Download presentation

Presentation is loading. Please wait.

Published byAlexander Jenne Modified over 2 years ago

1
Analysis of a New Gravitational Lens FLS 1718+59 Yoon Chan Taak Feb 14 2013 Survey Science Group Workshop 2013 1

2
What is Gravitational Lensing? Deflection of light by body of mass ◦ Deflection angle greater for GR (factor of 2) vs (r: source-lens distance) ◦ e.g. Solar eclipse of May 1919 Causes distortion of images 2

3
Images of GL 3 Abell 1689 cluster

4
Images of GL 4 Einstein Ring – SDSS J073728.45+321618.5 Einstein Cross – QSO 2237+030

5
Images of GL 5

6
Types of GL Strong GL ◦ Big distortions, e.g. rings, arcs, multiple img ◦ Lens is galaxy or cluster Weak GL ◦ Shear distortion ◦ Lens is galaxy or cluster, but further away from source Microlensing ◦ Brightness variations ◦ Lens has stellar masses (e.g. planets) 6

7
Why GL? Requires only mass Allows detection of dark matter Acts as “cosmic telescope” Lets us see more distant objects Determines cosmological parameters ◦ Deflection depends on redshift-distance formula ◦ Time delay related to Hubble constant Constrains geometry of universe 7

8
Gravitational Lensing Theory Point-mass lens Finite lens 8

9
Point Mass (Schwarzschild) Lens Lens (Ray-trace) equation ◦ 11 ◦ 1 9 θ S : lens-source angular distance α : deflection angle of light ray θ 1,2 : lens-img angular distances b : lens-deflection pt angular dist. α 0 : Einstein rad. [(4GM/c 2 ) (D LS /D L D S )] 1/2 α D LS θSDSθSDS (D S /D L )b

10
Finite Lens Ray-trace eqn is for 2-D plane ◦ Change scalars to vectors for 3-D Integrate deflection angle for all infinitesimal masses ◦ I Calculate numerical solution 10

11
gravlens: Software for G-Lensing Developed by C. Keeton (Rutgers) Useful for various g-lens images ◦ Able to find best set of lens parameters for multiple images (lensmodel) Contains 20+ lens models ◦ Can be superposed, diverse potentials possible 11

12
FLS 1718+59 G-lensing image in Spitzer First Look Survey Field z lens = 0.08 z source = 0.245 ◦ Closest source so far(?) RA = 17 h 18 m 17.6 s Dec = 59 d 31 m 46 s

13
FLS 1718+59

14
Procedures Simulated lensing images with several sets of input variables ◦ Mass scale of lens ◦ X coord. of source ◦ Ellipticity (angle) of source ◦ Ellipticity (angle) of lens* Assumed no external shear * Obtained from original HST image

15
Softened Power Law Ellipsoid

16
Results

17
Discussion Many sets of variables may yield similar images A more careful approach is necessary for constraining errors requires analysis with more sets of variables M gal ~ 10 10.75 M ʘ, σ ~ 150km/s Possibly an edge-on spiral

Similar presentations

OK

Physics 55 Monday, December 5, 2005 1.Course evaluations. 2.General relativity with applications to black holes, dark matter, and cosmology. 3.Hubble’s.

Physics 55 Monday, December 5, 2005 1.Course evaluations. 2.General relativity with applications to black holes, dark matter, and cosmology. 3.Hubble’s.

© 2018 SlidePlayer.com Inc.

All rights reserved.

Ads by Google

Ppt on the art of war sun Ppt on bluetooth based smart sensor networks machine Ppt on model view controller pattern Dr appt on the beach Ppt on tool condition monitoring Ppt on any one mathematician paul Download ppt on transportation in human beings what is the largest Ppt on conservation of momentum experiment Ppt on social contract theory summary Ppt on index numbers of illinois