Distance determination for RAVE stars using stellar models
M. A. Breddels, M. C. Smith, A. Helmi, O. Bienayme, J. Binney, J. Bland-Hawthorn, C. Boeche, B. C. M. Burnett, R. Campbell, K. C. Freeman, B. Gibson, G. Gilmore… 展开作者
M. A. Breddels, M. C. Smith, A. Helmi, O. Bienayme, J. Binney, J. Bland-Hawthorn, C. Boeche, B. C. M. Burnett, R. Campbell, K. C. Freeman, B. Gibson, G. Gilmore, E. K. Grebel, U. Munari, J. F. Navarro, Q. A. Parker, G. M. Seabroke, A. Siebert, A. Siviero, M. Steinmetz, F. G. Watson, M. Williams, R. F. G. Wyse, T. Zwitter
备注:
17 pages, 18 figures, data and future updates available at http://www.astro.rug.nl/~rave, accepted for publication in A&A
(Abridged) Aims:We develop a method for deriving distances from spectroscopic data and obtaining full 6D phase-space coordinates for the RAVE survey's second data release. Methods: We used stellar models combined with atmospheric properties from RAVE (Teff, logg and [Fe/H]) and (J-Ks) photometry from archival sources to derive absolute magnitudes. We are able to derive the full 6D phase-space coordinates for a large sample of RAVE stars. This method is tested with artificial data, Hipparcos trigonometric parallaxes and observations of the open cluster M67. Results: When we applied our method to a set of 16 146 stars, we found that 25% (4 037) of the stars have relative (statistical) distance errors of < 35%, while 50% (8 073) and 75% (12 110) have relative (statistical) errors smaller than 45% and 50%, respectively. Our various tests show that we can reliably estimate distances for main-sequence stars, but there is an indication of potential systematic problems with giant stars. For the main-sequence star sample (defined as those with log(g) > 4), 25% (1 744) have relative distance errors < 31%, while 50% (3 488) and 75% (5 231) have relative errors smaller than 36% and 42%, respectively. Our full dataset shows the expected decrease in the metallicity of stars as a function of distance from the Galactic plane. The known kinematic substructures in the U and V velocity components of nearby dwarf stars are apparent in our dataset, confirming the accuracy of our data and the reliability of our technique. We provide independent measurements of the orientation of the UV velocity ellipsoid and of the solar motion, and they are in very good agreement with previous work. Conclusions: The distance catalogue for the RAVE second data release is available at http://www.astro.rug.nl/~rave
We use the second Gaia data release (Gaia DR2), combined with RAVE spectroscopic surveys, to identify the substructures in the nearby stellar halo. We select 3,845 halo stars kinematically and chemically, and determine their density distribution in energy and angular momentum space. To select the substructures from overdensities, we reshuffle the velocities and estimate their significance. Two statistically significant substructures, GR-1 and GR-2, are identified. GR-1 has a high binding energy and small $z$-angular momentum. GR-2 is metal-rich but retrograde. They are both new substructure, a…
We investigate the vertical metallicity gradients of five mono-age stellar populations between 0 and 11 Gyr for a sample of 18 435 dwarf stars selected from the cross-matched Tycho-Gaia Astrometric Solution (TGAS) and RAdial Velocity Experiment (RAVE) Data Release 5. We find a correlation between the vertical metallicity gradients and age, with no vertical metallicity gradient in the youngest population and an increasingly steeper negative vertical metallicity gradient for the older stellar populations. The metallicity at disc plane remains almost constant between 2 and 8 Gyr, and it becomes s…
第五次RAVE数据发布基于457,588颗独特恒星的520,781个光谱($R\approx7500$位于$8410$ - $8795$的CaT区域)。RAVE DR 5提供了径向速度、恒星参数和多达七种元素的个别丰度,以及使用等时线为这些天体的相当一部分找到的距离。特别是,RAVE DR 5有255,922个恒星观测,也有来自盖亚DR 1中Tycho-Gaia天体测量解(TGAS)的自行和自行。因此,RAVE和TGAS的结合提供了目前最大的光谱和天基天体测量数据的重叠,因此可以作为Gaia在未来数据发布中提供的强大预览。本文介绍了RAVE+TGAS测量的基本性质及其衍生数据产品,以及在盘状结构中的首次应用。对第六次RAVE数据发布进行了展望。
We have analyzed the space velocities of stars with the proper motions and trigonometric parallaxes from the Gaia TGAS catalogue in combination with the line-of-sight velocities from the RAVE5 catalogue. In the (V,\sqrt{U^2+2V^2}) velocity plane we have identified three clumps, BB17-1, BB17-2, and BB17-3, in the region of large velocities (V<-150 km/s). The stars of the BB17-1 and BB17-2 clumps are associated with the kinematic groups VelHel-6 and VelHel-7 detected previously by Helmi et al. We give the greatest attention to the BB17-3 clump. The latter is shown to be most closely linked with …
We explore the connections between stellar age, chemistry, and kinematics across a Galactocentric distance of $7.5 < R\,(\mathrm{kpc}) < 9.0$, using a sample of $\sim 12\,000$ intermediate-mass (FGK) turnoff stars observed with the RAdial Velocity Experiment (RAVE) survey. The kinematics of this sample are determined using radial velocity measurements from RAVE, and parallax and proper motion measurements from the Tycho-Gaia Astrometric Solution (TGAS). In addition, ages for RAVE stars are determined using a Bayesian method, taking TGAS parallaxes as a prior. We divide our sample into young ($…
We present part 2 of the 6th and final Data Release (DR6 or FDR) of the Radial Velocity Experiment (RAVE), a magnitude-limited (9<I<12) spectroscopic survey of Galactic stars randomly selected in the southern hemisphere. The RAVE medium-resolution spectra (R~7500) cover the Ca-triplet region (8410-8795A) and span the complete time frame from the start of RAVE observations on 12 April 2003 to their completion on 4 April 2013. In the second of two publications, we present the data products derived from 518387 observations of 451783 unique stars using a suite of advanced reduction pipelines focus…
We aim to probe the dynamic structure of the extended Solar neighbourhood by calculating the radial metallicity gradients from orbit properties, which are obtained for axisymmetric and non-axisymmetric potential models, of red clump (RC) stars selected from the RAdial Velocity Experiment's Fourth Data Release. Distances are obtained by assuming a single absolute magnitude value in near-infrared, i.e. $M_{Ks}=-1.54\pm0.04$ mag, for each RC star. Stellar orbit parameters are calculated by using the potential functions: (i) for the MWPotential2014 potential, (ii) for the same potential with pertu…
Stellar halos contain tracers of the assembly history of massive galaxies like our own. Exploiting the synergy between the TGAS and the spectroscopic RAVE surveys, Helmi et al. (2017) recently discovered several distinct substructures in the Solar neighbourhood, defined in integrals of motion space. Some of these substructures may be examples of the building blocks that built up the stellar halo. We analyse the chemical properties of stars in these substructures, with focus on their iron and $α$-element abundances as provided by the RAVE survey chemical pipeline. We perform comparisons of the …
We combine parallaxes from the first Gaia data release with the spectrophotometric distance estimation framework for stars in the fifth RAVE survey data release. The combined distance estimates are more accurate than either determination in isolation - uncertainties are on average two times smaller than for RAVE-only distances (three times smaller for dwarfs), and 1.4 times smaller than TGAS parallax uncertainties (two times smaller for giants). We are also able to compare the estimates from spectrophotometry to those from Gaia, and use this to assess the reliability of both catalogues and imp…
Kinematic structures of the Solar neighbourhood revealed by Gaia DR1/TGAS and RAVE
太阳附近恒星的速度分布是不均匀的,并且有丰富的恒星流和运动学结构。这些可能保留了银河系形成和动力学历史的重要线索。然而,许多溪流和结构的性质和起源尚不清楚,阻碍了我们对银河系如何形成和演化的理解。我们的目标是研究太阳附近恒星的速度分布,并研究单个运动学结构的性质,以提高我们对它们起源的理解。利用Gaia DR 1/TGAS提供的天体测量数据和RAVE DR 5的径向速度,我们对55831颗U和V速度不确定度小于4 km/s的恒星进行了小波分析。使用自卷积直方图方法对输出数据进行滤波,然后运行蒙特卡罗模拟来验证由于速度不确定性而检测到的结构是真实的。此外,我们通过将所有恒星分为附近的样本(<300 pc)和遥远的样本(>300 pc)以及两个化学定义的样本来分析我们的恒星样本,这两个样本在第一程度上代表了薄盘和厚盘。通过盖亚DR 1 TGAS提供的更大的恒星样本和更高精度的距离,自行,我们已经表明,太阳附近恒星的速度分布包含比以前已知的更多的结构。发现了一个新的特征,并以高置信度确认了三个最近检测到的组。根据距离和/或金属丰度对样本进行划分,发现存在各种各样的结构,这些结构可分为大尺度和小尺度的组,其中一些具有明显的金属丰度趋势,另一些则是两种盘星的混合物,并在此基础上讨论了每一组的可能起源。
In the context of large spectroscopic surveys of stars, data-driven methods are key in deducing physical parameters for millions of spectra in a short time. Convolutional neural networks (CNNs) enable us to connect observables (e.g. spectra, stellar magnitudes) to physical properties (atmospheric parameters, chemical abundances, or labels in general). We trained a CNN, adopting stellar atmospheric parameters and chemical abundances from APOGEE DR16 (resolution R=22500) data as training set labels. As input, we used parts of the intermediate-resolution RAVE DR6 spectra (R~7500) overlapping with…
In this paper we investigate how the chemical and kinematic properties of stars vary as a function of age. Using data from a variety of photometric, astrometric and spectroscopic surveys, we calculate the ages, phase space information and orbits for $\sim$125,000 stars covering a wide range of stellar parameters. We find indications that the inner regions of the disk reached high levels of enrichment early, while the outer regions were more substantially enriched in intermediate and recent epochs. We consider these enrichment histories through comparison of the ages of stars, their metalliciti…
We test the performance of the semi-analytic self-consistent Just-Jahreiß disc model (JJ model) with the astrometric data from the Tycho-Gaia Astrometric Solution (TGAS) sub-catalogue of the first Gaia data release (Gaia DR1), as well as the radial velocities from the fifth data release of the Radial Velocity Experiment survey (RAVE DR5). We use a sample of 19,746 thin disc stars from the TGAS$\times$RAVE cross-match selected in the local solar cylinder of 300 pc radius and 1 kpc height below the Galactic plane and simulate this sample via the forward modelling technique. First, we convert the…
The local velocity distribution of dark matter plays an integral role in interpreting the results from direct detection experiments. We previously showed that metal-poor halo stars serve as excellent tracers of the virialized dark matter velocity distribution using a high-resolution hydrodynamic simulation of a Milky Way--like halo. In this paper, we take advantage of the first \textit{Gaia} data release, coupled with spectroscopic measurements from the RAdial Velocity Experiment (RAVE), to study the kinematics of stars belonging to the metal-poor halo within an average distance of $\sim 5$ kp…
The relation between velocity dispersions and chemical abundances in RAVE giants
我们开发了一个贝叶斯框架,以确定在一个强大的方式之间的关系速度分散和化学丰度的恒星样本。我们的建模考虑了化学和运动学性质的不确定性。我们使用RAVE DR 5径向速度和丰度以及Gaia DR 1自行和松弛(如果可能,否则使用UCAC 4数据)。我们发现,在一般情况下,速度分散增加减少[Fe/H]和增加[Mg/Fe]。高[Mg/Fe]恒星的速度色散可能会降低,这是一个可以忽略的恒星比例的性质,几乎不是一个可靠的结果。在低[Fe/H]和高[Mg/Fe]下,样品是不完整的,受到偏差的影响,并且可能不代表潜在的恒星星族。
We present a detailed analysis of kinematics of the Milky Way disk in solar neighborhood using GAIA DR3 catalog. To determine the local kinematics of the stellar disks of the Milky Way galaxy we use a complete sample of 278,228 red giant branch (RGB) stars distributed in a cylinder, centered at the Sun with a 1 kpc radius and half-height of 0.5 kpc. We determine separately the kinematical properties of RGB stars for each Galactic hemisphere in search for possible asymmetries. The kinematical properties of the RGB stars reveal the existence of two kinematically distinct components: the thin dis…
The origin of the Hercules stream, the most prominent velocity substructure in the Solar neighbour disc stars, is still under debate. Recent accurate measurements of position, velocity, and metallicity provided by Tycho Gaia Astrometric Solution (TGAS) and RAdial Velocity Experiments (RAVE) have revealed that the Hercules stream is most clearly seen in the metal-rich region ([Fe/H] > 0), while it is not clearly seen in lower metallicity region ([Fe/H] < -0.25). By using a large number of chemo-dynamical 2D test-particle simulations with a rotating bar and/or spiral arms, we find that the obser…
Asteroseismology has become widely accepted as a benchmark for accurate and precise fundamental stellar properties. It can therefore be used to validate and calibrate stellar parameters derived from other approaches. Meanwhile, one can leverage large-volume surveys in photometry, spectroscopy, and astrometry to infer stellar parameters over a wide range of evolutionary stages, independently of asteroseismology. Our pipeline, SEDEX, compares the spectral energy distribution predicted by the MARCS and BOSZ model spectra with 32 photometric bandpasses, combining data from 9 major, large-volume ph…
We report on the spectroscopic analysis of RAVE J183013.5-455510, an extremely metal-poor star, highly enhanced in CNO, and with discernible contributions from the rapid neutron-capture process. There is no evidence of binarity for this object. At [Fe/H]=-3.57, this is one of the lowest metallicity stars currently observed, with 18 measured abundances of neutron-capture elements. The presence of Ba, La, and Ce abundances above the Solar System r-process predictions suggest that there must have been a non-standard source of r-process elements operating at such low metallicities. One plausible e…
The Radial Velocity Experiment (RAVE) is a magnitude-limited (9<I<12) spectroscopic survey of Galactic stars randomly selected in the southern hemisphere. The RAVE medium-resolution spectra (R~7500) cover the Ca-triplet region (8410-8795A). The 6th and final data release (DR6 or FDR) is based on 518387 observations of 451783 unique stars. RAVE observations were taken between 12 April 2003 and 4 April 2013. Here we present the genesis, setup and data reduction of RAVE as well as wavelength-calibrated and flux-normalized spectra and error spectra for all observations in RAVE DR6. Furthermore, we…