Hmm, hard to tell, but those don't look like mandarins to me. Like hardlikearmour, I think of mandarins as a little flatter. And these look a little bigger than a lot of mandarins. But more important than the name, they sound pretty tasty.

its sweet sour taste and the skin is little thick I just took this picture

They could be. Is the flesh fairly sweet or quite sour? Is the skin thin or thick? Mandarins are pretty sweet, skin fairly thin, very easy to peel. They tend to be flattened rather than spherical. You picture also reminds me of calamondins which are quite sour, with a sweeter & edible skin.

Wow! I don't know what those are but they are beautiful!

Our citrus tree but some call Mandarin is that correct?