Maximum likelihood estimation of local stellar kinematics
Aghajani, T. and Lindegren, Lennart LU
(2013)
In Astronomy & Astrophysics
551.
- Abstract
- Context. Kinematical data such as the mean velocities and velocity dispersions of stellar samples are useful tools to study galactic structure and evolution. However, observational data are often incomplete (e. g., lacking the radial component of the motion) and may have significant observational errors. For example, the majority of faint stars observed with Gaia will not have their radial velocities measured. Aims. Our aim is to formulate and test a new maximum likelihood approach to estimating the kinematical parameters for a local stellar sample when only the transverse velocities are known (from parallaxes and proper motions). Methods. Numerical simulations using synthetically generated data as well as real data (based on the... (More)
- Context. Kinematical data such as the mean velocities and velocity dispersions of stellar samples are useful tools to study galactic structure and evolution. However, observational data are often incomplete (e. g., lacking the radial component of the motion) and may have significant observational errors. For example, the majority of faint stars observed with Gaia will not have their radial velocities measured. Aims. Our aim is to formulate and test a new maximum likelihood approach to estimating the kinematical parameters for a local stellar sample when only the transverse velocities are known (from parallaxes and proper motions). Methods. Numerical simulations using synthetically generated data as well as real data (based on the Geneva-Copenhagen survey) are used to investigate the statistical properties (bias, precision) of the method, and to compare its performance with the much simpler "projection method" described by Dehnen & Binney (1998, MNRAS, 298, 387). Results. The maximum likelihood method gives more correct estimates of the dispersion when observational errors are important, and guarantees a positive-definite dispersion matrix, which is not always obtained with the projection method. Possible extensions and improvements of the method are discussed. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/3749140
- author
- Aghajani, T.
and Lindegren, Lennart
LU
- organization
- publishing date
- 2013
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- methods: numerical, methods: analytical, astrometry
- in
- Astronomy & Astrophysics
- volume
- 551
- article number
- A9
- publisher
- EDP Sciences
- external identifiers
-
- wos:000316460600009
- scopus:84873933546
- ISSN
- 0004-6361
- DOI
- 10.1051/0004-6361/201220430
- language
- English
- LU publication?
- yes
- id
- bcacf50b-aa71-4756-81d8-ce9b855b22f5 (old id 3749140)
- date added to LUP
- 2016-04-01 13:49:35
- date last changed
- 2024-01-09 19:12:01
@article{bcacf50b-aa71-4756-81d8-ce9b855b22f5,
abstract = {{Context. Kinematical data such as the mean velocities and velocity dispersions of stellar samples are useful tools to study galactic structure and evolution. However, observational data are often incomplete (e. g., lacking the radial component of the motion) and may have significant observational errors. For example, the majority of faint stars observed with Gaia will not have their radial velocities measured. Aims. Our aim is to formulate and test a new maximum likelihood approach to estimating the kinematical parameters for a local stellar sample when only the transverse velocities are known (from parallaxes and proper motions). Methods. Numerical simulations using synthetically generated data as well as real data (based on the Geneva-Copenhagen survey) are used to investigate the statistical properties (bias, precision) of the method, and to compare its performance with the much simpler "projection method" described by Dehnen & Binney (1998, MNRAS, 298, 387). Results. The maximum likelihood method gives more correct estimates of the dispersion when observational errors are important, and guarantees a positive-definite dispersion matrix, which is not always obtained with the projection method. Possible extensions and improvements of the method are discussed.}},
author = {{Aghajani, T. and Lindegren, Lennart}},
issn = {{0004-6361}},
keywords = {{methods: numerical; methods: analytical; astrometry}},
language = {{eng}},
publisher = {{EDP Sciences}},
series = {{Astronomy & Astrophysics}},
title = {{Maximum likelihood estimation of local stellar kinematics}},
url = {{http://dx.doi.org/10.1051/0004-6361/201220430}},
doi = {{10.1051/0004-6361/201220430}},
volume = {{551}},
year = {{2013}},
}