deg}, 12{deg}, 15{deg}, 20{deg}, 26{deg} and 27{deg}, with the aim of analysing the stellar content present in those fields.
- ID:
- ivo://CDS.VizieR/J/A+A/435/1087
- Title:
- Nebular abundances of southern symbiotic stars
- Short Name:
- J/A+A/435/1087
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have calculated relative element abundances for a sample of 43 symbiotic stars. Helium abundances and the relative elemental abundances N/O, Ne/O, Ar/O were derived from new spectra collected in the optical range through low dispersion spectroscopy. The He ionic abundances were derived taking into account self-absorption effects in Balmer lines. We found that the symbiotic stars in the galactic bulge have heavy element abundances showing the same wide distribution as other bulge objects. In the galactic disk, the symbiotic stars follow the abundance gradient as derived from different kinds of objects.
- ID:
- ivo://CDS.VizieR/J/A+A/503/541
- Title:
- Neutral Li in late-type stars non-LTE calculations
- Short Name:
- J/A+A/503/541
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We perform non-LTE calculations of lithium in late-type stars for a wide range of stellar parameters, including quantum mechanical cross-sections for collisions with neutral hydrogen and the negative hydrogen ion. Non-LTE abundance corrections for the lithium resonance line at 670.7nm and the subordinate line at 610.3nm, are calculated using 1D MARCS model atmospheres spanning a large grid in effective temperature, surface gravity, and metallicity, and lithium abundance. The competing effects of ultraviolet over-ionization and photon losses in the resonance line govern the behaviour of the non-LTE effects with stellar parameters and lithium abundance. The size and sign of the non-LTE abundance corrections vary significantly over the grid for the 670.7nm line, but are typically positive and below 0.15dex for the 610.3nm line. The new collisional data play a significant role in determining the abundance corrections.
- ID:
- ivo://CDS.VizieR/J/A+A/586/A125
- Title:
- Neutron-capture elements abundances in Cepheids
- Short Name:
- J/A+A/586/A125
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new accurate abundances for five neutron-capture (Y, La, Ce, Nd, Eu) elements in 73 classical Cepheids located across the Galactic thin disk. Individual abundances are based on high spectral resolution (R~38000) and high signal-to-noise ratio (S/N~50-300) spectra collected with UVES at ESO VLT for the DIONYSOS project. Taking account for similar Cepheid abundances provided either by our group (111 stars) or available in the literature, we end up with a sample of 435 Cepheids covering a broad range in iron abundances (-1.6<[Fe/H]<0.6). We found, using homogeneous individual distances and abundance scales, well defined gradients for the above elements. However, the slope of the light s-process element (Y) is at least a factor of two steeper than the slopes of heavy s- (La, Ce, Nd) and r- (Eu) process elements. The s to r abundance ratio ([La/Eu]) of Cepheids shows a well defined anticorrelation with of both Eu and Fe. On the other hand, Galactic field stars attain an almost constant value and only when they approach solar iron abundance display a mild enhancement in La. The [Y/Eu] ratio shows a mild evidence of a correlation with Eu and, in particular, with iron abundance for field Galactic stars. We also investigated the s-process index -- [hs/ls] -- and we found a well defined anticorrelation, as expected, between [La/Y] and iron abundance. Moreover, we found a strong correlation between [La/Y] and [La/Fe] and, in particular, a clear separation between Galactic and Sagittarius red giants. Finally, the comparison between predictions for low-mass asymptotic giant branch stars and the observed [La/Y] ratio indicate a very good agreement over the entire metallicity range covered by Cepheids. However, the observed spread, at fixed iron content, is larger than predicted by current models.
