Advanced

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

Zwitter, Tomaž; Kos, Janez; Chiavassa, Andrea; Buder, Sven; Traven, Gregor LU ; Čotar, Klemen; Lin, Jane; Asplund, Martin; Bland-Hawthorn, Joss and Casey, Andrew R., et al. (2018) In Monthly Notices of the Royal Astronomical Society 481(1). p.645-654
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... (More)


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.

(Less)
Please use this url to cite or link to this publication:
@article{995f66b9-5c4d-4726-8303-73ba27127cc9,
  abstract     = {<p><br>
                            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<br>
                            <sup>-1</sup><br>
                             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.<br>
                        </p>},
  author       = {Zwitter, Tomaž and Kos, Janez and Chiavassa, Andrea and Buder, Sven and Traven, Gregor and Čotar, Klemen and Lin, Jane and Asplund, Martin and Bland-Hawthorn, Joss and Casey, Andrew R. and Silva, Gayandhi De 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 Žerja, Maruša},
  issn         = {0035-8711},
  keyword      = {Methods: data analysis -methods: observational,Stars: fundamental parameters,Surveys},
  language     = {eng},
  month        = {11},
  number       = {1},
  pages        = {645--654},
  publisher    = {Oxford University Press (OUP)},
  series       = {Monthly Notices of the Royal Astronomical Society},
  title        = {The GALAH survey : Accurate radial velocities and library of observed stellar template spectra},
  url          = {http://dx.doi.org/10.1093/mnras/sty2293},
  volume       = {481},
  year         = {2018},
}