The asymmetric drift, the local standard of rest, and implications from RAVE data

被引：32

作者：

Golubov, O. ^{[1
,2
,3
]}

Just, A. ^{[1
]}

Bienayme, O. ^{[4
]}

Bland-Hawthorn, J. ^{[5
]}

Gibson, B. K. ^{[6
,7
,8
]}

Grebel, E. K. ^{[1
]}

Munari, U. ^{[9
]}

Navarro, J. F. ^{[10
]}

Parker, Q. ^{[11
,12
,13
]}

Seabroke, G. ^{[14
]}

Reid, W. ^{[11
,12
]}

Siviero, A. ^{[15
]}

Steinmetz, M. ^{[16
]}

Williams, M. ^{[16
]}

Watson, F. ^{[13
]}

Zwitter, T. ^{[17
,18
]}

机构：

[1] Heidelberg Univ, Zentrum Astron, Astron Rechen Inst, D-69120 Heidelberg, Germany

[2] Univ Colorado, Dept Aerosp Engn Sci, Boulder, CO 80309 USA

[3] Kharkov Natl Univ, Inst Astron, UA-61022 Kharkov, Ukraine

[4] Observ Astron, F-67000 Strasbourg, France

[5] Univ Sydney, Sch Phys A28, Sydney Inst Astron, Sydney, NSW 2006, Australia

[6] St Marys Univ, Dept Phys & Astro, Halifax, NS B3H 3C3, Canada

[7] Monash Ctr Astrophys, Clayton, Vic 3800, Australia

[8] UCLan, Jeremiah Horrocks Inst, Preston PR1 2HE, Lancs, England

[9] NAF Osservatorio Astron Padova, I-36012 Asiago, Italy

[10] Univ Victoria, Dept Phys & Astron, Victoria V8P 5C2, BC, Canada

[11] Macquarie Univ, Dept Phys & Astron, Sydney, NSW 2109, Australia

[12] Macquarie Res Ctr Astron Astrophys & Astrophoton, Sydney, NSW 2109, Australia

[13] Australian Astron Observ, Sydney, NSW 2121, Australia

[14] Univ Coll London, Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England

[15] Univ Padua, Dept Phys & Astron, I-35122 Padua, Italy

[16] Leibniz Inst Astrophys Potsdam AIP, D-14482 Potsdam, Germany

[17] Univ Ljubljana, Fac Math & Phys, Ljubljana 1000, Slovenia

[18] Ctr Excellence SPACE SI, Ljubljana 1000, Slovenia

来源：

ASTRONOMY & ASTROPHYSICS | 2013年 / 557卷

关键词：

Galaxy: kinematics and dynamics; solar neighborhood; VELOCITY EXPERIMENT RAVE; SKY SURVEY DATA; ABUNDANCE GRADIENTS; CHEMICAL EVOLUTION; STELLAR KINEMATICS; GALACTIC STRUCTURE; MILKY; STARS; SEGUE; II;

D O I：

10.1051/0004-6361/201321559

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

Context. The determination of the local standard of rest (LSR), which corresponds to the measurement of the peculiar motion of the Sun based on the derivation of the asymmetric drift of stellar populations, is still a matter of debate. The classical value of the tangential peculiar motion of the Sun with respect to the LSR was challenged in recent years, claiming a significantly larger value. Aims. We present an improved Jeans analysis, which allows a better interpretation of the measured kinematics of stellar populations in the Milky Way disc. We show that the Radial Velocity Experiment (RAVE) sample of dwarf stars is an excellent data set to derive tighter boundary conditions to chemodynamical evolution models of the extended solar neighbourhood. Methods. We propose an improved version of the Stromberg relation with the radial scalelengths as the only unknown. We redetermine the asymmetric drift and the LSR for dwarf stars based on RAVE data. Additionally, we discuss the impact of adopting a different LSR value on the individual scalelengths of the subpopulations. Results. Binning RAVE stars in metallicity reveals a bigger asymmetric drift (corresponding to a smaller radial scalelength) for more metal-rich populations. With the standard assumption of velocity-dispersion independent radial scalelengths in each metallicity bin, we redetermine the LSR. The new Stromberg equation yields a joint LSR value of V-circle dot = 3.06 +/- 0.68 km s(-1), which is even smaller than the classical value based on Hipparcos data. The corresponding radial scalelength increases from 1.6 kpc for the metal-rich bin to 2.9 kpc for the metal-poor bin, with a trend of an even larger scalelength for young metal-poor stars. When adopting the recent Schonrich value of V-circle dot = 12.24 km s(-1) for the LSR, the new Stromberg equation yields much larger individual radial scalelengths of the RAVE subpopulations, which seem unphysical in part. Conclusions. The new Stromberg equation allows a cleaner interpretation of the kinematic data of disc stars in terms of radial scalelengths. Lifting the LSR value by a few km s(-1) compared to the classical value results in strongly increased radial scalelengths with a trend of smaller values for larger velocity dispersions.

引用

页数：11

共 42 条

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Read, M. A. ;

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ASTRONOMICAL JOURNAL, 2008, 136 (01) :421-451

[42] Distance determination for RAVE stars using stellar models II. Most likely values assuming a standard stellar evolution scenario [J].