Can I use the icinga logo as an icon in my project?

I have written a little nagstamon-style GUI app for my personal use. It uses the icinga logo as the window icon and for indicating problems in the system tray.

I would like to open-source the app. Do I have to change the icon? Or attribute it somehow? (I could not find a license for the logo anywhere… but then again, I don’t really know where to look for such things…)