From ASM instance.

SQL> select to_char(f.creation_date,’dd-mon-yyyy’), a.name, a.group_number, a.file_number
 from v$asm_file f, v$asm_alias a
 where a.name like ‘%AUX%’
 and    a.group_number = f.group_number 
 and    a.file_number = f.file_number;

date             name                            grp no  file no
======== ===============  ====  ====
09-aug-2007  SYSAUX.303.630175843    1       303
10-aug-2007  SYSAUX.307.630234687    1       307
09-aug-2007  SYSAUX.257.630159243    2       257
09-aug-2007  SYSAUX.308.630174583    6        30