Series expansion in deflection angle
{"Image DocumentName": "Series expansion in deflection angle?", "Image ImageDescription": "Only a good approximation when: - deflection angle much smaller than wavelength of temperature perturbation - OR, very small scales where temperature is close to a gradient. CMB lensing is a very specific physical second order effect; not accurately contained in 2nd order expansion \u2013 differs by significant 3rd and higher order terms. Series expansion only good on large and very small scales.", "Image XResolution": "37", "Image YResolution": "37", "Image ResolutionUnit": "Pixels/Centimeter", "Image Software": "SlidePlayer", "Image YCbCrPositioning": "Centered"}