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

Tomaž Zwitter, Janez Kos, Andrea Chiavassa, Sven Buder, Gregor Traven, Klemen Čotar, Jane Lin, Martin Asplund, Joss Bland-Hawthorn, Andrew R. Casey, Gayandhi De Silva, Ly Duong, Kenneth C. Freeman, Karin Lind, Sarah Martell, Valentina D'Orazi, Katharine J. Schlesinger, Jeffrey D. Simpson, Sanjib Sharma, Daniel B. Zucker & 17 others Borja Anguiano, Luca Casagrande, Remo Collet, Jonathan Horner, Michael J. Ireland, Prajwal R. Kafle, Geraint Lewis, Ulisse Munari, David M. Nataf, Melissa Ness, Thomas Nordlander, Dennis Stello, Yuan Sen Ting, Chris G. Tinney, Fred Watson, Rob A. Wittenmyer, Maruša Žerja

Research output: Contribution to journalArticle

8 Citations (Scopus)

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.

Original languageEnglish
Pages (from-to)645-654
Number of pages10
JournalMonthly Notices of the Royal Astronomical Society
Volume481
Issue number1
DOIs
Publication statusPublished - 21 Nov 2018

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radial velocity
templates
stars
metallicity
stellar atmospheres
signal-to-noise ratio
sky
dark matter
signal to noise ratios
gravity
gravitation
galaxies
wavelength
library
atmosphere
wavelengths
temperature

Cite this

Zwitter, Tomaž ; Kos, Janez ; Chiavassa, Andrea ; Buder, Sven ; Traven, Gregor ; Čotar, Klemen ; Lin, Jane ; Asplund, Martin ; Bland-Hawthorn, Joss ; Casey, Andrew R. ; Silva, Gayandhi De ; Duong, Ly ; Freeman, Kenneth C. ; Lind, Karin ; Martell, Sarah ; D'Orazi, Valentina ; Schlesinger, Katharine J. ; Simpson, Jeffrey D. ; Sharma, Sanjib ; Zucker, Daniel B. ; Anguiano, Borja ; Casagrande, Luca ; Collet, Remo ; Horner, Jonathan ; Ireland, Michael J. ; Kafle, Prajwal R. ; Lewis, Geraint ; Munari, Ulisse ; Nataf, David M. ; Ness, Melissa ; Nordlander, Thomas ; Stello, Dennis ; Ting, Yuan Sen ; Tinney, Chris G. ; Watson, Fred ; Wittenmyer, Rob A. ; Žerja, Maruša. / The GALAH survey : Accurate radial velocities and library of observed stellar template spectra. In: Monthly Notices of the Royal Astronomical Society. 2018 ; Vol. 481, No. 1. pp. 645-654.
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title = "The GALAH survey: Accurate radial velocities and library of observed stellar template spectra",
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.",
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author = "Tomaž Zwitter and Janez Kos and Andrea Chiavassa and Sven Buder and Gregor Traven and Klemen Čotar and Jane Lin and Martin Asplund and Joss Bland-Hawthorn and Casey, {Andrew R.} and Silva, {Gayandhi De} and Ly Duong and Freeman, {Kenneth C.} and Karin Lind and Sarah Martell and Valentina D'Orazi and Schlesinger, {Katharine J.} and Simpson, {Jeffrey D.} and Sanjib Sharma and Zucker, {Daniel B.} and Borja Anguiano and Luca Casagrande and Remo Collet and Jonathan Horner and Ireland, {Michael J.} and Kafle, {Prajwal R.} and Geraint Lewis and Ulisse Munari and Nataf, {David M.} and Melissa Ness and Thomas Nordlander and Dennis Stello and Ting, {Yuan Sen} and Tinney, {Chris G.} and Fred Watson and Wittenmyer, {Rob A.} and Maruša Žerja",
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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 2018, 'The GALAH survey: Accurate radial velocities and library of observed stellar template spectra' Monthly Notices of the Royal Astronomical Society, vol. 481, no. 1, pp. 645-654. https://doi.org/10.1093/mnras/sty2293

The GALAH survey : Accurate radial velocities and library of observed stellar template spectra. / Zwitter, Tomaž; Kos, Janez; Chiavassa, Andrea; Buder, Sven; Traven, Gregor; Čotar, Klemen; Lin, Jane; Asplund, Martin; Bland-Hawthorn, Joss; Casey, Andrew R.; Silva, Gayandhi De; Duong, Ly; Freeman, Kenneth C.; Lind, Karin; Martell, Sarah; D'Orazi, Valentina; Schlesinger, Katharine J.; Simpson, Jeffrey D.; Sharma, Sanjib; Zucker, Daniel B.; Anguiano, Borja; Casagrande, Luca; Collet, Remo; Horner, Jonathan; Ireland, Michael J.; Kafle, Prajwal R.; Lewis, Geraint; Munari, Ulisse; Nataf, David M.; Ness, Melissa; Nordlander, Thomas; Stello, Dennis; Ting, Yuan Sen; Tinney, Chris G.; Watson, Fred; Wittenmyer, Rob A.; Žerja, Maruša.

In: Monthly Notices of the Royal Astronomical Society, Vol. 481, No. 1, 21.11.2018, p. 645-654.

Research output: Contribution to journalArticle

TY - JOUR

T1 - The GALAH survey

T2 - Accurate radial velocities and library of observed stellar template spectra

AU - Zwitter, Tomaž

AU - Kos, Janez

AU - Chiavassa, Andrea

AU - Buder, Sven

AU - Traven, Gregor

AU - Čotar, Klemen

AU - Lin, Jane

AU - Asplund, Martin

AU - Bland-Hawthorn, Joss

AU - Casey, Andrew R.

AU - Silva, Gayandhi De

AU - Duong, Ly

AU - Freeman, Kenneth C.

AU - Lind, Karin

AU - Martell, Sarah

AU - D'Orazi, Valentina

AU - Schlesinger, Katharine J.

AU - Simpson, Jeffrey D.

AU - Sharma, Sanjib

AU - Zucker, Daniel B.

AU - Anguiano, Borja

AU - Casagrande, Luca

AU - Collet, Remo

AU - Horner, Jonathan

AU - Ireland, Michael J.

AU - Kafle, Prajwal R.

AU - Lewis, Geraint

AU - Munari, Ulisse

AU - Nataf, David M.

AU - Ness, Melissa

AU - Nordlander, Thomas

AU - Stello, Dennis

AU - Ting, Yuan Sen

AU - Tinney, Chris G.

AU - Watson, Fred

AU - Wittenmyer, Rob A.

AU - Žerja, Maruša

PY - 2018/11/21

Y1 - 2018/11/21

N2 - 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.

AB - 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.

KW - Methods: data analysis -methods: observational

KW - Stars: fundamental parameters

KW - Surveys

UR - http://www.scopus.com/inward/record.url?scp=85054098250&partnerID=8YFLogxK

U2 - 10.1093/mnras/sty2293

DO - 10.1093/mnras/sty2293

M3 - Article

VL - 481

SP - 645

EP - 654

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

SN - 0035-8711

IS - 1

ER -