ePhysics

In this section, we apply our algorithm to predict images of real gravitational lensing systems.

 

8 O'Clock Arc

SDSS Entry

Allam, et. al. presents the following data about the 8 O'Clock Arc:

• Source Parameters
• Red shift: 2.73
• Lens Parameters
• Red shift: 0.38
• Velocity dispersion: (390 ± 9.4) km/s.
• Image Parameters
• Einstein Radius: (3.32 ± 0.16) arcseconds.

 

By adjusting the parameters by hand, I found the following parameters which worked:

• Source Parameters
• Position: (0.4354, -0.09436) arcseconds
• Radius: 0.1 arcseconds
• Ellipticity: 0
• Rotation: 0 degrees
• Lens Parameters
• Axis ratio: 0.8

 

In particular, I used the following Matlab command:

gravLensing_SIE([complex(0.4354, -0.09436), 2.73, 1.446, 0.1, 0], [complex(0,0), 0.38, 390e3, 0.8], [complex(0,0), 512, 0.03]);

The image below shows the output of this Matlab simulation. Note that the green curve is the caustic of the lens. The critical curve is not shown in order that the image may be seen clearly.

 

Cosmic Horshoe

SDSS entry

Belokurov, et. al. presents the following data about the Cosmic Horseshoe:

• Source Parameters
•  Red shift: 2.39
• Lens Parameters
• Red shift: 0.444
• Velocity dispersion: (430 ± 50) km/s.
• Image Parameters
• Length: 300^o

 

By adjusting the parameters by hand, I found the following parameters which worked:

• Source Parameters
• (0.08063, 0.090524) arcseconds
• Radius: 0.1 arcseconds
• Ellipticity: 0
• Rotation: 0 degrees
• Lens Parameters
• Axis ratio: 0.8

In particular, I used the following Matlab command:

gravLensing_NIS([complex(0.08063, 0.090524), 2.49, 0.1, 0, 0], [complex(0,0), 0.444, 430e3, 0.8], [complex(0,0), 512, 0.02]);

The image below shows the output of this Matlab simulation. Note that
the green curve is the caustic of the lens while the red ellipse is the critical curve.