Estimating stellar birth radii and the time evolution of Milky Way’s ISM metallicity gradient
01 Dec 2018-Monthly Notices of the Royal Astronomical Society (Oxford University Press)-Vol. 481, Iss: 2, pp 1645-1657
TL;DR: In this article, a semi-empirical, largely model-independent approach for estimating Galactic birth radii, r_birth, for Milky Way disk stars is presented, which relies on the justifiable assumption that a negative radial metallicity gradient in the interstellar medium (ISM) existed for most of the disk lifetime.
Abstract: We present a semi-empirical, largely model-independent approach for estimating Galactic birth radii, r_birth, for Milky Way disk stars. The technique relies on the justifiable assumption that a negative radial metallicity gradient in the interstellar medium (ISM) existed for most of the disk lifetime. Stars are projected back to their birth positions according to the observationally derived age and [Fe/H] with no kinematical information required. Applying our approach to the AMBRE:HARPS and HARPS-GTO local samples, we show that we can constrain the ISM metallicity evolution with Galactic radius and cosmic time, [Fe/H]_ISM(r, t), by requiring a physically meaningful r_birth distribution. We find that the data are consistent with an ISM radial metallicity gradient that flattens with time from ~-0.15 dex/kpc at the beginning of disk formation, to its measured present-day value (-0.07 dex/kpc). We present several chemo-kinematical relations in terms of mono-r_birth populations. One remarkable result is that the kinematically hottest stars would have been born locally or in the outer disk, consistent with thick disk formation from the nested flares of mono-age populations and predictions from cosmological simulations. This phenomenon can be also seen in the observed age-velocity dispersion relation, in that its upper boundary is dominated by stars born at larger radii. We also find that the flatness of the local age-metallicity relation (AMR) is the result of the superposition of the AMRs of mono-r_birth populations, each with a well-defined negative slope. The solar birth radius is estimated to be 7.3+-0.6 kpc, for a current Galactocentric radius of 8 kpc.
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University of California, Berkeley1, University of Sydney2, Australian National University3, Macquarie University4, Heidelberg University5, Max Planck Society6, Monash University7, INAF8, Uppsala University9, University of New South Wales10, York University11, Columbia University12, University of Ljubljana13, University of Western Australia14, University of Rochester15, Carnegie Institution for Science16, Princeton University17, Institute for Advanced Study18, Johns Hopkins University19
TL;DR: In this paper, the authors used the second data releases of the European Space Agency Gaia astrometric survey and the high-resolution Galactic Archaeology with HERMES (GALAH) spectroscopic survey to analyse the structure of the ODE.
Abstract: We use the second data releases of the European Space Agency Gaia astrometric survey and the high-resolution Galactic Archaeology with HERMES (GALAH) spectroscopic survey to analyse the structure o ...
176 citations
Cites result from "Estimating stellar birth radii and ..."
...Consistent with that picture, most migration models (Roškar et al. 2012; Vera-Ciro et al. 2014; Daniel & Wyse 2018; Minchev et al. 2018) find that stars on circular orbits and close to the plane are those that move most easily, and this is what we see (cf. Solway et al. 2012)....
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117 citations
Leibniz Institute for Astrophysics Potsdam1, University of Barcelona2, Universidade Federal do Rio Grande do Sul3, University of Birmingham4, University of Porto5, University of São Paulo6, Andrés Bello National University7, Millennium Institute8, University of La Laguna9, Spanish National Research Council10, Carnegie Learning11, University of Notre Dame12, Apache Corporation13, Sternberg Astronomical Institute14, University of Utah15, University of Arizona16, Centre national de la recherche scientifique17, Texas Christian University18, Pontifical Catholic University of Chile19, University of Atacama20, University of Virginia21, Johns Hopkins University22, University of Antofagasta23, University of La Serena24, University of Washington25, University of Colorado Boulder26
TL;DR: The StarHorse code as mentioned in this paper is written in python 3.6 and makes use of several community-developed python packages, among them astropy (Astropy Collaboration 2013), ezpadova (https://github.com/mfouesneau/ezpadova), numpy and scipy (Virtanen et al. 2020), and matplotlib (Hunter 2007).
Abstract: The StarHorse code is written in python 3.6 and makes use of several community-developed python packages, among them astropy (Astropy Collaboration 2013), ezpadova (https://github.com/ mfouesneau/ezpadova), numpy and scipy (Virtanen et al. 2020), and matplotlib (Hunter 2007). The code also makes use of the photometric filter database of VOSA (Bayo et al. 2008), developed under the Spanish Virtual Observatory project supported from the Spanish MICINN through grant AyA2011-24052. Funding for the SDSS Brazilian Participation Group has been provided by the Ministerio de Ciencia e Tecnologia (MCT), Fundacao Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro (FAPERJ), Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq), and Financiadora de Estudos e Projetos (FINEP). Funding for the Sloan Digital Sky Survey IV has been provided by the Alfred P. Sloan Foundation, the US Department of Energy Office of Science, and the Participating Institutions. SDSS-IV acknowledges support and resources from the Center for High-Performance Computing at the University of Utah. The SDSS web site is www.sdss. org. SDSS-IV is managed by the Astrophysical Research Consortium for the Participating Institutions of the SDSS Collaboration including the Brazilian Participation Group, the Carnegie Institution for Science, Carnegie Mellon University, the Chilean Participation Group, the French Participation Group, Harvard-Smithsonian Center for Astrophysics, Instituto de Astrofisica de Canarias, The Johns Hopkins University, Kavli Institute for the Physics and Mathematics of the Universe (IPMU)/University of Tokyo, Lawrence Berkeley National Laboratory, Leibniz-Institut fur Astrophysik Potsdam (AIP), Max-Planck-Institut fur Astronomie (MPIA Heidelberg), Max-Planck-Institut fur Astrophysik (MPA Garching), Max-Planck-Institut fur Extraterrestrische Physik (MPE), National Astronomical Observatory of China, New Mexico State University, New York University, University of Notre Dame, Observatario Nacional/MCTI, The Ohio State University, Pennsylvania State University, Shanghai Astronomical Observatory, United Kingdom Participation Group, Uni-versidad Nacional Autonoma de Mexico, University of Arizona, University of Colorado Boulder, University of Oxford, University of Portsmouth, University of Utah, University of Virginia, University of Washington, University of Wisconsin, Vanderbilt University, and Yale University. Guoshoujing Telescope (the Large Sky Area Multi-Object Fiber Spectroscopic Telescope LAMOST) is a National Major Scientific Project built by the Chinese Academy of Sciences. Funding for the project has been provided by the National Development and Reform Commission. LAMOST is operated and managed by the National Astronomical Observatories, Chinese Academy of Sciences. Funding for RAVE has been provided by: the Australian Astronomical Observatory; the Leibniz-Institut fur Astrophysik Potsdam (AIP); the Australian National University; the Australian Research Council; the French National Research Agency; the German Research Foundation (SPP 1177 and SFB 881); the European Research Council (ERC-StG 240271 Galactica); the Istituto Nazionale di Astrofisica at Padova; The Johns Hopkins University; the National Science Foundation of the USA (AST-0908326); the W. M. Keck foundation; the Macquarie University; the Netherlands Research School for Astronomy; the Natural Sciences and Engineering Research Council of Canada; the Slovenian Research Agency; the Swiss National Science Foundation; the Science & Technology Facilities Council of the UK; Opticon; Strasbourg Observatory; and the Universities of Groningen, Heidelberg and Sydney. The RAVE web site is at https://www.rave-survey. org. This work has made use of data from the European Space Agency (ESA) mission Gaia (http://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, http://www.cosmos.esa. int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. This work has also made use of data from Gaia-ESO based on data products from observations made with ESO Telescopes at the La Silla Paranal Observatory under programme ID 188.B-3002. FA is grateful for funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No. 800502 H2020-MSCA-IF-EF-2017. CC acknowledges support from DFG Grant CH1188/2-1 and from the ChETEC COST Action (CA16117)
114 citations
Cites background or methods from "Estimating stellar birth radii and ..."
...…in the [α/Fe vs. [Fe/H] diagram) is indeed confined to the inner regions, whereas the geometrically-defined thick disc (by a cut in ZGal) is a mixture of flaring mono-age populations, and therefore would show an age gradient (see Martig et al. 2016; Mackereth et al. 2017; Minchev et al. 2018)....
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...…different fields of Galactic astrophysics, such as stellar populations in the local neighbourhood (e.g. Grieves et al. 2018; Anders et al. 2018; Minchev et al. 2018), the origin of the stellar halo (Fernández-Alvar et al. 2017, 2018), the physical carriers of diffuse interstellar bands…...
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...One example is the the birth radius estimation technique proposed by Minchev et al. (2018)....
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TL;DR: In this article, the authors examined the [Fe/H]-[$\alpha$/Fe] abundance plane in cosmological hydrodynamical simulations of Milky Way like galaxies from the NIHAO-UHD project and showed that the bimodal $\alpha$-sequence is a generic consequence of a gas-rich merger at some time in the Galaxy's evolution.
Abstract: The Milky Way's stellar disk exhibits a bimodality in the [Fe/H] vs. [$\alpha$/Fe] plane, showing a distinct high-$\alpha$ and low-$\alpha$ sequence whose origin is still under debate. We examine the [Fe/H]-[$\alpha$/Fe] abundance plane in cosmological hydrodynamical simulations of Milky Way like galaxies from the NIHAO-UHD project and show that the bimodal $\alpha$-sequence is a generic consequence of a gas-rich merger at some time in the Galaxy's evolution. The high-$\alpha$ sequence evolves first in the early galaxies, extending to high metallicities, while it is the low-$\alpha$ sequence that is formed after the gas-rich merger. The merger brings in fresh metal-poor gas diluting the interstellar medium's metallicity while keeping the [$\alpha$/Fe] abundance almost unchanged. The kinematic, structural and spatial properties of the bimodal $\alpha$-sequence in our simulations reproduces that of observations. In all simulations, the high-$\alpha$ disk is old, radially concentrated towards the galaxy's center and shows large scale heights. In contrast, the low-$\alpha$ disk is younger, more radially extended and concentrated to the disk mid-plane. Our results show that the abundance plane is well described by these two populations that have been distributed radially across the disk by migration: at present-day in the solar neighbourhood, low-$\alpha$ stars originate from both the inner and outer disk while most of the high-$\alpha$ stars have migrated from the inner disk. We show that age dating the stars in the [Fe/H]-[$\alpha$/Fe] plane can constrain the time of the low-$\alpha$ sequence forming merger and conclude that $\alpha$-bimodality is likely a not uncommon feature of disk galaxies.
104 citations
01 Jan 2013
TL;DR: In this article, the role of energy feedback in shaping the distribution of metals within cosmological hydrodynamical simulations of L ∗ disc galaxies was examined, and the authors concluded that spatially resolved metallicity distributions offer a unique and underutilised constraint on the uncertain nature of stellar feedback processes.
Abstract: Aims. We examine the role of energy feedback in shaping the distribution of metals within cosmological hydrodynamical simulations of L ∗ disc galaxies. While negative abundance gradients today provide a boundary condition for galaxy evolution models, in support of inside-out disc growth, empirical evidence as to whether abundance gradients steepen or flatten with time remains highly contradictory. Methods. We made use of a suite of L ∗ discs, realised with and without “enhanced” feedback. All the simulations were produced using the smoothed particle hydrodynamics code Gasoline, and their in situ gas-phase metallicity gradients traced from redshift z ∼ 2 to the present-day. Present-day age-metallicity relations and metallicity distribution functions were derived for each system. Results. The “enhanced” feedback models, which have been shown to be in agreement with a broad range of empirical scaling relations, distribute energy and re-cycled ISM material over large scales and predict the existence of relatively “flat” and temporally invariant abundance gradients. Enhanced feedback schemes reduce significantly the scatter in the local stellar age-metallicity relation and, especially, the [O/Fe]−[Fe/H] relation. The local [O/Fe] distribution functions for our L ∗ discs show clear bimodality, with peaks at [O/Fe] = −0.05 and +0.05 (for stars with [Fe/H] > −1), consistent with our earlier work on dwarf discs. Conclusions. Our results with “enhanced” feedback are inconsistent with our earlier generation of simulations realised with “conservative” feedback. We conclude that spatially-resolved metallicity distributions, particularly at high-redshift, offer a unique and under-utilised constraint on the uncertain nature of stellar feedback processes.
89 citations
References
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TL;DR: The solar chemical composition is an important ingredient in our understanding of the formation, structure, and evolution of both the Sun and our Solar System as discussed by the authors, and it is an essential refer...
Abstract: The solar chemical composition is an important ingredient in our understanding of the formation, structure, and evolution of both the Sun and our Solar System. Furthermore, it is an essential refer ...
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T. Prusti1, J. H. J. de Bruijne1, Anthony G. A. Brown2, Antonella Vallenari3 +621 more•Institutions (93)
TL;DR: Gaia as discussed by the authors is a cornerstone mission in the science programme of the European Space Agency (ESA). The spacecraft construction was approved in 2006, following a study in which the original interferometric concept was changed to a direct-imaging approach.
Abstract: Gaia is a cornerstone mission in the science programme of the EuropeanSpace Agency (ESA). The spacecraft construction was approved in 2006, following a study in which the original interferometric concept was changed to a direct-imaging approach. Both the spacecraft and the payload were built by European industry. The involvement of the scientific community focusses on data processing for which the international Gaia Data Processing and Analysis Consortium (DPAC) was selected in 2007. Gaia was launched on 19 December 2013 and arrived at its operating point, the second Lagrange point of the Sun-Earth-Moon system, a few weeks later. The commissioning of the spacecraft and payload was completed on 19 July 2014. The nominal five-year mission started with four weeks of special, ecliptic-pole scanning and subsequently transferred into full-sky scanning mode. We recall the scientific goals of Gaia and give a description of the as-built spacecraft that is currently (mid-2016) being operated to achieve these goals. We pay special attention to the payload module, the performance of which is closely related to the scientific performance of the mission. We provide a summary of the commissioning activities and findings, followed by a description of the routine operational mode. We summarise scientific performance estimates on the basis of in-orbit operations. Several intermediate Gaia data releases are planned and the data can be retrieved from the Gaia Archive, which is available through the Gaia home page.
5,164 citations
TL;DR: In this article, a new reduction of the Hipparcos data was published, which claimed accuracies for nearly all stars brighter than magnitude Hp = 8 to be better, by up to a factor 4, than in the original catalog.
Abstract: Context. A new reduction of the astrometric data as produced by the Hipparcos mission has been published, claiming accuracies for nearly all stars brighter than magnitude Hp = 8 to be better, by up to a factor 4, than in the original catalog ue. Aims. The new Hipparcos astrometric catalogue is checked for the quality of the data and the consistency of the formal errors as well as the possible presence of error correlations. The differences with the earlier publication are explained. Methods. The internal errors are followed through the reduction proc ess, and the external errors are investigated on the basis of a comparison with radio observations of a small selection of stars, and the distribution of negative parallaxes. Error co rrelation levels are investigated and the reduction by more than a factor 10 as obtained in the new catalogue is explained. Results. The formal errors on the parallaxes for the new catalogue are confirmed. The presence of a small amount of additional noise , though unlikely, cannot be ruled out. Conclusions. The new reduction of the Hipparcos astrometric data provides an improvement by a factor 2.2 in the total weight compared to the catalogue published in 1997, and provides much improved data for a wide range of studies on stellar luminosities and local galactic kinematics.
4,203 citations
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...Surface gravities were estimated from Hipparcos (van Leeuwen 2007)....
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Massachusetts Institute of Technology1, Harvard University2, Princeton University3, University of Chicago4, Las Cumbres Observatory Global Telescope Network5, University of Copenhagen6, Arizona State University7, Carnegie Institution for Science8, University of Birmingham9, Aarhus University10, Goddard Space Flight Center11, University of Maryland, College Park12, Northern Kentucky University13, Vanderbilt University14, Lowell Observatory15, University of Texas at Austin16, University of Florida17, Max Planck Society18, Tokyo Institute of Technology19, University of California, Berkeley20, University of California, Santa Cruz21, Johns Hopkins University22, Space Telescope Science Institute23, Spanish National Research Council24, Lehigh University25, INAF26, Fisk University27
TL;DR: The Transiting Exoplanet Survey Satellite (TESS) as discussed by the authors will search for planets transiting bright and nearby stars using four wide-field optical charge-coupled device cameras to monitor at least 200,000 main-sequence dwarf stars.
Abstract: The Transiting Exoplanet Survey Satellite (TESS) will search for planets transiting bright and nearby stars. TESS has been selected by NASA for launch in 2017 as an Astrophysics Explorer mission. The spacecraft will be placed into a highly elliptical 13.7-day orbit around the Earth. During its 2-year mission, TESS will employ four wide-field optical charge-coupled device cameras to monitor at least 200,000 main-sequence dwarf stars with I C ≈4−13 for temporary drops in brightness caused by planetary transits. Each star will be observed for an interval ranging from 1 month to 1 year, depending mainly on the star’s ecliptic latitude. The longest observing intervals will be for stars near the ecliptic poles, which are the optimal locations for follow-up observations with the James Webb Space Telescope. Brightness measurements of preselected target stars will be recorded every 2 min, and full frame images will be recorded every 30 min. TESS stars will be 10 to 100 times brighter than those surveyed by the pioneering Kepler mission. This will make TESS planets easier to characterize with follow-up observations. TESS is expected to find more than a thousand planets smaller than Neptune, including dozens that are comparable in size to the Earth. Public data releases will occur every 4 months, inviting immediate community-wide efforts to study the new planets. The TESS legacy will be a catalog of the nearest and brightest stars hosting transiting planets, which will endure as highly favorable targets for detailed investigations.
2,604 citations
TL;DR: The Transiting Exoplanet Survey Satellite (TESS) as mentioned in this paper was selected by NASA for launch in 2017 as an Astrophysics Explorer mission to search for planets transiting bright and nearby stars.
Abstract: The Transiting Exoplanet Survey Satellite (TESS) will search for planets transiting bright and nearby stars. TESS has been selected by NASA for launch in 2017 as an Astrophysics Explorer mission. The spacecraft will be placed into a highly elliptical 13.7-day orbit around the Earth. During its two-year mission, TESS will employ four wide-field optical CCD cameras to monitor at least 200,000 main-sequence dwarf stars with I = 4-13 for temporary drops in brightness caused by planetary transits. Each star will be observed for an interval ranging from one month to one year, depending mainly on the star's ecliptic latitude. The longest observing intervals will be for stars near the ecliptic poles, which are the optimal locations for follow-up observations with the James Webb Space Telescope. Brightness measurements of preselected target stars will be recorded every 2 min, and full frame images will be recorded every 30 min. TESS stars will be 10-100 times brighter than those surveyed by the pioneering Kepler mission. This will make TESS planets easier to characterize with follow-up observations. TESS is expected to find more than a thousand planets smaller than Neptune, including dozens that are comparable in size to the Earth. Public data releases will occur every four months, inviting immediate community-wide efforts to study the new planets. The TESS legacy will be a catalog of the nearest and brightest stars hosting transiting planets, which will endure as highly favorable targets for detailed investigations.
1,728 citations