Filing Fed tax return only for 2019

Hi,

 

Can I file only Fed tax return?
I have noticed that my AGI is below standard deduction and the threshold for filing state tax in CT. So I am not required to file Fed or State tax returns. It seems that I am entitled for certain refund (withheld tax, ACTC and EIC).
Can I file only Fed tax return and skip CT state tax return?

 

Thanks,