scholarly journals A STATISTICAL METHOD FOR MEASURING THE GALACTIC POTENTIAL AND TESTING GRAVITY WITH COLD TIDAL STREAMS

2012 ◽  
Vol 760 (1) ◽  
pp. 2 ◽  
Author(s):  
Jorge Peñarrubia ◽  
Sergey E. Koposov ◽  
Matthew G. Walker
Keyword(s):  
Statistical Method ◽  
Galactic Potential ◽  
Tidal Streams

scholarly journals ACTION-SPACE CLUSTERING OF TIDAL STREAMS TO INFER THE GALACTIC POTENTIAL

2015 ◽  
Vol 801 (2) ◽  
pp. 98 ◽  
Author(s):  
Robyn E. Sanderson ◽  
Amina Helmi ◽  
David W. Hogg
Keyword(s):  
Action Space ◽  
Galactic Potential ◽  
Tidal Streams

scholarly journals Action-space clustering of tidal streams to map the Galactic potential

2013 ◽  
Vol 9 (S298) ◽  
pp. 207-212 ◽  
Author(s):  
Robyn E. Sanderson ◽  
Amina Helmi ◽  
David W. Hogg
Keyword(s):  
Action Space ◽  
Leibler Divergence ◽  
Galactic Potential ◽  
Stellar Halo ◽  
Observational Errors ◽  
Tidal Streams ◽  
Potential Parameters ◽  
Best Fit ◽  
Membership Information ◽  
Input Potential

AbstractGiven a parametrized model of the Galactic potential, the best-fit parameters can be obtained by maximizing the Kullback-Leibler divergence of the action distribution of a set of stars initially clustered in action space (e.g. stars in tidal streams). This method will allow us to map the Milky Way's gravitational potential by simultaneously fitting multiple tidal streams without requiring stream membership information. With 20 streams of at least 20 stars each, including observational errors consistent with predictions for Gaia, this technique recovers the input potential parameters to a precision of 10-60% and an accuracy of 10%. With all the observed streams in our mock stellar halo (about 40) that fit the error criteria, the precision improves to 10%.

scholarly journals Tidal Streams as Probes of the Galactic Potential

1999 ◽  
Vol 512 (2) ◽  
pp. L109-L112 ◽  
Author(s):  
Kathryn V. Johnston ◽  
HongSheng Zhao ◽  
David N. Spergel ◽  
Lars Hernquist
Keyword(s):  
Galactic Potential ◽  
Tidal Streams

scholarly journals Stream-orbit misalignment & a new algorithm for constraining the Galactic potential with streams

2013 ◽  
Vol 9 (S298) ◽  
pp. 195-200
Author(s):  
Jason L. Sanders ◽  
James Binney
Keyword(s):  
Action Space ◽  
Galactic Potential ◽  
Alternative Algorithm ◽  
Orbit Fitting ◽  
Tidal Stream ◽  
Tidal Streams

AbstractIn general, a tidal stream is misaligned with the orbit of its progenitor. Here we present the formation of tidal streams in angle-action space to discuss the effect of this misalignment on orbit-fitting algorithms for constraining the Galactic potential. We close by presenting and testing an alternative algorithm which more fully accounts for the dynamics of streams by using the angle-action formalism.

Income and Life Quality of Farmer Households Suffering Social Exclusion

2012 ◽  
pp. 63-87
Author(s):  
Anh Mai Ngoc ◽  
Ha Do Thi Hai ◽  
Huyen Nguyen Thi Ngoc
Keyword(s):  
Labor Market ◽  
Statistical Method ◽  
Social Exclusion ◽  
Central Government ◽  
Life Quality ◽  
Economic Aspect ◽  
Local Authorities ◽  
The Impact

This study uses descriptive statistical method to analyze the income and life qual- ity of 397 farmer households who are suffering social exclusion in an economic aspect out of a total of 725 households surveyed in five Northern provinces of Vietnam in 2010. The farmers’ opinions of the impact of the policies currently prac- ticed by the central government and local authorities to give them access to the labor market are also analyzed in this study to help management officers see how the poli- cies affect the beneficiaries so that they can later make appropriate adjustments.

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