Hotpixels are pixels that are permanently lit. Almost all CCD and CMOS chips have them.

In astrophotography darkframes are used to allow correction for hot pixels.

Amplifier Glow is the glow in the corners of long exposure images. It is caused by electroluminescence of the readout amplifier on the camera's sensor.

This contrast enhanced picture shows the amplifier glow of my Canon 20D DSLR camera.

Thermal noise is the electronic noise generated by the thermal agitation of electrons inside an electrical conductor at equilibrium.