[![enter image description here][1]][1]


  [1]: https://i.sstatic.net/Dr5EQ.png

Hi. I've identified this as a AR(1) model as the ACF clearly shows a slow decay and the PACF seems like a cut off after lag 2. However, can it also be a ARMA (1,1) model because PACF seems like a damped sinusoid too?