For over fifteen years, the international collaboration of the Sloan Digital Sky Survey (SDSS) ha... more For over fifteen years, the international collaboration of the Sloan Digital Sky Survey (SDSS) has made terabytes of professional astronomical data freely available to the world. The vast archival imaging and spectroscopic datasets of the SDSS, coupled with its multiple access points and interfaces suitable for users of all levels of experience, provide a novel sandbox for audiences from a wide range of backgrounds to explore and engage with the data while cultivating interests and proficiency in astronomy. SDSS scientists, educators, technicians, and observers involved in the collaboration’s Education and Public Outreach working group have collaborated over the past decade to develop a large and diverse set of educational activities and exhibits built around SDSS data and engineering concepts. The recent expansion of SDSS-IV APOGEE-2 operations to Las Campanas Observatory in Chile has prompted a new emphasis on broadening the accessibility of these educational resources for Spanish...
We investigate the inner regions of the Milky Way using data from APOGEE and Gaia EDR3. Our inner... more We investigate the inner regions of the Milky Way using data from APOGEE and Gaia EDR3. Our inner Galactic sample has more than 26 500 stars within |XGal|< 5 kpc, |YGal|< 3.5 kpc, |ZGal|< 1 kpc, and we also carry out the analysis for a foreground-cleaned subsample of 8000 stars that is more representative of the bulge–bar populations. These samples allow us to build chemo-dynamical maps of the stellar populations with vastly improved detail. The inner Galaxy shows an apparent chemical bimodality in key abundance ratios [α/Fe], [C/N], and [Mn/O], which probe different enrichment timescales, suggesting a star formation gap (quenching) between the high- and low-α populations. Using a joint analysis of the distributions of kinematics, metallicities, mean orbital radius, and chemical abundances, we can characterize the different populations coexisting in the innermost regions of the Galaxy for the first time. The chemo-kinematic data dissected on an eccentricity–|Z|max plane rev...
Context. SDSS-IV APOGEE-2, GALAH, and Gaia-ESO are high-resolution, ground-based, multi-object sp... more Context. SDSS-IV APOGEE-2, GALAH, and Gaia-ESO are high-resolution, ground-based, multi-object spectroscopic surveys providing fundamental stellar atmospheric parameters and multiple elemental abundance ratios for hundreds of thousands of stars of the Milky Way. Data from these and other surveys contribute to investigations of the history and evolution of the Galaxy. Aims. We undertake a comparison between the most recent data releases of these surveys to investigate the accuracy and precision of derived parameters by placing the abundances on an absolute scale. We also discuss the correlations in parameter and abundance differences as a function of main parameters. Uncovering the variants provides a basis to continue the efforts of future sky surveys. Methods. Quality samples from the APOGEE−GALAH (15 537 stars), APOGEE−GES (804 stars), and GALAH−GES (441 stars) overlapping catalogs were collected. We investigated the mean variants between the surveys, and linear trends were also i...
The APOGEE Open Cluster Chemical Abundances and Mapping survey is used to probe the chemical evol... more The APOGEE Open Cluster Chemical Abundances and Mapping survey is used to probe the chemical evolution of the s-process element cerium in the Galactic disk. Cerium abundances were derived from measurements of Ce ii lines in the APOGEE spectra using the Brussels Automatic Code for Characterizing High Accuracy Spectra in 218 stars belonging to 42 open clusters. Our results indicate that, in general, for ages < 4 Gyr, younger open clusters have higher [Ce/Fe] and [Ce/α-element] ratios than older clusters. In addition, metallicity segregates open clusters in the [Ce/X]–age plane (where X can be H, Fe, or the α-elements O, Mg, Si, or Ca). These metallicity-dependent relations result in [Ce/Fe] and [Ce/α] ratios with ages that are not universal clocks. Radial gradients of [Ce/H] and [Ce/Fe] ratios in open clusters, binned by age, were derived for the first time, with d[Ce/H]/d R GC being negative, while d[Ce/Fe]/d R GC is positive. [Ce/H] and [Ce/Fe] gradients are approximately constan...
For over fifteen years, the international collaboration of the Sloan Digital Sky Survey (SDSS) ha... more For over fifteen years, the international collaboration of the Sloan Digital Sky Survey (SDSS) has made terabytes of professional astronomical data freely available to the world. The vast archival imaging and spectroscopic datasets of the SDSS, coupled with its multiple access points and interfaces suitable for users of all levels of experience, provide a novel sandbox for audiences from a wide range of backgrounds to explore and engage with the data while cultivating interests and proficiency in astronomy. SDSS scientists, educators, technicians, and observers involved in the collaboration’s Education and Public Outreach working group have collaborated over the past decade to develop a large and diverse set of educational activities and exhibits built around SDSS data and engineering concepts. The recent expansion of SDSS-IV APOGEE-2 operations to Las Campanas Observatory in Chile has prompted a new emphasis on broadening the accessibility of these educational resources for Spanish...
We investigate the inner regions of the Milky Way using data from APOGEE and Gaia EDR3. Our inner... more We investigate the inner regions of the Milky Way using data from APOGEE and Gaia EDR3. Our inner Galactic sample has more than 26 500 stars within |XGal|< 5 kpc, |YGal|< 3.5 kpc, |ZGal|< 1 kpc, and we also carry out the analysis for a foreground-cleaned subsample of 8000 stars that is more representative of the bulge–bar populations. These samples allow us to build chemo-dynamical maps of the stellar populations with vastly improved detail. The inner Galaxy shows an apparent chemical bimodality in key abundance ratios [α/Fe], [C/N], and [Mn/O], which probe different enrichment timescales, suggesting a star formation gap (quenching) between the high- and low-α populations. Using a joint analysis of the distributions of kinematics, metallicities, mean orbital radius, and chemical abundances, we can characterize the different populations coexisting in the innermost regions of the Galaxy for the first time. The chemo-kinematic data dissected on an eccentricity–|Z|max plane rev...
Context. SDSS-IV APOGEE-2, GALAH, and Gaia-ESO are high-resolution, ground-based, multi-object sp... more Context. SDSS-IV APOGEE-2, GALAH, and Gaia-ESO are high-resolution, ground-based, multi-object spectroscopic surveys providing fundamental stellar atmospheric parameters and multiple elemental abundance ratios for hundreds of thousands of stars of the Milky Way. Data from these and other surveys contribute to investigations of the history and evolution of the Galaxy. Aims. We undertake a comparison between the most recent data releases of these surveys to investigate the accuracy and precision of derived parameters by placing the abundances on an absolute scale. We also discuss the correlations in parameter and abundance differences as a function of main parameters. Uncovering the variants provides a basis to continue the efforts of future sky surveys. Methods. Quality samples from the APOGEE−GALAH (15 537 stars), APOGEE−GES (804 stars), and GALAH−GES (441 stars) overlapping catalogs were collected. We investigated the mean variants between the surveys, and linear trends were also i...
The APOGEE Open Cluster Chemical Abundances and Mapping survey is used to probe the chemical evol... more The APOGEE Open Cluster Chemical Abundances and Mapping survey is used to probe the chemical evolution of the s-process element cerium in the Galactic disk. Cerium abundances were derived from measurements of Ce ii lines in the APOGEE spectra using the Brussels Automatic Code for Characterizing High Accuracy Spectra in 218 stars belonging to 42 open clusters. Our results indicate that, in general, for ages < 4 Gyr, younger open clusters have higher [Ce/Fe] and [Ce/α-element] ratios than older clusters. In addition, metallicity segregates open clusters in the [Ce/X]–age plane (where X can be H, Fe, or the α-elements O, Mg, Si, or Ca). These metallicity-dependent relations result in [Ce/Fe] and [Ce/α] ratios with ages that are not universal clocks. Radial gradients of [Ce/H] and [Ce/Fe] ratios in open clusters, binned by age, were derived for the first time, with d[Ce/H]/d R GC being negative, while d[Ce/Fe]/d R GC is positive. [Ce/H] and [Ce/Fe] gradients are approximately constan...
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