Multiple Supernovae in the same galaxy

What are the odds?   Supposedly, in an average sized galaxy you should see a supernova once every century.   There being some 30,000 named galaxies, we should be seeing about 300 supernovae a year.   In reality, this number is more like 100.   Since Supernovae only last about 6 months, that means that a possibility of about 1.5 double supernova per year.   Also, some galaxies produce more supernovae than others.   Check The most prolific galaxies for more information.

When looking at these images, you should note just how big these galaxies are.   The typical galactic disk is 100,000 Light years side to side and about 750 light years thick.   Though the light from these two events reach us at the same time, they may have actually happened hundreds or thousands of years apart.  

Supernovae 2009as and 2009gb were both visible in ESO 447-G37.   SN 2009as and sn2009gb images sub-page

Supernovae 2008br and 2008co were both visible in IC 2522.   SN 2008br and sn2008co images sub-page

Supernovae 2007uy and 2008D were both visible in NGC 2770.   SN 2007uy and sn2008D images sub-page

Supernovae 2007ck and 2007co in MCG +5-43-16.   Similar to 2003iq, Joel Nicolas was taking an image of this galaxy and found 2007co.   SN 2007ck and sn2007co images sub-page

Supernovae 2006st and 2007an in NGC 4017

Supernovae 2006br and 2006dz in NGC 5185

Supernovae 2006dn and 2006el in UGC 12188

Supernovae 2006dd and 2006mr in NGC 1316

Supernovae 2005en and 2005eo in UGC 4132

Supernovae 2003hl and 2003iq in NGC 772.  LOTOSS discovered 2003hl, and a few weeks later JM Llapasset was taking an image of it, and he noticed a new star.  SN 2003hl and sn2003iq images sub-page

Supernovae 2003dt and 2002ha in NGC 6962 Both discovered by LOTOSS.  2003dt was discovered several weeks after maximum. This image was taken with 2003dt at Mag 17.5 and 6 month old 2002ha at Mag 19.2.

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Supernovae 2002cv and 2002bo in NGC 3190 2002cv was discovered by Campo Imperatore Observatory while observing 2002bo in IR.   2002cv was only visible in IR must likly due to it being behind a dust lane. SN 2002bo and 2002cv images sub-page

(click on image for full resolution)

Supernovae 2002cr and 2002ed in NGC 5468.  Berto Monard was observing 2002cr when he made the discovery of 2002ed. SN 2002cr and 2002ed images sub-page

Supernovae 2002dv and 2002eg in UGC 11486.  Ella Sanders has taken an interest in these double events, and found this one.  SN 2002dv and 2002eg images sub-page

Supernovae 1999ee and 1999ex in IC 5179.  The Perth Astronomy Research Group was observing at 1999ee and discovered 1999ex.   SN 1999ee and 1999ex images sub-page

Supernovae 2000E and 1999el in NGC 6951.  Italian Teramo Observatory was looking at 1999el and found this thing looking back at them.   SN 1999el and 2000E images sub-page

Supernovae 1996bw and 1997W in NGC 664 the SN are the two stars to the right of the galaxy's nucleus 1996bw is the yellow one on the top and 1997W is the blue one on the bottom. CfA was not sure which one was the supernova, so they took a spectrum of both of them. They both turned out to be supernovae.

(click on image for full resolution)

1998X and 1998dq in NGC 6754.

1992R and 1992ac in MCG 10-24-007.