argsort does not work for multidimensional arrays

consider the following code:
a = np.random.random([5,5])
ind = np.argsort(a, axis=1)
a_sorted = a[ind]
np.sort(a, axis=1)

now a_sorted and a should be both sorted along the 1-axis. However not even the shapes are identical anymore. a is still of (5,5) while a_sorted is (5,5,5). If this is the intended behaviour, can someone tell me why?