Odd "core" files created in /etc/asterisk

I am finding these files getting created twice a day in my /etc/asterisk dir, they seem to be slowly growing from 12 - 15 mb in size. It is a trixbox with the latest freepbx 2.3.

Any ideas what these are?

Here is an example filename:
core.pbx.mydomain.com-2007-09-29T14:19:56-0700

nothing to do with FreePBX, you may want to check with the trixbox guys - maybe some sort of backup of theirs.

Philippe Lindheimer - FreePBX Project Lead
http//freepbx.org - IRC #freepbx