We present HST/WFPC2 , GALEX and Chandra observations of the position of the type Ia supernova SN2007sr in the Antennae galaxy , taken before the explosion .
No source is found in any of the observations , allowing us to put interesting constraints on the progenitor luminosity .
In total there is about 450 kilosecond of Chandra data , spread over 7 different observations .
Limiting magnitudes of FUV ( 23.7 AB mag ) , NUV ( 23.8 AB mag ) , F555W ( 26.5 Vega mag ) and F814W ( 24.5-25 Vega mag ) are derived .
The distance to the Antennae galaxy is surprisingly poorly known , with almost a factor of 2 difference between the latest distance based on the tip of the red giant branch ( 13.3 Mpc ) and the distance derived from the 2007sr light curve ( 25 Mpc ) .
Using these distances we derive limits on absolute optical and UV magnitudes of any progenitor but these are still above the brightest ( symbiotic ) proposed progenitors .
From the Chandra data a 3 \sigma upper limit to the X-ray luminosity of 0.5 – 8.0 10 ^ { 37 } erg/s in the 0.3-1 keV range is found .
This is below the X-ray luminosity of the potential progenitor of the type Ia supernova 2007on that we recently discovered and for which we report a corrected X-ray luminosity .
If that progenitor is confirmed it suggests the two supernovae have different progenitors .
The X-ray limit is comparable to the brightest supersoft X-ray sources in the Galaxy , the LMC and the SMC and significantly below the luminosities of the brightest supersoft and quasi-soft X-ray sources found in nearby galaxies , ruling out such sources as progenitors of this type Ia supernova .