how to tell if you are getting a partition wise join

I am doing some simple tests. I made 2 copies of dba_objects that are hash 
partitioned with 8 partitions. called hash_test_a and hash_test_c
I added a small attachment with the two plans. I want to make sure it formats 
properly. 

I ran this query:

explain plan for
    select /*+ parallel (a,8) parallel (b,8) */ count(*)
    from hash_test_a a, hash_test_b b
   where a.object_id = b.object_id

My expectation before running this query was:
1. Each slave will scan a partition
2. Then eight slaves will each do a partition wise hash join.
3. The results will queued. The query coordinator will dequeue the results. 

Is this a correct interpretation? I am not sure if the plan says that. 

This is the second plan:
   explain plan for
       select /*+ parallel (a,8) parallel (b,8) */ count(*)
       from hash_test_a partition(HASH_TEST_A01) a, hash_test_c 
partition(HASH_TEST_A01) b
      where a.object_id = b.object_id

This is the same query accept it is restricted to just the first partition. The 
plan changes considerably. This is what I find interesting:
 PX RECEIVE  
    PX SEND HASH 
        PX BLOCK ITERATOR

This happens before each table scan. This tells me(if I am reading it 
correctly) that 1 parallel slave is reading a partition and then queing it up 
for the query coordinator. However, how come I don't see that when I do not 
restrict the partition and read the whole table? 

I read the partition docs and it does not give examples of partition wise join 
explain plans. 
explain plan for
    select count(*)
    from hash_test_a a, hash_test_b b
   where a.object_id = b.object_id


--------------------------------------------------------------------------------------------------------------------------------------
| Id  | Operation                 | Name        | Rows  | Bytes | Cost (%CPU)| 
Time     | Pstart| Pstop |    TQ  |IN-OUT| PQ Distrib |
--------------------------------------------------------------------------------------------------------------------------------------
|   0 | SELECT STATEMENT          |             |     1 |     7 |     5  (20)| 
00:00:01 |       |       |        |      |            |
|   1 |  SORT AGGREGATE           |             |     1 |     7 |            |  
        |       |       |        |      |            |
|   2 |   PX COORDINATOR          |             |       |       |            |  
        |       |       |        |      |            |
|   3 |    PX SEND QC (RANDOM)    | :TQ10002    |     1 |     7 |            |  
        |       |       |  Q1,02 | P->S | QC (RAND)  |
|   4 |     SORT AGGREGATE        |             |     1 |     7 |            |  
        |       |       |  Q1,02 | PCWP |            |
|*  5 |      HASH JOIN            |             |   121 |   847 |     5  (20)| 
00:00:01 |       |       |  Q1,02 | PCWP |            |
|   6 |       PX RECEIVE          |             |   121 |   363 |     2   (0)| 
00:00:01 |       |       |  Q1,02 | PCWP |            |
|   7 |        PX SEND HASH       | :TQ10000    |   121 |   363 |     2   (0)| 
00:00:01 |       |       |  Q1,00 | P->P | HASH       |
|   8 |         PX BLOCK ITERATOR |             |   121 |   363 |     2   (0)| 
00:00:01 |     1 |     1 |  Q1,00 | PCWC |            |
|   9 |          TABLE ACCESS FULL| HASH_TEST_A |   121 |   363 |     2   (0)| 
00:00:01 |     1 |     1 |  Q1,00 | PCWP |            |
|  10 |       PX RECEIVE          |             |   131 |   524 |     2   (0)| 
00:00:01 |       |       |  Q1,02 | PCWP |            |
|  11 |        PX SEND HASH       | :TQ10001    |   131 |   524 |     2   (0)| 
00:00:01 |       |       |  Q1,01 | P->P | HASH       |
|  12 |         PX BLOCK ITERATOR |             |   131 |   524 |     2   (0)| 
00:00:01 |     1 |     1 |  Q1,01 | PCWC |            |
|  13 |          TABLE ACCESS FULL| HASH_TEST_C |   131 |   524 |     2   (0)| 
00:00:01 |     1 |     1 |  Q1,01 | PCWP |            |
--------------------------------------------------------------------------------------------------------------------------------------

  explain plan for
       select /*+ parallel (a,8) parallel (b,8) */ count(*)
       from hash_test_a partition(HASH_TEST_A01) a, hash_test_c 
partition(HASH_TEST_A01) b
      where a.object_id = b.object_id

--------------------------------------------------------------------------------------------------------------------------------------
| Id  | Operation                 | Name        | Rows  | Bytes | Cost (%CPU)| 
Time     | Pstart| Pstop |    TQ  |IN-OUT| PQ Distrib |
--------------------------------------------------------------------------------------------------------------------------------------
|   0 | SELECT STATEMENT          |             |     1 |     7 |    15   (7)| 
00:00:01 |       |       |        |      |            |
|   1 |  SORT AGGREGATE           |             |     1 |     7 |            |  
        |       |       |        |      |            |
|   2 |   PX COORDINATOR          |             |       |       |            |  
        |       |       |        |      |            |
|   3 |    PX SEND QC (RANDOM)    | :TQ10000    |     1 |     7 |            |  
        |       |       |  Q1,00 | P->S | QC (RAND)  |
|   4 |     SORT AGGREGATE        |             |     1 |     7 |            |  
        |       |       |  Q1,00 | PCWP |            |
|   5 |      PX PARTITION HASH ALL|             |   999 |  6993 |    15   (7)| 
00:00:01 |     1 |     8 |  Q1,00 | PCWC |            |
|*  6 |       HASH JOIN           |             |   999 |  6993 |    15   (7)| 
00:00:01 |       |       |  Q1,00 | PCWP |            |
|   7 |        TABLE ACCESS FULL  | HASH_TEST_A |   999 |  2997 |     7   (0)| 
00:00:01 |     1 |     8 |  Q1,00 | PCWP |            |
|   8 |        TABLE ACCESS FULL  | HASH_TEST_C |   999 |  3996 |     7   (0)| 
00:00:01 |     1 |     8 |  Q1,00 | PCWP |            |
--------------------------------------------------------------------------------------------------------------------------------------

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