Killing session- Need Help IMP

Hi Experts,

In one of our database below sessions are running since long almost from the time this server is migrated to new datacenter.

They are consuming a lot of system resources but we are not able to find any query based on them and there are no RMAN backup or recover cocmand running but they keep on running all the time.

Can we kill them from database? or at OS lavel? Please help:

   INST_ID        SID    SERIAL# SPID                     USERNAME                       PROGRAM
---------- ---------- ---------- ------------------------ ------------------------------ ------------------------------------------------
             1        230      51877 8186                     SYS                            rman@abcd (TNS V1-V3)
         1       1206      48387 8187                     SYS                            rman@abcd  (TNS V1-V3)

SQL> select spid from v$process where addr = (select paddr from v$session where sid=1206 and serial#=48387);