How can I recreate the curve in this image?

[TylerRickard]

I'm trying to recreate the curve next to the red line but I don't know how to make the shape.

 

[Aravind]

It did be better if you could highlight what exactly you want to reproduce.

Here is what I do normally when I have a curve I do not know to draw:

Make a new layer. Use pentool and draw over it. Then right click and click stoke path. You can also use the direct selection cursor to adjust your pentool to make it more aligned over the original image.