temporary tables ?

Hi all,

My database is full of tables... What's that ? Temporary tables ?
May I drop safety these tables ?
|  Owner           |             Relation             |   Type
|+------------------+----------------------------------+----------+|postgres         | _rpt16567_r1
|table    || postgres         | _rpt16574_r1                     | table    || postgres         | _rpt18155_r1
          | table    || postgres         | _rpt18207_r1                     | table    || postgres         |
_rpt18256_r1                    | table    || postgres         | _rpt18309_r1                     | table    ||
postgres        | _rpt21859_r1                     | table    || postgres         | _rpt21861_r1                     |
table   || postgres         | _rpt21865_r1                     | table    || postgres         | _rpt21869_r1
        | table    || postgres         | _rpt22065_r1                     | table    || postgres         | _rpt22067_r1
                   | table    || postgres         | _rpt22069_r1                     | table    || postgres         |
_rpt22345_r1                    | table    || postgres         | _rpt22353_r1                     | table    ||
postgres        | _rpt22568_r1                     | table    || postgres         | _rpt22574_r1                     |
table   || postgres         | _rpt26970_r1                     | table    || postgres         | _rpt27142_r1
        | table    || postgres         | _rpt27144_r1                     | table    || postgres         | _rpt27146_r1
                   | table    || postgres         | _rpt27154_r1                     | table    |
 
:

-Jose'-