275 results on '"Anguiano B."'
Search Results
2. The 16th Data Release of the Sloan Digital Sky Surveys: First Release from the APOGEE-2 Southern Survey and Full Release of eBOSS Spectra
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Ahumada, R, Prieto, CA, Almeida, A, Anders, F, Anderson, SF, Andrews, BH, Anguiano, B, Arcodia, R, Armengaud, E, Aubert, M, Avila, S, Avila-Reese, V, Badenes, C, Balland, C, Barger, K, Barrera-Ballesteros, JK, Basu, S, Bautista, J, Beaton, RL, Beers, TC, Benavides, BIT, Bender, CF, Bernardi, M, Bershady, M, Beutler, F, Bidin, CM, Bird, J, Bizyaev, D, Blanc, GA, Blanton, MR, Boquien, M, Borissova, J, Bovy, J, Brandt, WN, Brinkmann, J, Brownstein, JR, Bundy, K, Bureau, M, Burgasser, A, Burtin, E, Cano-Díaz, M, Capasso, R, Cappellari, M, Carrera, R, Chabanier, S, Chaplin, W, Chapman, M, Cherinka, B, Chiappini, C, Doohyun Choi, P, Chojnowski, SD, Chung, H, Clerc, N, Coffey, D, Comerford, JM, Comparat, J, Da Costa, L, Cousinou, MC, Covey, K, Crane, JD, Cunha, K, Ilha, GDS, Dai, YS, Damsted, SB, Darling, J, Davidson, JW, Davies, R, Dawson, K, De, N, De La Macorra, A, De Lee, N, Queiroz, ABDA, Deconto Machado, A, De La Torre, S, Dell'Agli, F, Du Mas Des Bourboux, H, Diamond-Stanic, AM, Dillon, S, Donor, J, Drory, N, Duckworth, C, Dwelly, T, Ebelke, G, Eftekharzadeh, S, Davis Eigenbrot, A, Elsworth, YP, Eracleous, M, Erfanianfar, G, Escoffier, S, Fan, X, Farr, E, Fernández-Trincado, JG, Feuillet, D, Finoguenov, A, Fofie, P, Fraser-Mckelvie, A, Frinchaboy, PM, Fromenteau, S, Fu, H, and Galbany, L
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astro-ph.GA ,astro-ph.CO ,astro-ph.IM ,Astronomical and Space Sciences ,Atomic ,Molecular ,Nuclear ,Particle and Plasma Physics ,Physical Chemistry ,Astronomy & Astrophysics ,Atomic ,Molecular ,Nuclear ,Particle and Plasma Physics ,Physical Chemistry (incl. Structural) - Abstract
This paper documents the 16th data release (DR16) from the Sloan Digital Sky Surveys (SDSS), the fourth and penultimate from the fourth phase (SDSS-IV). This is the first release of data from the Southern Hemisphere survey of the Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2); new data from APOGEE-2 North are also included. DR16 is also notable as the final data release for the main cosmological program of the Extended Baryon Oscillation Spectroscopic Survey (eBOSS), and all raw and reduced spectra from that project are released here. DR16 also includes all the data from the Time Domain Spectroscopic Survey and new data from the SPectroscopic IDentification of ERosita Survey programs, both of which were co-observed on eBOSS plates. DR16 has no new data from the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey (or the MaNGA Stellar Library "MaStar"). We also preview future SDSS-V operations (due to start in 2020), and summarize plans for the final SDSS-IV data release (DR17).
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- 2020
3. A comprehensive comparison between APOGEE and LAMOST: Radial Velocities and Atmospheric Stellar Parameters
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Anguiano, B., Majewski, S. R., Allende-Prieto, C., Meszaros, S., Jönsson, H., García-Hernández, D. A., Beaton, R. L., Stringfellow, G. S., Cunha, K., and Smith, V. V.
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Astrophysics - Astrophysics of Galaxies ,Astrophysics - Solar and Stellar Astrophysics - Abstract
We undertake a critical and comprehensive comparison of the radial velocities and the main stellar atmospheric parameters for stars in common between the latest data releases from the APOGEE and the LAMOST surveys. There is a total of 42,420 dwarfs/giants stars in common between the APOGEE DR14 - LAMOST DR3 stellar catalogs. A comparison between the RVs shows an offset of 4.54 $\pm$ 0.03 km/s, with a dispersion of 5.8 km/s, in the sense that APOGEE RVs are larger. We observe a small offset in the Teff of about 13 K, with a scatter of 155 K. Small offset in [Fe/H] of about 0.06 dex together with a scatter of 0.13 dex is also observed. We notice that the largest offset between the surveys occurs in the surface gravities. Using only surface gravities in calibrated red giants from APOGEE DR14, where there are 24,074 stars in common, a deviation of 0.14 dex is found with substantial scatter. There are 17,482 red giant stars in common between APOGEE DR14 and those in LAMOST tied to APOGEE DR12 via the Cannon. There is generally good agreement between the two data-sets. However, we find dependencies of the differences of the stellar parameters on effective temperature. For metal-rich stars, a different trend for the [Fe/H] discrepancies is found. Surprisingly, we see no correlation between the internal APOGEE DR14 - DR12 differences in Teff and those in DR14 - LAMOST tied to DR12, where a correlation should be expected since LAMOST has been calibrated to APOGEE DR12. We also find no correlation between the [Fe/H] discrepancies, suggesting that LAMOST/Cannon is not well coupled to the APOGEE DR12 stellar parameters scale. A [Fe/H] dependence between the stellar parameters in APOGEE DR12 and those in DR14 is reported. We find a weak correlation in the differences between APOGEE DR14 - DR12 and LAMOST on DR12 surface gravity for stars hotter than 4800 K and in the log g range between 2.0 and 2.8., Comment: 14 pages, 20 figures. Accepted for publication in Astronomy & Astrophysics (A&A)
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- 2018
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4. The GALAH Survey: Second Data Release
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Buder, S., Asplund, M., Duong, L., Kos, J., Lind, K., Ness, M. K., Sharma, S., Bland-Hawthorn, J., Casey, A. R., De Silva, G. M., D'Orazi, V., Freeman, K. C., Lewis, G. F., Lin, J., Martell, S. L., Schlesinger, K. J., Simpson, J. D., Zucker, D. B., Zwitter, T., Amarsi, A. M., Anguiano, B., Carollo, D., Cotar, K., Cottrell, P. L., Da Costa, G., Gao, X. D., Hayden, M. R., Horner, J., Ireland, M. J., Kafle, P. R., Munari, U., Nataf, D. M., Nordlander, T., Stello, Dennis, Ting, Y. -S., Traven, G., Watson, F., Wittenmyer, R. A., Wyse, R. F. G., Yong, D., Zinn, J. C., and Zerjal, M.
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Astrophysics - Solar and Stellar Astrophysics ,Astrophysics - Astrophysics of Galaxies - Abstract
The Galactic Archaeology with HERMES (GALAH) survey is a large-scale stellar spectroscopic survey of the Milky Way and designed to deliver chemical information complementary to a large number of stars covered by the $Gaia$ mission. We present the GALAH second public data release (GALAH DR2) containing 342,682 stars. For these stars, the GALAH collaboration provides stellar parameters and abundances for up to 23 elements to the community. Here we present the target selection, observation, data reduction and detailed explanation of how the spectra were analysed to estimate stellar parameters and element abundances. For the stellar analysis, we have used a multi-step approach. We use the physics-driven spectrum synthesis of Spectroscopy Made Easy (SME) to derive stellar labels ($T_\mathrm{eff}$, $\log g$, $\mathrm{[Fe/H]}$, $\mathrm{[X/Fe]}$, $v_\mathrm{mic}$, $v \sin i$, $A_{K_S}$) for a representative training set of stars. This information is then propagated to the whole survey with the data-driven method of $The~Cannon$. Special care has been exercised in the spectral synthesis to only consider spectral lines that have reliable atomic input data and are little affected by blending lines. Departures from local thermodynamic equilibrium (LTE) are considered for several key elements, including Li, O, Na, Mg, Al, Si, and Fe, using 1D MARCS stellar atmosphere models. Validation tests including repeat observations, Gaia benchmark stars, open and globular clusters, and K2 asteroseismic targets lend confidence in our methods and results. Combining the GALAH DR2 catalogue with the kinematic information from $Gaia$ will enable a wide range of Galactic Archaeology studies, with unprecedented detail, dimensionality, and scope., Comment: 34+7 pages, 31 Figures, 5 tables, 1 catalog, submitted to MNRAS
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- 2018
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5. The GALAH survey: properties of the Galactic disk(s) in the solar neighbourhood
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Duong, L., Freeman, K. C., Asplund, M., Casagrande, L., Buder, S., Lind, K., Ness, M., Bland-Hawthorn, J., De Silva, G. M., D'Orazi, V., Kos, J., Lewis, G. F., Lin, J., Martell, S. L., Schlesinger, K., Sharma, S., Simpson, J. D., Zucker, D. B., Zwitter, T., Anguiano, B., Da Costa, G. S., Hyde, E., Horner, J., Kafle, P. R., Nataf, D. M., Reid, W., Stello, D., Ting, Y. -S., and Wyse, R. F. G.
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Astrophysics - Astrophysics of Galaxies - Abstract
Using data from the GALAH pilot survey, we determine properties of the Galactic thin and thick disks near the solar neighbourhood. The data cover a small range of Galactocentric radius ($7.9 \leq R_\mathrm{GC} \leq 9.5$ kpc), but extend up to 4 kpc in height from the Galactic plane, and several kpc in the direction of Galactic anti-rotation (at longitude $260 ^\circ \leq \ell \leq 280^\circ$). This allows us to reliably measure the vertical density and abundance profiles of the chemically and kinematically defined `thick' and `thin' disks of the Galaxy. The thin disk (low-$\alpha$ population) exhibits a steep negative vertical metallicity gradient, at d[M/H]/d$z=-0.18 \pm 0.01$ dex kpc$^{-1}$, which is broadly consistent with previous studies. In contrast, its vertical $\alpha$-abundance profile is almost flat, with a gradient of d[$\alpha$/M]/d$z$ = $0.008 \pm 0.002$ dex kpc$^{-1}$. The steep vertical metallicity gradient of the low-$\alpha$ population is in agreement with models where radial migration has a major role in the evolution of the thin disk. The thick disk (high-$\alpha$ population) has a weaker vertical metallicity gradient d[M/H]/d$z = -0.058 \pm 0.003$ dex kpc$^{-1}$. The $\alpha$-abundance of the thick disk is nearly constant with height, d[$\alpha$/M]/d$z$ = $0.007 \pm 0.002$ dex kpc$^{-1}$. The negative gradient in metallicity and the small gradient in [$\alpha$/M] indicate that the high-$\alpha$ population experienced a settling phase, but also formed prior to the onset of major SNIa enrichment. We explore the implications of the distinct $\alpha$-enrichments and narrow [$\alpha$/M] range of the sub-populations in the context of thick disk formation., Comment: 18 pages, 15 figures, 3 tables. Accepted for publication in MNRAS
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- 2018
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6. The Fifteenth Data Release of the Sloan Digital Sky Surveys: First Release of MaNGA-derived Quantities, Data Visualization Tools, and Stellar Library
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Aguado, DS, Ahumada, R, Almeida, A, Anderson, SF, Andrews, BH, Anguiano, B, Ortiz, EA, Aragón-Salamanca, A, Argudo-Fernández, M, Aubert, M, Avila-Reese, V, Badenes, C, Barboza Rembold, S, Barger, K, Barrera-Ballesteros, J, Bates, D, Bautista, J, Beaton, RL, Beers, TC, Belfiore, F, Bernardi, M, Bershady, M, Beutler, F, Bird, J, Bizyaev, D, Blanc, GA, Blanton, MR, Blomqvist, M, Bolton, AS, Boquien, M, Borissova, J, Bovy, J, Nielsen Brandt, W, Brinkmann, J, Brownstein, JR, Bundy, K, Burgasser, A, Byler, N, Cano Diaz, M, Cappellari, M, Carrera, R, Cervantes Sodi, B, Chen, Y, Cherinka, B, Doohyun Choi, P, Chung, H, Coffey, D, Comerford, JM, Comparat, J, Covey, K, Da Silva Ilha, G, Da Costa, L, Sophia Dai, Y, Damke, G, Darling, J, Davies, R, Dawson, K, De Sainte Agathe, V, Deconto Machado, A, Del Moro, A, De Lee, N, Diamond-Stanic, AM, Dominguez Sánchez, H, Donor, J, Drory, N, Du Mas Des Bourboux, H, Duckworth, C, Dwelly, T, Ebelke, G, Emsellem, E, Escoffier, S, Fernández-Trincado, JG, Feuillet, D, Fischer, JL, Fleming, SW, Fraser-Mckelvie, A, Freischlad, G, Frinchaboy, PM, Fu, H, Galbany, L, Garcia-Dias, R, Garcia-Hernández, DA, Alberto Garma Oehmichen, L, Antonio Geimba Maia, M, Gil-Marin, H, Grabowski, K, Gu, M, Guo, H, Ha, J, Harrington, E, Hasselquist, S, Hayes, CR, Hearty, F, Hernandez Toledo, H, Hicks, H, Hogg, DW, Holley-Bockelmann, K, Holtzman, JA, Hsieh, BC, and Hunt, JAS
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atlases ,catalogs ,surveys ,astro-ph.IM ,Astronomy & Astrophysics ,Astronomical and Space Sciences ,Organic Chemistry ,Physical Chemistry ,Atomic ,Molecular ,Nuclear ,Particle and Plasma Physics ,Atomic ,Molecular ,Nuclear ,Particle and Plasma Physics ,Physical Chemistry (incl. Structural) - Abstract
Twenty years have passed since first light for the Sloan Digital Sky Survey (SDSS). Here, we release data taken by the fourth phase of SDSS (SDSS-IV) across its first three years of operation (2014 July-2017 July). This is the third data release for SDSS-IV, and the 15th from SDSS (Data Release Fifteen; DR15). New data come from MaNGA - we release 4824 data cubes, as well as the first stellar spectra in the MaNGA Stellar Library (MaStar), the first set of survey-supported analysis products (e.g., stellar and gas kinematics, emission-line and other maps) from the MaNGA Data Analysis Pipeline, and a new data visualization and access tool we call "Marvin." The next data release, DR16, will include new data from both APOGEE-2 and eBOSS; those surveys release no new data here, but we document updates and corrections to their data processing pipelines. The release is cumulative; it also includes the most recent reductions and calibrations of all data taken by SDSS since first light. In this paper, we describe the location and format of the data and tools and cite technical references describing how it was obtained and processed. The SDSS website (www.sdss.org) has also been updated, providing links to data downloads, tutorials, and examples of data use. Although SDSS-IV will continue to collect astronomical data until 2020, and will be followed by SDSS-V (2020-2025), we end this paper by describing plans to ensure the sustainability of the SDSS data archive for many years beyond the collection of data.
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- 2019
7. The Galah Survey: Classification and diagnostics with t-SNE reduction of spectral information
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Traven, G., Matijevič, G., Zwitter, T., Žerjal, M., Kos, J., Asplund, M., Bland-Hawthorn, J., Casey, A. R., De Silva, G., Freeman, K., Lin, J., Martell, S. L., Schlesinger, K. J., Sharma, S., Simpson, J. D., Zucker, D. B., Anguiano, B., Da Costa, G., Duong, L., Horner, J., Hyde, E. A., Kafle, P. R., Munari, U., Nataf, D., Navin, C. A., Reid, W., and Ting, Y. -S.
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Astrophysics - Solar and Stellar Astrophysics ,Astrophysics - Astrophysics of Galaxies ,Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
Galah is an ongoing high-resolution spectroscopic survey with the goal of disentangling the formation history of the Milky Way, using the fossil remnants of disrupted star formation sites which are now dispersed around the Galaxy. It is targeting a randomly selected, magnitude limited ($V \leq 14$) sample of stars, with the goal of observing one million objects. To date, 300,000 spectra have been obtained. Not all of them are correctly processed by parameter estimation pipelines and we need to know about them. We present a semi-automated classification scheme which identifies different types of peculiar spectral morphologies, in an effort to discover and flag potentially problematic spectra and thus help to preserve the integrity of the survey's results. To this end we employ a recently developed dimensionality reduction technique t-SNE (t-distributed Stochastic Neighbour Embedding), which enables us to represent the complex spectral morphology in a two-dimensional projection map while still preserving the properties of the local neighbourhoods of spectra. We find that the majority (178,483) of the 209,533 Galah spectra considered in this study represents normal single stars, whereas 31,050 peculiar and problematic spectra with very diverse spectral features pertaining to 28,579 stars are distributed into 10 classification categories: Hot stars, Cool metal-poor giants, Molecular absorption bands, Binary stars, H$\alpha$/H$\beta$ emission, H$\alpha$/H$\beta$ emission superimposed on absorption, H$\alpha$/H$\beta$ P-Cygni, H$\alpha$/H$\beta$ inverted P-Cygni, Lithium absorption, and Problematic. Classified spectra with supplementary information are presented in the catalogue, indicating candidates for follow-up observations and population studies of the short-lived phases of stellar evolution.
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- 2016
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8. The fourteenth data release of the sloan digital sky survey: First spectroscopic data from the extended baryon oscillation spectroscopic survey and from the second phase of the apache point observatory galactic evolution experiment
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Abolfathi, B, Aguado, DS, Aguilar, G, Prieto, CA, Almeida, A, Ananna, TT, Anders, F, Anderson, SF, Andrews, BH, Anguiano, B, Aragón-Salamanca, A, Argudo-Fernández, M, Armengaud, E, Ata, M, Aubourg, E, Avila-Reese, V, Badenes, C, Bailey, S, Balland, C, Barger, KA, Barrera-Ballesteros, J, Bartosz, C, Bastien, F, Bates, D, Baumgarten, F, Bautista, J, Beaton, R, Beers, TC, Belfiore, F, Bender, CF, Bernardi, M, Bershady, MA, Beutler, F, Bird, JC, Bizyaev, D, Blanc, GA, Blanton, MR, Blomqvist, M, Bolton, AS, Boquien, M, Borissova, J, Bovy, J, Bradna Diaz, CA, Nielsen Brandt, W, Brinkmann, J, Brownstein, JR, Bundy, K, Burgasser, AJ, Burtin, E, Busca, NG, Canãs, CI, Cano-Diáz, M, Cappellari, M, Carrera, R, Casey, AR, Sodi, BC, Chen, Y, Cherinka, B, Chiappini, C, Choi, PD, Chojnowski, D, Chuang, CH, Chung, H, Clerc, N, Cohen, RE, Comerford, JM, Comparat, J, Do Nascimento, JC, Da Costa, L, Cousinou, MC, Covey, K, Crane, JD, Cruz-Gonzalez, I, Cunha, K, Ilha, GDS, Damke, GJ, Darling, J, Davidson, JW, Dawson, K, De Icaza Lizaola, MAC, MacOrra, ADL, De La Torre, S, De Lee, N, Sainte Agathe, VD, Deconto MacHado, A, Dell'Agli, F, Delubac, T, Diamond-Stanic, AM, Donor, J, Downes, JJ, Drory, N, Mas Des Bourboux, HD, Duckworth, CJ, Dwelly, T, Dyer, J, Ebelke, G, Eigenbrot, AD, Eisenstein, DJ, Elsworth, YP, and Emsellem, E
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atlases ,catalogs ,surveys ,astro-ph.GA ,astro-ph.IM ,Astronomy & Astrophysics ,Astronomical and Space Sciences ,Atomic ,Molecular ,Nuclear ,Particle and Plasma Physics ,Physical Chemistry ,Atomic ,Molecular ,Nuclear ,Particle and Plasma Physics ,Physical Chemistry (incl. Structural) - Abstract
The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) has been in operation since 2014 July. This paper describes the second data release from this phase, and the 14th from SDSS overall (making this Data Release Fourteen or DR14). This release makes the data taken by SDSS-IV in its first two years of operation (2014-2016 July) public. Like all previous SDSS releases, DR14 is cumulative, including the most recent reductions and calibrations of all data taken by SDSS since the first phase began operations in 2000. New in DR14 is the first public release of data from the extended Baryon Oscillation Spectroscopic Survey; the first data from the second phase of the Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE-2), including stellar parameter estimates from an innovative data-driven machine-learning algorithm known as "The Cannon"; and almost twice as many data cubes from the Mapping Nearby Galaxies at APO (MaNGA) survey as were in the previous release (N = 2812 in total). This paper describes the location and format of the publicly available data from the SDSS-IV surveys. We provide references to the important technical papers describing how these data have been taken (both targeting and observation details) and processed for scientific use. The SDSS web site (www.sdss.org) has been updated for this release and provides links to data downloads, as well as tutorials and examples of data use. SDSS-IV is planning to continue to collect astronomical data until 2020 and will be followed by SDSS-V.
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- 2018
9. The age-metallicity relation in the solar neighbourhood from a pilot sample of white dwarf-main sequence binaries
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Rebassa-Mansergas, A., Anguiano, B., García-Berro, E., Freeman, K. C., Cojocaru, R., Manser, C. J., Pala, A. F., Gänsicke, B. T., and Liu, X. -W.
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Astrophysics - Solar and Stellar Astrophysics ,Astrophysics - Astrophysics of Galaxies - Abstract
The age-metallicity relation (AMR) is a fundamental observational constraint for understanding how the Galactic disc formed and evolved chemically in time. However, there is not yet an agreement on the observational properties of the AMR for the solar neighbourhood, primarily due to the difficulty in obtaining accurate stellar ages for individual field stars. We have started an observational campaign for providing the much needed observational input by using wide white dwarf-main sequence (WDMS) binaries. White dwarfs are natural clocks and can be used to derive accurate ages. Metallicities can be obtained from the main sequence companions. Since the progenitors of white dwarfs and the main sequence stars were born at the same time, WDMS binaries provide a unique opportunity to observationally constrain in a robust way the properties of the AMR. In this work we present the AMR derived from analysing a pilot sample of 23 WDMS binaries and provide clear observational evidence for the lack of correlation between age and metallicity at young and intermediate ages (0-7 Gyrs)., Comment: Accepted for publication by MNRAS
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- 2016
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10. Identification of Globular Cluster Stars in RAVE data II: Extended tidal debris around NGC 3201
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Anguiano, B., De Silva, G. M., Freeman, K., Da Costa, G. S., Zwitter, T., Quillen, A. C., Zucker, D. B., Navarro, J. F., Kunder, A., Siebert, A., Wyse, R. F. G., Grebel, E. K., Kordopatis, G., Gibson, B. K., Seabroke, G., Sharma, S., Wojno, J., Bland-Hawthorn, J., Parker, Q. A., Steinmetz, M., Boeche, C., Gilmore, G., Bienayme, O., Reid, W., and Watson, F.
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Astrophysics - Astrophysics of Galaxies - Abstract
We report the identification of extended tidal debris potentially associated with the globular cluster NGC 3201, using the RAVE catalogue. We find the debris stars are located at a distance range of 1-7 kpc based on the forthcoming RAVE distance estimates. The derived space velocities and integrals of motion show interesting connections to NGC 3201, modulo uncertainties in the proper motions. Three stars, which are among the 4 most likely candidates for NGC 3201 tidal debris, are separated by 80 degrees on the sky yet are well matched by the 12 Gyr, [Fe/H] = -1.5 isochrone appropriate for the cluster. This is the first time tidal debris around this cluster has been reported over such a large spatial extent, with implications for the cluster$'$s origin and dynamical evolution., Comment: Accepted 2016 January 8. Received 2015 December 10; in original form 2015 November 13 MNRAS
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- 2016
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11. Identification of Globular Cluster Stars in RAVE data I: Application to Stellar Parameter Calibration
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Anguiano, B., Zucker, D. B., Scholz, R. -D., Grebel, E. K., Seabroke, G., Kunder, A., Binney, J., McMillan, P. J., Zwitter, T., Wyse, R. F. G., Kordopatis, G., Bienaymé, O., Bland-Hawthorn, J., Boeche, C., Freeman, K. C., Gibson, B. K., Gilmore, G., Munari, U., Navarro, J., Parker, Q., Reid, W., Siebert, A., Siviero, A., Steinmetz, M., and Watson, F.
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Astrophysics - Astrophysics of Galaxies - Abstract
We present the identification of potential members of nearby Galactic globular clusters using radial velocities from the RAdial Velocity Experiment Data Release 4 (RAVE-DR4) survey database. Our identifications are based on three globular clusters -- NGC 3201, NGC 5139 ($\omega$ Cen) and NGC 362 -- all of which are shown to have |RV|>100 km/s. The identification of globular cluster stars in RAVE DR4 data offers a unique opportunity to test the precision and accuracy of the stellar parameters determined with the currently available Stellar Parameter Pipelines (SPPs) used in the survey, as globular clusters are ideal testbeds for the validation of stellar atmospheric parameters, abundances, distances and ages. For both NGC 3201 and $\omega$ Cen, there is compelling evidence for numerous members (> 10) in the RAVE database; in the case of NGC 362 the evidence is more ambiguous, and there may be significant foreground and/or background contamination in our kinematically-selected sample. A comparison of the RAVE-derived stellar parameters and abundances with published values for each cluster and with BASTI isochrones for ages and metallicities from the literature reveals overall good agreement, with the exception of the apparent underestimation of surface gravities for giants, in particular for the most metal-poor stars. Moreover, if the selected members are part of the main body of each cluster our results would also suggest that the distances from Binney et al. 2013, where only isochrones more metal-rich than -0.9 dex were used, are typically underestimated by ~ 40% with respect to the published distances for the clusters, while the distances from Zwitter et al. 2010 show stars ranging from 1 to ~ 6.5 kpc -- with indications of a trend toward higher distances at lower metallicities -- for the three clusters analysed in this study., Comment: Accepted for publication MNRAS, 3 April 2015
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- 2015
12. The GALAH Survey: Scientific Motivation
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De Silva, G. M., Freeman, K. C., Bland-Hawthorn, J., Martell, S., de Boer, E. Wylie, Asplund, M., Keller, S., Sharma, S., Zucker, D. B., Zwitter, T., Anguiano, B., Bacigalupo, C., Bayliss, D., Beavis, M. A., Bergemann, M., Campbell, S., Cannon, R., Carollo, D., Casagrande, L., Casey, A. R., Da Costa, G., D'Orazi, V., Dotter, A., Duong, L., Heger, A., Ireland, M. J., Kafle, P. R., Kos, J., Lattanzio, J., Lewis, G. F., Lin, J., Lind, K., Munari, U., Nataf, D. M., O'Toole, S., Parker, Q. A., Reid, W., Schlesinger, K. J., Sheinis, A., Simpson, J. D., Stello, D., Ting, Y-S., Traven, G., Watson, F., Wittenmyer, R., Yong, D., and Zerjal, M.
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Astrophysics - Astrophysics of Galaxies ,Astrophysics - Instrumentation and Methods for Astrophysics ,Astrophysics - Solar and Stellar Astrophysics - Abstract
The GALAH survey is a large high-resolution spectroscopic survey using the newly commissioned HERMES spectrograph on the Anglo-Australian Telescope. The HERMES spectrograph provides high-resolution (R ~28,000) spectra in four passbands for 392 stars simultaneously over a 2 degree field of view. The goal of the survey is to unravel the formation and evolutionary history of the Milky Way, using fossil remnants of ancient star formation events which have been disrupted and are now dispersed throughout the Galaxy. Chemical tagging seeks to identify such dispersed remnants solely from their common and unique chemical signatures; these groups are unidentifiable from their spatial, photometric or kinematic properties. To carry out chemical tagging, the GALAH survey will acquire spectra for a million stars down to V~14. The HERMES spectra of FGK stars contain absorption lines from 29 elements including light proton-capture elements, alpha-elements, odd-Z elements, iron-peak elements and n-capture elements from the light and heavy s-process and the r-process. This paper describes the motivation and planned execution of the GALAH survey, and presents some results on the first-light performance of HERMES., Comment: 16 pages, 7 figures
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- 2015
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13. Spectroscopic Signatures of Extra-Tidal Stars Around the Globular Clusters NGC 6656 (M22), NGC 3201 and NGC 1851 from RAVE
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Kunder, Andrea, Bono, G., Piffl, T., Steinmetz, M., Grebel, E. K., Anguiano, B., Freeman, K., Kordopatis, G., Zwitter, T., Scholz, R., Gibson, B. K., Bland-Hawthorn, J., Seabroke, G., Boeche, C., Siebert, A., Wyse, R. F. G., Bienayme, O., Navarro, J., Siviero, A., Minchev, I., Parker, Q., Reid, W., Gilmore, G., Munari, U., and Helmi, A.
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Astrophysics - Solar and Stellar Astrophysics ,Astrophysics - Astrophysics of Galaxies - Abstract
Stellar population studies of globular clusters have suggested that the brightest clusters in the Galaxy might actually be the remnant nuclei of dwarf spheroidal galaxies. If the present Galactic globular clusters formed within larger stellar systems, they are likely surrounded by extra-tidal halos and/or tails made up of stars that were tidally stripped from their parent systems. The stellar surroundings around globular clusters are therefore one of the best places to look for the remnants of an ancient dwarf galaxy. Here an attempt is made to search for tidal debris around the supernovae enriched globular clusters M22 and NGC 1851 as well as the kinematically unique cluster NGC 3201. The stellar parameters from the Radial Velocity Experiment (RAVE) are used to identify stars with RAVE metallicities, radial velocities and elemental-abundances consistent with the abundance patterns and properties of the stars in M22, NGC 1851 and NGC 3201. The discovery of RAVE stars that may be associated with M22 and NGC 1851 are reported, some of which are at projected distances of ~10 degrees away from the core of these clusters. Numerous RAVE stars associated with NGC 3201 suggest that either the tidal radius of this cluster is underestimated, or that there are some unbound stars extending a few arc minutes from the edge of the cluster's radius. No further extra-tidal stars associated with NGC 3201 could be identified. The bright magnitudes of the RAVE stars make them easy targets for high resolution follow-up observations, allowing an eventual further chemical tagging to solidify (or exclude) stars outside the tidal radius of the cluster as tidal debris. In both our radial velocity histograms of the regions surrounding NGC 1851 and NGC 3201, a peak of stars at 230 km/s is seen, consistent with extended tidal debris from omega Centauri., Comment: accepted to A&A
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- 2014
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14. Quantitative chemical tagging, stellar ages and the chemo-dynamical evolution of the Galactic disc
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Mitschang, A. W., De Silva, G., Zucker, D. B., Anguiano, B., Bensby, T., and Feltzing, S.
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Astrophysics - Astrophysics of Galaxies - Abstract
The early science results from the new generation of high-resolution stellar spectroscopic surveys, such as GALAH and the Gaia-ESO survey, will represent major milestones in the quest to chemically tag the Galaxy. Yet this technique to reconstruct dispersed coeval stellar groups has remained largely untested until recently. We build on previous work that developed an empirical chemical tagging probability function, which describes the likelihood that two field stars are conatal, that is, they were formed in the same cluster environment. In this work we perform the first ever blind chemical tagging experiment, i.e., tagging stars with no known or otherwise discernable associations, on a sample of 714 disc field stars with a number of high quality high resolution homogeneous metal abundance measurements. We present evidence that chemical tagging of field stars does identify coeval groups of stars, yet these groups may not represent distinct formation sites, e.g. as in dissolved open clusters, as previously thought. Our results point to several important conclusions, among them that group finding will be limited strictly to chemical abundance space, e.g. stellar ages, kinematics, colors, temperature and surface gravity do not enhance the detectability of groups. We also demonstrate that in addition to its role in probing the chemical enrichment and kinematic history of the Galactic disc, chemical tagging represents a powerful new stellar age determination technique., Comment: 12 pages, 9 figures, accepted for publication in Monthly Notices of the Royal Astronomical Society (MNRAS)
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- 2013
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15. The RAdial Velocity Experiment (RAVE): Fourth data release
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Kordopatis, G., Gilmore, G., Steinmetz, M., Boeche, C., Seabroke, G. M., Siebert, A., Zwitter, T., Binney, J., de Laverny, P., Recio-Blanco, A., Williams, M. E. K., Piffl, T., Enke, H., Roeser, S., Bijaoui, A., Wyse, R. F. G., Freeman, K., Munari, U., Carillo, I., Anguiano, B., Burton, D., Campbell, R., Cass, C. J. P., Fiegert, K., Hartley, M., Parker, Q. A., Reid, W., Ritter, A., Russell, K. S., Stupart, M., Watson, F. G., Bienayme, O., Bland-Hawthorn, J., Gerhard, O., Gibson, B. K., Grebel, E. K., Helmi, A., Navarro, J. F., Conrad, C., Famaey, B., Faure, C., Just, A., Kos, J., Matijevic, G., McMillan, P. J., Minchev, I., Scholz, R., Sharma, S., Siviero, A., de Boer, E. Wylie, and Zerjal, M.
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Astrophysics - Astrophysics of Galaxies ,Astrophysics - Solar and Stellar Astrophysics - Abstract
We present the stellar atmospheric parameters (effective temperature, surface gravity, overall metallicity), radial velocities, individual abundances and distances determined for 425 561 stars, which constitute the fourth public data release of the RAdial Velocity Experiment (RAVE). The stellar atmospheric parameters are computed using a new pipeline, based on the algorithms of MATISSE and DEGAS. The spectral degeneracies and the 2MASS photometric information are now better taken into consideration, improving the parameter determination compared to the previous RAVE data releases. The individual abundances for six elements (magnesium, aluminum, silicon, titanium, iron and nickel) are also given, based on a special-purpose pipeline which is also improved compared to that available for the RAVE DR3 and Chemical DR1 data releases. Together with photometric information and proper motions, these data can be retrieved from the RAVE collaboration website and the Vizier database., Comment: 40 pages, 36 figures, accepted in AJ
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- 2013
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16. The RAdial Velocity Experiment (RAVE): Third Data Release
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Siebert, A., Williams, M. E. K., Siviero, A., Reid, W., Boeche, C., Steinmetz, M., Fulbright, J., Munari, U., Zwitter, T., Watson, F. G., Wyse, R. F. G., de Jong, R. S., Enke, H., Anguiano, B., Burton, D., Cass, C. J. P., Fiegert, K., Hartley, M., Ritter, A., Russel, K. S., Stupar, M., Bienayme, O., Freeman, K. C., Gilmore, G., Grebel, E. K., Helmi, A., Navarro, J. F., Binney, J., Bland-Hawthorn, J., Campbell, R., Famaey, B., Gerhard, O., Gibson, B. K., Matijevic, G., Parker, Q. A., Seabroke, G. M., Sharma, S., Smith, M. C., and Boer, E. Wylie-de
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Astrophysics - Astrophysics of Galaxies - Abstract
We present the third data release of the RAdial Velocity Experiment (RAVE) which is the first milestone of the RAVE project, releasing the full pilot survey. The catalog contains 83,072 radial velocity measurements for 77,461 stars in the southern celestial hemisphere, as well as stellar parameters for 39,833 stars. This paper describes the content of the new release, the new processing pipeline, as well as an updated calibration for the metallicity based upon the observation of additional standard stars. Spectra will be made available in a future release. The data release can be accessed via the RAVE webpage: http://www.rave-survey.org., Comment: AJ accepted. 54 pages, 20 figures. Figure 17 in low resolution mode
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- 2011
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17. The Radial Velocity Experiment (RAVE): second data release
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Zwitter, T., Siebert, A., Munari, U., Freeman, K. C., Siviero, A., Watson, F. G., Fulbright, J. P., Wyse, R. F. G., Campbell, R., Seabroke, G. M., Williams, M., Steinmetz, M., Bienayme, O., Gilmore, G., Grebel, E. K., Helmi, A., Navarro, J. F., Anguiano, B., Boeche, C., Burton, D., Cass, P., Dawe, J., Fiegert, K., Hartley, M., Russell, K., Veltz, L., Bailin, J., Binney, J., Bland-Hawthorn, J., Brown, A., Dehnen, W., Evans, N. W., Fiorentin, P. Re, Fiorucci, M., Gerhard, O., Gibson, B., Kelz, A., Kujken, K., Matijevic, G., Minchev, I., Parker, Q. A., Penarrubia, J., Quillen, A., Read, M. A., Reid, W., Roeser, S., Ruchti, G., Scholz, R. -D., Smith, M. C., Sordo, R., Tolstoi, E., Tomasella, L., Vidrih, S., and de Boer, E. Wylie
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Astrophysics - Abstract
We present the second data release of the Radial Velocity Experiment (RAVE), an ambitious spectroscopic survey to measure radial velocities (RVs) and stellar atmosphere parameters of up to one million stars using the 6dF multi-object spectrograph on the 1.2-m UK Schmidt Telescope of the Anglo-Australian Observatory (AAO). It is obtaining medium resolution spectra (median R=7,500) in the Ca-triplet region (8,410--8,795 \AA) for southern hemisphere stars in the magnitude range 9
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- 2008
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18. PP01.65 Treatment Patterns of Malignant Pleural Mesothelioma in a Resource Limited Setting: A “Real World” Study
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Morales Hernández, K., primary, Zarroca Palacio, S., additional, Antonio Hernández Castillo, M., additional, Remolina Bonilla, D.Y., additional, Jose Sánchez Hernández, J., additional, Vélez Martínez, A., additional, Chaires Navarro, G., additional, Najar Rodríguez, M., additional, Irigoyen Alvarez, A., additional, Lizcano Aguilar, N., additional, Sánchez Roman, E., additional, Lorena Rubio Anguiano, B., additional, Angelica De Jesús Hernández, D., additional, Peña Campos, C., additional, and Rogelio Trejo Rosales, R., additional
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- 2023
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19. The Seventeenth Data Release of the Sloan Digital Sky Surveys: Complete Release of MaNGA, MaStar, and APOGEE-2 Data
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Abdurro'Uf, Accetta, K, Aerts, C, Silva Aguirre, V, Ahumada, R, Ajgaonkar, N, Filiz Ak, N, Alam, S, Allende Prieto, C, Almeida, A, Anders, F, Anderson, SF, Andrews, BH, Anguiano, B, Aquino-Ortíz, E, Aragón-Salamanca, A, Argudo-Fernández, M, Ata, M, Aubert, M, Avila-Reese, V, Badenes, C, Barbá, RH, Barger, K, Barrera-Ballesteros, JK, Beaton, RL, Beers, TC, Belfiore, F, Bender, CF, Bernardi, M, Bershady, MA, Beutler, F, Bidin, CM, Bird, JC, Bizyaev, D, Blanc, GA, Blanton, MR, Boardman, NF, Bolton, AS, Boquien, M, Borissova, J, Bovy, J, Brandt, WN, Brown, J, Brownstein, Brusa, M, Buchner, J, Bundy, K, Burchett, JN, Bureau, M, Burgasser, A, Cabang, TK, Campbell, S, Cappellari, M, Carlberg, JK, Wanderley, FC, Carrera, R, Cash, J, Chen, YP, Chen, WH, Cherinka, B, Chiappini, C, Choi, PD, Chojnowski, SD, Chung, H, Clerc, N, Cohen, RE, Comerford, JM, Comparat, J, Da Costa, L, Covey, K, Crane, JD, Cruz-Gonzalez, I, Culhane, C, Cunha, K, Dai, YS, Damke, G, Darling, J, Davidson, JW, Davies, R, Dawson, K, De Lee, N, Diamond-Stanic, AM, Cano-Díaz, M, Sánchez, HD, Donor, J, Duckworth, C, Dwelly, T, Eisenstein, DJ, Elsworth, YP, Emsellem, E, Eracleous, M, Escoffier, S, Fan, X, Farr, E, Feng, S, Fernández-Trincado, JG, Feuillet, D, Filipp, A, Fillingham, SP, Frinchaboy, PM, Silva Aguirre, V [0000-0002-6137-903X], Ajgaonkar, N [0000-0003-1469-8246], Filiz Ak, N [0000-0003-3016-5490], Allende Prieto, C [0000-0002-0084-572X], Andrews, BH [0000-0001-8085-5890], Anguiano, B [0000-0001-5261-4336], Aquino-Ortíz, E [0000-0003-1083-9208], Aragón-Salamanca, A [0000-0001-8215-1256], Argudo-Fernández, M [0000-0002-0789-2326], Ata, M [0000-0002-5934-9018], Avila-Reese, V [0000-0002-3461-2342], Badenes, C [0000-0003-3494-343X], Barger, K [0000-0001-5817-0932], Barrera-Ballesteros, JK [0000-0003-2405-7258], Beaton, RL [0000-0002-1691-8217], Beers, TC [0000-0003-4573-6233], Belfiore, F [0000-0002-2545-5752], Bender, CF [0000-0003-4384-7220], Bershady, MA [0000-0002-3131-4374], Bizyaev, D [0000-0002-3601-133X], Blanc, GA [0000-0003-4218-3944], Blanton, MR [0000-0003-1641-6222], Boquien, M [0000-0003-0946-6176], Borissova, J [0000-0002-5936-7718], Bovy, J [0000-0001-6855-442X], Brandt, WN [0000-0002-0167-2453], Brownstein, JR [0000-0002-8725-1069], Brusa, M [0000-0002-5059-6848], Buchner, J [0000-0003-0426-6634], Bundy, K [0000-0001-9742-3138], Burchett, JN [0000-0002-1979-2197], Bureau, M [0000-0003-4980-1012], Burgasser, A [0000-0002-6523-9536], Cappellari, M [0000-0002-1283-8420], Carlberg, JK [0000-0001-5926-4471], Chen, YP [0000-0001-8821-0309], Cherinka, B [0000-0002-4289-7923], Chojnowski, SD [0000-0001-9984-0891], Comparat, J [0000-0001-9200-1497], Da Costa, L [0000-0002-7731-277X], Covey, K [0000-0001-6914-7797], Cruz-Gonzalez, I [0000-0002-2653-1120], Cunha, K [0000-0001-6476-0576], Dai, YS [0000-0002-7928-416X], Darling, J [0000-0003-2511-2060], Davies, R [0000-0001-7897-3812], Dawson, K [0000-0002-0553-3805], De Lee, N [0000-0002-3657-0705], Cano-Díaz, M [0000-0001-9553-8230], Eisenstein, DJ [0000-0002-2929-3121], Emsellem, E [0000-0002-6155-7166], Eracleous, M [0000-0002-3719-940X], Escoffier, S [0000-0002-2847-7498], Fan, X [0000-0003-3310-0131], Feng, S [0000-0002-9767-9237], Feuillet, D [0000-0002-3101-5921], Fillingham, SP [0000-0002-8425-0351], Frinchaboy, PM [0000-0002-0740-8346], and Apollo - University of Cambridge Repository
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Particle and Plasma Physics ,5101 Astronomical Sciences ,Molecular ,Nuclear ,Astronomy & Astrophysics ,Atomic ,51 Physical Sciences ,Astronomical and Space Sciences ,Physical Chemistry (incl. Structural) - Abstract
This paper documents the seventeenth data release (DR17) from the Sloan Digital Sky Surveys; the fifth and final release from the fourth phase (SDSS-IV). DR17 contains the complete release of the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey, which reached its goal of surveying over 10,000 nearby galaxies. The complete release of the MaNGA Stellar Library accompanies this data, providing observations of almost 30,000 stars through the MaNGA instrument during bright time. DR17 also contains the complete release of the Apache Point Observatory Galactic Evolution Experiment 2 survey that publicly releases infrared spectra of over 650,000 stars. The main sample from the Extended Baryon Oscillation Spectroscopic Survey (eBOSS), as well as the subsurvey Time Domain Spectroscopic Survey data were fully released in DR16. New single-fiber optical spectroscopy released in DR17 is from the SPectroscipic IDentification of ERosita Survey subsurvey and the eBOSS-RM program. Along with the primary data sets, DR17 includes 25 new or updated value-added catalogs. This paper concludes the release of SDSS-IV survey data. SDSS continues into its fifth phase with observations already underway for the Milky Way Mapper, Local Volume Mapper, and Black Hole Mapper surveys.
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- 2022
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20. Undertreatment of human immunodeficiency virus in psychiatric inpatients: a cross-sectional study of seroprevalence and associated factors
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Gonzalez-Torres MA, Salazar MA, Imaz M, Inchausti L, Ibañez B, Fernandez-Rivas A, Pastor J, Anguiano B, Muñoz P, Ruiz E, Oraa R, Bustamante S, Alvarez de Eulate S, and Cisterna R
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Neurosciences. Biological psychiatry. Neuropsychiatry ,RC321-571 ,Neurology. Diseases of the nervous system ,RC346-429 - Abstract
Miguel Angel Gonzalez-Torres,1,2 Miguel Angel Salazar,3 Manuel Imaz,4 Lucía Inchausti,1,2 Berta Ibañez,5 Aranzazu Fernandez-Rivas,1,2 Javier Pastor,3 Bosco Anguiano,3 Pedro Muñoz,3 Eduardo Ruiz,1,2 Rodrigo Oraa,3 Sonia Bustamante,1,2 Sofia Alvarez de Eulate,2 Ramón Cisterna4,61Department of Neuroscience, University of the Basque Country, 2Psychiatry Service, Basurto University Hospital, Bilbao, 3Mental Health Network of Biscay, Basque Health Service, Biscay, 4Microbiology Service, Basurto University Hospital, Bilbao, 5Navarra Biomed-Miguel Servet Foundation, Red de Investigación en Servicios Sanitarios y Enfermedades Crónicas (REDISSEC), Pamplona, 6Department of Microbiology, University of the Basque Country, Bilbao, SpainBackground: The aims of this study were to evaluate the prevalence of HIV and its associated demographic and clinical factors among psychiatric inpatients of a general hospital.Methods: This was a single-center, observational, cross-sectional study that included patients consecutively admitted to our unit aged 16 years or older and with no relevant cognitive problems. The patients were evaluated using a semistructured interview and an appropriate test for HIV infection.Results: Of the 637 patients who were screened, 546 (86%) who consented to participate were included in the analyses. Twenty-five (4.6%, 95% confidence interval [CI] 3.0–6.8) patients were HIV-positive. The prevalence was higher among patients with substance misuse (17.4%, 95% CI 9.7–28.8). All except one of the 25 patients knew of their seropositive condition prior to participation in the study. Only 14 (56%) of the 25 seropositive patients had previously received pharmacological treatment for their infection. According to the multiple logistic regression analysis, the likelihood of HIV infection was lower in patients with higher levels of education and higher among patients who were single, had history of intravenous drug use, and had an HIV-positive partner, particularly if they did not use condoms. Among the patients with HIV infection, 18 (72%) had a history of suicide attempts compared with 181 (34.7%) of the patients without HIV infection (relative risk 2.1, 95% CI 1.6–2.7; P
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- 2015
21. Communication strategies in the climate change debate on Facebook. Discourse on the Madrid Climate Summit (COP 25)
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De-Lara, A. (Alicia), Erviti, M.C. (Mª Carmen), and León-Anguiano, B. (Bienvenido)
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Social media ,Facebook ,COP 25 ,Emotions ,Climate change ,Social networks ,Madrid Climate Summit ,Communication strategies - Abstract
Climate change (CC) has become a topic of great interest in traditional and social media, two valuable sources of information that contribute to discussion on current affairs. Facebook is the social network with the most users in the world and also promotes mobilization, which makes it a platform of great interest for the study of CC communication strategies. The aim of this study is to analyse the content of the messages on CC posted on Facebook by prominent users: the relevance of the topic in the posts as a whole, objectives pursued, type of discourse and the emotions associated with messages. After validating a selection of 10 accounts (Greta Thunberg, Donald Trump, Scott Morrison, Alexandria Ocasio- Cortez, Extinction Rebellion USA, Justin Trudeau, Bernie Sanders, United Nations, Extinction Rebellion UK and Jane Fonda), the methodology was based on content analysis applied to messages on CC (n = 599) posted on Facebook by the selected accounts between 1 November 2019 and 10 January 2020, the period covering the Madrid Climate Summit (COP 25, held in 2019). The results revealed different CC communication strategies. Regarding the presence of CC as a topic, we observed three different strategies: omission, simple mention and high presence. In terms of discourse, we noticed two different strategies: an emotional strategy that was more successful at generating interaction with others, and an analytical strategy that was generally more belligerent in its fight against CC.
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- 2022
22. Representación del cambio climático en YouTube: un análisis cuantitativo de los vídeos más populares
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Muñoz-Pico, H.P. (Hilda Paola), León-Anguiano, B. (Bienvenido), and García-Martínez, A.N. (Alberto Nahum)
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Medio Ambiente ,Youtube ,Cambio climático ,Periodismo ,Comunicación científica - Abstract
Este artículo examina si los contenidos de YouTube sobre el cambio climático contribuyen a que se generen nuevas propuestas de comunicación, con voces y enfoques distintos, lo que implicaría una mejor información de los ciudadanos y podría facilitar su implicación y participación en la toma de medidas necesarias para enfrentar el problema (decisiones de consumo, presión a los políticos para que adopten medidas, etc.), o si, por el contrario, se han amplificado las voces que, en general, predominan en los medios, como las de los políticos. Mediante un análisis de contenido, este estudio analiza la representación del cambio climático en los vídeos más populares en YouTube. Tras examinar una muestra de 288 vídeos difundidos durante el periodo octubre 2016-octubre 2017, se constata que los políticos, como el expresidente estadounidense Donald Trump, son las voces más citadas en las piezas de YouTube sobre cambio climático, seguidas de periodistas y científicos. Respecto de los productores de esos vídeos, los medios de comunicación ocupan un lugar privilegiado de popularidad. Incluso, parte de sus contenidos se reutilizan total o parcialmente por otros usuarios de la plataforma. La vocación principal de los mensajes es informativa, con un discurso enfocado, sobre todo, en las consecuencias del cambio climático en los países desarrollados. Los resultados del análisis de contenido también ponen de manifiesto que las informaciones que ayudan a entender los procesos en los que se inscriben los problemas ambientales quedan relegadas por la prominencia de la coyuntura política en los vídeos más populares sobre el cambio climático en YouTube. Entre las conclusiones de este estudio, destaca el predominio de políticos, funcionarios o exfuncionarios por encima de voces expertas, como los científicos, que conlleva el riesgo de una menor discusión social e implicación ciudadana en las acciones necesarias para enfrentar el cambio climático.
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- 2021
23. Final Targeting Strategy for the Sloan Digital Sky Survey IV Apache Point Observatory Galactic Evolution Experiment 2 North Survey
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Beaton, RL, Beaton, RL, Oelkers, RJ, Hayes, CR, Covey, KR, Chojnowski, SD, De Lee, N, Sobeck, JS, Majewski, SR, Cohen, RE, Fernández-Trincado, J, Longa-Pea, P, O'Connell, JE, Santana, FA, Stringfellow, GS, Zasowski, G, Aerts, C, Anguiano, B, Bender, C, Caas, CI, Cunha, K, Donor, J, Fleming, SW, Frinchaboy, PM, Feuillet, D, Harding, P, Hasselquist, S, Holtzman, JA, Johnson, JA, Kollmeier, JA, Kounkel, M, Mahadevan, S, Price-Whelan, AM, Rojas-Arriagada, A, Román-Zúiga, C, Schlafly, EF, Schultheis, M, Shetrone, M, Simon, JD, Stassun, KG, Stutz, AM, Tayar, J, Teske, J, Tkachenko, A, Troup, N, Albareti, FD, Bizyaev, D, Bovy, J, Burgasser, AJ, Comparat, J, Downes, JJ, Geisler, D, Inno, L, Manchado, A, Ness, MK, Pinsonneault, MH, Prada, F, Roman-Lopes, A, Simonian, GVA, Smith, VV, Yan, R, Zamora, O, Beaton, RL, Beaton, RL, Oelkers, RJ, Hayes, CR, Covey, KR, Chojnowski, SD, De Lee, N, Sobeck, JS, Majewski, SR, Cohen, RE, Fernández-Trincado, J, Longa-Pea, P, O'Connell, JE, Santana, FA, Stringfellow, GS, Zasowski, G, Aerts, C, Anguiano, B, Bender, C, Caas, CI, Cunha, K, Donor, J, Fleming, SW, Frinchaboy, PM, Feuillet, D, Harding, P, Hasselquist, S, Holtzman, JA, Johnson, JA, Kollmeier, JA, Kounkel, M, Mahadevan, S, Price-Whelan, AM, Rojas-Arriagada, A, Román-Zúiga, C, Schlafly, EF, Schultheis, M, Shetrone, M, Simon, JD, Stassun, KG, Stutz, AM, Tayar, J, Teske, J, Tkachenko, A, Troup, N, Albareti, FD, Bizyaev, D, Bovy, J, Burgasser, AJ, Comparat, J, Downes, JJ, Geisler, D, Inno, L, Manchado, A, Ness, MK, Pinsonneault, MH, Prada, F, Roman-Lopes, A, Simonian, GVA, Smith, VV, Yan, R, and Zamora, O
- Abstract
The Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2) is a dual-hemisphere, near-infrared (NIR), spectroscopic survey with the goal of producing a chemodynamical mapping of the Milky Way. The targeting for APOGEE-2 is complex and has evolved with time. In this paper, we present the updates and additions to the initial targeting strategy for APOGEE-2N presented in Zasowski et al. (2017). These modifications come in two implementation modes: (i) "Ancillary Science Programs"competitively awarded to Sloan Digital Sky Survey IV PIs through proposal calls in 2015 and 2017 for the pursuit of new scientific avenues outside the main survey, and (ii) an effective 1.5 yr expansion of the survey, known as the Bright Time Extension (BTX), made possible through accrued efficiency gains over the first years of the APOGEE-2N project. For the 23 distinct ancillary programs, we provide descriptions of the scientific aims, target selection, and how to identify these targets within the APOGEE-2 sample. The BTX permitted changes to the main survey strategy, the inclusion of new programs in response to scientific discoveries or to exploit major new data sets not available at the outset of the survey design, and expansions of existing programs to enhance their scientific success and reach. After describing the motivations, implementation, and assessment of these programs, we also leave a summary of lessons learned from nearly a decade of APOGEE-1 and APOGEE-2 survey operations. A companion paper, F. Santana et al. (submitted; AAS29036), provides a complementary presentation of targeting modifications relevant to APOGEE-2 operations in the Southern Hemisphere.
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- 2021
24. Desinformación en tiempos de pandemia: tipología de los bulos sobre la Covid-19
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Salaverría-Aliaga, R. (Ramón), Buslón-Valdéz, N. (Nataly), López-Pan, F. (Fernando), León-Anguiano, B. (Bienvenido), Lopez-Goñi, I. (Ignacio), and Erviti, M.C. (Mª Carmen)
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Coronavirus ,Ciberperiodismo ,Infodemias ,Bulos ,Periodismo digital ,España ,Noticias falsas ,Desinformación ,Periodismo ,Covid-19 ,Redes sociales ,Verificación ,Pandemias - Abstract
Se presenta un análisis de contenido de todos los bulos (N=292) relacionados con la pandemia Covid-19 identificados por las tres plataformas de verificación acreditadas en España, durante el primer mes del estado de alarma decretado por el Gobierno (14 marzo 2020 – 13 abril 2020). El estudio muestra que los bulos sobre el coronavirus fueron diseminados principalmente en las redes sociales y, entre ellas, sobre todo en las cerradas, como la aplicación móvil de mensajería WhatsApp. También detecta las particularidades formales y de contenido más frecuentes de los contenidos falsificados. Los resultados revelan que la pandemia, además de generar un gran número de bulos sobre salud y ciencia, casi un tercio de la muestra, también propició la difusión de numerosos contenidos falsos de tema político y gubernamental. El artículo explora los formatos, fuentes y territorios de procedencia de los bulos. Más allá de sus resultados empíricos, este estudio realiza contribuciones teóricas en el marco de los emergentes estudios sobre desórdenes informativos. En concreto, aporta una definición propia de bulo, así como una tipología en la que se identifican cuatro tipos de bulos: broma, exageración, descontextualización y engaño. A partir de esos cuatro tipos, se propone un ‘diagrama de gravedad de los bulos’.
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- 2020
25. Food-Restricted and Dehydrated-Induced Anorexic Rats Present Differential TRH Expression in Anterior and Caudal PVN. Role of Type 2 Deiodinase and Pyroglutamyl Aminopeptidase II
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Alvarez-Salas, E., Aceves, C., Anguiano, B., Uribe, R. M., García-Luna, C., Sánchez, E., and de Gortari, P.
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- 2012
26. Precision Stellar Astrophysics and Galactic Archaeology: 2020
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Kollmeier, J., Fuller, J., Gaensicke, B., Gaudi, S., Nataf, D., Rix, H., Aerts, C., Anderson, S., Anderson, L., Anguiano, B., Basu, S., Bird, J., Brown, A., Bullock, J., Cunha, K., De Lee, N., Hekker, S., Johnson, J., Lane, R., Ness, M., Pinsonneault, M., Schwope, A., Aguirre, V., Steinmetz, M., Stevens, D., Teske, J., Tkachenko, A., Stassun, K., Ting, Y., Stutz, A., Weinberg, D., and Zasowski, G.
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Astrophysics::Instrumentation and Methods for Astrophysics ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Physics::History of Physics ,Astrophysics::Galaxy Astrophysics - Abstract
This white paper is meant to capture many different elements of stellar astrophysics and galactic archaeology that highlight the important role this science will play in the 2020s era of precision astronomy.
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- 2019
27. APOGEE Chemical Abundances of the Large Magellanic Cloud
- Author
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Hasselquist, S., Nidever, D., Hayes, C., Anguiano, B., Majewski, S., Sobeck, J., Stringfellow, G., Beers, T., Jonsson, H., Lian, J., Cohen, R., Zasowski, G., Mackereth, J., Battaglia, G., Weinberg, D., Lane, R., Long-Pena, P., Gallart, C., Villanova, S., Rix, H., Andrews, B., Cunha, K., Smith, V., Choi, Y., Geisler, D., Carrera, R., Almeida, A., and Fernandez-Trincado, J.
- Abstract
To date, the SDSS-IV APOGEE survey has obtained S/N > 70 spectra for over 2,500 red giant stars distributed across much of the Large Magellanic Cloud (LMC), allowing for the characterization of the detailed abundance patterns for 10+ chemical elements. In this project, we interpret the chemical abundance patterns of the LMC by comparing them to the chemical abundance patterns of the Sagittarius Dwarf Galaxy (Sgr) and the Milky Way (MW), as well as by invoking chemical evolution models (such as flexCE and chempy) that include the LMC's star formation history. Preliminary results show that the LMC shares [Ni/Fe] and [Al/Fe] deficiencies with Sgr, but exhibits alpha-element abundances ([O/Fe], [Mg/Fe], and [Si/Fe]) that are near-solar. There is also a correlation with [O/Fe] and [Mg/Fe] with [Fe/H] at [Fe/H] > -1.0. These results suggest that the LMC exhibited low star formation efficiency (as compared to Sgr and the MW) at early times, but has since experienced several starbursts which spawned the stars with [Fe/H] > -1.0. Using these APOGEE chemical abundance patterns as constraints, we use chemical evolution models to better characterize the nature (strength, time, duration, IMF, etc.) of these starbursts.
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- 2019
28. In Pursuit of Galactic Archaeology
- Author
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Ness, M., Bird, J., Johnson, J., Zasowski, G., Kollmeier, J., Rix, H.-W., Aguirre, V.S., Anguiano, B., Basu, S., Brown, A., Buder, S., Chiappini, C., Cunha, K., Dongia, E., Frinchaboy, P., Hekker, S., Hunt, J., Johnston, K., Lane, R., Lucatello, S., Meza, A., Minchev, I., Nataf, D., Price-Whelan, A.M., Sanderson, R., Sobeck, J., Stassun, K., Steinmetz, M., Ting, Y.-S., Venn, K., Xue, X., ITA, USA, GBR, FRA, and DEU
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ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,ComputingMethodologies_COMPUTERGRAPHICS - Abstract
The next decade affords tremendous opportunity to achieve the goals of Galactic archaeology. That is, to reconstruct the evolutionary narrative of the Milky Way, based on the empirical data that describes its current morphological, dynamical, temporal and chemical structures. Here, we describe the path to achieving this goal.
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- 2019
29. The GALAH survey: a catalogue of carbon-enhanced stars and CEMP candidates
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Čotar, K., Zwitter, T., Kos, J., Munari, U., Martell, S., Asplund, M., Bland-Hawthorn, J., Buder, S., de Silva, G., Freeman, K., Sharma, S., Anguiano, B., Carollo, D., Horner, J., Lewis, G., Nataf, D., Nordlander, T., Stello, D., Ting, Y., Tinney, C., Traven, G., Wittenmyer, R., and Collaboration, G.
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Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics::Galaxy Astrophysics - Abstract
Swan bands - characteristic molecular absorption features of the C2 molecule - are a spectroscopic signature of carbon- enhanced stars. They can also be used to identify carbon-enhanced metal- poor (CEMP) stars. The GALAH (GALactic Archaeology with Hermes) is a magnitude-limited survey of stars producing high-resolution, high- signal-to-noise spectra. We used 627 708 GALAH spectra to search for carbon-enhanced stars with a supervised and unsupervised classification algorithm, relying on the imprint of the Swan bands. We identified 918 carbon-enhanced stars, including 12 already described in the literature. An unbiased selection function of the GALAH survey allows us to perform a population study of carbon-enhanced stars. Most of them are giants, out of which we find 28 CEMP candidates. A large fraction of our carbon- enhanced stars with repeated observations show variation in radial velocity, hinting that there is a large fraction of variables among them. 32 of the detected stars also show strong Lithium enhancement in their spectra.
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- 2019
30. The power of storytelling and video: a visual rhetoric for science communication
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Finkler, W. (Wiebke) and León-Anguiano, B. (Bienvenido)
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theory and models [Science communication] ,Science and media ,Visual communication - Abstract
This research develops a conceptual framework for telling visual stories about science using short-format videos, termed SciCommercial videos, that draw upon marketing communication. The framework is illustrated by an exemplar, the Good Whale Watching video, which is explained using a visual rhetoric keyframe analysis. Finally, the effectiveness of the video is evaluated as a science communication tool using an empirical online survey with 1698 respondents. The results highlight the benefits of using video for storytelling about science by using our framework formula, modified from marketing practices, to produce videos that are Simple, Unexpected, Concrete, Credible, Emotional, Science Storytelling (SUCCESS).
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- 2019
31. Adrenal gland 5′deiodinase activity (AG-5′d). Kinetic characterization and fractional turnover rate (FTr)
- Author
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Luna, M., Anguiano, B., and Valverde-R, C.
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- 1995
- Full Text
- View/download PDF
32. The GALAH survey: Velocity fluctuations in the Milky Way using Red Clump giants
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Khanna, S, Sharma, S, Bland-Hawthorn, J, Hayden, M, Nataf, DM, Ting, YS, Kos, J, Martell, S, Zwitter, T, De Silva, G, Asplund, M, Buder, S, Duong, L, Lin, J, Simpson, JD, Anguiano, B, Horner, J, Kafle, PR, Lewis, GF, Nordlander, T, Wyse, RFG, Wittenmyer, RA, Zucker, DB, Khanna, S, Sharma, S, Bland-Hawthorn, J, Hayden, M, Nataf, DM, Ting, YS, Kos, J, Martell, S, Zwitter, T, De Silva, G, Asplund, M, Buder, S, Duong, L, Lin, J, Simpson, JD, Anguiano, B, Horner, J, Kafle, PR, Lewis, GF, Nordlander, T, Wyse, RFG, Wittenmyer, RA, and Zucker, DB
- Abstract
If the Galaxy is axisymmetric and in dynamical equilibrium, we expect negligible fluctuations in the residual line-of-sight velocity field. Recent results using the APOGEE survey find significant fluctuations in velocity for stars in the mid-plane (|z| <0.25 kpc) out to 5 kpc, suggesting that the dynamical influence of non-axisymmetric features, i.e. the Milky Way's bar, spiral arms, and merger events extends out to the Solar neighbourhood. Their measured power spectrum has a characteristic amplitude of 11 km s−1 on a scale of 2.5 kpc. The existence of such large-scale streaming motions has important implications for determining the Sun's motion about the Galactic Centre. Using Red Clump stars from GALAH and APOGEE, we map the line-of-sight velocities around the Sun (d < 5 kpc), and |z| <1.25 kpc from the mid-plane. By subtracting a smooth axisymmetric model for the velocity field, we study the residual fluctuations and compare our findings with mock survey generated by GALAXIA. We find negligible large-scale fluctuations away from the plane. In the mid-plane, we reproduce the earlier APOGEE power spectrum but with 20 per cent smaller amplitude (9.3 km s−1) after taking into account a few systematics (e.g. volume completeness). Using a flexible axisymmetric model the power amplitude is further reduced to 6.3 km s−1. Additionally, our simulations show that, in the plane, distances are underestimated for high-mass Red Clump stars which can lead to spurious power amplitude of about 5.2 km s−1. Taking this into account, we estimate the amplitude of real fluctuations to be <4.6 km s−1, about a factor of three less than the APOGEE result.
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- 2019
33. Stellar Astrophysics and Exoplanet Science with the Maunakea Spectroscopic Explorer (MSE)
- Author
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Bergemann, Maria, Huber, D., Adibekyan, V., Angelou, George, Barr'ia, D., Beers, T.~C., Beck, P.~G., Bellinger, E.~P., Bestenlehner, J.~M., Bitsch, B., Burgasser, A.~J., Buzasi, D., Cassisi, S., Catelan, M., Escorza, A., Fleming, S.~W., Gansicke, B.~T., Gandolfi, D., Garc'ia, R.~A., Gieles, M., Karakas, A., Lebreton, Yveline, Lodieu, N., Melis, C., Merle, Thibault, Mészáros, S., Miglio, A., Molaverdikhani, K., Monier, R, Morel, Thierry, Neilson, H.~R., Oshagh, M., Rybizki, J., Serenelli, A., Smiljanic, Rodolfo, Szabó, G.~M., Toonen, Silvia, Tremblay, P.-E., Valentini, M., Van Eck, Sophie, Zwintz, Konstanze, Bayo, A., Cami, J., Casagrande, L., Gabdeev, M., Gaulme, P., Guiglion, G., Handler, G., Hillenbrand, L., Yildiz, M., Marley, M., Mosser, B., Price-Whelan, A.~M., Prsa, A., Hernández Santisteban, J.~V., Silva Aguirre, V., Sobeck, Jennifer, Stello, D., Szabo, R., Tsantaki, M., Villaver, E., Wright, N.~J., Xu, S., Zhang, H., Anguiano, B., Bedell, M., Chaplin, B., Collet, Remo, Kamath, Devika, Martell, S., Sousa, S.~G., Ting, Y.-S., Venn, K., Bergemann, Maria, Huber, D., Adibekyan, V., Angelou, George, Barr'ia, D., Beers, T.~C., Beck, P.~G., Bellinger, E.~P., Bestenlehner, J.~M., Bitsch, B., Burgasser, A.~J., Buzasi, D., Cassisi, S., Catelan, M., Escorza, A., Fleming, S.~W., Gansicke, B.~T., Gandolfi, D., Garc'ia, R.~A., Gieles, M., Karakas, A., Lebreton, Yveline, Lodieu, N., Melis, C., Merle, Thibault, Mészáros, S., Miglio, A., Molaverdikhani, K., Monier, R, Morel, Thierry, Neilson, H.~R., Oshagh, M., Rybizki, J., Serenelli, A., Smiljanic, Rodolfo, Szabó, G.~M., Toonen, Silvia, Tremblay, P.-E., Valentini, M., Van Eck, Sophie, Zwintz, Konstanze, Bayo, A., Cami, J., Casagrande, L., Gabdeev, M., Gaulme, P., Guiglion, G., Handler, G., Hillenbrand, L., Yildiz, M., Marley, M., Mosser, B., Price-Whelan, A.~M., Prsa, A., Hernández Santisteban, J.~V., Silva Aguirre, V., Sobeck, Jennifer, Stello, D., Szabo, R., Tsantaki, M., Villaver, E., Wright, N.~J., Xu, S., Zhang, H., Anguiano, B., Bedell, M., Chaplin, B., Collet, Remo, Kamath, Devika, Martell, S., Sousa, S.~G., Ting, Y.-S., and Venn, K.
- Abstract
info:eu-repo/semantics/published
- Published
- 2019
34. Reduction of exposure of cyclists to urban air pollution
- Author
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Santamaria-Ulecia, J.M. (Jesús Miguel), Ariño-Plana, A.H. (Arturo Hugo), León-Anguiano, B. (Bienvenido), Llorente, E. (Eladio), Martín, F. (Fernando), Pons-Izquierdo, J.J. (Juan José), Martilli, A. (Alberto), Santamaria-Elola, C. (Carolina), Sánchez, C. (Cristina), Oltra, C. (Christian), Elustondo, D. (David), Galicia-Paredes, D. (David), Moya, E. (Eloy), Baquero-Martin, E. (Enrique), Lasheras, E. (Esther), Rivas, E. (Esther), Calvete, H. (Héctor), García, H. (Héctor), González, I. (Ignacio), Puig-i-Baguer, J. (Jordi), Santiago, J.L. (José Luis), Barnó, M. (Miguel), Serrano-Martínez, M. (Miriam), Alonso, R. (Rocío), Sala, R. (Roser), López, S. (Sergi), Izquieta-Rojano, S. (Sheila), Elvira, S. (Susana), Bermejo, V. (Victoria), and Lechón, Y. (Yolanda)
- Subjects
Área Biología Vegetal y Animal, Ecología - Abstract
This book collects the main outcomes that were generated during the implementation of the LIFE+RESPIRA project (LIFE13 ENV/ES/000417), carried out in the city of Pamplona, Navarra, Spain. The research was conducted by a cross-functional team made up of more than 30 researchers belonging to three entities: The University of Navarra, the Centre for Energy, Environmental and Technological Research (CIEMAT) and Environmental Management of Navarra (GAN-NIK).
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- 2018
35. The kinematics of white dwarfs from the SDSS DR12
- Author
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García-Berro Montilla, Enrique|||0000-0002-1623-5838, Skorobogatov, G., Torres Gil, Santiago|||0000-0001-5777-5251, Anguiano, B., Rebassa Mansergas, Alberto|||0000-0002-6153-7173, Universitat Politècnica de Catalunya. Departament de Física, and Universitat Politècnica de Catalunya. GAA - Grup d'Astronomia i Astrofísica
- Subjects
Stars - white dwarfs ,Galaxy - kinematics and dynamics ,Galàxies -- Evolució ,White dwarfs ,kinematics, stars: white dwarfs, Galaxy: fundamental parameters, Galaxy:kinematics and dynamics [stars] ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Estels nans ,Dinàmica estel·lar ,Stellar evolution ,Galactic dynamics ,Galaxy - fundamental parameters ,Física::Astronomia i astrofísica [Àrees temàtiques de la UPC] ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Stars - kinematics ,Astrophysics::Galaxy Astrophysics ,Stellar dynamics - Abstract
We use the Sloan Digital Sky Survey Data Release 12, which is the largest availablewhite dwarf catalogue to date, to study the evolution of the kinematical properties of the pop-ulation of white dwarfs of the Galactic disk. We derive masses, ages, photometric distances andradial velocities for all white dwarfs with hydrogen-rich atmospheres. For those stars for whichproper motions from the USNO-B1 catalogue are available, the three-dimensional componentsof the velocity are obtained. This subset of the original sample comprises 20,247 stars, makingit the largest sample of white dwarfs with measured three-dimensional velocities. The volumeprobed by our sample is large, allowing us to obtain relevant kinematical information. In partic-ular, our sample extends from a Galactocentric radial distanceRG=7.8 to 9.3 kpc, and verticaldistances from the Galactic plane ranging fromZ=+0.5to–0.5kpc.
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- 2018
36. Comprehensive comparison between APOGEE and LAMOST
- Author
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Anguiano, B., primary, Majewski, S. R., additional, Allende-Prieto, C., additional, Meszaros, S., additional, Jönsson, H., additional, García-Hernández, D. A., additional, Beaton, R. L., additional, Stringfellow, G. S., additional, Cunha, K., additional, and Smith, V. V., additional
- Published
- 2018
- Full Text
- View/download PDF
37. The GALAH survey: Stellar streams and how stellar velocity distributions vary with Galactic longitude, hemisphere, and metallicity
- Author
-
Quillen, AC, De Silva, G, Sharma, S, Hayden, M, Freeman, K, Bland-Hawthorn, J, Zerjal, M, Asplund, M, Buder, S, D'Orazi, V, Duong, L, Kos, J, Lin, J, Lind, K, Martell, S, Schlesinger, K, Simpson, JD, Zucker, DB, Zwitter, T, Anguiano, B, Carollo, D, Casagrande, L, Cotar, K, Cottrell, PL, Ireland, M, Kafle, PR, Horner, J, Lewis, GF, Nataf, DM, Ting, YS, Watson, F, Wittenmyer, R, Wyse, R, Quillen, AC, De Silva, G, Sharma, S, Hayden, M, Freeman, K, Bland-Hawthorn, J, Zerjal, M, Asplund, M, Buder, S, D'Orazi, V, Duong, L, Kos, J, Lin, J, Lind, K, Martell, S, Schlesinger, K, Simpson, JD, Zucker, DB, Zwitter, T, Anguiano, B, Carollo, D, Casagrande, L, Cotar, K, Cottrell, PL, Ireland, M, Kafle, PR, Horner, J, Lewis, GF, Nataf, DM, Ting, YS, Watson, F, Wittenmyer, R, and Wyse, R
- Abstract
Using GALAH (GALactic Archaeology with HERMES) survey data of nearby stars, we look at how structure in the planar (u, v) velocity distribution depends on metallicity and on viewing direction within the Galaxy. In nearby stars with distance d ≲ 1 kpc, the Hercules stream is most strongly seen in higher metallicity stars [Fe/H] > 0.2. The Hercules stream peak v value depends on viewed galactic longitude, which we interpret as due to the gap between the stellar stream and more circular orbits being associated with a specific angular momentum value of about 1640 km s-1 kpc. The association of the gap with a particular angular momentum value supports a bar resonant model for the Hercules stream. Moving groups previously identified in Hipparcos (HIgh Precision Parallax COllecting Satellite) observations are easiest to see in stars nearer than 250 pc, and their visibility and peak velocities in the velocity distributions depends on both viewing direction (galactic longitude and hemisphere) and metallicity. We infer that there is fine structure in local velocity distributions that varies over distances of a few hundred pc in the Galaxy.
- Published
- 2018
38. The GALAH survey: Accurate radial velocities and library of observed stellar template spectra
- Author
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Zwitter, T, Kos, J, Chiavassa, A, Buder, S, Traven, G, Čotar, K, Lin, J, Asplund, M, Bland-Hawthorn, J, Casey, AR, Silva, GD, Duong, L, Freeman, KC, Lind, K, Martell, S, D'Orazi, V, Schlesinger, KJ, Simpson, JD, Sharma, S, Zucker, DB, Anguiano, B, Casagrande, L, Collet, R, Horner, J, Ireland, MJ, Kafle, PR, Lewis, G, Munari, U, Nataf, DM, Ness, M, Nordlander, T, Stello, D, Ting, YS, Tinney, CG, Watson, F, Wittenmyer, RA, Žerja, M, Zwitter, T, Kos, J, Chiavassa, A, Buder, S, Traven, G, Čotar, K, Lin, J, Asplund, M, Bland-Hawthorn, J, Casey, AR, Silva, GD, Duong, L, Freeman, KC, Lind, K, Martell, S, D'Orazi, V, Schlesinger, KJ, Simpson, JD, Sharma, S, Zucker, DB, Anguiano, B, Casagrande, L, Collet, R, Horner, J, Ireland, MJ, Kafle, PR, Lewis, G, Munari, U, Nataf, DM, Ness, M, Nordlander, T, Stello, D, Ting, YS, Tinney, CG, Watson, F, Wittenmyer, RA, and Žerja, M
- Abstract
GALAH is a large-scale magnitude-limited southern stellar spectroscopic survey. Its second data release (GALAH DR2) provides values of stellar parameters and abundances of 23 elements for 342 682 stars (Buder et al.). Here we add a description of the public release of radial velocities with a typical accuracy of 0.1 km s-1 for 336 215 of these stars, achievable due to the large wavelength coverage, high resolving power, and good signal-to-noise ratio of the observed spectra, but also because convective motions in stellar atmosphere and gravitational redshift from the star to the observer are taken into account. In the process we derive medians of observed spectra that are nearly noiseless, as they are obtained from between 100 and 1116 observed spectra belonging to the same bin with a width of 50 K in temperature, 0.2 dex in gravity, and 0.1 dex in metallicity. Publicly released 1181 median spectra have a resolving power of 28 000 and trace the well-populated stellar types with metallicities between -0.6 and +0.3. Note that radial velocities from GALAH are an excellent match to the accuracy of velocity components along the sky plane derived by Gaia for the same stars. The level of accuracy achieved here is adequate for studies of dynamics within stellar clusters, associations, and streams in the Galaxy. So it may be relevant for studies of the distribution of dark matter.
- Published
- 2018
39. The K2-HERMES Survey. I. Planet-candidate Properties from K2 Campaigns 1-3
- Author
-
Wittenmyer, RA, Sharma, S, Stello, D, Buder, S, Kos, J, Asplund, M, Duong, L, Lin, J, Lind, K, Ness, M, Zwitter, T, Horner, J, Clark, J, Kane, SR, Huber, D, Bland-Hawthorn, J, Casey, AR, De Silva, GM, D'Orazi, V, Freeman, K, Martell, S, Simpson, JD, Zucker, DB, Anguiano, B, Casagrande, L, Esdaile, J, Hon, M, Ireland, M, Kafle, PR, Khanna, S, Marshall, JP, Mohd Saddon, MH, Traven, G, Wright, D, Wittenmyer, RA, Sharma, S, Stello, D, Buder, S, Kos, J, Asplund, M, Duong, L, Lin, J, Lind, K, Ness, M, Zwitter, T, Horner, J, Clark, J, Kane, SR, Huber, D, Bland-Hawthorn, J, Casey, AR, De Silva, GM, D'Orazi, V, Freeman, K, Martell, S, Simpson, JD, Zucker, DB, Anguiano, B, Casagrande, L, Esdaile, J, Hon, M, Ireland, M, Kafle, PR, Khanna, S, Marshall, JP, Mohd Saddon, MH, Traven, G, and Wright, D
- Abstract
Accurate and precise radius estimates of transiting exoplanets are critical for understanding their compositions and formation mechanisms. To know the planet, we must know the host star in as much detail as possible. We present first results from the K2-HERMES project, which uses the HERMES multi-object spectrograph on the Anglo-Australian Telescope to obtain R ∼ 28000 spectra of up to 360 stars in one exposure. This ongoing project aims to derive self-consistent spectroscopic parameters for about half of K2 target stars. We present complete stellar parameters and isochrone-derived masses and radii for 46 stars hosting 57 K2 candidate planets in Campaigns 1-3. Our revised host-star radii cast severe doubt on three candidate planets: EPIC 201407812.01, EPIC 203070421.01, and EPIC 202843107.01, all of which now have inferred radii well in excess of the largest known inflated Jovian planets.
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- 2018
40. The GALAH Survey: Second data release
- Author
-
Buder, S, Asplund, M, Duong, L, Kos, J, Lind, K, Ness, MK, Sharma, S, Bland-Hawthorn, J, Casey, AR, De Silva, GM, D'Orazi, V, Freeman, KC, Lewis, GF, Lin, J, Martell, SL, Schlesinger, KJ, Simpson, JD, Zucker, DB, Zwitter, T, Amarsi, AM, Anguiano, B, Carollo, D, Casagrande, L, Čotar, K, Cottrell, PL, Costa, GD, Gao, XD, Hayden, MR, Horner, J, Ireland, MJ, Kafle, PR, Munari, U, Nataf, DM, Nordlander, T, Stello, D, Ting, YS, Traven, G, Watson, F, Wittenmyer, RA, Wyse, RFG, Yong, D, Zinn, JC, Žerjal, M, Buder, S, Asplund, M, Duong, L, Kos, J, Lind, K, Ness, MK, Sharma, S, Bland-Hawthorn, J, Casey, AR, De Silva, GM, D'Orazi, V, Freeman, KC, Lewis, GF, Lin, J, Martell, SL, Schlesinger, KJ, Simpson, JD, Zucker, DB, Zwitter, T, Amarsi, AM, Anguiano, B, Carollo, D, Casagrande, L, Čotar, K, Cottrell, PL, Costa, GD, Gao, XD, Hayden, MR, Horner, J, Ireland, MJ, Kafle, PR, Munari, U, Nataf, DM, Nordlander, T, Stello, D, Ting, YS, Traven, G, Watson, F, Wittenmyer, RA, Wyse, RFG, Yong, D, Zinn, JC, and Žerjal, M
- Abstract
The Galactic Archaeology with HERMES (GALAH) survey is a large-scale stellar spectroscopic survey of theMilkyWay, designed to deliver complementary chemical information to a large number of stars covered by the Gaia mission. We present the GALAH second public data release (GALAH DR2) containing 342 682 stars. For these stars, the GALAH collaboration provides stellar parameters and abundances for up to 23 elements to the community. Here we present the target selection, observation, data reduction, and detailed explanation of how the spectra were analysed to estimate stellar parameters and element abundances. For the stellar analysis, we have used a multistep approach. We use the physics-driven spectrum synthesis of Spectroscopy Made Easy (SME) to derive stellar labels (Teff, logg, [Fe/H], [X/Fe], vmic, vsin i, AKS) for a representative training set of stars. This information is then propagated to the whole sample with the data-driven method of The Cannon. Special care has been exercised in the spectral synthesis to only consider spectral lines that have reliable atomic input data and are little affected by blending lines. Departures from local thermodynamic equilibrium (LTE) are considered for several key elements, including Li, O, Na, Mg, Al, Si, and Fe, using 1D MARCS stellar atmosphere models. Validation tests including repeat observations, Gaia benchmark stars, open and globular clusters, and K2 asteroseismic targets lend confidence to our methods and results. Combining the GALAH DR2 catalogue with the kinematic information from Gaia will enable a wide range of Galactic Archaeology studies, with unprecedented detail, dimensionality, and scope.
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- 2018
41. The GALAH survey: Chemical tagging of star clusters and new members in the Pleiades
- Author
-
Kos, J, Bland-Hawthorn, J, Freeman, K, Buder, S, Traven, G, De Silva, GM, Sharma, S, Asplund, M, Duong, L, Lin, J, Lind, K, Martell, S, Simpson, JD, Stello, D, Zucker, DB, Zwitter, T, Anguiano, B, Costa, GD, D'Orazi, V, Horner, J, Kafle, PR, Lewis, G, Munari, U, Nataf, DM, Ness, M, Reid, W, Schlesinger, K, Ting, YS, Wyse, R, Kos, J, Bland-Hawthorn, J, Freeman, K, Buder, S, Traven, G, De Silva, GM, Sharma, S, Asplund, M, Duong, L, Lin, J, Lind, K, Martell, S, Simpson, JD, Stello, D, Zucker, DB, Zwitter, T, Anguiano, B, Costa, GD, D'Orazi, V, Horner, J, Kafle, PR, Lewis, G, Munari, U, Nataf, DM, Ness, M, Reid, W, Schlesinger, K, Ting, YS, and Wyse, R
- Abstract
The technique of chemical tagging uses the elemental abundances of stellar atmospheres to 'reconstruct' chemically homogeneous star clusters that have long since dispersed. The GALAH spectroscopic survey - which aims to observe one million stars using the Anglo- Australian Telescope - allows us to measure up to 30 elements or dimensions in the stellar chemical abundance space, many of which are not independent. How to find clustering reliably in a noisy high-dimensional space is a difficult problem that remains largely unsolved. Here, we explore t-distributed stochastic neighbour embedding (t-SNE) - which identifies an optimal mapping of a high-dimensional space into fewer dimensions - whilst conserving the original clustering information. Typically, the projection is made to a 2D space to aid recognition of clusters by eye. We show that this method is a reliable tool for chemical tagging because it can: (i) resolve clustering in chemical space alone, (ii) recover known open and globular clusters with high efficiency and low contamination, and (iii) relate field stars to known clusters. t-SNE also provides a useful visualization of a high-dimensional space. We demonstrate the method on a data set of 13 abundances measured in the spectra of 187 000 stars by the GALAH survey. We recover seven of the nine observed clusters (six globular and three open clusters) in chemical space with minimal contamination from field stars and low numbers of outliers. With chemical tagging, we also identify two Pleiades supercluster members (which we confirm kinematically), one as far as 6° - one tidal radius away from the cluster centre.
- Published
- 2018
42. The GALAH survey: Verifying abundance trends in the open cluster M67 using non-LTE modelling
- Author
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Gao, X, Lind, K, Amarsi, AM, Buder, S, Dotter, A, Nordlander, T, Asplund, M, Bland-Hawthorn, J, De Silva, GM, D'Orazi, V, Freeman, KC, Kos, J, Lewis, GF, Lin, J, Martell, SL, Schlesinger, KJ, Sharma, S, Simpson, JD, Zucker, DB, Zwitter, T, Costa, GD, Anguiano, B, Horner, J, Hyde, EA, Kafle, PR, Nataf, DM, Reid, W, Stello, D, Ting, YS, Gao, X, Lind, K, Amarsi, AM, Buder, S, Dotter, A, Nordlander, T, Asplund, M, Bland-Hawthorn, J, De Silva, GM, D'Orazi, V, Freeman, KC, Kos, J, Lewis, GF, Lin, J, Martell, SL, Schlesinger, KJ, Sharma, S, Simpson, JD, Zucker, DB, Zwitter, T, Costa, GD, Anguiano, B, Horner, J, Hyde, EA, Kafle, PR, Nataf, DM, Reid, W, Stello, D, and Ting, YS
- Abstract
Open cluster members are coeval and share the same initial bulk chemical composition. Consequently, differences in surface abundances between members of a cluster that are at different evolutionary stages can be used to study the effects of mixing and internal chemical processing. We carry out an abundance analysis of seven elements (Li, O, Na, Mg, Al, Si, and Fe) in 66 stars belonging to the open cluster M67, based on high resolution GALAH spectra, 1D MARCS model atmospheres, and non-local thermodynamic equilibrium (non-LTE) radiative transfer. From the non-LTE analysis, we find a typical star-to-star scatter in the abundance ratios of around 0.05 dex. We find trends in the abundance ratios with effective temperature, indicating systematic differences in the surface abundances between turn-off and giant stars; these trends are more pronounced when LTE is assumed. However, trends with effective temperature remain significant for Al and Si also in non-LTE. Finally, we compare the derived abundances with prediction from stellar evolution models including effects of atomic diffusion. We find overall good agreement for the abundance patterns of dwarfs and sub-giant stars, but the abundances of cool giants are lower relative to less evolved stars than predicted by the diffusion models, in particular for Mg.
- Published
- 2018
43. The GALAH survey: Properties of the Galactic disc(s) in the solar neighbourhood
- Author
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Duong, L, Freeman, KC, Asplund, M, Casagrande, L, Buder, S, Lind, K, Ness, M, Bland-Hawthorn, J, De Silva, GM, D'Orazi, V, Kos, J, Lewis, GF, Lin, J, Martell, SL, Schlesinger, K, Sharma, S, Simpson, JD, Zucker, DB, Zwitter, T, Anguiano, B, Da Costa, GS, Hyde, E, Horner, J, Kafle, PR, Nataf, DM, Reid, W, Stello, D, Ting, YS, Wyse, RFG, Duong, L, Freeman, KC, Asplund, M, Casagrande, L, Buder, S, Lind, K, Ness, M, Bland-Hawthorn, J, De Silva, GM, D'Orazi, V, Kos, J, Lewis, GF, Lin, J, Martell, SL, Schlesinger, K, Sharma, S, Simpson, JD, Zucker, DB, Zwitter, T, Anguiano, B, Da Costa, GS, Hyde, E, Horner, J, Kafle, PR, Nataf, DM, Reid, W, Stello, D, Ting, YS, and Wyse, RFG
- Abstract
Using data from the GALAH pilot survey, we determine properties of the Galactic thin and thick discs near the solar neighbourhood. The data cover a small range of Galactocentric radius (7.9 ≲ RGC ≲ 9.5 kpc), but extend up to 4 kpc in height from the Galactic plane, and several kpc in the direction of Galactic anti-rotation (at longitude 260° ≤ ℓ ≤ 280°). This allows us to reliably measure the vertical density and abundance profiles of the chemically and kinematically defined 'thick' and 'thin' discs of the Galaxy. The thin disc (low-α population) exhibits a steep negative vertical metallicity gradient, at d[M/H]/dz = -0.18 ± 0.01 dex kpc-1, which is broadly consistent with previous studies. In contrast, its vertical α-abundance profile is almost flat, with a gradient of d[α/M]/dz = 0.008 ± 0.002 dex kpc-1. The steep vertical metallicity gradient of the low-α population is in agreement with models where radial migration has a major role in the evolution of the thin disc. The thick disc (high-α population) has a weaker vertical metallicity gradient d[M/H]/dz = -0.058 ± 0.003 dex kpc-1. The α-abundance of the thick disc is nearly constant with height, d[α/M]/dz = 0.007 ± 0.002 dex kpc-1. The negative gradient in metallicity and the small gradient in [α/M] indicate that the high-α population experienced a settling phase, but also formed prior to the onset of major Type Ia supernova enrichment. We explore the implications of the distinct α-enrichments and narrow [α/M] range of the sub-populations in the context of thick disc formation.
- Published
- 2018
44. The age-metallicity relation from a sample of white dwarf-main sequence binarie
- Author
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Universitat Politècnica de Catalunya. Departament de Física, Universitat Politècnica de Catalunya. GAA - Grup d'Astronomia i Astrofísica, Rebassa Mansergas, Alberto, Anguiano, B., García-Berro Montilla, Enrique, Freeman, K. C., Universitat Politècnica de Catalunya. Departament de Física, Universitat Politècnica de Catalunya. GAA - Grup d'Astronomia i Astrofísica, Rebassa Mansergas, Alberto, Anguiano, B., García-Berro Montilla, Enrique, and Freeman, K. C.
- Abstract
The age-metallicity relation (AMR) is a fundamental observational constraint for un-derstanding how the Galactic disc formed and evolved chemically in time. However, there is not yet an agreement on the observational properties of the AMR, primarily due to the difficulty inobtaining accurate ages for individual field stars. We have started an observational campaign for providing new observational input by using wide white dwarf-main sequence (WDMS) binaries.WDs are natural clocks and can be used to derive accurate ages. Metallicities can be obtained from the MS companions. Since the progenitors of WDs and the MS stars were born at the sametime, WDMS provide a unique opportunity to constrain in a robust way the properties of the AMR. We present the AMR derived from analysing a pilot sample of 23 WDMS and provide clear evidence for the lack of correlation between age and metallicity at young and intermediate ages., Peer Reviewed, Postprint (published version)
- Published
- 2018
45. The kinematics of white dwarfs from the SDSS DR12
- Author
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Universitat Politècnica de Catalunya. Departament de Física, Universitat Politècnica de Catalunya. GAA - Grup d'Astronomia i Astrofísica, García-Berro Montilla, Enrique, Skorobogatov, G., Torres Gil, Santiago, Anguiano, B., Rebassa Mansergas, Alberto, Universitat Politècnica de Catalunya. Departament de Física, Universitat Politècnica de Catalunya. GAA - Grup d'Astronomia i Astrofísica, García-Berro Montilla, Enrique, Skorobogatov, G., Torres Gil, Santiago, Anguiano, B., and Rebassa Mansergas, Alberto
- Abstract
We use the Sloan Digital Sky Survey Data Release 12, which is the largest availablewhite dwarf catalogue to date, to study the evolution of the kinematical properties of the pop-ulation of white dwarfs of the Galactic disk. We derive masses, ages, photometric distances andradial velocities for all white dwarfs with hydrogen-rich atmospheres. For those stars for whichproper motions from the USNO-B1 catalogue are available, the three-dimensional componentsof the velocity are obtained. This subset of the original sample comprises 20,247 stars, makingit the largest sample of white dwarfs with measured three-dimensional velocities. The volumeprobed by our sample is large, allowing us to obtain relevant kinematical information. In partic-ular, our sample extends from a Galactocentric radial distanceRG=7.8 to 9.3 kpc, and verticaldistances from the Galactic plane ranging fromZ=+0.5to–0.5kpc., Peer Reviewed, Postprint (published version)
- Published
- 2018
46. El rigor científico en el vídeo online. La percepción de los expertos sobre los vídeos de contaminación del aire en Youtube
- Author
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Bortoliero, S.T. (Simone Terezinha) and León-Anguiano, B. (Bienvenido)
- Subjects
Scientific rigor ,Youtube ,Air pollution ,Rigor científico ,Vídeo online ,Contaminación del aire ,Online video - Abstract
Este artículo tiene por objetivo evaluar el rigor científico de los vídeos online sobre contaminación del aire, difundidos en la plataforma Youtube y publicadas en portugués y español en 2014. Se trata de una investigación realizada en colaboración con 17 científicos de Brasil y España, que evaluaron el rigor científico de una muestra de 100 videos, 50 en español y 50 en portugués. Los resultados indican que, según los científicos, los vídeos sobre contaminación del aire publicados en Youtube, tanto en español como en portugués, tienen un bajo nivel de rigor científico. This article aims to evaluate the scientific rigor of online videos on air pollution, broadcast on the YouTube platform and published in Portuguese and Spanish in 2014. This research was carried out in collaboration with 17 scientists from Brazil and Spain who evaluated the scientific rigor of a sample of 100 videos, 50 in Spanish and 50 inPortuguese. The results show that, according to scientists,those videos about air pollution that have been published in Youtube, either in Spanish or Portuguese, have a low level of scientific rigor.
- Published
- 2017
47. The kinematics of the white dwarf population from the SDSS DR12
- Author
-
Anguiano, B., Rebassa Mansergas, Alberto|||0000-0002-6153-7173, Torres Gil, Santiago|||0000-0001-5777-5251, García-Berro Montilla, Enrique|||0000-0002-1623-5838, Freeman, K. C., Universitat Politècnica de Catalunya. Departament de Física, and Universitat Politècnica de Catalunya. GAA - Grup d'Astronomia i Astrofísica
- Subjects
Galaxy - evolution ,Galàxies -- Evolució ,Galaxy - kinematics anddynamics ,White dwarfs ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Estels nans ,Galaxy - solar neighborhood ,Física::Astronomia i astrofísica [Àrees temàtiques de la UPC] ,Galaxies -- Evolution ,Astrophysics::Solar and Stellar Astrophysics ,Galaxy - general ,Astrophysics::Earth and Planetary Astrophysics ,Galaxy - stellar content ,Astrophysics::Galaxy Astrophysics - Abstract
We use the Sloan Digital Sky Survey Data Release 12, which is the largest avail-able white dwarf catalog to date, to study the evolution of the kinematical properties of thepopulation of white dwarfs in the Galactic disc. We derive masses, ages, photometric distancesand radial velocities for all white dwarfs with hydrogen-rich atmospheres. For those stars forwhich proper motions from the USNO-B1 catalog are available the true three-dimensional com-ponents of the stellar space velocity are obtained. This subset of the original sample comprises20,247 objects, making it the largest sample of white dwarfs with measured three-dimensionalvelocities. Furthermore, the volume probed by our sample is large, allowing us to obtain rel-evant kinematical information. In particular, our sample extends from a Galactocentric ra-dial distanceRG=7.8 kpc to 9.3 kpc, and vertical distances from the Galactic plane rang-ing fromZ=−0.5 kpc to 0.5 kpc. We examine the mean components of the stellar three-dimensional velocities, as well as their dispersions with respect to the Galactocentric and ver-tical distances. We confirm the existence of a mean Galactocentric radial velocity gradient,∂〈VR〉/∂RG=−3±5kms−1kpc−1. We also confirm North-South differences in〈Vz〉. Specifi-cally, we find that white dwarfs withZ>0 (in the North Galactic hemisphere) have〈Vz〉
- Published
- 2017
48. The GALAH survey: properties of the Galactic disc(s) in the solar neighbourhood
- Author
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Duong, L, primary, Freeman, K C, additional, Asplund, M, additional, Casagrande, L, additional, Buder, S, additional, Lind, K, additional, Ness, M, additional, Bland-Hawthorn, J, additional, De Silva, G M, additional, D'Orazi, V, additional, Kos, J, additional, Lewis, G F, additional, Lin, J, additional, Martell, S L, additional, Schlesinger, K, additional, Sharma, S, additional, Simpson, J D, additional, Zucker, D B, additional, Zwitter, T, additional, Anguiano, B, additional, Da Costa, G S, additional, Hyde, E, additional, Horner, J, additional, Kafle, P R, additional, Nataf, D M, additional, Reid, W, additional, Stello, D, additional, Ting, Y-S, additional, and Wyse, R F G, additional
- Published
- 2018
- Full Text
- View/download PDF
49. The kinematics of the white dwarf population from the SDSS DR12
- Author
-
Universitat Politècnica de Catalunya. Departament de Física, Universitat Politècnica de Catalunya. GAA - Grup d'Astronomia i Astrofísica, Anguiano, B., Rebassa Mansergas, Alberto, Torres Gil, Santiago, García-Berro Montilla, Enrique, Freeman, K. C., Universitat Politècnica de Catalunya. Departament de Física, Universitat Politècnica de Catalunya. GAA - Grup d'Astronomia i Astrofísica, Anguiano, B., Rebassa Mansergas, Alberto, Torres Gil, Santiago, García-Berro Montilla, Enrique, and Freeman, K. C.
- Abstract
We use the Sloan Digital Sky Survey Data Release 12, which is the largest avail-able white dwarf catalog to date, to study the evolution of the kinematical properties of thepopulation of white dwarfs in the Galactic disc. We derive masses, ages, photometric distancesand radial velocities for all white dwarfs with hydrogen-rich atmospheres. For those stars forwhich proper motions from the USNO-B1 catalog are available the true three-dimensional com-ponents of the stellar space velocity are obtained. This subset of the original sample comprises20,247 objects, making it the largest sample of white dwarfs with measured three-dimensionalvelocities. Furthermore, the volume probed by our sample is large, allowing us to obtain rel-evant kinematical information. In particular, our sample extends from a Galactocentric ra-dial distanceRG=7.8 kpc to 9.3 kpc, and vertical distances from the Galactic plane rang-ing fromZ=−0.5 kpc to 0.5 kpc. We examine the mean components of the stellar three-dimensional velocities, as well as their dispersions with respect to the Galactocentric and ver-tical distances. We confirm the existence of a mean Galactocentric radial velocity gradient,∂〈VR〉/∂RG=−3±5kms−1kpc−1. We also confirm North-South differences in〈Vz〉. Specifi-cally, we find that white dwarfs withZ>0 (in the North Galactic hemisphere) have〈Vz〉<0,while the reverse is true for white dwarfs withZ<0. The age-velocity dispersion relation de-rived from the present sample indicates that the Galactic population of white dwarfs may haveexperienced an additional source of heating, which adds to the secular evolution of the Galacticdisc., Peer Reviewed, Postprint (published version)
- Published
- 2017
50. The GALAH survey: Observational overview and Gaia DR1 companion
- Author
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Martell, SL, Sharma, S, Buder, S, Duong, L, Schlesinger, KJ, Simpson, J, Lind, K, Ness, M, Marshall, JP, Asplund, M, Bland-Hawthorn, J, Casey, AR, De Silva, G, Freeman, KC, Kos, J, Lin, J, Zucker, DB, Zwitter, T, Anguiano, B, Bacigalupo, C, Carollo, D, Casagrande, L, Da Costa, GS, Horner, J, Huber, D, Hyde, EA, Kafle, PR, Lewis, GF, Nataf, D, Navin, CA, Stello, D, Tinney, CG, Watson, FG, Wittenmyer, R, Martell, SL, Sharma, S, Buder, S, Duong, L, Schlesinger, KJ, Simpson, J, Lind, K, Ness, M, Marshall, JP, Asplund, M, Bland-Hawthorn, J, Casey, AR, De Silva, G, Freeman, KC, Kos, J, Lin, J, Zucker, DB, Zwitter, T, Anguiano, B, Bacigalupo, C, Carollo, D, Casagrande, L, Da Costa, GS, Horner, J, Huber, D, Hyde, EA, Kafle, PR, Lewis, GF, Nataf, D, Navin, CA, Stello, D, Tinney, CG, Watson, FG, and Wittenmyer, R
- Abstract
The Galactic Archaeology with HERMES (GALAH) survey is amassive observational project to trace the MilkyWay's history of star formation, chemical enrichment, stellar migration and minor mergers. Using high-resolution (R ≃ 28 000) spectra, taken with the High Efficiency and Resolution Multi-Element Spectrograph (HERMES) instrument at the Anglo-Australian Telescope, GALAH will determine stellar parameters and abundances of up to 29 elements for up to one million stars. Selecting targets from a colour-unbiased catalogue built from 2MASS, APASS and UCAC4 data, we expect to observe dwarfs at 0.3-3 kpc and giants at 1-10 kpc. This enables a thorough local chemical inventory of the Galactic thin and thick discs, and also captures smaller samples of the bulge and halo. In this paper, we present the plan, process and progress as of early 2016 for GALAH survey observations. In our first two years of survey observing we have accumulated the largest high-quality spectroscopic data set at this resolution, over 200 000 stars. We also present the first public GALAH data catalogue: stellar parameters (Teff, log(g), [Fe/H], [α/Fe]), radial velocity, distance modulus and reddening for 10 680 observations of 9860 Tycho-2 stars, 7894 of which are included in the first Gaia data release.
- Published
- 2017
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