Results 81 to 90 of about 64,072 (295)
Lensing galaxies: light or dark? [PDF]
, 1998 In a recent paper, Hawkins (1997) argues on the basis of statistical studies of double-image gravitational lenses and lens candidates that a large population of dark lenses exists and that these outnumber galaxies with more normal mass-to-light ratios by
Browne, I. W. A. +6 more
core +3 more sources
Perturbative Approach to the Gravitational Lensing by a Non-spherically Distorted Compact Object
, 2011 We investigate the gravitational lens effect caused by a non-spherically distorted compact object. The non-spherical property of the gravitational potential is modeled by a quadrupole moment. Under the assumption that the quadrupole contribution is small,
Alard +14 more
core +1 more source
The quadrupole gravitational lens
The Astrophysical Journal, 1987 An asymmetric lens made of a spherically symmetric galaxy and a quadrupole tidal part allows a very simple pictorial examination of the multiplicity and positions of the images, for any mass density profile. The lens equations can be reduced to one equation in one variable.
openaire +1 more source
A VLA Gravitational Lens Survey [PDF]
Symposium - International Astronomical Union, 1987 Gravitational lens surveys are of cosmological interest because they provide a way to measure the gravitational field of both luminous and dark matter. Many of the other methods used to detect the presence of dark matter, such as studies of galaxy rotation curves and cluster dynamics, require that there be luminous objects in the gravitational field ...
J. N. Hewitt +6 more
openaire +1 more source
British Educational Research Journal, EarlyView.Abstract International student mobility (ISM) has historically followed a pattern of movement from developing regions to developed countries. However, in recent years, there has been a noticeable increase in the number of Chinese students pursuing doctoral studies in Southeast Asian developing countries, an area that has received relatively little ...
Yueyang Zheng +2 more
wiley +1 more source
European Physical Journal C: Particles and FieldsIn this manuscript, we provide a comprehensive study of gravitational lensing by dark compact objects predicted by modified gravity (MOG) based on the scalar–vector–tensor action, with the aim of providing new insights into the nature of gravitational ...
Nagina Rehman +3 more
doaj +1 more source
Primordial black hole detection through diffractive microlensing
, 2018 Recent observations of gravitational waves motivate investigations for the existence of Primordial Black Holes (PBHs). We propose the observation of gravitational microlensing of distant quasars for the range of infrared to the submillimeter wavelengths ...
Mehrabi, A., Naderi, T., Rahvar, S.
core +1 more source
British Educational Research Journal, EarlyView.Abstract As front‐line observers and active participants in pupils' daily lives, teachers closely monitor pupils' social interactions, emotional states and behavioural changes. Their unique perspective enables them to detect problems in the social lives of their pupils that may not be immediately visible to peers, parents or mental health professionals.
Yixuan Zheng +4 more
wiley +1 more source
Inferring Properties of Dark Galactic Halos Using Strongly Lensed Gravitational Waves
The Astrophysical JournalGravitational waves (GWs) can be deflected, similarly to electromagnetic (EM) waves, by massive objects through the phenomenon of gravitational lensing .
Eungwang Seo +2 more
doaj +1 more source
The first direct detection of a gravitational micro-lens toward the Galactic bulge
, 2007 We present a direct detection of the gravitational lens that caused the microlensing event MACHO-95-BLG-37. This is the first fully resolved microlensing system involving a source in the Galactic bulge, and the second such system in general. The lens and
A. Wood +10 more
core +1 more source