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- ID:
- ivo://CDS.VizieR/J/A+A/420/135
- Title:
- Abundances in intracluster medium with XMM
- Short Name:
- J/A+A/420/135
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- XMM-Newton observations of 19 galaxy clusters are used to measure the elemental abundances and their spatial distributions in the intracluster medium. The sample mainly consists of X-ray bright and relaxed clusters with a cD galaxy. Along with detailed Si, S and Fe radial abundance distributions within 300-700kpc in radius, the O abundances are accurately derived in the central region of the clusters. The Fe abundance maxima towards the cluster center, possibly due to the metals from the cD galaxy, are spatially resolved. The Si and S abundances also exhibit central increases in general, resulting in uniform Fe-Si-S ratios within the cluster. In contrast, the O abundances are in general uniform over the cluster. The mean O to Fe ratio within the cluster core is sub-solar, while that of the cluster scale is larger than the solar ratio. These measurements indicate that most of the Fe-Si-S and O in the intracluster medium have different origins, presumably in supernovae Ia and II, respectively. The obtained Fe and O mass are also used to discuss the past star formation history in clusters.
- ID:
- ivo://CDS.VizieR/J/AJ/120/1364
- Title:
- Abundances in M3 and M13
- Short Name:
- J/AJ/120/1364
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyze high-resolution, high signal-to-noise ratio spectra of six red giant branch (RGB) stars in the globular cluster M3 (NGC 5272) and three in M13 (NGC 6205) that were obtained with the 4 m Mayall Telescope and echelle spectrometer on Kitt Peak. The spectra include lines of O, Na, Mg, Al, Si, Ca, Ti, V, Mn, Fe, and Ni. We also analyze the [Al/Fe] values of 96 RGB stars in M13 covering the brightest 3.5 mag, which include 66 measurements that were derived from moderate-resolution, low signal-to-noise ratio spectra obtained with the WIYN 3.5 m telescope and Hydra multiobject spectrograph, also on Kitt Peak.
- ID:
- ivo://CDS.VizieR/J/ApJ/900/146
- Title:
- Abundances in 2 metal-poor GCs, M53 & NGC5053
- Short Name:
- J/ApJ/900/146
- Date:
- 02 Feb 2022 13:00:59
- Publisher:
- CDS
- Description:
- We search for extratidal stars around two metal-poor Galactic globular clusters, M53 and NGC 5053, using the near-infrared APOGEE spectra. Applying the t-distributed stochastic neighbor embedding (t-SNE) algorithm on the chemical abundances and radial velocities results in identification of two isolated stellar groups composed of cluster member stars in the t-SNE projection plane. With additional selection criteria of radial velocity, location in the color-magnitude diagram, and abundances from a manual chemical analysis, we find a total of 73 cluster member candidates; seven extratidal stars are found beyond the tidal radii of the two clusters. The extratidal stars around the clusters tend to be located along the leading direction of the cluster proper motion, and the individual proper motion of these stars also seems to be compatible to those of clusters. Interestingly, we find that one extratidal star of NGC 5053 is located on the southern outskirts of M53, which is part of common stellar envelope by the tidal interaction between two clusters. We discuss the nature of this star in the context of the tidal interaction between two clusters. We find apparent Mg-Al anticorrelations with a clear gap and spread (~0.9dex) in Al abundances for both clusters, and a light Si abundance spread (~0.3dex) for NGC 5053. Since all extratidal stars have Mg-enhanced and Al-depleted features, they could be first-generation stars of two globular clusters. Our results support that M53 and NGC5053 originated in dwarf galaxies and are surrounded by extended stellar substructures of more numerous populations of clusters.
- ID:
- ivo://CDS.VizieR/J/ApJ/675/1213
- Title:
- Abundances in M33 HII regions
- Short Name:
- J/ApJ/675/1213
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new determination of the metallicity gradient in M33, based on Keck LRIS measurements of oxygen abundances using the temperature-sensitive emission line [OIII] {lambda}4363 in 61 HII regions. These data approximately triple the sample of direct oxygen abundances in M33. We find a central abundance of 12+log(O/H)=8.36+/-0.04 and a slope of -0.027+/-0.012dex/kpc, in agreement with infrared measurements of the neon abundance gradient but much shallower than most previous oxygen gradient measurements. There is substantial intrinsic scatter of 0.11dex in the metallicity at any given radius in M33, which imposes a fundamental limit on the accuracy of gradient measurements that rely on small samples of objects. We also show that the ionization state of neon does not follow the ionization state of oxygen as is commonly assumed, suggesting that neon abundance measurements from optical emission lines require careful treatment of the ionization corrections.
- ID:
- ivo://CDS.VizieR/J/A+A/438/139
- Title:
- Abundances in Milky Way's disk
- Short Name:
- J/A+A/438/139
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have compiled a large catalogue of metallicities and abundance ratios from the literature in order to investigate abundance trends of several alpha and iron peak elements in the thin disk and the thick disk of the Galaxy. The catalogue includes 743 stars with abundances of Fe, O, Mg, Ca, Ti, Si, Na, Ni and Al in the metallicity range -1.30<[Fe/H]<+0.50. We have checked that systematic differences between abundances measured in the different studies were lower than random errors before combining them. Accurate distances and proper motions from Hipparcos, and radial velocities from several sources have been retrieved for 639 stars and their velocities (U,V,W) and galactic orbits have been computed. Ages of 322 stars have been estimated with the Bayesian method of isochrone fitting developed by Pont & Eyer (2004MNRAS.351..487P). Two samples kinematically representative of the thin and thick disks have been selected, taking into account the Hercules stream which is intermediate in kinematics, but with a probable dynamical origin. Our results show that the two disks are chemically well separated, they overlap greatly in metallicity and both show parallel decreasing trends of alpha elements with increasing metallicity, in the interval -0.80<[Fe/H]<-0.30. The Mg enhancement with respect to Fe of the thick disk is measured to be 0.14dex. An even larger enhancement is observed for Al. The thick disk is clearly older than the thin disk with a tentative evidence of an AMR over 2-3Gyr and a hiatus in star formation before the formation of the thin disk. We do not observe a vertical gradient in the metallicity of the thick disk. The Hercules stream have properties similar to that of the thin disk, with a wider range of metallicity. Metal-rich stars assigned to the thick disk and super metal rich stars assigned to the thin disk appear as outliers in all their properties.
- ID:
- ivo://CDS.VizieR/J/A+A/486/941
- Title:
- Abundances in M71 (NGC 6838)
- Short Name:
- J/A+A/486/941
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Abundance variations in moderately metal-rich globular clusters can give clues about the formation and chemical enrichment of globular clusters. CN, CH, Na, Mg and Al indices in spectra of 89 stars of the template metal-rich globular cluster M71 are measured and implications on internal mixing are discussed.
- ID:
- ivo://CDS.VizieR/J/AJ/141/175
- Title:
- Abundances in M15 RGB/RHB stars
- Short Name:
- J/AJ/141/175
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The globular cluster M15 is unique in its display of star-to-star variations in the neutron-capture elements. Comprehensive abundance surveys have been previously conducted for handfuls of M15 red giant branch (RGB) and red horizontal branch (RHB) stars. No attempt has been made to perform a single, self-consistent analysis of these stars, which exhibit a wide range in atmospheric parameters. In the current effort, a new comparative abundance derivation is presented for three RGB and six RHB members of the cluster. The analysis employs an updated version of the line transfer code MOOG, which now appropriately treats coherent, isotropic scattering.
- ID:
- ivo://CDS.VizieR/J/A+A/283/911
- Title:
- Abundances in NGC 2243 and Mel 66
- Short Name:
- J/A+A/283/911
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/A+A/579/A104
- Title:
- Abundances in NGC 5053 and NGC 5634
- Short Name:
- J/A+A/579/A104
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The tidal disruption of the Sagittarius dwarf Spheroidal galaxy (Sgr dSph) is producing the most prominent substructure in the Milky Way (MW) halo, the Sagittarius Stream. Aside from field stars, the Sgr dSph is suspected to have lost a number of globular clusters (GC). Many Galactic GC are suspected to have originated in the Sgr dSph. While for some candidates an origin in the Sgr dSph has been confirmed due to chemical similarities, others exist whose chemical composition has never been investigated. NGC 5053 and NGC 5634 are two among these scarcely studied Sgr dSph candidate-member clusters. To characterize their composition we analyzed one giant star in NGC 5053, and two in NGC 5634. We analize high-resolution and signal-to-noise spectra by means of the MyGIsFOS code, determining atmospheric parameters and abundances for up to 21 species between O and Eu. The abundances are compared with those of MW halo field stars, of "unassociated" MW halo globulars, and of the metal poor Sgr dSph main body population. We derive a metallicity of [FeII/H]=-2.26+/-0.10 for NGC 5053, and of [FeI/H]=-1.99+/-0.075 and -1.97+/-0.076 for the two stars in NGC 5634. This makes NGC 5053 one of the most metal poor globular clusters in the MW. Both clusters display an alpha enhancement similar to the one of the halo at comparable metallicity. The two stars in NGC 5634 clearly display the Na-O anticorrelation widespread among MW globulars. Most other abundances are in good agreement with standard MW halo trends. The chemistry of the Sgr dSph main body populations is similar to the one of the halo at low metallicity. It is thus difficult to discriminate between an origin of NGC 5053 and NGC 5634 in the Sgr dSph, and one in the MW. However, the abundances of these clusters do appear closer to that of Sgr dSph than of the halo, favoring an origin in the Sgr dSph system.
