Results 111 to 120 of about 11,137 (251)

Introduction to Gravitational Microlensing

open access: yes, 2008
The basic concepts of gravitational microlensing are introduced. We start with the lens equation, and then derive the image positions and magnifications. The statistical quantities of optical depth and event rate are then described. We finish with a summary and a list of challenges and open questions. A problem set is given for students to practice.
openaire   +2 more sources

Gravitational Microlensing by Rotating Stars

open access: yes, 2005
12 pages, 4 figures, AAS ...
Rahbari, Habib Ebrahimnejad   +2 more
openaire   +2 more sources

Microlensing Optical Depth, Event Rate, and Limits on Compact Objects in Dark Matter Based on 20 Yr of OGLE Observations of the Small Magellanic Cloud

open access: yesThe Astrophysical Journal Supplement Series
Some previous studies have suggested that massive and intermediate-mass primordial black holes (PBHs) could comprise a substantial fraction of dark matter in the Universe.
Przemek Mróz   +14 more
doaj   +1 more source

OGLE-2017-BLG-0448Lb: A Low Mass–Ratio Wide-orbit Microlensing Planet?

open access: yesThe Astronomical Journal
The gravitational microlensing technique is most sensitive to planets in a Jupiter-like orbit and has detected more than 200 planets. However, only a few wide-orbit ( s > 2) microlensing planets have been discovered, where s is the planet-to-host ...
Ruocheng Zhai   +44 more
doaj   +1 more source

Investigating the Binary Source Degeneracy for Wide-orbit Planets

open access: yesThe Astronomical Journal
Wide-orbit planets are particularly sensitive to detection by the Roman Galactic Bulge Time Domain Survey (GBTDS). This study investigates the degeneracy of these events with binary sources, focusing on how observation cadence affects the resolution of ...
Parisa Sangtarash, Jennifer C. Yee
doaj   +1 more source

Gravitational Microlensing by Globular Clusters

open access: yes, 1998
Stars in globular clusters can act either as sources for MACHOs (Massive Astrophysical Compact Halo Objects) located along the line of sight or as lenses for more distant background stars. Although the expected rate of microlensing events is small, such observations can lead to very useful results.
Jetzer, P., Strässle, M., Wandeler, U.
openaire   +2 more sources

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