scholarly journals Strong lensing cross-sections for isothermal models. I. Finite source effects in the circular case

2018 ◽  
Vol 481 (2) ◽  
pp. 2189-2204 ◽  
Author(s):  
Vanessa P de Freitas ◽  
Martin Makler ◽  
Habib S Dúmet-Montoya
Keyword(s):  
Cross Sections ◽  
Source Effects ◽  
Finite Source ◽  
Strong Lensing ◽  
Circular Case

scholarly journals Estimating Finite Source Effects in Microlensing Events due to Free-Floating Planets with the Euclid Survey

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Lindita Hamolli ◽  
Mimoza Hafizi ◽  
Francesco De Paolis ◽  
Achille A. Nucita
Keyword(s):  
Spatial Distribution ◽  
Power Law ◽  
Mass Function ◽  
Physical Parameters ◽  
Galactic Bulge ◽  
Source Effect ◽  
Source Effects ◽  
Function Index ◽  
Finite Source ◽  
Einstein Radius

In recent years free-floating planets (FFPs) have drawn a great interest among astrophysicists. Gravitational microlensing is a unique and exclusive method for their investigation which may allow obtaining precious information about their mass and spatial distribution. The planned Euclid space-based observatory will be able to detect a substantial number of microlensing events caused by FFPs towards the Galactic bulge. Making use of a synthetic population algorithm, we investigate the possibility of detecting finite source effects in simulated microlensing events due to FFPs. We find a significant efficiency for finite source effect detection that turns out to be between 20% and 40% for a FFP power law mass function index in the range [0.9, 1.6]. For many of such events it will also be possible to measure the angular Einstein radius and therefore constrain the lens physical parameters. These kinds of observations will also offer a unique possibility to investigate the photosphere and atmosphere of Galactic bulge stars.

scholarly journals Simulating the Role of Stellar Rotation in the Spectroscopic Effects of Differential Limb Magnification

2013 ◽  
Vol 30 ◽  
Author(s):  
Adam R. H. Stevens ◽  
Michael D. Albrow
Keyword(s):  
Simulated Data ◽  
Absorption Lines ◽  
High Magnification ◽  
Stellar Rotation ◽  
Dwarf Stars ◽  
Source Effects ◽  
Synthetic Spectra ◽  
Finite Source ◽  
Stellar Properties

AbstractFinite-source effects of gravitationally microlensed stars have been well discussed in the literature, but the role that stellar rotation plays has been neglected. A differential magnification map applied to a differentially Doppler-shifted surface alters the profiles of absorption lines, compromising their ordinarily symmetric nature. Herein, we assess the degree to which this finite-source effect of differential limb magnification (DLM), in combination with stellar rotation, alters spectroscopically derived stellar properties. To achieve this, we simulated a grid of high-magnification microlensing events using synthetic spectra. Our analysis shows that rotation of the source generates differences in the measured equivalent widths of absorption lines supplementary to DLM alone, but only of the order of a few per cent. Using the wings of Hα from the same simulated data, we confirmed the result of Johnson and colleagues that DLM alters measurements of effective temperature by ≲100 K for dwarf stars, while showing rotation to bear no additional effect.

scholarly journals Cluster cross-sections for strong lensing: analytic and numerical lens models

2003 ◽  
Vol 340 (1) ◽  
pp. 105-114 ◽  
Author(s):  
M. Meneghetti ◽  
M. Bartelmann ◽  
L. Moscardini
Keyword(s):  
Cross Sections ◽  
Strong Lensing

scholarly journals FINITE-SOURCE EFFECTS IN MICROLENSING: A PRECISE, EASY TO IMPLEMENT, FAST, AND NUMERICALLY STABLE FORMALISM

2009 ◽  
Vol 695 (1) ◽  
pp. 200-207 ◽  
Author(s):  
C.-H. Lee ◽  
A. Riffeser ◽  
S. Seitz ◽  
R. Bender
Keyword(s):  
Source Effects ◽  
Finite Source

scholarly journals A fast method for computing strong-lensing cross sections: application to merging clusters

2006 ◽  
Vol 447 (2) ◽  
pp. 419-430 ◽  
Author(s):  
C. Fedeli ◽  
M. Meneghetti ◽  
M. Bartelmann ◽  
K. Dolag ◽  
L. Moscardini
Keyword(s):  
Cross Sections ◽  
Fast Method ◽  
Strong Lensing

scholarly journals OGLE‐2003‐BLG‐262: Finite‐Source Effects from a Point‐Mass Lens

2004 ◽  
Vol 603 (1) ◽  
pp. 139-151 ◽  
Author(s):  
Jaiyul Yoo ◽  
D. L. DePoy ◽  
A. Gal‐Yam ◽  
B. S. Gaudi ◽  
A. Gould ◽  
...  
Keyword(s):  
Point Mass ◽  
Source Effects ◽  
Finite Source

Analysis of STEM micrographs of thick objects

1978 ◽  
Vol 36 (2) ◽  
pp. 106-107
Author(s):  
S. Golladay
Keyword(s):  
Inelastic Scattering ◽  
Multiple Scattering ◽  
Mass Distribution ◽  
Cross Sections ◽  
Phase Contrast ◽  
Image Point ◽  
Contrast Effects ◽  
Total Cross Sections ◽  
Elastic And Inelastic Scattering

The theory of multiple scattering has been worked out by Groves and comparisons have been made between predicted and observed signals for thick specimens observed in a STEM under conditions where phase contrast effects are unimportant. Independent measurements of the collection efficiencies of the two STEM detectors, calculations of the ratio σe/σi = R, where σe, σi are the total cross sections for elastic and inelastic scattering respectively, and a model of the unknown mass distribution are needed for these comparisons. In this paper an extension of this work will be described which allows the determination of the required efficiencies, R, and the unknown mass distribution from the data without additional measurements or models. Essential to the analysis is the fact that in a STEM two or more signal measurements can be made simultaneously at each image point.

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