The GALAH survey: accurate radial velocities and library of observed stellar template spectra

Zwitter, Tomaz and Kos, Janez and Chiavassa, Andrea and Buder, Sven and Traven, Gregor and Cotar, Klemen and Lin, Jane and Asplund, Martin and Bland-Hawthorn, Joss and Casey, Andrew R. and de Silva, Gayandhi and Duong, Ly and Freeman, Kenneth C. and Lind, Karin and Martell, Sarah and D'Orazi, Valentina and Schlesinger, Katharine J. and Simpson, Jeffrey D. and Sharma, Sanjib and Zucker, Daniel B. and Anguiano, Borja and Casagrande, Luca and Collet, Remo and Horner, Jonathan and Ireland, Michael J. and Kafle, Prajwal R. and Lewis, Geraint and Munari, Ulisse and Nataf, David M. and Ness, Melissa and Nordlander, Thomas and Stello, Dennis and Ting, Yuan-Sen and Tinney, Chris G. and Watson, Fred and Wittenmyer, Rob A. and Zerjal, Marusa (2018) The GALAH survey: accurate radial velocities and library of observed stellar template spectra. Monthly Notices of the Royal Astronomical Society, 481 (1). pp. 645-654. ISSN 0035-8711

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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<SUP>-1</SUP> 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.

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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Published version deposited in accordance with the copyright policy of the publisher.
Faculty/School / Institute/Centre: Current - Faculty of Health, Engineering and Sciences - School of Agricultural, Computational and Environmental Sciences
Date Deposited: 15 Feb 2019 02:52
Last Modified: 17 Feb 2019 23:11
Uncontrolled Keywords: data analysis; observational; surveys; fundamental parameters; astrophysics; solar and stellar astrophysics; astrophysics of galaxies
Fields of Research : 02 Physical Sciences > 0201 Astronomical and Space Sciences > 020110 Stellar Astronomy and Planetary Systems
Identification Number or DOI: 10.1093/mnras/sty2293

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