Evidence for gravitational microlensing by dark objects in the Galactic halo

1994 ◽  
Vol 35 ◽  
pp. 137-144 ◽  
Author(s):  
A. Milsztajn
Keyword(s):  
Galactic Halo ◽  
Gravitational Microlensing

Evidence for gravitational microlensing by dark objects in the Galactic halo

Nature ◽  
1993 ◽  
Vol 365 (6447) ◽  
pp. 623-625 ◽  
Author(s):  
E. Aubourg ◽  
P. Bareyre ◽  
S. Bréhin ◽  
M. Gros ◽  
M. Lachièze-Rey ◽  
...  
Keyword(s):  
Galactic Halo ◽  
Gravitational Microlensing

scholarly journals The MACHO Project: Limits on Planetary Mass Dark Matter in the Galactic Halo from Gravitational Microlensing

1996 ◽  
Vol 471 (2) ◽  
pp. 774-782 ◽  
Author(s):  
C. Alcock ◽  
R. A. Allsman ◽  
D. Alves ◽  
T. S. Axelrod ◽  
A. C. Becker ◽  
...  
Keyword(s):  
Dark Matter ◽  
Galactic Halo ◽  
Planetary Mass ◽  
Gravitational Microlensing

scholarly journals Gravitational microlensing I: A unique astrophysical tool

2015 ◽  
Vol 24 (07) ◽  
pp. 1530020 ◽  
Author(s):  
Sohrab Rahvar
Keyword(s):  
Gravitational Lensing ◽  
Galactic Halo ◽  
Mass Function ◽  
Line Of Sight ◽  
High Magnification ◽  
Gravitational Microlensing ◽  
Single Lens ◽  
History Of ◽  
Degeneracy Problem ◽  
Remnant Mass

In this paper, we review the astrophysical application of gravitational microlensing. After introducing the history of gravitational lensing, we present the key equations and concept of microlensing. The most frequent microlensing events are single-lens events and historically it has been used for searching dark matter in the form of compact astrophysical halo objects in the Galactic halo. We discuss about the degeneracy problem in the parameters of lens and perturbation effects that can partially break the degeneracy between the lens parameters. The rest of paper is about the astrophysical applications of microlensing. One of the important applications is in the stellar physics by probing the surface of source stars in the high magnification microlensing events. The astrometric and polarimetric observations will be complimentary for probing the atmosphere and stellar spots on the surface of source stars. Finally we discuss about the future projects as space-based telescopes for parallax and astrometry observations of microlensing events. With this project, we would expect to produce a complete stellar and remnant mass function and study the structure of Galaxy in term of distribution of stars along our line of sight towards the center of galaxy.

On population 3 stars as gravitational microlensing objects in the galactic halo

1995 ◽  
Vol 444 ◽  
pp. 175 ◽  
Author(s):  
Masayuki Y. Fujimoto ◽  
Kiyoshi Sugiyama ◽  
Icko, Jr. Iben ◽  
David Hollowell
Keyword(s):  
Galactic Halo ◽  
Gravitational Microlensing

scholarly journals Gravitational microlensing and the galactic halo

1996 ◽  
Vol 53 (8) ◽  
pp. 4138-4176 ◽  
Author(s):  
Evalyn I. Gates ◽  
Geza Gyuk ◽  
Michael S. Turner
Keyword(s):  
Galactic Halo ◽  
Gravitational Microlensing

Distribution of R- and S-Process Elements in the Galactic Halo

1988 ◽  
Vol 132 ◽  
pp. 501-506
Author(s):  
C. Sneden ◽  
C. A. Pilachowski ◽  
K. K. Gilroy ◽  
J. J. Cowan
Keyword(s):  
Heavy Element ◽  
Galactic Halo ◽  
Low Noise ◽  
Heavy Elements ◽  
Process Synthesis ◽  
Element Abundances ◽  
Halo Stars ◽  
Abundance Patterns ◽  
R Process ◽  
Process Elements

Current observational results for the abundances of the very heavy elements (Z>30) in Population II halo stars are reviewed. New high resolution, low noise spectra of many of these extremely metal-poor stars reveal general consistency in their overall abundance patterns. Below Galactic metallicities of [Fe/H] Ã −2, all of the very heavy elements were manufactured almost exclusively in r-process synthesis events. However, there is considerable star-to-star scatter in the overall level of very heavy element abundances, indicating the influence of local supernovas on element production in the very early, unmixed Galactic halo. The s-process appears to contribute substantially to stellar abundances only in stars more metal-rich than [Fe/H] Ã −2.

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