Why observe Novae in M 31?

• M 31 is the only nearby galaxy with many (more than 100 novae that exploded over the last 5 years!) reported optical novae within the FOV of one XMM-Newton or Chandra observation
• All novae are at the same, known distance, thus allowing easy comparison of light curves and maximum brightness/luminosity in the optical and X-ray regime
• Low Galactic foreground as well as intrinsic M 31 absorption allows accurate determination of color and temperature
• Comparatively little observing time allows us to obtain a homogeneous nova sample and to follow the X-ray evolution of all of them over time
• The derived durations of nova supersoft source states will allow us to constrain envelope and white dwarf masses, and potentially to correlate differences in metallicity with location in M 31 (bulge versus disk population)
• X-ray parameters will be correlated with nova type (Fe II, He/N) and speed class
• Recurrent novae will be discovered through the detection of a delayed supersoft source phase. This may establish them as believable progenitors of SNe-Ia.

© X-Ray Group at MPE (group)
last update:19-12-2006, editor of this page:Wolfgang Pietsch, Frank Haberl